IVC & Volume Status
Data on optimal fluid management strategies for those who develop critical illness remain sparse. Adding to the challenge, the fluid volume status of these patients has been found to be dynamic. Some present with several days of malaise, gastrointestinal symptoms, and consequent hypovolemia requiring aggressive fluid resuscitation, while a subset develop acute respiratory distress syndrome with renal dysfunction and lingering congestion necessitating restrictive fluid management. Conventional point-of-care ultrasonography (POCUS) enables the reliable assessment of fluid status and reducing the staff exposure. However, due to specific characteristics of COVID-19 (e.g., rapidly expanding lung lesions), a single imaging method such as lung POCUS will have significant limitations. Herein, we suggest a Tri-POCUS approach that represents concurrent bedside assessment of the lungs, heart, and the venous system.
Review article on why using IVC for fluid status assessment is likely not useful.
Results: A total of 5 studies qualified for study eligibility from 4 different countries, 3 being casecontrol and 2 before-and-after design, studying 86 cases and 189 controls. Maximal IVC diameter was significantly lower in hypovolemic status compared with euvolemic status; mean difference (95% confidence interval) was 6.3 mm (6.0-6.5 mm). None of the studies blinded interpreters for volume status of participants.
Measurements of IVC-CI by bedside ultrasound can provide a useful guide to noninvasive volume status assessment in SICU patients. IVC-CI appears to correlate best with CVP in the setting of low (<0.20) and high (>0.60) collapsibility ranges. Additional studies are needed to confirm and expand on findings of this study.
After limited training (4 hours didactic and 20 studies), 4 internal medicine residents using an HCU device estimated RA pressure from images of the IVC in 40 consecutive patients <1 hour after right-sided cardiac catheterization. RA pressure was also estimated from examination of the jugular venous pulse (JVP) in 40 patients before right-sided cardiac catheterization. RA pressure was successfully estimated from HCU images of the IVC in 90% of patients, compared with 63% from JVP examination. The sensitivity for predicting RA pressure >10 mm Hg was 82% with HCU and 14% from JVP inspection. Specificities were similar between the techniques. Overall accuracies were 71% using HCU and 60% with JVP assessment. In conclusion, internal medicine residents with brief training in echocardiography can more frequently and more accurately predict elevated RA pressure using HCU measurements of the IVC than with physical examination of the JVP.
Aorta / AAA
A total of 127 patients were enrolled: 72 in the US group and 55 in the control group. In the US group, compared with CTA, the sensitivity of EP POCUS was 86.4%, and the specificity was 100.0%. The door-to-diagnosis times were 10.5 minutes in the US group and 79.0 minutes in the control group (P < .05). The door-to-CTA examination time and the door-to-targeted-treatment time had no differences between the US and control groups (P > .05). The in-hospital mortality and mortality within 3 months after discharge were 4.2% and 25.0% in the US group and 9.1% and 20.8% in the control group (P > .05).
Compared with CTA, EP POCUS in patients suspected of having AD is highly sensitive and specific and has shown no adverse effect on the treatment start-up time, in-hospital mortality, and mortality within 3 months after discharge.
11 studies including 944 patients evaluated for non-radiologist performed ultrasound to detect AAA. Pooled sensitivity of 97.5% and 98.9% specificity.
The weighted average prevalence of AAA in symptomatic patients over the age of 50 years is 23%. On history, 50% of AAA patients will lack the classic triad of hypotension, back pain, and pulsatile abdominal mass. The sensitivity of abdominal palpation for AAA increases as the diameter of the AAA increases. The pooled operating characteristics of ED US for the detection of AAA were sensitivity 99% (95% confidence interval [CI] = 96% to 100%) and specificity 98% (95% CI = 97% to 99%).
Tayal et al. 2008. Ultrasound for Abdominal Aortic Aneurysm over Two Years.
A total of 125 patients had EUS‐AA performed over a two‐year period. The patient population had the following characteristics: average age 66 years, male 54%, hypertension 56%, coronary artery disease 39%, diabetes 22%, and peripheral vascular disease 14%. Confirmatory tests included radiology ultrasound, 28/125 (22%); abdominal computed tomography, 95/125 (76%); abdominal magnetic resonance imaging, 1/125 (1%); and laparotomy, 1/125 (1%). AAA was diagnosed in 29/125 (23%); of those, 27/29 patients had AAA on confirmatory testing. EUS‐AA had 100% sensitivity (95% CI = 89.5 to 100), 98% specificity (95% CI = 92.8 to 99.8), 93% positive predictive value (27/29), and 100% negative predictive value (96/96).
120 focused ultrasound scans looking for AAA were performed by 19 different UK emergency physicians of various grades. Of the 120 scans, 26 (22%) were positive for an AAA, of which 17 cases represented a new diagnosis. Ruptured aneurysms represented 46% (12/26) of all positive scans, of which four patients underwent emergency repair. In the remaining 14 patients the AAA was an incidental finding that was not the reason for their presentation to the emergency department. Emergency ultrasound had a sensitivity of 96.3% (95% confidence interval (CI) 81.0% to 99.9%); a specificity of 100% (95% CI 91.8% to 100%); a negative predictive value of 98.6% (95% CI 88.0% to 99.9%); and positive predictive value of 100% (95% CI 86.8% to 100%) for the detection of AAA.
Constantino et al. 2005. Accuracy of emergency medicine ultrasound in the evaluation of abdominal aortic aneurysm.
There were 238 aortic EUS performed from 1999-2000; 36 were positive for AAA. The EUS finding of "AAA" had a sensitivity of 0.94 (0.86-1.0 95% confidence interval [CI]) and specificity of 1 (0.98-1.0 95% CI). Mean aortic diameter among patients with AAA identified by EUS was 5.43+/-1.95 cm and by RAD was 5.35+/-1.83 cm. The mean absolute difference between EUS and RAD diameters was 4.4 mm (95% CI 3.7-5.5 mm). Regression of EUS on RAD diameters is strongly correlated, with R(2)=0.92. EM residents with appropriate training can accurately determine the presence of AAA as well as the maximal aortic diameter.
Forty physicians enrolled a total of 104 patients into the study. Ultrasonographic measurements of aortic diameter were slightly smaller than those obtained by CT scan, with a difference of means of -0.39 cm (95% CI -0.25 to -0.53) at the level of the SMA, -0.26 cm (95% CI -0.17 to -0.36) on longitudinal view, and -0.11 cm (95 % CI -0.01 to 0.22) at the bifurcation. At the level of the SMA, the difference in measurements by ultrasound and CT would be expected to be less than 1.41 cm, 95% of the time. At the bifurcation, we expect 95% of the differences to be less than 1.05 cm. Agreement was closest on longitudinal view, with 95% of the differences expected to be less than 0.94 cm. Participating physicians estimated the time required to complete their ultrasound studies to be less than 5 min in a majority of cases. In conclusion, ultrasonographic measurement of aortic diameter by emergency physicians rapidly and effectively approximates measurements obtained by CT scan.
AAA was diagnosed in 29/125 (23%); of those, 27/29 patients had AAA on confirmatory testing. EUS-AA had 100% sensitivity (95% CI = 89.5 to 100), 98% specificity (95% CI = 92.8 to 99.8), 93% positive predictive value (27/29), and 100% negative predictive value (96/96). Admission rate for the study group overall was 70%. Immediate operative management was considered in 17 of 27 (63%) patients with AAA; ten patients were taken to the operating room.
Ultrasonographic measurements of aortic diameter were slightly smaller than those obtained by CT scan, with a difference of means of −0.39 cm (95% CI −0.25 to −0.53) at the level of the SMA, −0.26 cm (95% CI −0.17 to −0.36) on longitudinal view, and −0.11 cm (95 % CI −0.01 to 0.22) at the bifurcation. At the level of the SMA, the difference in measurements by ultrasound and CT would be expected to be less than 1.41 cm, 95% of the time. At the bifurcation, we expect 95% of the differences to be less than 1.05 cm. Agreement was closest on longitudinal view, with 95% of the differences expected to be less than 0.94 cm. Participating physicians estimated the time required to complete their ultrasound studies to be less than 5 min in a majority of cases. In conclusion, ultrasonographic measurement of aortic diameter by emergency physicians rapidly and effectively approximates measurements obtained by CT scan.
The mean times for hand-held and conventional duplex US examinations were 5.3 +/- 3.2 minutes and 3.1 +/- 2.4 minutes (not significant), respectively. Using the conventional duplex US as a reference, the sensitivity and specificity of the hand-held device in detecting a AAA were 93% and 97%, respectively. The positive and negative predictive values of the hand-held device were 89% and 98%, respectively. The likelihood ratios of positive and negative tests of the hand-held US device examination were 82 and 0.14, respectively. The diagnostic accuracy of the hand-held US device as compared with the conventional duplex US was 98%.
Constantino et al 2002. Accuracy of emergency medicine ultrasound in the evaluation of abdominal aortic ultrasound.
This study assesses the accuracy of Emergency Medicine (EM) residents in detecting the size and presence of abdominal aortic aneurysms (AAAs) using EM ultrasound (EUS) compared to radiology measurement (RAD) by computed tomography (CT) scan, magnetic resonance imaging (MRI), angiography, or operative findings. There were 238 aortic EUS performed from 1999–2000; 36 were positive for AAA. The EUS finding of “AAA” had a sensitivity of 0.94 (0.86–1.0 95% confidence interval [CI]) and specificity of 1 (0.98–1.0 95% CI). Mean aortic diameter among patients with AAA identified by EUS was 5.43 ± 1.95 cm and by RAD was 5.35 ± 1.83 cm. The mean absolute difference between EUS and RAD diameters was 4.4 mm (95% CI 3.7–5.5 mm). Regression of EUS on RAD diameters is strongly correlated, with R2 = 0.92. EM residents with appropriate training can accurately determine the presence of AAA as well as the maximal aortic diameter.
A prospective pilot study was undertaken to assess a protocol to educate primary care residents in how to personally perform ultrasonography for abdominal aortic aneurysm screening. Resident exams were proctored by a primary care physician trained in ultrasonography and were scored on the level of competence in doing the examination. Patients had ultrasound performed by a resident, followed by repeat examination by the vascular lab. Primary care resident abdominal aortic imaging was achieved in 79 of 80 attempts. Four abdominal aortic aneurysms were identified. There were 75 normal examinations; resident ultrasonography results were consistent with the results of the vascular lab. Ten residents achieved an abdominal aortic ultrasound-independent competence level after an average of 3.4 proctored exams. The main outcome of this study is that a primary care resident, with minimal training in ultrasonography imaging, is able to rapidly learn the technique of ultrasonography imaging of the abdominal aorta.
Rowland et al. 2001. Accuracy of emergency department bedside ultrasonography
Between September 1997 and January 1999, 221 scans were studied. Accuracy varied widely depending on the type of scan performed: aortic scans were 100% accurate whereas renal scans had 68% accuracy. On bivariate analyses, there was little variation in the various operators’ levels of proficiency and accuracy of interpretation was not associated with patient body habitus, image quality or operator confidence.
Our convenience sample includes 68 scans for AAAs; findings of 26 scans were positive, 40 scans yielded negative findings, and 2 scans were indeterminate. Scan interpretations were 100% accurate. The ultrasound results would have improved the care of 46 patients without adverse sequelae. Ultrasound scanning served primarily to exclude AAA in patients who proved not to have aneurysms; however, scans also provided significant benefits for those with AAAs and improved patient management plans.
