Novice emergency physician ultrasonography of optic nerve sheath diameter compared to ophthalmologist fundoscopic evaluation for papilledema

Chanel O’Brien, DO| EM PGY-3

The Article: Novice emergency physician ultrasonography of optic nerve sheath diameter compared to ophthalmologist fundoscopic evaluation for papilledema. Wilson et al. (2021), JACEP Open 2021;2:e12355.

The Idea: The purpose of this study was to determine the sensitivity and specificity of novice emergency physician-performed point-of-care ultrasound diagnosis of papilledema using optic nerve sheath diameter (ONSD) against ophthalmologist performed dilated fundoscopy.

The Study: This was an observational study performed at a large, >100,000 annual volume, tertiary-care urban academic medical center which retrospectively analyzed results regarding ultrasound measured ONSD of emergency department (ED) patients. The study looked at patients over the age of 18 years that presented with primary vision complaints evaluated for papilledema both by an emergency physician-performed ultrasound and an ophthalmologist-performed fundoscopic examination. Operators were novice resident emergency physicians and had varying levels of POCUS experience. Images were collected on a Phillips Sparq or a Sonosite Xporte ultrasound machine using a high-frequency linear transducer with patients in an upright position. Optic-nerve sheath diameter was measured 3 mm posterior to the papilla with calipers placed at the interior border of the hypoechoic nerve, measured in two planes with the average of the measurements recorded. Patients were excluded if they did not receive both formal ophthalmology evaluation and bedside ocular ultrasound performed by an emergency physician. A retrospective chart review was conducted for adult patients that meet the study criteria above. All POCUS ocular examinations reviewed had been stored within the centralized image repository and were queried for concomitant ED visit ophthalmology consultation via electronic health record database query. As a second measure, the ultrasound images were also reviewed in QPath. During the chart review, the results of the ophthalmologist-performed fundoscopic examination including detection of papilledema and grading of the papilledema (if applicable) were recorded against the physician-measured ONSD. ONSD measurement greater than 5 mm on ocular ultrasound was diagnosed as papilledema.

The Findings: A total of 206 individuals (51% female, 49% male) were included in the analysis for a total of 212 considered encounters performed by 55 unique resident physician operators ranging from PGY1–PGY4. Of those 212 encounters included in the final analysis, 28 (13.2%) resulted in a diagnosis of papilledema by funduscopic examination for at least 1 eye. There was no significant difference in sex amoung the encounters (female: 53.3%, male: 46.7%), but there was a statistically significant difference in sex between encounters with (female: 78.6%; male: 21.4%) and without (female: 49.5%; male: 50.5%) papilledema. There was also a significant difference in age between individuals with (median: 37.0 years, interquartile range: 27.0-46.5 years) and without (median: 48.0 years, interquartile range: 33.0-60.0 years) fundoscopic- diagnosed papilledema. A total of 372 instances of ophthalmologist fundoscopy and emergency physician-performed ONSD measurement were used to calculate the sensitivity and specificity as well as positive and negative predictive value of the emergency physicians’ ocular ultrasound evaluation for papilledema. Sensitivity for the ocular ultrasound (cutoff = 5.0 mm) performed by emergency physicians to diagnose papilledema was calculated to be 46.9%, and specificity was 87.0%. The PPV was 35.4%, and the NPV was 91.5%. 

The Takeaway: Compared to the standard of care of formal ophthalmology evaluation via fundoscopy, the ocular ultrasound performed by novice emergency physicians has low sensitivity and high specificity, showing that although it may be a useful tool for ruling in a diagnosis of papilledema, it is not sufficiently sensitive to rule out papilledema. For now, ocular ultrasound cannot be used as a screening tool for evaluation of increased intracranial pressure in the emergency department, and if the physician is concerned for papilledema, the patient should undergo formal ophthalmology evaluation. 

Randomized, Controlled Trial of Immediate Versus Delayed Goal-Directed Ultrasound To Identify The Cause of Nontraumatic Hypotension In Emergency Department Patients.

Danielle Parker, DO | EM PGY3

 The Article: Randomized, Controlled Trial of Immediate Versus Delayed Goal-Directed Ultrasound To Identify The Cause of Nontraumatic Hypotension In Emergency Department Patients. Jones et al. (2004), Crit Care Med Vol 32, No. 8               

The Idea: To determine if the use of physician-performed immediate vs. delayed goal-directed ultrasound protocol in the management of non-traumatic, symptomatic, hypotensive ER patients led to increased diagnosis accuracy

The Study: This was a randomized, control trial performed between July 2002 and September 2003 in the emergency department of Carolinas Medical Center which is an urban tertiary care center with over 100,000 patient visits per year. 184 patients were randomized into two groups: group 1 received immediate (time 0) goal-directed ultrasound in addition to standard care (history, physical, lab work, x ray); group 2 received a delayed goal-directed ultrasound 15 mins after receiving standard care.

Inclusion criteria included: nontrauma emergency department patients age of 17 or older; initial vitals consistent with shock (systolic blood pressure < 100 mmHg systolic or shock index >1) and agreement of two independent observers for at least one sign and one symptom of shock (inadequate tissue perfusion). Once a patient was deemed to be eligible for the study, attending ER physicians and third year ER residents received a random numbered, sealed envelope that contained the randomization assignment (group 1 (immediate US) or 2 (delayed US)) and data collection sheets. Both groups of patients received standard history and physical, lab work, blood gases and xrays. Group 1 received an immediate ultrasound (at time 0) which included the following views: subcostal to assess for RV diastolic collapse, IVC to assess intravascular volume status, parasternal long axis to assess LV function and pericardial effusion, apical 4 chamber to compare ventricle size, hepatorenal recess to assess for free intraperitoneal fluid, pelvis to assess for intraperitoneal fluid and aorta to assess for AAA. Goal-directed US was performed by either a board certified ER attending or a third year ER resident. At time 15 mins examining physicians in both groups completed a data sheet with their differential diagnoses based on the information they had acquired. Group 2 participants then received the same goal-directed US after 15 minutes (time = 15). At 30 mins both groups completed the data sheets again.