Two echocardiographic features were found to support a diagnosis of aortic dissection: a dilation of at least one segment of the aorta (sensitivity 95%, specificity 51%) and a typical abnormal linear intraluminal echo corresponding to the intimal flap (sensitivity 67%, specificity 100%). This pathognomonic intimal flap was observed in 86 cases, of which three types could be distinguished: (1) a long oscillating flap (n = 15), (2) a long but minimally mobile linear echo which was duplicated and parallel to one or two aortic walls (n = 64), (3) a short, double linear image with a rapid systolic motion and high frequency oscillations. These features were found to have a high sensitivity in type I aortic dissection (88%), although in types II and III the sensitivity was much lower. In some cases, a fourth type of abnormal image could be detected: a small intraluminal echo moving in parallel to the aortic wall. This feature should be interpreted with caution since its predictive value for a positive examination was low (48%). Out of 23 cases in which the diagnosis of aortic dissection was suspected on the basis of this doubtful abnormal echo, it was confirmed in only 11 patients. The results in these 128 cases of aortic dissection indicate that two-dimensional echocardiography, which is easily performed at the patient's bedside, could take priority in investigations of this condition. It is extremely sensitive in the diagnosis of ascending aortic dissection, but much less so in the diagnosis of descending aortic dissection.
Eight studies met the inclusion criteria, yielding a sample of 710 subjects. All included studies used appropriate selection criteria and reference standards, but only one study reported uninterpretable or indeterminate results. The pooled estimates for sensitivity and specificity were 89.8% (95% confidence interval [CI] = 86.4% to 92.5%) and 88.0% (95% CI = 83.7% to 91.4%), respectively.
Young et al. 2010. Economic impact of additional radiographic studies after registered diagnostic medical sonographer (RDMS)-certified emergency physician-performed identification of cholecystitis by ultrasound.
There were 37 patients enrolled; 32 patients exhibited RUQ pain with a focused ED ultrasound significant for cholecystitis. Eight (25%) patients received no further radiographic tests and exhibited positive pathology. Twenty-four (75%) patients had additional diagnostic examinations; 22 (92%) showed positive pathology. Based upon Medicare compensation indices, an opportunity cost of $6885.34 was incurred at our institution over 9 months due to additional examinations. Using nationally comparable indices, this was extrapolated to an opportunity cost of $63 million (95% confidence interval $48.3-$78.9 million) per year across the nation, assuming that 50% of patients with cholecystitis present to the ED and receive an ultrasound examination by an RDMS-certified Emergency Physician.
The test characteristics of bedside ultrasonography were sensitivity 87% (95% confidence interval [CI] 66% to 97%), specificity 82% (95% CI 74% to 88%), positive likelihood ratio 4.7 (95% CI 3.2 to 6.9), negative likelihood ratio 0.16 (95% CI 0.06 to 0.46), positive predictive value 44% (95% CI 29% to 59%), and negative predictive value 97% (95% CI 93% to 99%). The test characteristics of radiology ultrasonography were sensitivity 83% (95% CI 61% to 95%), specificity 86% (95% CI 77% to 92%), positive likelihood ratio 5.7 (95% CI 3.3 to 9.8), negative likelihood ratio 0.20 (95% CI 0.08 to 0.50), positive predictive value 59% (95% CI 41% to 76%), and negative predictive value 95% (95% CI 88% to 99%).
Miller et al. 2006. ED ultrasound in hepatobiliary disease.
Diagnostic categories included: "normal gallbladder"; "uncomplicated symptomatic cholelithiasis" (uncomplicated SCL; stones present but symptoms and signs relieved and no abnormal blood-work); or "complicated symptomatic cholelithiasis" (CSCL; stones and positive symptoms and signs including abnormal blood-work). Final Emergency Department patient assessments based on the Radiology ultrasound read were compared to the ED physician US. Over 2-years, 127 patients were enrolled. The sensitivity of the Emergency physician POCUS for detecting stones was 94% (positive predictive value 99%; specificity 96%; negative predictive value 73%). In conclusion, the ED doctor POCUS is a highly sensitive and reliable indicator of the presence of gallstones.
Fifty-one had gallstones. Compared to formal radiology study, forty-nine were detected by EPs, yielding a sensitivity of 96% [95% confidence interval (CI).87-.99]. Of the 58 patients without gallstones, 51 were correctly diagnosed by EPs (specificity = 88%, 95% CI.77-.95). The sonographic Murphy sign was present during 54 emergency examinations, but in only 24 formal studies. When compared to pathology reports, the emergency sonographic Murphy sign had a sensitivity of 75% compared to the formal ultrasound sensitivity of 45% for acute cholecystitis. EPs were less accurate for other sonographic findings, and level of experience had little effect on sensitivity or specificity for detecting gallstones. Eighty-three percent of emergency studies were completed in less than 10 min. Gallstones are accurately detected by EPs in a timely fashion. Additionally, compared to the radiologist's interpretation, the EP-detected sonographic Murphy sign was more sensitive for diagnosing acute cholecystitis.
Rosen et al. 2001. Ultrasonography by emergency physicians in patients with suspected cholecystitis.
This article investigates the use of bedside abdominal ultrasonography (BAU) performed by emergency physicians (EPs) to screen patients for cholelithiasis and cholecystitis. In this prospective study EPs performed BAU on 116 patients. Agreement between BAU and formal abdominal ultrasound (FUS) performed in the radiology department for detecting cholelithiasis and cholecystitis was determined using Kappa statistics. Test characteristics of BAU for detecting cholelithiasis and acute cholecystitis were calculated. Agreement between BAU and FUS was 0.71 for cholelithiasis and 0.46 for acute cholecystitis. Test characteristics of BAU for cholelithiasis were sensitivity 92%, specificity 78%, positive predictive value (PPV) 86%, negative predictive value (NPV) 88%. Test characteristics of BAU for acute cholecystitis compared with clinical follow-up were sensitivity 91%, specificity 66%, PPV 70%, NPV 90%. BAU may be used to exclude cholelithiasis and is sensitive for cholecystitis. However, when EPs with limited experience identify cholecystitis a confirmatory test is warranted before cholecystectomy.
The cost of ED POCUS was more than offset by savings in avoiding calling in ultrasound technicians after regular Medical Imaging Department hours. The indeterminate rate for ED POCUS was 18%. Excluding indeterminates, the sensitivity of ED POCUS for detection of gallstones was 88.6% (95% CI 83.1-92.8%), the specificity 98.2% (95% CI 96.0-99.3%), and the accuracy 94.8% (95% CI 92.5-96.5%). We conclude that greater availability of radiology ultrsound in the ED was associated with improved quality in the evaluation of patients with suspected symptomatic cholelithiasis but also with increased ultrasound costs. The availability of ED POCUS in addition to readily available radiology ultrasound was associated with further improved quality and decreased costs. The indeterminate rate for ED POCUS was relatively high, but excluding indeterminates, the accuracy of ED POCUS was comparable with published reports of radiology ultrasound.
Blaivass et al. 1999. Decreasing length of stay with emergency ultrasound examination of the gallbladder.
In a teaching hospital with a residency program, Emergency physician ultrasounds decrease ED LOS for these patients by up to 1.5 hours. The difference was most apparent for patients presenting after hours.
Sonographic findings in 497 patients with suspected acute cholecystitis were analyzed prospectively. Combined use of primary and secondary sonographic signs led to excellent positive and negative predictive values. Positive predictive values for stones combined with either a positive sonographic Murphy sign (92.2%) or with gallbladder wall thickening (95.2%) were excellent for acute cholecystitis. Positive predictive value of these signs for patients requiring cholecystectomy was even higher (99.0%). Negative predictive values for combined use of primary and secondary signs to exclude acute cholecystitis were also excellent (95.0% for no stones and negative sonographic Murphy sign). Real-time sonography alone, using both primary and secondary signs, can be definitive in nearly 80% of patients with suspected acute cholecystitis. These patients require no further imaging evaluation. Sonography should be the screening test of choice in acute cholecystitis because it is cost effective, prospectively highly accurate, quick, and better at characterizing and detecting other abdominal lesions than cholescintigraphy. A proposed algorithm is described.
PoCUS for hydronephrosis in suspected renal colic has moderate accuracy when performed by providers with varied experience for the binary outcome of presence or absence of hydronephrosis. Hydronephrosis on PoCUS is associated with increased rates of complications. PoCUS for hydronephrosis is limited in its utility as a stand-alone test, however this inexpensive, readily available test may be useful in conjunction with clinical course to determine which patients would beneft from formal imaging or urologic consultation.
In total, 128 of 147 analyzed patients were confirmed to have ureter stones. The ED length of stay was significantly lower in the UG group than in the CG group (mean 172 min; 95% confidence interval (CI): 151–194 min vs. mean 234 min; 95% CI: 216–252 min). The medical cost was also remarkably lower in the UG group than in the CG group (259 USD vs. 319 USD; p < 0.001). The incidence of complications within 30 days after visiting ED and missed or delayed high-risk diagnosis were not significantly different between the two groups. Conclusions: We found that protocolized point-of-care ultrasonography in patients with acute renal colic who visited the ED can more effectively reduce the length of stay and medical cost without 30-day complication than usual clinical practice.
The overall sensitivity and specificity of point-of-care ultrasonography for diagnosing urolithiasis was 70.2% and 75.4%, respectively . When the 2 studies assessing the degree of hydronephrosis were evaluated, moderate to severe was found to be 94.4% specific, but only 29% sensitive.3, 4. The current review found that point-of-care ultrasonography was moderately sensitive and specific for the diagnosis of urolithiasis when hydronephrosis was present but was much more specific with moderate to severe hydronephrosis. Unfortunately, the pooled likelihood ratios for the overall assessment with either all patients or those with moderate to severe hydronephrosis were relatively small and unlikely to significantly influence the posttest probability in isolation.
Point-of-care ultrasound has modest diagnostic accuracy for diagnosing nephrolithiasis. The finding of moderate or severe hydronephrosis is highly specific for the presence of any stone, and the presence of any hydronephrosis is suggestive of a larger (>5 mm) stone in those presenting with renal colic.
The 28 participating doctors undertook 138 kidney and 60 bladder scans during the study. POCUS of the bladder as a test for urinary retention had a sensitivity of 100% (95% CI 88-100) and specificity of 100% (95% CI 93-100). POCUS of the kidney as a test for hydronephrosis had a sensitivity 90% (95% CI 74-96) and specificity of 96% (95% CI 89-98). The accuracy of other findings such as renal stones and bladder clot was lower. POCUS of the bladder appeared to have made a positive contribution to patient care in 92% of cases without evidence of harm. POCUS of the kidney benefited 93% of cases, although in three cases (2%), it may have had a negative effect on patient care. DISCUSSION POCUS as a test for urinary retention and hydronephrosis in the hands of rural doctors was technically straightforward, improved diagnostic certainty, increased discharges and overall had a positive effect on patient care.
Fowler et al. 2002. US for detecting renal calculi with nonenhanced CT as a reference standard.
US depicted 24 of 101 calculi identified at CT, yielding a sensitivity of 24% and a specificity of 90%. There was no substantial difference for the detection of calculi in the right and left kidneys. The sensitivity of US for any calculi in a patient was 44%, equal to that of the original US interpretation. US enabled identification of 39% of patients with multiple calculi and demonstrated all calculi in 17% of these patients. The mean size of calculi detected with US was 7.1 mm +/- 1.2 (95% CI); 73% of calculi not visualized at US were less than 3.0 mm in size. Calculus size based on US and CT measurements was concordant in 79% of cases and differed by a mean of 1.5 mm +/- 0.7. US is of limited value for detecting renal calculi.