The Findings:

Outcomes included the number of viable diagnoses at 15 mins and the rank of their likelihood of occurrence at both 15 and 30 mins. At 15 minutes, group 1 had a median of 4 differential diagnoses while group 2 had a median of 9 (median difference= 5; 95% CI, 4 - 6; Mann-Whitney U test, p < .0001). At 30 minutes group 1 still had a median of 4 diagnoses while group 2 had a revised median of 3 diagnoses (Mann-Whitney U test, p < .4463). At time 15 mins physicians in group one indicated the correct diagnosis in 80% (95% CI, 70 – 87%) of their patients while group 2 was only 50% (95% CI, 40-60%). There was no difference in mortality between patients in group 1 and 2.

The Takeaway:

It was determined that the incorporation of goal-directed ultrasound in the evaluation of nontraumatic, symptomatic, undifferentiated hypotension helped physicians determine fewer viable diagnoses and causes. Goal-directed ultrasound results in a more accurate impression of patients and final diagnosis.

Quantifying systemic congestion with Point-Of-Care ultrasound: development of the venous excess ultrasound grading system

Amy Han, DO | EM PGY3

The Article: Quantifying Systemic Congestion With Point-of-Care Ultrasound: Development of the Venous Excess Ultrasound Grading System. Beaubien-Souligny et al. (2020). The Ultrasound Journal. 12(1):16.

The Idea:

To develop several grading system prototypes using POCUS and to determine their respective ability to predict acute kidney injury (AKI) after cardiac surgery.

The Study:

This was a prospective cohort study at a tertiary cardiac surgery center from August 2016 to July 2017, of non-critically ill patients 18 years and older undergoing cardiac surgery with the use of cardiopulmonary bypass. All patients underwent POCUS assessment the day before surgery, at ICU admission after surgery, and daily from postoperative days 1 to 3. Each US assessment consisted of hepatic vein Doppler, portal vein Doppler, intra-renal venous Doppler, and inferior vena cava US.

A multidisciplinary team developed five venous excess ultrasound (VExUS) grading system prototypes based on the severity of venous ultrasonographic markers. For hepatic vein Doppler, a systolic phase of lesser amplitude than the diastolic phase but toward the liver was considered mild; the presence of a reversed systolic phase (toward the heart) was considered severe. For portal vein Doppler, a pulsatile fraction (PF, variation in velocities during cardiac cycle) of 30-49% was considered mild; a PF>50% was considered severe. For intra-renal venous Doppler, a discontinuous pattern with a systolic and a diastolic phase was considered mild; a discontinuous pattern with only a diastolic phase was considered severe. The prototype grading systems were named VExUS “A” through “E”. The VExUS score was determined for all patients and for all timepoints.

The Findings:

A total of 705 US assessments from 145 participants were analyzed. The association between each score and AKI was assessed using time-dependent Cox models. In post-operative period, severe congestion (Grade 3) defined by the VExUS C grading system was the most strongly associated with AKI (HR 3.69, CI 1.65-8.24, p=0.001). This association remained significant after adjustment for baseline risk for AKI and vasopressor/inotropic support (HR 2.82, CI 1.21-6.55, p=0.02). At time of ICU admission after surgery, severe congestion (Grade 3) defined by the VExUS C grading system had high specificity (96% CI 89-99%) but low sensitivity (27% CI 15-41%) for development of subsequent AKI, resulting in a moderate positive likelihood ratio of 6.37 (CI 2.19-18.5) which outperformed the use of common central venous pressure cut-offs. In comparison, IVC dilatation alone had poor diagnostic performance (specificity 41%), suggesting that this commonly used US assessment is not sufficient to detect clinically significant congestion.

The Takeaway:

Severe congestion, defined as the presence of severe flow abnormalities in multiple Doppler patterns with a dilated IVC (VExUS grading system C - Grade 3), offered the strongest association with the development of subsequent AKI. POCUS may enable the clinician to detect clinically significant systemic venous hypertension.

Accuracy of Posterior Approach Ultrasound for Shoulder Dislocation

Kyle Forte, DO | EM/FM PGY3

The Article:

Pilot Study to Determine Accuracy of Posterior Approach Ultrasound for Shoulder Dislocation by Novice Sonographers. Lahham et al. (2016) Western Journal of Emergency Medicine. 17(3): 377-382. 

The Idea: 

To explore the efficacy of diagnosing shoulder dislocation using a single view posterior approach point of care ultrasound (POCUS) and to determine a measured distance that helps to distinguish a normal versus dislocated shoulder.

 The Study:

This was a prospective, observation study conducted in a single emergency department which aimed at using a single view POCUS for diagnosing shoulder dislocation. The study enrolled 84 adult (>18 years of age) patients who presented to the emergency department for acute, traumatic shoulder pain whom the treating physician ordered plain radiographs of the shoulder. POCUS was performed by novice sonographers who were blinded to the results of the radiographs. The novice sonographers used a single view posterior approach with the linear transducer placed transversely to look at the relative positioning of the glenoid fossa and the humeral head. Once structures were identified, horizontal lines were then placed tangent to the posterior aspect of the humeral head and the glenoid fossa. The distance between the two lines was measured (in cm) and was defined as the Glenohumeral Separation Distance (GhSD). The GhSD was given a positive or negative value based on the location of the glenoid rim relative to the humeral head. A positive GhSD indicated a posterior position of the glenoid rim relative to the humeral head and a negative GhSD indicated an anterior position of the glenoid rim relative to the humeral head. The GhSD was the primary measurement of interest and was used to correlate with the presence or absence of a shoulder dislocation seen with conventional radiography.

The Findings:

Of the 84 patients enrolled in the study 19 patients (22.6%) had radiography confirmed dislocations, all of which were anterior. Confirmed diagnosis of shoulder dislocations all had GhSD < 0 cm. Confirmed diagnosis of non dislocations all had GhSD > 0 cm. Based on this data a GhSD = 0 cm was chosen as cutoff value for diagnosis of anterior shoulder dislocation. Their derived POCUS demonstrated a 100% sensitivity, 100% specificity, PPV of 100% and NPV of 100% only in the diagnosis of anterior shoulder dislocations.