Tamburini et al. 2020. Ultrasound Signs in the Diagnosis and Staging of Small Bowel Obstruction.
Ultrasound (US) is highly accurate in the diagnosis of small bowel obstruction (SBO). Because the indications for and timing of surgical intervention for SBO have changed over the past several decades, there is a widespread assumption that the majority of patients with simple SBO may be conservatively managed; in this scenario, staging SBO is crucial. This study evaluated the association between morphological and functional US signs in the diagnosis and staging (simple, decompensated and complicated), and the associations and prevalence of US signs correlated with clinical or surgical outcome. The US signs were divided into diagnostic (dilated bowel loops and altered kinesis) and staging criteria (extraluminal free fluid, parietal and villi alterations). We performed a retrospective, single-center cohort, observational study examining the prevalence of morphologic and functional US signs in the staging of simple, decompensated and complicated SBO. The most significant US signs were dilated bowel loops (100%), hypokinesis (90.46%), thickened walls (82.54%) and free fluid (74.60%). By linear regression, free fluid was positively correlated to US staging in both univariate and multivariate analysis; that is, the more advanced the stage of SBO, the more probable the presence of free fluid between the bowel loops. In univariate analysis only, we found a positive correlation between US staging/thickened walls and the prominence of valvulae conniventes. Additionally, the multivariate analysis indicated that parietal stratification and bowel jump kinesis were negative predictors for US staging in comparison to other US signs. In addition, we found significant associations between conservative treatment or surgery and hypokinesis (p = 0.0326), akinesis (p = 0.0326), free fluid (p = 0.0013) and prominence of valvulae conniventes (p = 0.011). Free fluid in particular was significantly less present in patients that were conservatively treated (p = 0.040). We conclude that the US staging of SBO may be crucial, with a valuable role in the initial diagnosis and staging of the pathology, saving time and reducing total radiation exposure to the patient.
A Lines / B lines / Pulmonary edema
Among the 117 included patients, AHF (n = 69) was identified in 27.4%, 56.2%, 54.8%, and 76.7% of patients with the 4-point (two bilateral positive points), 6-point, 8-point (≥ 1 bilateral positive point), and 28-point (B-line count ≥ 30) methods, respectively. The C-index (95% CI) of the Brest score was 72.8 (65.3-80.3), whereas the C-index of the 4-, 6-, 8-, and 28-point methods were 63.7 (58.5-68.8), 72.4 (65.0-79.8), 74.0 (67.1-80.9), and 72.4 (63.9-80.9). The highest increase in the C-index on top of the BREST score was observed with the 8-point method in the whole population (6.9; 95% CI, 1.6-12.2; P = .010) and in the population with an intermediate Brest score, followed by the 6-point method.In patients with diagnostic uncertainty, the 6-point/8-point LUS method (using the 1 bilateral positive point threshold) improves AHF diagnosis accuracy on top of the BREST score.
Tierney et al 2019 Comparative Performance of Pulmonary Ultrasound, Chest Radiograph and CT Among Patients with Acute Respiratory Failure
A 9 point pulmonary ultrasound protocol strongly agreed with CT findings in mechanically ventilated patients with acute respiratory failure and significantly outperformed chest xray
used 9 point exam, Lung US had significantly better overall lobe-specific agreement with CT than CXR did, with greatest difference for interstitial findings.
Overall Lung US exam was consistent with final diagnosis in 62/67 patients
Markarian et al. 2019. A lung ultrasound score for early triage of elderly patients with acute dyspnea.
Among 137 patients analysed (mean age 79 ± 13 years, 74 [54%] women), 43 (31%) were categorized into the critical care group. The time taken to obtain the modified lung ultrasound score(MLUS) was 30 ± 22 min. The area under the receiver operating characteristic curve of the MLUS for predicting the critical care group was 0.97 (0.92-0.99; p < 0.01) with a cut-off set strictly above 17 for 93% sensitivity (81-99), 99% specificity (94-100), a positive predictive value of 98% (87-100), a negative predictive value of 97% (91-99), a positive likelihood ratio of 86, a negative likelihood ratio of 0.07, and a diagnostic accuracy of 97% (93-99). In a multivariate analysis, the MLUS was the only independent associated factor for the critical care group.
Maw et al. 2019. Diagnostic Accuracy of Point-of-Care Lung Ultrasonography and Chest Radiography in Adults With Symptoms Suggestive of Acute Decompensated Heart FailureA Systematic Review and Meta-analysis
Meta-analysis revealing that lung ultrasonography was found to be more sensitive than chest radiography for the detection of cardiogenic pulmonary edema and had comparable specificity.
128 patients with a mean age of 64 ± 17 years were included in the study. Using a reference standard of composite final diagnoses, POCUS had equal or higher specificity to CXR for all indications for which it was used, except for pneumonia. POCUS correctly identified all patients with pneumothorax, pleural effusion and pericardial effusion. In patients with a normal thoracic ultrasound, CXR never provided any actionable clinical information. Adding POCUS to the initial evaluation causes a significant narrowing of the differential diagnoses in which the median differential diagnosis from 5 (IQR 3-6) to 3 (IQR 2-4) p < 0.001.
Wang et al 2018 Sensitivity and specificity of ultrasound for diagnosis of acute pulmonary edema: systemic review and meta-analysis
984 articles identified but only 8 studies involving 1301 patients were used for the meta-analysis. The overall sensitivity of ultrasound for the diagnosis of acute pulmonary edema is 97% (95% CI: 96%-98%) and the overall specificity was 98% (95% CI: 97%-99%).
Al Deeb et al 2014 Point‐of‐care Ultrasonography for the Diagnosis of Acute Cardiogenic Pulmonary Edema in Patients Presenting With Acute Dyspnea: A Systematic Review and Meta‐analysis
Seven articles (n = 1,075) were identified that met inclusion criteria (two studies completed in the ED, two in the intensive care unit [ICU], two on inpatient wards, and one in the pre-hospital setting). The sensitivity of US using B-lines to diagnosis Acute cardiogenic pulmonary edema is 94.1% (95% confidence interval [CI] = 81.3% to 98.3%) and the specificity is 92.4% (95% CI = 84.2% to 96.4%).
Lichtenstein et al 2014 Lung ultrasound in the critically ill
Review article on pulmonary ultrsound and BLUE protocol
Gargani et al. 2011. Lung ultrasound: a new tool for the cardiologist
Review article: For many years the lung has been considered off-limits for ultrasound. However, it has been recently shown that lung ultrasound (LUS) may represent a useful tool for the evaluation of many pulmonary conditions in cardiovascular disease. The main application of LUS for the cardiologist is the assessment of B-lines. B-lines are reverberation artifacts, originating from water-thickened pulmonary interlobular septa. Multiple B-lines are present in pulmonary congestion, and may help in the detection, semi-quantification and monitoring of extravascular lung water, in the differential diagnosis of dyspnea, and in the prognostic stratification of chronic heart failure and acute coronary syndromes.
Koenig et al. 2011. Thoracic Ultrasonography for the Pulmonary Specialist.
Ultrasonography is useful in imaging lung consolidation, pleural-based masses and effusions, pneumothorax, and diaphragmatic dysfunction. It can identify complex or loculated effusions and be useful in planning treatment. Identifying intrathoracic mass lesions can guide sampling by aspiration and biopsy. This article summarizes thoracic ultrasonography applications for the pulmonary specialist, related procedural codes, and reimbursement.
A-predominance indicates dry interlobular septa. Specific to predicting a low PAOP value, A-predominance suggests that fluid may be given without initial concern for the development of hydrostatic pulmonary edema. B-predominance indicates interstitial syndrome, which is usually related to interstitial edema. B-predominance is observed in a wide range of PAOP values, precluding conclusions about the need for fluid therapy. This bedside potential will be appreciated by those intensivists who envision fluid therapy based on low PAOP values and who consider that using the concept of a safety factor provided by lung ultrasound is logical.
Lichtenstein et al 2008 Relevance of Lung Ultrasound in the Diagnosis of Acute Respiratory Failure: The BLUE Protocol
Objective: Usefulness of pulmonary ultrasound in acute respiratory failure
Study Design: Observational study of 260 patients admitted to ICU with acute respiratory distress
Predominant A lines plus lung sliding indicated asthma (n = 34) or COPD (n = 49) with 89% sensitivity and 97% specificity.
Multiple anterior diffuse B lines with lung sliding indicated pulmonary edema (n = 64) with 97% sensitivity and 95% specificity.
A normal anterior profile plus deep venous thrombosis indicated pulmonary embolism (n = 21) with 81% sensitivity and 99% specificity.
Anterior absent lung sliding plus A lines plus lung point indicated pneumothorax (n = 9) with 81% sensitivity and 100% specificity. Anterior alveolar consolidations, anterior diffuse B lines with abolished lung sliding, anterior asymmetric interstitial patterns, posterior consolidations or effusions without anterior diffuse B lines indicated pneumonia (n 5 83) with 89% sensitivity and 94% specificity. The use of these profiles would have provided correct diagnoses in 90.5% of cases.
Pleuroparenchimal patterns in Alveolar interstitial symdrome/ARDS do find a characterization through ultrasonographic lung scan. In the critically ill the ultrasound demonstration of a dyshomogeneous AIS with spared areas, pleural line modifications and lung consolidations is strongly predictive, in an early phase, of non-cardiogenic pulmonary edema.
To assess correlation between lung comet tails and wedge pressure and extravascular lung water.
Significant positive linear correlations were found between comet score and extravascular lung water determined by the PiCCO System (r 0.42, p 0.001), between comet score and wedge pressure (r 0.48, p 0.01), and between comet score and radiologic lung water score (r 0.60, p 0.0001).
Lichtenstein et al 1998. A lung ultrasound sign allowing bedside distinction between pulmonary edema and COPD: the comet-tail artifact.
Prospective clinical trial in 66 patients assessing ultrasound ability to distinguish COPD vs pulmonary edema using 1 minute lung ultrasound exam.
Comet tails: at least 3 hyperechoic bright lines that reach the end of the screen and arise from the pleural line in one lung location
Comet tails were present in all 40 patients with pulmonary edema
Comet tails absent in 24/26 COPD cases, as well as absent in 79/80 patients without respiratory distress
Comet tails in pulmonary edema: Sens 100%, specificity 92% when compared to COPD
When performed by one highly trained physician, our study demonstrated high concordance between ultrasonography and radiography. When ultrasound scans and radiographs disagreed, ultrasonography proved to be more accurate in distinguishing free pleural effusion. Thus, considering the short time needed to have a final ultrasound report, this technique could become the routine imaging modality for patients with dyspnea presenting to the ED.
Qureshi et al 2009. Thoracic ultrasound in the diagnosis of malignant pleural effusion.
Results: Thoracic ultrasound (TUS) is useful in differentiating malignant from benign pleural disease in patients presenting with suspected MPE and may become an important adjunct in the diagnostic pathway. TUS correctly diagnosed malignancy in 26/33 patients (sensitivity 73%, specificity 100%, positive predictive value 100%, negative predictive value 79%) and benign disease in 19/19. Pleural thickening .1 cm, pleural nodularity and diaphragmatic thickening .7 mm were highly suggestive of malignant disease.
Pleural effusion patterns in sonographic appearances can be subclassified as anechoic, complex nonseptated, complex septated and homogeneously echogenic. Previous studies have suggested that transudates are usually anechoic; however, in daily practice we find frequently that heterogeneous echogenic material is present in transudative pleural effusions. This clinical study was to re-evaluate the sonographic appearances of transudative pleural effusions. A total of 127 patients with transudative pleural effusion that met Light's criteria ( a pleural fluid-serum protein ratio of <0.5,  a pleural fluid-serum lactate dehydrogenase [(LDH] ratio of <0.6 and  a pleural fluid LDH of less than two thirds of the upper limit of normal for serum LDH) and clinical presentations were enrolled. Results showed that transudative pleural effusions had the following sonographic appearances: an anechoic pattern in 45% (57/127) and a complex nonseptated pattern in 55% (70/127). There was no complex septated or homogenously echogenic pattern. In conclusion, sonographic presentations in transudative pleural effusions are not always in an anechoic pattern. If an afebrile patient without infectious symptoms/signs has bilateral pleural effusion compatible with transudate of Light's criteria, treat the underlying problems and ignore the complex nonseptated sonographic appearance.
92 effusions were evaluated and drained; 11 (12%) were excluded for incomplete aspiration. Success rate of obtaining fluid under ultrasound guidance was 100%; the incidence of pneumothorax or bleeding was zero. Mean distance between parietal and visceral pleural (Sep) was 35+/-13 mm. Mean Volume was 658+/-320 ml. Significant positive correlation between both Sep and Volume was found: r=0.72; r(2)=0.52; p<0.001. The amount of pleural fluid volume can be estimated with the simplified formula: Volume (ml)=20 x Sep (mm). Mean prediction error of V using Sep was 158.4+/-160.6 ml.
Portable chest radiography and pleural ultrasonography yielded discordant results for 47 patients (48%) in the diagnosis of pleural effusion. The expiratory interpleural distance measured at the thoracic base with ultrasonography was significantly correlated with the volume of fluid (p < .0001; coefficient of determination: right, 0.78; left, 0.51). A pleural effusion > or =800 mL was predicted when this distance was >45 mm (right) or >50 mm (left), with a sensitivity of 94% and 100% and a specificity of 76% and 67%, respectively. In group II, the mean bias between the predicted and observed volumes of pleural effusion determined by thoracentesis was 24 +/- 355 mL, and this decreased to 28 +/- 146 mL for the prediction of pleural effusion <1400 mL.
The distance between the lung and posterior chest wall at the lung base (PLDbase) and the distance between the lung and posterior chest wall at the fifth intercostal space (PLD5) were significantly correlated with the drained volume (PLDbase, r = 0.68, p < 0.001; PLD5, r = 0.56, p < 0.001). A PLDbase > 5 cm predicted a drained volume > 500 mL with a sensitivity of 83%, specificity of 90%, positive predictive value of 91%, and negative predictive value of 82%. Interobserver and intraobserver percentages of error were, respectively, 7 +/- 6% and 9 +/- 6% for PLDbase, and 6 +/- 5% and 8 +/- 5% for PLD5. The PaO2/fraction of inspired oxygen ratio significantly increased after chest drainage in patients with collected volumes > 500 mL (p < 0.01).
Eibenberger et al. 1994. Quantification of pleural effusions: sonography versus radiography.
Sonographic measurements correlated statistically significantly better with actual effusion volume (r = .80) than did radiographic measurements (r = .58) (P < or = .05). With sonographic measurement, an effusion width of 20 mm had a mean volume of 380 mL +/- 130 (standard deviation), while one of 40 mm had a mean volume of 1,000 mL +/- 330. Prediction error with sonographic measurement (mean, 224 mL) was statistically significantly less (P < or = .002) than that with radiographic measurement (mean, 465 mL).
Our results showed that the two types of effusions could be distinguished on the basis of sonographic findings. Transudates were anechoic, whereas an anechoic effusion could be either a transudate or an exudate. Pleural effusions with complex septated, complex nonseptated, or homogeneously echogenic patterns were always exudates (p less than .01). Sonographic findings of thickened pleura and associated parenchymal lesions in the lung also were indicative of an exudate (p less than .01). Homogenous echogenic effusions were due to hemorrhagic effusion or empyema. Sonographic evidence of a pleural nodule was a specific finding in patients with a malignant effusion. We conclude that sonography is useful in determining the nature of pleural effusion.
Hirsh et al. 1981. Real time sonography of pleural opacities.
Fifty patients with radiographic pleural or pleural-based opacities were examined
with high resolution real-time sonographic sector scanning. In 90% of cases selected
for thoracentesis, fluid sufficient for diagnosis was obtained. Complex, septated pleural
loculations contained an exudative effusion in 74% of the patients, while anechoic
areas yielded exudative and transudative effusions with almost equal frequency. The use of real-time scanning is stressed because of greater flexibility and shorter examination time compared to compound scanning, and its utility for portable scanning on
critically ill patients.
We enrolled 87 patients in this study. Twenty-three (26.4%) of these patients were diagnosed with PE. Of patients with PE, fifteen (65%) were found to have a clinically significant acute PE (aPE). Analysis of mean TAPSE measurements between patients with clinically significant aPE and those with insignificant or no PE was 15.2 mm and 22.7 mm, respectively (p=<0.0001). Following ROC curve analysis, optimum TAPSE measurement to identify clinically significant aPE is 18.2 mm. A cutoff TAPSE measurement of 15.2 mm shows a sensitivity of 53.33% (95% CI 26.67%−80.00%) and a specificity of 100% (95% CI 100%−100%) for the diagnosis of a clinically significant PE. Our data suggest that TAPSE measurements less than 15.2 mm have a high specificity for identifying clinically significant aPE.
Nazerian et al. 2016 Diagnostic Performance of Wells Score Combined With Point-of-care Lung and Venous Ultrasound in Suspected Pulmonary Embolism
Results: A total of 446 patients were studied. PE was confirmed in 125 patients (28%). USWs performed significantly better than Ws, with a sensitivity of 69.6% versus 57.6% and a specificity of 88.2% versus 68.2%. In combination with D-dimer, USWs showed an optimal failure rate (0.8%) and a significantly superior efficiency than Ws (32.3% vs. 27.2%). A strategy based on lung and venous ultrasound combined with D-dimer would allow to avoid CT pulmonary angiography in 50.5% of patients with suspected PE, compared to 27.2% when the rule without ultrasound is applied
Results: Right ventricular dilatation and right ventricular dysfunction identified on emergency physician performed echocardiography were found to be highly specific for pulmonary embolism but had poor sensitivity. Thirty of 146 patients had a pulmonary embolism. Right ventricular dilatation on echocardiography had a sensitivity of 50% (95% confidence interval [CI] 32% to 68%), a specificity of 98% (95% CI 95% to 100%), a positive predictive value of 88% (95% CI 66% to 100%), and a negative predictive value of 88% (95% CI 83% to 94%). Positive and negative likelihood ratios were determined to be 29 (95% CI 6.1% to 64%) and 0.51 (95% CI 0.4% to 0.7%), respectively. Ten of 11 patients with right ventricular hypokinesis had a pulmonary embolism. All 6 patients with McConnell's sign and all 8 patients with paradoxical septal motion had a diagnosis of pulmonary embolism. There was a 96% observed agreement between co-investigators and principal investigator interpretation of images obtained and recorded.
Of 96 subjects who underwent CTPA, 12 subjects (12.5%) were positive for PE. All 96 subjects had an ultrasound study; two subjects (2.1%) were positive for lower extremity DVT, and 54 subjects (56.2%) had an alternative diagnosis suggested by ultrasonography, such as alveolar consolidation consistent with pneumonia or pulmonary edema, which correlated with CTPA findings. In no patient did the CTPA add an additional diagnosis over the screening ultrasound study. We conclude that ultrasound examination indicated that CTPA was not needed in 56 of 96 patients (58.3%). A screening, point-of-care ultrasonography protocol may predict the need for CTPA. Furthermore, an alternative diagnosis can be established that correlates with CTPA. This study needs further verification, but it offers a possible approach to reduce the cost and radiation exposure that is associated with CTPA.
Lichtenstein et al. 1995. A bedside ultrasound sign ruling out pneumothorax in the critically ill. Lung sliding.
Feasibility was 98.1%. Disappearance of "lung sliding" was observed in 100% of 41 analyzable cases of pneumothorax vs 8.8% of the hemithorax without pneumothorax (6 of 68). In this series, sensitivity was 95.3%, specificity 91.1%, and negative predictive value 100% (p < 0.001). Ultrasound was a sensitive test for detection of pneumothorax, although false-positive cases were noted. The principal value of this test was that it could immediately exclude anterior pneumothorax.
Ketalaars et al. 2018. Which ultrasound transducer type is best for diagnosing pneumothorax?
In total, 15 observers assessed 990 ultrasound video clips. The overall sensitivity and specificity were 98.2% and 97.2%, relatively. No significant difference was found in the diagnostic performance between transducers. A diagnosis was made slightly faster in the linear-array transducer clips, compared to the phased-array transducer (p = .031). For the linear-, curved-, and phased-array transducer, the image quality was rated at a median (interquartile range [IQR]) of 4 (IQR 3-4), 3 (IQR 2-4), and 2 (IQR 1-2), relatively. Between the transducers, the difference in image quality was significant (p < .0001).
Twenty-five traumatic PTXs were detected in the 218 hemithoraxes (109 patients; 2 patients had a bilateral PTX) evaluated by spiral CT scan; of these, only 13 of 25 PTXs (52%) were revealed by chest Rx (sensitivity, 52%; specificity, 100%), while 23 of 25 PTXs (92%) were identified by lung US with one false-positive result (sensitivity, 92%; specificity, 99.4%). Lung US scans carried out in the ED detect occult PTX and its extension with an accuracy that is almost as high as the reference standard (CT scanning).
Lichenstein et al. 2005. Ultrasound diagnosis of occult pneumothorax.
A total of 357 hemithoraces were analyzed in this study, 47 with occult pneumothorax and 310 controls. Ultrasound scans in all 43 examinable patients with pneumothorax showed absent lung sliding, 41 of 43 patients had the A line sign, and 34 exhibited a lung point. Among 302 analyzable controls, 65 had absent lung sliding, 16 of them showed an A line sign, and none showed a lung point. For the diagnosis of occult pneumothorax, the abolition of lung sliding alone had a sensitivity of 100% and a specificity of 78%. Absent lung sliding plus the A line sign had a sensitivity of 95% and a specificity of 94%. The lung point had a sensitivity of 79% and a specificity of 100%.
Lichtenstein et al. 2000. The "lung point": an ultrasound sign specific to pneumothorax.
The "lung point" was sought in 66 consecutive cases of proven pneumothorax and 233 cases of proven no ptx. The"lung point" was observed in 44 of 66 cases of pneumothorax (including 6 of 8 radio-occult cases) and in no case in the control group. The location of this sign roughly correlated with the radiological size of the pneumothorax. The "lung point" therefore had an overall sensitivity of 66% (75% in the case of radio-occult pneumothorax alone) and a specificity of 100%. The presence of a "lung point" allows positive diagnosis of pneumothorax at the bedside using ultrasound.
Pneumonia / ARDS
Out of 43 patients that underwent Lung US, CXR and COVID19 test, 27/43 (63%) tested positive. LUS was more sensitive (88.9%, 95% confidence interval (CI), 71.1-97.0) for the associated diagnosis of COVID-19 than CXR (51.9%, 95% CI, 34.0-69.3; p = 0.013). LUS and CXR specificity were 56.3% (95% CI, 33.2-76.9) and 75.0% (95% CI, 50.0-90.3), respectively (p = 0.453). Secondary LUS findings of patients with COVID-19 demonstrated 21/27 (77.8%) had pleural abnormalities and 10/27 (37%) had subpleural consolidations.