The Takeaway:

Overall this study demonstrated that even a novice sonographer can use a posterior transverse approach with POCUS to obtain a GhSD measurement to make a diagnosis of an anterior shoulder dislocation with high sensitivity and specificity. More research is needed to validate the GhSD measurement so a standard definition of sonographic shoulder dislocation can be established. If the measurement is validated, POCUS could help to reduce a potential delay in diagnosis and treatment. Further studies would be needed to determine if this measurement could be used to help prevent a delay in definitely treatment once shoulder reduction has taken place.

A Doppler Echocardiographic Pulmonary Flow Marker of Massive or Submassive Acute Pulmonary Embolus

Jessica A. Schumann | EM/IM PGY-3

The Article:

A Doppler Echocardiographic Pulmonary Flow Marker of Massive or Submassive Acute Pulmonary Embolus. Afonso et al. (2019). Journal of the American Society of Echocardiography. 32(7): 799-806.

The Idea:

To explore the clinical utility of early systolic notching (ESN) of the right ventricular outflow tract (RVOT) pulsed-wave Doppler envelope in the detection of massive pulmonary embolism (MPE) or submassive pulmonary embolism (SMPE)

The Study:

Retrospective study at Wayne State University where 277 (187 with PE, 90 control subjects without PE) patients without known pulmonary hypertension, who underwent contrast computed tomographic angiography (CTA) for suspected pulmonary embolism (PE) and underwent transthoracic echocardiography within 48 hours were studied. Patients with suboptimal pulsed-wave Doppler signals across the RVOT, more than moderate valvular disease, known history of PE, established chronic thromboembolic pulmonary hypertension, and preexisting pulmonary hypertension were excluded from the study.

The authors also evaluated other echocardiographic parameters, including McConnell’s sign and 60/60 sign.

Doppler interrogation of the RVOT was performed in the parasternal short-axis view at the level of the aortic valve or from the subcostal short-axis view with sample volume placed approximately 0.5 cm proximal to pulmonic valve.

• Early Systolic Notching: Early systolic notching pattern (spike and dome morphology) Doppler envelope exhibits a narrow peaked initial wave (spike) with early deceleration of the RVOT envelope producing a sharp notch within the first half of systole (notch location within initial 50% of ejection, estimated with caliper tool) followed by a second Doppler wave (dome) that was more curvilinear in appearance.

• Midsystolic Notching: Midsystolic notching is defined as a distinct notch falling within the second half of the systolic ejection period or, if the nadir occurred closer to the end of ejection, dividing the flow profile into two distinct peaks

The Findings:

Two authors blinded to the PE diagnosis evaluated 277 patients’ echocardiograms. Of these patients, 187 patients had a PE diagnosed on CTA within 48 hours of the echocardiogram. There was good interobserver agreement (96.7%).

In patients with massive pulmonary embolus or submassive pulmonary embolus, early systolic notching was observed in 92% of patients and midsystolic notching was observed in 1% of these patients.

In patients with subsegmental pulmonary embolus, early systolic notching was observed in 2% of patients and midsystolic notching was observed in 16% of patients.

In the control group of 90 patients, no systolic notching was observed.

Early systolic notching pattern for MPE and SMPE was shown to have good to excellent predictive ability: 92% sensitive and 99% specific. ESN had a positive predictive value of 96% and a negative predictive value of 96%. This is superior predictive ability when compared to McConnell’s sign, which yielded a sensitivity of 52% in this study.

The Takeaway:

ESN reliably identified patients with MPE and SMPE, but it did not identify those with subsegmental PE. ESN demonstrated superior predictive value with a high negative predictive value. Echocardiography should not be viewed as the primary screening test or gatekeeper for CTA in the diagnosis of acute PE. Prospective studies are required in broader populations, and the findings will need validated. In the future, echocardiography may offer a more cost-effective screening tool when compared to CTA

Integrating Lung Ultrasound with Clinical Assessment to Improve Diagnosis of Acute Decompensated Heart Failure in Dyspneic Patients.

Matt Olson, DO | EMIM PGY3

The Article:

Lung ultrasound integrated with clinical assessment for the diagnosis of acute decompensated heart failure in the emergency department: a randomized control trial. Pivetta et al. (2018) European Journal of Heart Failure. 21, 754-766

The Idea:

To determine if using Lung ultrasound (LUS), in addition to clinical assessment, for patients with acute dyspnea can aid in the diagnosis of acute decompensated heart failure (ADHF).

The Study:

This was a randomized control trial that was conducted in two emergency departments from January 2014 to March 2015 on patients with acute dyspnea. 518 patients were enrolled in the study and randomized into one of two arms, the lung ultrasound arm and the CXR/Nt-proBNP arm. Every patient started with an initial clinical evaluation including history and physical exam. After the clinical exam the physician was asked to indicate a presumptive cause of the dyspnea. Afterwards the patients were separated into their arm (lung ultrasound vs. CXR/Nt-proBNP). Lung ultrasound was performed at bedside by the clinician with a curvilinear probe in eight zones looking for 3 or more B-lines to indicate a positive exam. After the lung ultrasound or CXR/Nt-proBNP a new presumptive diagnosis was recorded by the provider. Afterwards a CXR and Nt-proBNP were conducted on the lung ultrasound group. After hospital discharge two expert intensivists/emergency physicians (blinded to LUS results) reviewed the medical record and determined if the patient fit the diagnosis/definition of acute decompensated heart failure (based on European Society of Cardiology). 

The Findings:

The study found that the accuracy of clinical evaluation alone in the identification of acute decompensated heart failure was not significantly different in the groups. It also showed that combining CXR/Nt-proBNP with clinical evaluation was not statistically significant for sensitivity or specificity however the combined group with lung ultrasound was statistically significant. The lung ultrasound group also was showed to have a higher net reclassification improvement verses CXR/Nt-proBNP (8.9% vs. 4.5% for ADHF and non ADHF respectively). The median time needed to formulate the diagnostic hypothesis (measured from when the first diagnostic hypothesis was recorded to when the integrated diagnosis taking test results into account) was 104.5min in the CXR/Nt-proBNP group vs. 5min in the lung ultrasound group. The lung ultrasound arm was shown to be more sensitive (84.7 vs. 81.0), more specific (91.0 vs. 88.8) and had a higher positive predictive value (89.7 vs. 81.8) in the clinical evaluation along with the integrated evaluation. 