The sensitivity of LUS to diagnose pneumonia ranged from 0.68 to 1.00; however, in 14 studies, sensitivity was ≥0.91. Specificities varied from 0.57 to 1.00. We found no obvious differences between studies with low and high diagnostic accuracy. The non-imaging specialists were emergency physicians, internal medicine physicians, intensivists or ‘speciality not described’. Five studies described LUS training, which varied from a 1-hour course to fully credentialed ultrasound education
Mathews et al. 2020. Clinical Progress Note: Point-of-Care Ultrasound Applications in COVID-19.
Literature review on how POCUS can augment clinical care in the COVID era on topics from lung findings, cardiac function, DVT assessment and disinfection.
Comparing CT and lung US findings in COVID patients in China
COVID–19 foci are mainly observed in the posterior fields in both lungs, especially in the posterior lower fields.
Fused B lines and waterfall signs are visible under the pleura. The B lines are in fixed position.
The pleural line is unsmooth, discontinuous and interrupted.
The subpleural lesions show patchy, strip, and nodule consolidation.
Air bronchogram sign or air bronchiologram sign can be seen in the consolidation.
The involved interstitial tissues have localized thickening and edema, and there is localized pleural effusion around the lesions.
CDFI ultrasound shows insufficient blood supply in the lesions.
High frequency linear array probe is suggested to be used for minor subpleural lesions, as it can provide rich information and improve diagnostic accuracy.
Results: based on lung ultrasound of 20 patients, Characteristic findings included the following:
1. Thickening of the pleural line with pleural line irregularity
2. B lines in a variety of patterns including focal, multifocal, and confuent
3. Consolidations in a variety of patterns including multifocal small, non-translobar, and translobar with occasional mobile air bronchograms
4. Appearance of A lines during recovery phase
5. Pleural effusions are uncommon.
Volpicelli et al. 2020. What’s new in lung ultrasound during the COVID-19 pandemic.
Review article, lung ultrasound images and usefulness of POCUS during the COVID19 pandemic.
Convissar et al. 2020. Application of Lung Ultrasound During the Coronavirus Disease 2019 Pandemic: A Narrative Review.
This review highlights the ultrasound findings reported from a number of studies and case reports and discusses the unifying findings from coronavirus disease (COVID-19) patients and from the avian (H7N9) and H1N1 influenza epidemics. We discuss the potential role for portable point-of-care ultrasound (PPOCUS) as a safe and effective bedside option in the initial evaluation, management, and monitoring of disease progression in patients with confirmed or suspected COVID-19 infection.
Of the 73 study individuals, majority were male 46 (63%). The distributions of study individuals were as follows: 27% – mild ARDS, 37% – moderate ARDS, and 36% – severe ARDS. Coalescent B lines are present in about 70.4% and 92.3% of moderate and severe ARDS patients, respectively. Consolidations are predominantly present in moderate (100%) and severe (92.3%) ARDS.
120 patients entered the study. A discharge diagnosis of pneumonia was confirmed in 81 (67.5%). The first CXR was positive in 54/81 patients (sensitivity 67%; 95% CI 56.4% to 76.9%) and negative in 33/39 (specificity 85%; 95% CI 73.3% to 95.9%), whereas lung ultrasound was positive in 80/81 (sensitivity 98%; 95% CI 93.3% to 99.9%) and negative in 37/39 (specificity 95%; 95% CI 82.7% to 99.4%). A CT scan was performed in 30 patients (26 of which were positive for pneumonia); in this subgroup the first CXR was diagnostic for pneumonia in 18/26 cases (sensitivity 69%), whereas ultrasound was positive in 25/26 (sensitivity 96%). The feasibility of ultrasound was 100% and the examination was always performed in less than 5 min. Bedside chest ultrasound is a reliable tool for the diagnosis of pneumonia in the ED, probably being superior to CXR in this setting. It is likely that its wider use will allow a faster diagnosis, conducive to a more appropriate and timely therapy
Xirouchaki et al. 2011. Lung ultrasound in critically ill patients: comparison with bedside chest radiography
Results: Using CT scan as gold standard, sensitivity and specificity and diagnostic accuracy all favored lung ultrasound over chest xray
chest xray: Sens 38%, Spec 80%, accuracy 49%
Lung US: Sens 100%, Spec 78%, accuracy 95%
Chest xray: Sens 46%, Spec 80%, accuracy 58%
Lung US: Sens 94%, Spec 93%, accuracy 94%
Chest xray: Sens 0%, Spec 99%, accuracy 89%
Lung US: Sens 75%, Spec 93%, accuracy 92%
Chest xray: Sens 65%, Spec 81%, accuracy 69%
Lung US: Sens 100%, Spec 100%, accuracy 100%
Lichtenstein et al. 2009. The dynamic air bronchogram. A lung ultrasound sign of alveolar consolidation ruling out atelectasis.
In patients with alveolar consolidation displaying air bronchograms on an ultrasound, the dynamic air bronchogram indicated pneumonia, distinguishing it from resorptive atelectasis. Static air bronchograms were seen in most resorptive atelectases and one third of cases of pneumonia. This finding increases the understanding of the pathophysiology of lung diseases within the clinical context and decreases the need for fibroscopy in practice.
Lichtenstein et al 2004 Ultrasound Diagnosis of alveolar consolidation in the critically ill.
65 cases of alveolar consolidation proven on CT were compared to 53 controls. In 65 cases of alveolar consolidation, ultrasound positive in 59, negative in 6. In the control group, ultrasound was correctly negative in 51 and positive in 1.
Lung consolidation defined based on: pattern arising from pleural line, tissue like pattern (hepatization), anatomic boundaries
Lung US sens 90%, spec 98% for consolidation
Auscultation had a diagnostic accuracy of 61% for pleural effusion, 36% for alveolar consolidation, and 55% for alveolar-interstitial syndrome. Bedside chest radiography had a diagnostic accuracy of 47% for pleural effusion, 75% for alveolar consolidation, and 72% for alveolar-interstitial syndrome. Lung ultrasonography had a diagnostic accuracy of 93% for pleural effusion, 97% for alveolar consolidation, and 95% for alveolar-interstitial syndrome. Lung ultrasonography, in contrast to auscultation and chest radiography, could quantify the extent of lung injury. Interobserver agreement for the ultrasound findings as assessed by the kappa statistic was satisfactory: 0.74, 0.77, and 0.73 for detection of alveolar-interstitial syndrome, alveolar consolidation, and pleural effusion, respectively.
123 patients admitted for HF were randomized to either a standard follow-up (n = 62, control group) or a LUS-guided follow-up (n = 61, LUS group). The primary endpoint was a composite of urgent visit, hospitalization for worsening HF and death during follow-up. The mean±SD left ventricular ejection fraction was 39±14%. The hazard ratio for the primary outcome in the LUS group was 0.518 [95% confidence interval (CI) 0.268–0.998; P = 0.049], mainly resulting from a decrease in the number of urgent visits for worsening HF. The number of patients needed to treat to avoid an event was 5 (95% CI 3–62). Other secondary endpoints such as N-terminal pro-B-type natriuretic peptide reduction were not achieved. The safety parameters were similar in the two groups. Patients in the LUS group received more loop diuretics [51 (91%) vs. 42 (75%); P = 0.02] and showed an improvement in the distance achieved in the 6-min walking test [60 m (interquartile range: 29–125 m) vs. 37 m (interquartile range: 5–70 m); P = 0.023].
Pivetta et al 2019 Lung ultrasound integrated with clinical assessment for the diagnosis of acute decompensated heart failure in the emergency department: a randomized controlled trial.
In this trial we found that, in adult patients presenting to the ED with acute dyspnea, a diagnostic approach combining LUS with clinical evaluation outperforms the current standard diagnostic work-up (based on clinical evaluation plus CXR and NT-proBNP measurement) in the diagnosis of acute decompensated heart failure. In particular, in this study, adding LUS to the initial clinical assessment (i.e. past medical history, history of present illness, physical examination, ABGand ECG) significantly increased both Sensitivity and Specificity, whereas inclusion of CXR and NT-proBNP did not improve diagnostic accuracy for acute decompensated heart failure.
Goonewardena et al. 2008. Comparison of Hand-Carried Ultrasound Assessment of the Inferior Vena Cava and N-Terminal Pro-Brain Natriuretic Peptide for Predicting Readmission After Hospitalization for Acute Decompensated Heart Failure
The maximal IVC diameter throughout the respiratory cycle. The maximum (IVCmax) and minimum (IVCsniff) diameter after having the patient sniff were measured 2.0 cm from the IVC right atrial junction with the use of electronic calipers. Images were not stored. The IVC collapsibility index (IVCCI) was calculated as (IVCmax − IVCsniff)/(IVCmax).During the 30-day follow-up, 31 patients were rehospitalized or presented to the emergency department...Patients who required repeat hospitalization had a larger IVC size on admission as well as at discharge. In addition, patients who were readmitted had persistently plethoric IVCs with lower IVC collapsibility indexes. At discharge, only serum sodium, log-transformed BNP, IVC size, and collapsibility were statistically significant predictors of readmission
Myocardial Infarction / NSTEMI
Bergmann et al 2018 Pre-hospital Transthoracic Echo for early identification of non-ST-elevation myocardial infarction in patients with acute coronary syndrome.
Pre-hospital transthoracic echocardiography by the emergency physician can correctly diagnose NSTEMI in more than 90% of cases. This can expedite the initiation of appropriate therapy and could thereby conceivably reduce morbidity and mortality.
Technique: 5-minute protocol focused on the emergency cardiac situation. The following 8 standard views were evaluated: apical four chamber (1), five-chamber (2), two-chamber (3), three chamber (4), parasternal long (5) and short (6) axes, and subcostal long (7) and short (8) axes. Left ventricular function was assessed and signs of other possible causes, such as aortic or mitral valve disorder, aortic dissection, pulmonary embolism, cardiac tamponade or hypovolemia, were sought
Conclusion: Pre-hospital transthoracic echocardiography by the emergency physician can correctly diagnose NSTEMI in more than 90% of cases. This can expedite the initiation of appropriate therapy and could thereby conceivably reduce morbidity and mortality. RWMA in pre-hospital TTE had 100% specificity and 100% positive predictive value for predicting myocardial infarction in our patients.
General Cardiac / LV Function
Boon et al. 2020. POCUS series: E-point septal separation, a quick assessment of reduced left ventricular ejection fraction in a POCUS setting.
In the last decade ultrasound has found its place in the intensive care unit. Initially ultrasound was used primarily to increase safety and efficacy of line insertion but now many intensivists use point-of-care ultrasound (POCUS) to aid in diagnosis, assessment of therapy and therapeutic interventions. In this series we aim to highlight one specific POCUS technique at a time, which we believe will prove to be useful in your clinical practice. In this issue our aim is to provide you with a short and practical description of the measurement of E-point septal separation to identify a severely reduced left ventricular ejection fraction.
The CLUE exam included 5 quick‐look signs of left ventricular dysfunction, left atrial enlargement, lung B‐lines, pleural effusions, and inferior vena cava plethora and had been performed. An abnormal admission point of care ultrasound exam was related to complex hospitalization, specifically a longer length of stay.
A simplified cardiac limited ultrasound exam (CLUE) can augment physical exam and provide enormous amount of additonal information. The current practice of physical diagnosis is dependent on physician skills and biases, inductive reasoning, and time efficiency. Although the clinical utility of echocardiography is well known, few data exist on how to integrate 2-dimensional screening “quicklook” ultrasound applications into a novel, modernized cardiac physical examination. We discuss the evidence basis behind ultrasound “signs” pertinent to the cardiovascular system and elemental in synthesis of bedside diagnoses and propose the application of a brief cardiac limited ultrasound examination based on these signs. An ultrasound- augmented cardiac physical examination can be taught in traditional medical education and has the potential to improve bedside diagnosis and patient care.
Of 78 inpatient studies, 19% of pocket ultrasound and 13% of standard studies were technically limited (P = NS). Of 61 technically adequate studies, subjective interpretation of pocket ultrasound images had a sensitivity, specificity, and accuracy of 79%, 52%, and 64% for left atrial diameter more than 4 cm; 47%, 98%, and 82% for E-point septal separation more than 1 cm of; 83%, 62%, and 74% for either abnormality; and 92%, 82%, and 87% for either abnormality when interpretive confidence was present (n = 23). The pocket ultrasound image quality scores were significantly lower than the standard echocardiograph (P < .001).
In this study, junior EPs were able to obtain measurements of EPSS that correlated closely with visual estimates of LVEF by clinicians with extensive point‐of‐care and comprehensive echocardiography experience.
Lucas et al. 2011. Hand-carried echocardiography by hospitalists: a randomized trial.
Hospitalist care guided by hand-carried echocardiography for unselected general medicine patients does not meaningfully affect length of stay. Whether or not it affects care quality remains unstudied.
Melamed et al. 2009. Assessment of left ventricular function by intensivists using hand-held echocardiography.
Using the formal TTE as the "gold standard," intensivists correctly identified normal LV function in 22 of 24 cases (92%) and abnormal LV function in 16 of 20 cases (80%). The kappa statistic for the agreement between intensivist and echocardiographer for any abnormality in LV function was 0.72 (95% confidence interval [CI], 0.52 to 0.93; p < 0.001). Intensivists correctly placed LV function into one of three categories in 36 of 44 cases (82%); in 6 of the 8 cases that were misclassified, the error involved an overestimation of LV function. The kappa statistic for agreement between the intensivist and echocardiographer with regard to placement into one of three categories of LV function was 0.68 (95% CI, 0.48 to 0.88; p < 0.001).
In conclusion, clinically useful quantitative prediction of the LVEF as a continuous variable can be obtained from the EPSS with a simple linear regression equation in a substantial portion of patients and may be a useful adjunct for assessment of LV function.
Equation for EF: 75.5 - (2.5 x EPSS in mm)
Comparison of Emergency Physician (EP) vs. primary cardiologist estimate of EF yielded a Pearson's correlation coefficient R = 0.86. This compared favorably with interobserver correlation between cardiologists (R = 0.84). In categorization of LVF, the weighted agreement between EPs and the primary cardiologist was 84%, with a weighted kappa of 0.61 (p < 0.001). Echocardiographic quality was rated by the primary cardiologist as good in 33%, moderate in 43%, and poor in 22%. The EF was significantly lower in patients with a cardiac cause of hypotension vs. other patients (25 +/- 10% vs. 48 +/- 17%, p < 0.001).
Mandl et al. 2012. Ultrasound Evaluation of Fluid in Knee Recesses at Varying Degrees of Flexion.
The sagittal diameter of synovial fluid in all 3 recesses was greatest at 30° flexion. Analysis of variance and Tukey’s test revealed that the suprapatellar scan and 30° flexion is the best combination for detecting effusion as confirmed by receiver operator characteristic curve analysis. The suprapatellar scan of the knee in 30° flexion was the most sensitive position to detect fluid in knee joints. Sagittal diameter of fluid in all 3 recesses increased with the knee in the 30° flexed position as compared to the extended position
Hong et al 2010. Detection of Knee Effusion by Ultrasonography.
For detecting knee effusion by ultrasonography, lateral transverse and longitudinal scans were the most sensitive in the knee extension posture. With knee flexion at 30 degrees, effusion was more
readily detected on the medial and midline longitudinal scans than with knee extension.
Yoon et al. 2008. Validity of sonographic longitudinal sagittal image for assessment of the cartilage thickness in knee osteoarthritis.
Medial and lateral condyle cartilage measurement compared to MRI gold standard. In lateral condyle, both suprapatellar transverse ultrasound and longitudinal sagittal view. In medial condyle, suprapatellar transverse US did not correlate with MRI.
Canty et al. 2020. Point‐of‐care ultrasound for deep venous thrombosis of the lower limb.
Review article on DVT exam using POCUS. The incidence and morbidity of deep venous thrombosis (DVT) and pulmonary embolus are high. An abbreviated ultrasound where DVT is inferred from incomplete venous compressibility has an equivalent accuracy to venous duplex, requiring less time and training enabling its widespread use by emergency, critical care and anaesthesia clinicians. In this review, the evolution and method of lower limb venous compression ultrasound is described along with evidence for its use in patients at high risk for DVT in these clinical settings.
Seventeen studies from 16 original articles were included (2-point, 1337 patients in 9 studies; 3-point, 1035 patients in 8 studies). Overall, 2-point POCUS had similar pooled sensitivity [0.91; 95% confidence interval (95% CI), 0.68–0.98; P = .86) and specificity (0.98; 95% CI, 0.96–0.99; P = .60) as 3-point POCUS (sensitivity, 0.90; 95% CI, 0.83–0.95 and specificity, 0.95; 95% CI, 0.83–0.99). The false-negative rates of 2-point (4.0%) and 3-point POCUS (4.1%) were almost similar. Meta-regression analysis showed that high sensitivity and specificity tended to be associated with an initial POCUS performer (including attending emergency physician > only resident) and separate POCUS training for DVT (trained > not reported), respectively.
One hundred twenty-five limbs from 73 patients were scanned. The prevalence of DVT was 6.4% (8/125). The sensitivity of POCUS for DVT was 100% (95% CI 74-100%) and specificity was 95.8% (95% CI 91-98%) with a positive predictive value of 61.5% (95% CI 35-84%) and a negative predictive value of 100% (95% CI 98-100%). The median time from order to POCUS completion was 5.8 h versus 11.5 h median time from order until the radiology report was finalized (p = 0.001).
A total of 240 patients were enrolled, with a mean (standard deviation) age of 59.46 (16.58). 3PCUS has a sensitivity and a specificity of 100% (95% confidence interval [CI], 96.55%-100%) and 93.33% (95% CI, 87.72%-96.91%), respectively, in comparison with DUS (whole-leg compression ultrasound). Negative predictive value and positive predictive value were 100% and 92.11% (95% CI, 86.12%-95.64%), respectively, with an accuracy of 96.25% (95% CI, 93%-98.27%).
A total of 109 patients (66.1%) had a three-point compression point-of-care ultrasound in the ED and a second ultrasound performed by the Radiology Department. Bedside three-point compression ultrasound of the lower extremity performed by physicians in the ED had a sensitivity of 93.2% (95% confidence interval [CI] 83.8-97.3%) and a specificity of 90.0% (95% CI 78.6-95.7%), with an accuracy of 91.7% (95% CI 85-95.6%).
A total of 128 POCUS ultrasound were compared with an Formal study. Eighty-one percent of the POCUS exams were performed by fellows with <2 years of clinical ultrasonography experience. Prevalence of DVT was 20%. POCUS studies yielded a sensitivity of 86% and a specificity of 96% with a diagnostic accuracy of 95%. Median time delay between the ordering of formal study and completion of the formal ultrasound study was 13.8 h.
A total of 1002 patients were included. A clinical decision rule indicating DVT to be unlikely and a normal D‐dimer finding occurred in 481 patients (48%), with a VTE incidence of 0.4% [95% confidence interval (CI) 0.05–1.5%] during follow‐up. DVT was confirmed in 59 of the 257 patients (23%) who underwent rapid CUS examination, and in 99 of the 264 patients (38%) who underwent complete CUS examination. VTE during follow‐up occurred in four patients (2.0%; 95% CI 0.6–5.1%) in the rapid CUS arm, and in two patients (1.2%; 95% CI 0.2–4.3%) in the complete CUS arm.
Bernardi et al. 2008. Serial 2-Point Ultrasonography Plus D-Dimer vs Whole-Leg Color-Coded Doppler Ultrasonography for Diagnosing Suspected Symptomatic Deep Vein ThrombosisA Randomized Controlled Trial.
Of 2465 eligible patients, 345 met 1 or more exclusion criteria and 22 refused to participate; therefore, 2098 patients were randomized to either 2-point (n = 1045) or whole-leg (n = 1053) ultrasonography. Symptomatic venous thromboembolism occurred in 7 of 801 patients (incidence, 0.9%; 95% confidence interval [CI], 0.3%-1.8%) in the 2-point strategy group and in 9 of 763 patients (incidence, 1.2%; 95% CI, 0.5%-2.2%) in the whole-leg strategy group. This met the established equivalence criterion (observed difference, 0.3%;95% CI, −1.4% to 0.8%). The 2 diagnostic strategies are equivalent when used for the management of symptomatic outpatients with suspected DVT of the lower extremities.
183 patients, and 27 (15%) had deep venous thrombosis(+). The sensitivity and specificity emergency clinician-performed ultrasonography was 70% (95% confidence interval [CI] 60% to 80%) and 89% (95% CI 83% to 94%), respectively, with overall diagnostic accuracy of 85% (95% CI 79% to 90%). The posterior probability of deep venous thrombosis(+) among the 88 low-risk patients with a negative emergency clinician-performed ultrasonographic result was 1 of 88, or 1.1% (95% CI 0% to 6%), and the posterior probability of deep venous thrombosis(+) among 14 high-risk patients with a positive emergency clinician-performed ultrasonographic result was 11 of 14, or 79% (95% CI 49% to 95%).
A total of 399 patients were studied. The POCUS findings were normal in 301 (75%), abnormal in 90 (23%), and uncertain in eight (2%). All abnormal test results were confirmed by the formal duplex ultrasound evaluation, and three patients (0.8%) with uncertain findings on POCUS examination were subsequently diagnosed as having a distal DVT (positive predictive value, 95% [95% confidence interval, 92% to 95%]; negative predictive value, 100% [95% confidence interval = 99% to 100%]). No patients with normal findings on POCUS examination died or experienced venous thromboembolism at the one-month follow-up. POCUS examination yielded a high negative predictive value and good positive predictive value, allowing rapid discharge and avoiding improper anticoagulant treatment.
We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4).
Eight residents with limited ultrasound (US) experience and no prior experience with deep vein thrombosis (DVT) US volunteered to participate in this study, enrolling 72 patients. Their average scan time was 11.7 minutes (95% CI = 9.4 to 14). There were 23 true positives, 4 false positives, 45 true negatives, and 0 false negatives. The test characteristics for PLEDVT gave a sensitivity of 100% (95% CI = 82.2 to 100) and a specificity of 91.8% (95% CI = 79.5 to 97.4).
EPs ordered the corroborative ultrasound, then performed their own examination. EPs recorded patient triage time, ED results, and disposition times for both EP and IS departments. One hundred fifty-six patients were enrolled. Thirty-four (22%) were diagnosed with a DVT. Mean time from triage to EP disposition was 95 minutes and mean time from triage to radiology disposition was 220 minutes. The difference of 125 minutes was statistically significant (P <.0001). EPs and ISs had excellent agreement (kappa = 0.9). Compression ultrasound performed by EPs resulted in a significant decreased time to disposition. Agreement with ISs was excellent.