The Takeaway:

Overall this study demonstrated that in adult patients presenting to the emergency department with acute dyspnea, a diagnostic protocol based on integration of lung ultrasound and clinical assessment is more accurate than currently recommended CXR/NT-proBNP. Lung ultrasound can increase sensitivity and specificity of diagnosing acute decompensated heart failure. It can also improve time to diagnosis of acute decompensated heart failure when compared to only using CXR/NT-proBNP. 

Accuracy of early RUSH exam for diagnosis of shock etiology in critically ill patients

Robert Cameron Sooby, DO| EM PGY3

The Article:

Accuracy of early rapid ultrasound in shock (RUSH) examination performed by emergency physician for diagnosis of shock etiology in critically ill patients. Ghane et al. (2015). Journal of Emergencies, Trauma, and Shock. 8(1): 5–10.

 The Idea:

To determine the accuracy of early RUSH examination in predicting shock type in critically ill patients, and thus allowing for earlier identification of shock etiology and initiation of shock-specific treatments.

The Study:

This was a prospective study performed between April 2013 and October 2013. A total of 52 patients in shock state (defined as SBP < 100 or shock index (HR/SBP) > 1) were enrolled. Excluded were patients with a clear cause for shock (external hemorrhage, active GI bleeding, etc.). Early bedside RUSH was performed on all patients by a single board-certified ED physician, and all patients received standard of care without delay. All patients were followed to document their final diagnosis. Of note, subsequent physicians were not blinded to results of RUSH examination. A one-page checklist was designed incorporating the main components of the RUSH exam, which included evaluation of heart, IVC, thoracic and abdominal compartments, and large vessels. Five subtypes were defined for shock: hypovolemic, distributive, cardiogenic, obstructive and mixed shock. Agreement (Kappa index) of initial impression provided by RUSH with final diagnosis, and also sensitivity, specificity, PPV, and NPV of RUSH for diagnosis of each shock type were calculated.

The Findings:

The mean duration for exam (patient's arrival till RUSH conclusion) was 20 minutes (range, 10-25 minutes). The most frequent types of shock were cardiogenic shock (12 patients, 23.1%) and mixed shock (10 patients, 19.2%). Eight patients had hypovolemic, eight distributive, and seven obstructive type of shock. Seven cases (13.5%) died before the precise cause of shock could be determined and was classified as “not defined etiology”. Kappa index for general agreement between shock type using RUSH protocol and final diagnosis was 0.70 (P value = 0.000), reflecting acceptable general agreement. For hypovolemic shock, RUSH showed excellent sensitivity and good specificity (100% and 94.6%, respectively). NPV and PPV were 94.6% and 80%, respectively. In hypovolemic patients, RUSH protocol showed 86% agreement with final diagnosis (P value < 0.001). For cardiogenic shock, RUSH showed good sensitivity (91.7%) and specificity (97.0%). RUSH showed 89% agreement (P value < 0.001) with final diagnosis. PPV and NPV were 91.7 and 97.0%, respectively. For obstructive shock, RUSH showed excellent sensitivity (100%) and good specificity (97.0%). It had the largest agreement with final diagnosis (92%, P value < 0.001). PPV and NPV were 87.5% and 100%, respectively. For distributive shock, RUSH had excellent specificity (100%) but low sensitivity (75%). It had an acceptable agreement with final diagnosis (83%, P value < 0.001). PPV and NPV were 100% and 94.9%, respectively. For mixed etiology shock, RUSH had excellent specificity (100%) but had the lowest sensitivity (70%). It also had the lowest agreement (74%, P value < 0.001) with final diagnosis. PPV and NPV were 100% and 92.1%, respectively.

The Takeaway:

When performed by experienced clinicians, RUSH can rapidly and accurately diagnose shock type in the undifferentiated hypotensive patient. This in turn allows the clinician to initiate goal-directed therapies earlier and with greater confidence. Due to its inherently dynamic physiologic nature, RUSH was less sensitive in diagnosing distributive shock. Further studies utilizing more physicians and a larger sample size will need to be conducted to assess the shortcomings of this particular study.

Isolated Deep Venous Thrombosis: Implications for 2-Point Compression Ultrasonography of the Lower Extremity

Onyinye Okorji | DO EM/IM PGY3

The Article

Isolated Deep Venous Thrombosis: Implications for 2-Point Compression Ultrasonography of the Lower Extremity Srikar Adhikari, MD, MS; Wes Zeger, DO; Christopher Thom, MD; J. Matthew Fields, MD

The Idea

Should emergency physicians use an extended proximal compression ultrasonographic technique to assess for isolated thrombi in locations beyond the common femoral and popliteal veins? The objective of this study is to determine the prevalence and distribution of deep venous thrombi isolated to lower-extremity veins other than the common femoral and popliteal veins in emergency department (ED) patients with clinically suspected deep venous thrombosis.

The Study

This was a retrospective study of all patients who received a lower-extremity venous duplex ultrasonographic examination in the ED during a 6-year period.

Inclusion criteria: all adult patients (> 19 years) who received a comprehensive lower extremity venous duplex ultrasonographic examination in the ED for evaluation of deep venous thrombosis were included in this study. Total of 2,451 patients (women 1,595; men 856). The ultrasonographic examinations were performed by vascular surgery division sonographers.

The Findings

Superficial vein thrombosis was detected in 96 cases (3.9%; 95% CI 3.1% to 4.7%). Deep venous thrombosis was detected in 362 patients (14.7%; 95% CI 13.3% to 16.1%). Thrombus confined to the common femoral vein alone was found in 5 of 362 cases (1.4%; 95% CI 0.2% to 2.6%). Isolated femoral vein thrombus was identified in 20 of 362 patients (5.5%; 95% CI 3.2% to 7.9%). Isolated deep femoral vein thrombus was found in 3 of 362 cases (0.8%; 95% CI –0.1% to 1.8%). Thrombus in the popliteal vein alone was identified in 53 of 362 cases (14.6%; 95% CI 11% to 18.2%).