One hundred twelve patients were enrolled in the study, with 34 positive for DVT. The median examination time was 3 minutes 28 seconds (95% CI = 2 min 45 sec to 4 min 2 sec; IQR 3 min 9 sec). Times ranged from 1:02 to 18:20 minutes. The ED results had a high correlation with vascular laboratory studies, giving a kappa of 0.9 and a 98% agreement (95% CI = 95.4% to 100%). Emergency physicians can perform LE duplex ultrasound examinations accurately and quickly.
The sensitivity, specificity, and positive predictive value (with 95% confidence intervals [CIs]) of compression ultrasound for the detection of proximal DVT were 60% (39%-81%), 96% (92%-99%), and 71% (48%-89%) respectively. The sensitivity, specificity, and positive predictive value (with 95% CIs) of compression ultrasound for the detection of calf vein thrombosis were 33% (18%-52%), 91% (83%-96%), and 58% (34%-80%), respectively. Color Doppler ultrasonography did not identify any additional proximal or calf vein thrombi to those detected by compression ultrasound alone. The sensitivity for all thrombi was 47% (95% CI, 34%-61%) with a positive predictive value of 65% (95% CI, 48%-79%).
The technical failure rate of compression technique was three of 144. In all technically satisfactory examinations, the compression technique result was positive in 15 of 14 limbs, and the Color doppler result was positive in 13. Sensitivity of compression technique was 100%, specificity was 98%, and overall accuracy was 99%. There were two false-positive results with compression technique; both were cases of popliteal veins deep to the artery leading to difficulty in compression. The compression technique was able to detect chronic thrombus, floating thrombus, and small thrombus behind femoral vein valve cusps.
Skin & Soft Tissue
Adhikari et al. 2012. Sonography First for Subcutaneous Abscess and Cellulitis Evaluation.
This article reviews clinical scenarios in which point‐of‐care soft tissue sonography is useful in suspected skin infections and describes pathologic findings and commonly accepted scanning approaches.
Sixty‐four of 107 patients had I + D–proven abscess, 17 of 107 had negative I + D, and 26 of 107 improved with antibiotic therapy alone. The sensitivity of clinical examination for abscesses was 86% (95% confidence interval [CI] = 76% to 93%), and the specificity was 70% (95% CI = 55% to 82%). The positive predictive value was 81% (95% CI = 70% to 90%), and the negative predictive value was 77% (95% CI = 62% to 88%). The sensitivity of US for abscess was 98% (95% CI = 93% to 100%), and the specificity was 88% (95% CI = 76% to 96%). The positive predictive value was 93% (95% CI = 84% to 97%), and the negative predictive value was 97% (95% CI = 88% to 100%). Of 18 cases in which US disagreed with the clinical examination, US was correct in 17 (94% of cases with disagreement, χ2= 14.2, p = 0.0002)
The current practice for cellulitis in diagnosis and treatment is mainly based on subjective clinical judgement without validated objective guidance. For patients with non-purulent cellulitis needing intravenous antibiotic treatment in hospital, we found soft tissue sonography performed around 4 days after initiation of antibiotics might have prognostic values. The patients with soft tissue sonographic pattern of subcutaneous thickening alone had shorter duration of antibiotic treatment and higher rate of early treatment response to antibiotics than those with the pattern of cobblestone appearance.
Yayal et al. 2006. The effect of soft-tissue ultrasound on the management of cellulitis in the emergency department.
Ultrasound changed the management of patients with cellulitis in 71/126 (56%) of cases. In the pretest group that was believed not to need further drainage, US changed the management in 39/82 (48%), with 33 receiving drainage and 6 receiving further diagnostics or consultation. In the pretest group in which further drainage was believed to be needed, US changed the management in 32/44 (73%), including 16 in whom drainage was eliminated and 16 who had further diagnostic interventions. US had a management effect in all pretest probabilities for fluid from 10% to 90%.
Yen et al. 2002. Ultrasonographic screening of clinically-suspected necrotizing fasciitis.
The ultrasonographic diagno-sis of necrotizing fasciitis was based on the criterion of a diffuse thickening of the subcutaneous tissue,accompanied by a layer of ﬂuid accumulation more than 4 millimeters in depth along the deep fascial layer. Data were collected for 62 patients, of whom 17 (27.4%) were considered to suffer from necrotizing fasciitis. Ultrasonography revealed a sensitivity of 88.2%, a specificity of 93.3%, a positive predictive value of 83.3%, a negative predictive value of 95.4%, and an accuracy of 91.9% as regards the diagnosis of necrotizing fasciitis. Ultrasonography can provide accurate information for emergency physicians for the diagnosis of necrotizing fasciitis.
Chow et al. 2000. Sonographic evaluation of cellulitis in children.
Ultrasonographic features of cellulitis included subcutaneous tissue thickening without distortion and pus (25 cases, 29%), distortion of subcutaneous tissue without pus accumulation (26 cases, 30%), distortion of subcutaneous tissue with pus accumulation (19 cases, 23%), and distortion of tissue with abscess formation (16 cases, 18%). The presence of sonographic features of tissue distortion with or without pus accumulation, including abscess formation in children with cellulitis, correlated with a longer duration of symptoms (greater than 4 days), the presence of high-grade fever, higher peripheral leukocyte count, and higher serum C-reactive protein levels. Those patients who underwent sonographically guided aspiration or surgical intervention showed a shorter hospital stay and fever duration than those without such aspiration. Our results indicated that ultrasonography is of great value in managing cellulitis by providing information regarding the progression of inflammation. Sonographically guided aspiration of pus may be a treatment of choice, as it may decrease the need for operation.
Results: The sensitivity and specificity of lung auscultation is poor. The criteria for pulmonary edema diagnosed by LUS were met in 307 of 926 patients (33%). In 156 of these patients (51%), auscultation was normal. A total of 302 of 926 patients (32%) had pulmonary edema diagnosed by pulmonary auscultation. From these patients, 151 patients (50%) had pulmonary edema on LUS. From 130 patients with crepitations, 86 patients (66%) had pulmonary edema on LUS, and of the 209 patients with rhonchi, 96 patients (46%) had pulmonary edema on LUS. The agreement between auscultation and LUS was poor (κ statistic 0.25).
Conclusions: A large proportion of physicians could obtain and interpret FCU images from critically ill patients after a 2-day training course. However, they still scored low on the parasternal short-axis view and were more
Jahanian et al. 2019. Diagnostic Accuracy of a Three-point Compression Ultrasonography Performed by Emergency Medicine Resident for the Diagnosis of Deep Vein Thrombosis: a Prospective Diagnostic Study.
Of the 72 patients enrolled in our study, 50% of the patients were male, with an average age of 36±19 years. The mean of patient admission time to perform ultrasonography by an emergency medicine resident and radiologist were 14.05±19 and 216±140.1 minutes, respectively. The two groups had a statistically significant difference (P<0.0001). In ultrasonography performed by emergency medicine resident and doper ultrasonography by radiologist, 91.67% and 36.1% of patients were diagnosed with DVT, respectively. Although the ultrasonography performed by emergency medicine resident has a relatively low sensitivity (53.8%), it has a good specificity (85.7%). The positive and negative predictive value was 70 and 75%, respectively.
Soni et al. 2015.Diagnostic point-of-care ultrasound for hospitalists.
Literature review of diagnostic point-of-care applications most relevant to hospitalists include cardiac ultrasound for left ventricular systolic function, pericardial effusion, and severe mitral regurgitation; lung ultrasound for pneumonia, pleural effusion, pneumothorax, and pulmonary edema; abdominal ultrasound for ascites, aortic aneurysm, and hydronephrosis; and venous ultrasound for central venous volume assessment and lower extremity deep venous thrombosis.
Razi et al 2011. Bedside hand-carried ultrasound by internal medicine residents versus traditional clinical assessment for the identification of systolic dysfunction in patients admitted with decompensated heart failure.
The average ejection fraction was 32 ± 16% (range, 7%-70%), with 66% of patients having EFs < 40%. The residents' ability to detect an EF < 40% with ultrasound was excellent (sensitivity, 94%; specificity, 94%; negative predictive value, 88%; positive predictive value, 97%). Binary logistic regression demonstrated that ultrasound EF was the most powerful predictor of EF < 40%, with minimal additional value from clinical, exam, lab, and electrocardiographic variables. The time interval between clinical assessment and availability of formal echocardiographic results was 22 ± 17 hours.
Hospitalists can learn aspects of hand-carried echocardiography, but after 35 training echocardiograms cannot replicate the quality of conventional echocardiography. Whether the lower performance skills are important will depend on the clinical context of hand-carried echocardiography performed by hospitalists.
Adding hand-carried ultrasound to the physical examination improved hospitalists' assessment of left ventricular function, cardiomegaly, and pericardial effusion. For left ventricular function, using hand-carried ultrasound increased the percentage of exact matches with the expert cardiologist's assessment from 46% to 59% (P=.005) and improved the percentage of within 1-level matches from 67% to 88% (P=.0001). The addition of hand-carried ultrasound failed to improve the assessments of aortic stenosis, aortic regurgitation, and mitral regurgitation.
A total of 314 patients underwent both Standard echo and POCUS within a median time of 2.8 hours (25th to 75th percentiles, 1.4 to 5.1 hours). Positive and negative likelihood ratios for POCUS increased and decreased, respectively, the prior odds by 5-fold or more for LV systolic dysfunction, severe MR regurgitation, and moderate or large pericardial effusion. Likelihood ratios changed the prior odds by 2-fold or more for moderate or severe LA enlargement, moderate or severe LV hypertrophy, and IVC dilatation. Indeterminate POCUS results occurred in 2% to 6% of assessments.The diagnostic accuracy of POCUS performed by hospitalists after a brief training program was moderate to excellent for 6 important cardiac abnormalities.
Seventy-two consecutive medical clinic patients were enrolled with an average image acquisition time of 4.45 minutes. Residents obtained diagnostic images in 94% of the cases and interpreted them correctly 93% of the time. They correctly identified 92% of the major echo findings and 78% of the minor findings. Their diagnosis of LV dysfunction, valvular disease, and LV hypertrophy improved by 19%, 39%, and 14% with hand-carried echo compared to history and physical alone. Management decisions were reinforced in 76% and changed in 40% of patients with the use of hand-carried echo.
Kobal et al 2005 Comparison of Effectiveness of Hand-Carried Ultrasound to Bedside Cardiovascular Physical Examination
Researchers at Cedar Sinai Medical center compared the diagnostic accuracy of medical students using handheld ultrasound with 18 hours of training, with board certified cardiologists, in detecting various cardiac pathologies. Diagnostic accuracy was determined by standard echo. Two-hundred thirty-nine abnormal findings were detected by standard echocardiography. The students correctly identified 75% (180 of 239) of the pathologies, whereas cardiologists found 49% (116 of 239) (p <0.001). The students’ diagnostic specificity of 87% was also greater than cardiologists’ specificity of 76% (p <0.001). For nonvalvular pathologies (115 findings), students’ sensitivity was 61%, compared with 47% for cardiologists (p 0.040). There were 124 clinically significant valvular lesions (111 regurgitations, 13 stenoses). Students’ and cardiologists’ sensitivities for recognizing lesions that cause a systolic murmur were 93% and 62% (p <0.001), respectively. Students’ sensitivity for diagnosing lesions that produce a diastolic murmur was 75%; cardiologists recognized 16% of these lesions (p <0.001).
Buonsenso et al. 2020. Pediatrician performed point-of-care ultrasound for the detection of ingested foreign bodies: case series and review of the literature.