The Takeaway

 In this study, 6.3% of ED patients with suspected deep venous thrombosis had isolated thrombi in proximal veins other than common femoral and popliteal vein. Exclusion of the femoral vein imaging with 2-point compression ultrasonography would have resulted in missing a significant number of isolated lower-extremity thrombi. The results of this study support the use of extended point-of-care compression ultrasonographic technique evaluating the common femoral vein, femoral vein, proximal deep femoral vein, and popliteal vein. It was recommended to perform compression of the proximal deep femoral vein because there is a small incidence (<1%) of isolated thrombus in this region. It requires only translation of the probe down from the common femoral vein over the femoral and proximal deep femoral veins to assess for compressibility. The use of extended point-of-care compression ultrasonographic technique may decrease D-dimer testing and therefore decrease the incidence of false-positive D-dimer test results that would require whole-leg, color-coded, duplex, lower extremity ultrasonography.

Ultrasound for Evaluation of Peritonsillar Abscess

TaReva Warrick-Stone, DO | FMEM PGY3

The Article:

Impact of Transcervical Ultrasound for the Diagnosis of Pediatric Peritonsillar Abscesses on Emergency Department Performance Measures. Zhao et al. (2020). J Ultrasound Med. 39: 715-720.

The Idea:

To determine the effects of adopting transcervical US as the initial imaging study to diagnose pediatric peritonsillar abscesses on median ED length of stay as an indicator of performance.

The Study: 

A retrospective cohort study of all ED patients who had a CT or US scan performed on the neck region for suspected peritonsillar abscess at one freestanding tertiary care children’s hospital between Jan 2009 - Apr 2017. The institution adopted a protocol to use transcervical US first for the evaluation of PTAs in May 2013. The ED length of stay before and after implementation of the US-first approach were extracted from the EMR, along with imaging study performed and presence or absence of PTA on imaging. For patients with CT scans, they estimated the radiation dose, and for all patients, they estimated the amount billed and the amount reimbursed. As a balancing measure, they determined whether there were return patient visits within 2 weeks of the index ED visit related to head and neck infections or pain. All US studies were performed in the radiology department by board-certified sonographers trained in the transcervical technique. Images were reviewed and interpreted by pediatric radiologists. The CT studies were done with contrast and were obtained with a 64-slice system either in the ED or in the radiology department, and images were interpreted by pediatric radiologists. All abnormal findings were discussed between the ED physician and an ENT consultant regarding surgical or medical management.

The Findings:

Of the 962 ED patients who had neck imaging studies, 387 were included in the study; 286 were evaluated with US and 101 were evaluated with CT. None of the patients who had US scans required a subsequent CT scan. There were similar rates of positive results for CT (36, 35.6%) and US (99, 34.6%). The mean length of stay was significantly less for patients who had US (347 +/- 145 minutes) compared to CT (426 +/- 171 minutes), with an absolute difference of 79 minutes (95% CI, 44, 113 minutes). The difference was more pronounced in patients with negative results. Patients with negative CT results had a mean LOS of 115 minutes longer than in the US group (95% CI, 70, 160 minutes). The difference between the groups for patients with positive results was 12 minutes (95% CI, –40, 63 minutes), which was not statistically significant. Patients who were evaluated by US scan did not have a statistically significant increased rate of return visits within 2 weeks, 8.0% compared to 5.9% (P = 0.66). The median effective radiation dose of a neck CT scan was estimated at 3.9 mSV compared to no radiation exposure for US. At the time of this study, the mean billed cost of a neck CT scan was $2846, and the hospital was reimbursed on average $1138. The mean billed cost of a transcervical US scan was $1208, and the hospital was reimbursed on average $483 for each study. After implementation of the protocol, significantly more neck US (6.5) were ordered per month than neck CT (2.1) prior to the protocol with a mean difference in studies of 4.4 per month (95% CI, 3.5, 5.4).

The Takeaway:

A transcervical US-first strategy for the evaluation of pediatric peritonsillar abscess is associated with an overall decrease in the ED length of stay, however, this difference was only true for patients who had negative study results as there was no difference in LOS for those patients who were found to have PTAs.

Abscess Incision and Drainage With or Without Ultrasonography: A Randomized Controlled Trial

Elise Patel, D.O. FM PGY-3

The Article: Gaspari, R., Sanseverino, A. and Gleeson, T., 2019. Abscess Incision and Drainage With or Without Ultrasonography: A Randomized Controlled Trial. Annals of Emergency Medicine, 73(1), pp.1-7.

The Idea: This prospective randomized control trial sought to evaluate whether the use of point-of-care ultrasound (POCUS) in conjunction with incision and drainage (I&D) would improve uncomplicated abscess treatment outcomes. The hypothesis was that using POCUS in I&D for uncomplicated abscess would decrease the failure-rate of treatment which was defined by the need for a second I&D procedure within the ten days following the initial procedure.

The Study: Over the course of two years, 125 patients presenting to an academic institution with uncomplicated abscess were enrolled in the study and randomly assigned to either physical exam alone (control group) or physical exam with the addition of POCUS (experimental group) prior to I&D. After loss to follow-up, the final sample size of patients was 107. The physicians performing the procedures were emergency medicine physicians (residents and attendings) who had comparable experience in performing incision and drainage and soft-tissue POCUS as evidenced by the number of procedures they had logged prior to participation in the study. The physical-exam-only group had the abscess measured either by area of fluctuance or area of induration if fluctuance was absent. If there was doubt of the presence of abscess, ultrasound was utilized to confirm the presence of abscess, but the details of the ultrasound were kept from the physician performing the incision and drainage. The POCUS arm was not standardized in terms of how POCUS was utilized in the treatment course. There were three treatment strategies:

1. Using POCUS prior to the I&D to visualize the abscess, but not using during or post-procedure,

2. Using POCUS dynamically: before, during, and post-procedure,

3. Using POCUS pre-procedure and post-procedure, but performing the I&D itself without POCUS.

The patients and physicians performing the initial encounter were not blinded to which treatment arm a patient was included within, but the research staff and physicians performing the follow-up exams were blinded. The individual physicians performing the I&Ds were given liberty to decide whether to place packing and prescribe antibiotics. The patients were re-evaluated in-person by a blinded doctor on post-op day two or three, and blinded research staff reached out to patients via telephone and asked a standardized list of questions on post-op day seven through fourteen.

The Findings:

The primary outcome evaluated was the need for repeat I&D with purulent drainage expressed at the ten-day mark which was considered a failure of therapy. The total failure rate of the patients enrolled in the study was 10.3% [5.7-17.6% 95% CI] which was comparable to the rate previously given in the literature per the authors of this article. The failure rate in the POCUS group was 3.7%, and the failure rate in the control group was 17%, and the difference between the groups was 13.3% [0.0-19.4%]. The odds ratio was statistically significant with an odds ratio for failure of therapy of 0.19 in the ultrasound group [CI 0.04-0.97]. The secondary outcomes evaluated were need for additional antibiotics and symptoms at follow-up. There was no statistical significance between the groups for either of these outcomes.

Critiques:

The randomized control study is the first of its kind trying to evaluate the efficacy of POCUS in the treatment of abscesses, and the researchers did an excellent job in explaining their process and the methods taken to blind the evaluation of the outcomes to researcher bias. They also selected uncomplicated abscess patients which helped to select a more controlled population and also prevent harm from delay of care in the case of unstable patients. The authors reported that the use of POCUS improved outcomes compared to I&D with physical exam alone, but the confidence interval included zero which means that it could have potentially not been a statistically significant difference. The odds ratio did however reveal statistically significant benefit in outcomes with the use of POCUS. The sample size was the minimum needed to power the study, so it seems that the small sample size may have affected the ability of the study to demonstrate statistical significance. The control group had more men and more IVDA users which may have influenced the results. The method of POCUS was not standardized which could also have impacted the results of the study. In order to have a study that can clearly demonstrate the benefits of POCUS in treating abscesses, there needs to be additional research done with a larger sample size and more standardization of the methods and the two patient groups.

The Takeaway: 

Utilization of POCUS in the performance of bedside I&D likely improves treatment outcomes, but further studies with larger sample sizes need to be performed to confirm these results.

A preliminary study on the ultrasonic manifestations of peripulmonary lesions of non-critical novel coronavirus pneumonia (COVID-19)

Andrew Lee, DO | EM PGY3

The Article: 

Huang, Yi, et al. “A Preliminary Study on the Ultrasonic Manifestations of Peripulmonary Lesions of Non-Critical Novel Coronavirus Pneumonia (COVID-19).” SSRN Electronic Journal, 2020, doi:10.21203/ssrn.3544750.

The Idea:

To observe the ultrasonic manifestations of peripulmonary lesions in non-critical COVID-19 so as to provide reference for clinical diagnosis and efficacy evaluation 

The Study:

A retrospective analysis of the color doppler ultrasound information of peripulmonary lesions in early and progressive COVID-19. Ultrasound findings of twenty patents (11 male, 9 female) who had the following criteria were involved in the analysis:

• history of travel in Wuhan, China or areas with COVID-19 transmission within 14 days of prior to onset of illness

• exposure to patients with fever or respiratory symptoms who were from Wuhan or other areas with COVID-19 transmission within 14 days prior to the onset of disease,

• Clusters or epidemiological associations with COVID-19 infections

• Fever

• Radiographic features of pneumonia with ground glass opacity or patchy consolidation in the lungs

• Normal or decreased WBC count

• Decreased lymphocyte count in the early stage of disease

• Positive nucleic acid of SARS-Cov-2 detected by real time fluorescence

• Highly homologous virus gene sequencing with SARS-Cov-2

Each lung was divided into six sonographic regions: an upper and lower anterior area, an upper and lower axillary area, and an upper and lower posterior area. The areas were scanned by two physicians, each with more than 5 years of ultrasound experience, with a linear array probe or with a convex array probe. They observed for:

• A smooth, continuous, or interrupted pleural line

• The distribution, number, and fusion of B lines in the peripulmonary area of both lungs

• The echo, location, shape and range of peripulmonary lesions

• The presence of absence of air bronchograms in the consolidation

• The presence of absence of blood flow in the consolidation

• The presence of absence of pleural effusion around the lesion

• The presence of absence of localized pleural thickening

The Findings:

Many of the sonographic manifestations seen with typical pneumonia were identified, such as interrupted pleural lines, B lines, air bronchograms, and subpleural consolidations. Peripulmonary lesions were mostly located in the posterior fields of both lungs. Multiple B lines under the pleural line were visible. Unique to COVID-19 patients, B lines could be discontinuous or continuous, however, they were more likely to be continuous, fixed and fused (waterfall sign) rather than discontinuous as is typically seen in cardiogenic pulmonary edema. Localized pleural thickening with a local pleural effusion around the subpleural lesion was identified. Also unique to COVID-19 patients, color doppler showed poor blood flow in the subpleural consolidation.

The Takeaway: 

Ultrasound can show typical findings associated with any pneumonia in COVID-19 pneumonia. However, if poor blood flow in the subpleural consolidation is found by doppler and B lines are fused, this may suggest atypical/COVID pneumonia. However, ultrasound is limited to evaluation of peripulmonary lesions, and cannot replace CT in evaluation of intrapulmonary and apical lesions.

Bedside Evaluation of Femoral Nerve Block Versus Parenteral Opioids in Hip Fractures

Jeff Holoman, D.O. | EM/FM PGY 3

The Article:

Beaudoin, Francesca L., et al. “A Comparison of Ultrasound-Guided Three-in-One Femoral Nerve Block Versus Parenteral Opioids Alone for Analgesia in Emergency Department Patients With Hip Fractures: A Randomized Controlled Trial.” Academic Emergency Medicine, vol. 20, no. 6, 2013, pp. 584–591., doi:10.1111/acem.12154.