Conclusion: Appropriate and limited training allows pediatric emergency physicians to correctly identify foreign body in the esophagus or stomach. Point-of-care ultrasound in foreign body ingestion in the Emergency Department may allow to prioritize the escalation of care in children and it can contribute to reduce the time to endoscopic management when needed.
Heart Disease / CHF
Review article on feasibility and efficacy of using POCUS to screen young athletes for LV/RV and aortic root abnormalities.
This review examined whether the addition of point-of-care ultrasound (POCUS) to electrocardiography (ECG)-inclusive pre-participation screening strategies has the potential to reduce false-positive results and detect diseases associated with sudden cardiac death that may not be identified through current modalities. Five studies, representing 2646 athletes, demonstrated that ECG-inclusive pre-participation screening strategies resulted in positive results in 19.9% of the cohort. With the addition of POCUS, positive results were reduced to 4.9%, and 1 additional condition potentially associated with sudden cardiac death was identified. The magnitude of positive results with POCUS may be reduced if current ECG criteria were applied.
Of 207 patients with interpretable images, 11 (5.3%) had a left ventricular ejection fraction of 50% or lower. Patients with left ventricular systolic dysfunction had more heart failure risk factors than those without left ventricular systolic dysfunction (3.09±0.8 vs 2.5±1.0, P=.04). The total number of heart failure risk factors trended towards an association with a greater prevalence of asymptomatic left ventricular systolic dysfunction, but this did not reach significance (odds ratio 1.74; 95% confidence interval, 0.97-3.12, P=.06).
Hand-carried echocardiographic results were abnormal in 90 patients (55%). During 48 ± 7 months of follow-up, the combined end point occurred in 41 patients (25%). On multivariate analysis, only abnormal echocardiography (hazard ratio, 5.55; 95% confidence interval, 2.04-14.28; P = .0004) was an independent predictor of outcomes. Hand-carried echocardiographic examinations performed by an internist with basic echocardiographic training can provide important prognostic information, independent of N-terminal pro-B-type natriuretic peptide levels.
To address the heart failure burden, our focus needs to shift to disease prevention. Strategies to initially screen for heart failure precursors such as asymptomatic left ventricular systolic dysfunction have been evaluated, including clinical scores, the 12-lead electrocardiogram, and natriuretic peptides. However, their specificity limits their broad application as screening tools in asymptomatic populations. High-quality images are now available from hand-carried cardiac ultrasound devices, at a fraction of the capital cost of standard echocardiography with favorable diagnostic performance, especially when experienced staff perform the imaging. Questions that remain to be addressed include how we should select the target population to screen, who should perform the screening studies, how much training is required, and how often screening studies should be performed.
In the derivation cohort, the combination of two signs, denoting left atrial enlargement and inferior vena cava plethora resulted in the highest accuracy of 72% [95% CI: 65%, 78%] in detecting an abnormal echocardiogram. In the validation cohort, mortality at 5.5 years was 14.6% overall, 23% in patients with the left atrial enlargement sign (OR 3.5 [1.6, 7.6]), 25% with inferior vena cava plethora sign (OR 2.2 [0.8, 6.0]), and 8.0% (OR 0.3 [0.2, 0.7]) in those lacking both signs. After adjusting for age, both diabetes (OR 4.8 [2.0, 11.6]), and the left atrial enlargement sign (OR 2.4 [1.1, 5.4]) remained independently associated with mortality (p<0.05). In the referral model, patients younger than 65 years of age without diabetes and without the left atrial enlargement sign would not have received echo referral, resulting in a 33% reduction in total echo cost and would have constituted a low-risk group with a 1.2% 5.5-year mortality.
Kirkpatrick et al. 2008. Hand carried echocardiography screening for LV systolic dysfunction in a pulmonary function laboratory.
All subjects with normal PFT had normal LV systolic function. Among subjects with abnormal PFT, 6 (15%) had LV systolic dysfunction and the remainder had normal LV systolic function. No subjects with LV systolic dysfunction by full-featured echocardiograms were missed by the handheld ultrasound (sensitivity 100%, specificity 95%, negative predictive value 100%, positive predictive value 75%).LV systolic dysfunction is prevalent among patients with pulmonary disease and can be accurately screened for by a physician using a hand carried ultrasound device with subsequent confirmation with complete echocardiography.
One hundred ninety-six patients underwent coronary heart disease risk stratification by National Cholesterol Education Program guidelines and CLUE with a hand-carried ultrasound device with cardiac and vascular transducers. CLUE included brief imaging of the carotid arteries, the heart, and the intra-abdominal aorta. The prevalence of abnormal CLUE results and their effect on clinical management were tabulated and stratified by coronary heart disease risk class. Patient age (mean +/- SD) was 56 +/- 14 years (range 22 to 95), and 32.1% were at low risk, 30.6% at intermediate risk, and 37.2% at high risk. Of the 196 CLUEs, abnormalities were present in 37.2% (32.7% had carotid atheroma, 3.1% had systolic dysfunction, 6.1% had left atrial enlargement, and 1.0% had abdominal aortic aneurysm) and were related to age, increasing coronary heart disease risk, and male gender. Overall, CLUE resulted in new management recommendations in 20% of patients, primarily in coronary heart disease risk prevention. In patients at intermediate risk or aged 60 to 69 years, CLUE resulted in new recommendations in 39% and 37%, respectively. In conclusion, when applied to a clinic population, brief cardiovascular ultrasound exams frequently demonstrate unsuspected findings that can change management.
Galasko et al. 2006. What is the most cost-effective strategy to screen for left ventricular systolic dysfunction: natriuretic peptides, the electrocardiogram, hand-held echocardiography, traditional echocardiography, or their combination?
A total of 1205 subjects attended. Ninety six per cent of subjects with LVSD in the general population had identifiable risk factors. All screening strategies gave excellent negative predictive value. Screening high-risk subjects was most cost-effective, screening low-risk subjects least cost-effective. Traditional Echo screening was the least cost-effective strategy. NTproBNP screening gave similar cost savings to ECG screening; Handheld Echo screening greater cost-savings, and Handheld Eecho screening following NTproBNP or ECG pre-screening the greatest cost-savings, costing approximately 650 Euros per case of LVSD diagnosed in high-risk subjects (63% cost-savings vs.Traditional Echo).
The mean age was 75 +/- 13 years; 49% were female. Coronary artery disease was present in 29%; 82% were NYHA class I or II. At the time of HCU imaging, 48% of patients were receiving RV pacing. HCU images were interpretable in 91% (73/80) and required 3.7 +/- 0.9 min to complete. Based on the full-feature echo, LV dysfunction prevalence was 17/80 (21%); 25% of these patients were NYHA class I. The sensitivity of the HCU exam was 75%, specificity was 91%, negative predictive value was 93%, positive predictive value was 71%, and accuracy was 88%.Pocket Ultrasound screening in a pacemaker clinic by a non-cardiologist can rapidly and accurately identify pacemaker recipients with at least moderate LV dysfunction who might be candidates for device upgrades
Vourvouri et al. 2003. Screening for left ventricular dysfunction using a hand-carried cardiac ultrasound device.
19 out of 82 patients had LV dysfunction. The ultrasound and BNP could identify 17 and 18 out of these 19 patients, respectively. The agreement for LVEF and IVC collapse between SE and ultrasound was 96% for both parameters. The sensitivity of IVC collapse, ultrasound-LVEF and BNP in identifying patients with LV dysfunction was 26, 89 and 94%, respectively. Conclusion: A handheld ultrasound device can reliably be used as a screening tool for LV dysfunction.
Of patients, 70% did not have a clinical indication for echocardiography and of these patients, 39% had an abnormal study with the portable ultrasound device. There was a high rate of false-positive examinations, but approximately 17% of patients without a clinical indication for echocardiography had an important cardiac abnormality detected, including 10% with unsuspected left ventricular systolic dysfunction.
Qualitative measures of valvular regurgitation and quantitative measures of left ventricular hypertrophy were also compared. An estimate of ejection fraction was possible in 97%
of cases using portable echocardiography. It gave a sensitivity, specificity and negative predictive value in diagnosing left ventricular systolic dysfunction of 96%, 98% and 99.6%, respectively.Echocardiography performed...using fully portable devices is an accurate and reproducible technique for detecting left ventricular systolic dysfunction, left ventricular hypertrophy and valvular regurgitation in both high risk and low-risk members of the community. Its very high negative predictive values would allow their use in future community-based screening programs.
Sixty patients were enrolled, 39 on odd days and 21 on even days. Success rate was greater for the ultrasonographic group (97%) versus control (33%), difference in proportions of 64% (95% confidence interval [CI] 39% to 71%). The ultrasonographic group required less overall time (13 minutes versus 30 minutes, for a difference of 17 [95% CI 0.8 to 25.6]), less time to successful cannulation from first percutaneous puncture (4 minutes versus 15 minutes, for a difference of 11 [95% CI 8.2 to 19.4]), and fewer percutaneous punctures (1.7 versus 3.7, for a difference of 2.0 [95% CI 1.27 to 2.82]) and had greater patient satisfaction (8.7 versus 5.7, for a difference of 3.0 [95% CI 1.82 to 4.29]) than the traditional landmark approach. Ultrasonographic-guided peripheral intravenous access is more successful than traditional "blind" techniques, requires less time, decreases the number of percutaneous punctures, and improves patient satisfaction in the subgroup of patients who have difficult intravenous access.
A total of 321 surveys were collected in a five-month period no ENs declined to participate. There were 280 (87%) successful attempts. Twelve (29%) of the 41 failure patients required central lines, 9 (22%) received external jugular IVs, and 20 (49%) had peripheral IV access placed under US guidance by another nurse or physician. Twenty-eight percent (90) of all patients were obese, 18% (57) had sickle cell anemia, 10% (31) were renal dialysis patients, 12% (40) were IV drug abusers, and 19% (61) had unspecified chronic illness. The remainder had no reason for difficult access given. There were four arterial punctures.
One hundred one patients were enrolled, of whom 50 were injection drug users and 21 were obese. Cannulation was successful in 91 patients (91%) and accomplished on the first attempt in 73 (73%). The mean (+/-SD) time required for cannulation was 77 seconds (+/-129, range 4 to 600 seconds). The line infiltrated or fell out within 1 hour of cannulation in 8 (8%) patients. One patient reported severe pain. There were 2 (2%) cases of brachial artery puncture. Ultrasound-guided brachial and basilic vein cannulation is safe, rapid, and has a high success rate in ED patients with difficult peripheral intravenous access.
Sudden Cardiac Death
A total of 2332 participants were enrolled. There were 137 (5.8%) with a positive screening for HCM, of which 7 (5.1%) were confirmed to have HCM by a pediatric cardiologist. In a small cohort with positive screen for HCM, there was a 100% sensitivity (95% confidence interval, 59.04 to 100%) and 4.86% (95% confidence interval, 1.98 to 9.76%) positive predictive value of for having HCM.
Wyman et al. 2007. The 5-minute screening echocardiogram for athletes.
A limited 2-dimensional echocardiogram was performed on athletes as part of a routine sports physical examination. The examination was performed by sonographers and senior cardiovascular medicine fellows and interpreted in real time by cardiologists using a 1-page checklist. The limited 2-dimensional echocardiogram took approximately 5 minutes per athlete. The majority of studies revealed normal findings (84%). A total of 55 had minor abnormalities not requiring follow-up. Five had abnormalities requiring a full echocardiogram and consultation with a cardiologist.