The Idea:

To compare the efficacy of US guided three-in-one femoral nerve blocks to standard treatment with IV morphine for pain control in elderly patients with hip fractures in the Emergency Department.

The Study:

A blinded, randomized control clinical trial at Rhode Island Hospital which included all patients over the age of 55 with radiographic findings of a femoral neck fracture or intertrochanteric fracture. Identified patients were also neurovascular intact, in moderate to severe pain (numerical pain rating scale > 5), and were able to consent to the study. After consent, the patients were randomized using sequentially numbered cards in sealed envelopes to one of two groups: femoral nerve block plus morphine (FNB) or standard care, morphine alone + sham injection (SC). Each participant in the FNB group received an US-guided femoral nerve block performed by physicians who had prior experience performing the technique and underwent a 30-minute training session to standardize the approach. FNB procedures were standardized according to patient positioning, injections of 25mL of bupivacaine, as well as holding manual pressure post injection for 5 minutes, 1 cm below the injection site. Each patient in the SC group received a sham injection that was intended to blind the participant and the treating physician. Set up and procedure of the SC group was also standardized to entail a 3mL 0.9% injection of saline, given subcutaneously over 5 minutes. Following administration of the FNB or sham injection, it was then left to the physician caring for the patient to choose analgesia dosing and frequency for the remainder of their ED stay. To assess the primary goal of pain relief, a patient reported pain scoring system was used. The summed pain-intensity difference (SPID) was used over a 4 hour study period. Trained professionals then asked participants to report their pain using an 11 point numerical rating scale (NRS), 0 being “no pain,” up to 10 being “worst pain imaginable.” Repeat measurements were then taken at the 15 minute, 1, 2 and 4 hour periods after the study procedure was performed. A pain – intensity difference (PID) was calculated at each time point. The PID was calculated as the change from baseline NRS for each measurement in time for the two groups. Secondly, review of the dose and amount of opioids used were measured to assess if those in the FNB group received less opioids. This secondary efficient variable was the total amount of opioid received after the study procedure, while the patient was in the Emergency Department. Rescue analgesia and SPID measurements for each group were also tested and compared.

The Findings:

Sixty-four patients were screened for the study with 38 being enrolled, with two patients from each arm dropping out after randomization. Eighteen patients in each arm completed the study. There was no significant difference between treatment groups with respect to age, sex, fracture type and vital signs or length of stay in the ED. There was also no significant difference between pre-enrollment analgesia or baseline pain intensity. Of note, there was a significant decrease in pain intensity in the patients in the FNB group over time ( p < 0.01 ), whereas those in the SC did not have any change in pain reduction over time ( p = 0.882 ). The SPID over 4 hours was significant greater in the FNB group ( 11.0 vs. 4.0). In addition, a significantly higher proportion of individuals in the FNB group achieved as least 33% reduction in pain intensity over time, 33% SPID, (12 vs. 0). 1/3 of the patients in the SC group had a negative %SPID, indicating that they had increasing pain throughout the study period. Regarding the second measure of the study, opioid use, patients in the FNB group received far less than the SC group (0.0 to 6.0 mg vs. 0.0 to 21.0 mg). Five patients in the FNB group received rescue analgesia versus 14 patients in the SC group. There was no significant association between dose of rescue analgesia and %SPID in the FNB group (r=-.-7, r^2=0.005) and only a weak association in the SC group (r=0.20 , r^2=0.04). There were no differences in the adverse effects of hypotension, hypoxia, or nausea/vomiting.

The Takeaway:

Usage of bedside US guided femoral three-in-one nerve blocks seemingly provides superior pain relief in comparison to parenteral opioids alone and requires less rescue analgesia while in the Emergency Department.

Integration of transthoracic focused cardiac ultrasound in the diagnostic algorithm for suspected acute aortic syndromes

Lee McChesney | EM PGY3

The Article: 

Nazerian, Peiman, et al. “Integration of Transthoracic Focused Cardiac Ultrasound in the Diagnostic Algorithm for Suspected Acute Aortic Syndromes.” European Heart Journal, vol. 40, no. 24, 2019, pp. 1952–1960., doi:10.1093/eurheartj/ehz207.

The Idea:

To determine the feasibility and diagnostic accuracy of bedside emergency ultrasound in the management of ED patients presenting with acute dyspnea. 

The Study:

A prespecified subanalysis  of the ADvISED multicenter prospective study from 5 centers in 4 countries in which 839 patients with suspected acute aortic syndromes (AAS) had transthoracic focused cardiac ultrasound (FoCUS) to find either direct or indirect signs of AAS to assist in clinical judgement. Using the aortic dissection risk score (ADD-RS) to determine clinical probability of AAS, which the European Society of Cardiology endorses as the bedside tool to use in suspected AAS, patients can be defined as low or high probability. Those in high probability warrant a CTA/TOE and low probability need additional testing. FoCUS can quickly recognize those who need CTA/TOA despite low clinical probability and be used to safely rule-out those low risk patients with additional negative D-dimer testing. The aim of the study was to give additional validation to the algorithm endorsed by the ESC. Patients were included if AAS was included in the ED attending differential diagnoses and they were able to undergo FoCUS before any advanced cardiac imaging was performed. FoCUS was looking for direct and indirect signs of AAS. Direct signs looked for were intimal flap, intramural aortic hematoma or a penetrating aortic ulcer. Indirect signs included thoracic aorta dilatation greater than 4cm, pericardial effusion or tamponade, or aortic valve regurgitation.

The Findings:

A total of 864 patients were eligible and a total of 839 were included in the study after exclusion criteria. 170 patients had FoCUS performed by a cardiologist and 669 were performed by a non-cardiologist. Direct signs of AAS were found in 84 patients and any signs of AAS were found in 307 patients. Using FoCUS in addition to clinical assessment tool like ADD-RS, greatly increased the diagnostic accuracy of AAS. Using just the ADD-RS, a total of 671 were considered low probability of having AAS, but 67 patients had AAS. Using the tool, less than/equal to 1, with a negative FoCUS, the sensitivity to rule out AAS was 93.8%. D-Dimer testing was available in 812 of the patients, including 652 which were considered low probability. There was only false negative of 2 patients with AAS who had direct or indirect signs of AAS.

The Takeaway:

Making the clinical decision to obtain immediate CTA/TOE in stable patients in which ASS is considered, can be difficult and lead to misdiagnoses, wrong treatment choices, ED discharge and over-testing. In those patients with low probability of AAS, using US in conjunction with clinical assessment and D-Dimer testing, can provided a safe and effective way to make the decision regarding CTA/TOE. It can be inferred that in those patients with only indirect signs of AAS and a negative D-Dimer, CTA/TOE can be avoided by a case-by-case basis.

Transesophageal echocardiography use during cardiac arrest in the emergency department

Ali Elsaied, DO | EM PGY 3

The Article:

Teran, F., Dean, A. J., Centeno, C., Panebianco, N. L., Zeidan, A. J., Chan, W., & Abella, B. S. (2019). Evaluation of out-of-hospital cardiac arrest using transesophageal echocardiography in the emergency department. Resuscitation, 137, 140–147.

The Idea:

To determine the potential added benefit of utilizing transesophageal echocardiography in out-of-hospital cardiac arrest patients brought to the ED.

The Study:

A prospective observational study at an urban academic tertiary care center of all patients over 18 years old, not pregnant, found to be DNR, or had any visible evidence of trauma who presented to the ED either actively in cardiac arrest, or immediately post-ROSC. The emergency physicians performing the TEEs were trained extensively in its use prior to the study launch. A total of 33 out-of-hospital cardiac arrest patients were enrolled in the study. The emergency physicians performing the ultrasound utilized the real-time TEE images to provide the primary ED team with information that may be beneficial in guiding resuscitative efforts, such as so-called ‘Area of Maximal Compression’ or AMC, sonographic volume status, RV dilation, aortic dissection, and more detailed view of ventricular dysrhythmia, such as very fine VF. The study evaluated how often TEE in cardiac arrest provided additional clinical information which may alter resuscitative management in any way.

The Findings:

Of the 33 patients enrolled in the study, 21 arrived to the ED with ongoing CPR, and 12 arrived having already achieved ROSC, or achieved ROSC within the first five minutes of arriving to the ED. The mean time from patient arrival to the ED to TEE 12 minutes. In the cohort of patients enrolled in this study, 7 patients were found to be in PEA, 6 were in asystole, 2 in non-pulseless ventricular arrythmias, and 16 had ROSC at arrival. 2 of these patients re-arrested shortly after arrival to the ED. 2 of the 7 patients thought to be in PEA by conventional measures were found on TEE to actually be in pseudo-PE, and 3 cases of what was thought to be asystole were found to be in fine VF, all of which were defibrillated.

39% of patients in the study were found to have RV dilatation on TEE, however not all of these patients were thought to have PE by the primary team.

One case identified a mass within the heart, thought to be a thrombus, for which the patient received thrombolysis.

In 17 of the intra-arrest cases, Area of Maximal Compression was evaluated by TEE. Of these, only 8 were found to have compressions over the LV, whereas 9 were receiving compressions over the LVOT or aortic root. Hemodynamic parameters seemed to improve via ETCO2 monitoring and SBP/DBP measurements with correction of compression position.

The Takeaway:

TEE in cardiac arrest may provide emergency physicians with more clinical data, potentially altering management to improve outcomes in out-of-hospital cardiac arrest patients.

Review: Ultrasound-Guided LPs

Katelyn Hanson, DO

The Article: Millington S, Silva Restrepo M, Koenig S. Better With Ultrasound, Lumbar Puncture. CHEST 2018; 154(5):1223-1229

Overview: Lumbar puncture is a common procedure performed in both critical care and emergency medicine, and is typically associated with a high rate of success and favorable risk profile. However, as procedural ultrasound becomes more widely used in both specialties, it is reasonable to consider using ultrasound guidance to reduce the rate of failure and the risk of complications, especially in patients with difficult surface anatomy. 

Risks and Benefits: The authors of this review state that using ultrasound improves the rate of procedural success, reduces the number of required attempts, and decreases the incidence of specific complications that will be further described next. Ultrasound has been associated with a higher rate of first-pass success and lower risk of failure in all comers. They postulate that reducing the number of failed attempts and there for having fewer needle insertion attempts will lead to less incidence of postdural puncture headaches, back pain, spinal hematomas, epidural abscess and meningitis. They also suggest that injury to deep structures can be prevented by accurately quantifying the depth required to reach the subarachnoid space and avoiding excessive needle depth, and by accurately identifying the appropriate intervertebral spaces of L5-S1, L4-L5, or L3-L4.

Techniques:

#1 Identify Spinous Processes: It is recommended to use the curvilinear probe in the transverse plane with the probe marker position to the left of the screen. The first step is to identify the midline; it is recommended to start with traditional surface land marking by locating the superior aspects of the iliac crests to find the L4 spinous process. In cases where the iliac crests cannot be easily palpated, the authors recommend starting just above the intergluteal crest. The spinous process will appear as a peaked hyperechoic structure with acoustic shadow that will obscure deeper structures. Once the spinous process is identified in the exact middle of the screen, this location should be marked at the transducer midpoint with a skin pen to delineate the patient’s midline. The probe can then be moved cranially and caudally to identify neighboring spinous processes, and these should be marked with a skin pen as well, providing a map of L5, L4, and L3 spinous processes. Between the individual spinous processes will be the interspinous space, in which the hyperechoic spinous process will start to disappear and the hyperechoic articular processes will appear laterally, which is often referred to as the “bat sign.” The location of these articular processes can also be marked with a skin pen, and then a line between these landmarks is made, as well as a line between the superior and inferior spinous processes; the intersection between these two lines may represent the optimal site for needle insertion.

#2 Identify Intervertebral Levels: It is recommended to use the curvilinear probe in the sagittal plane with the probe marker position to the left of the screen. The first step is to identify the midline; see technique one for this part of the procedure. One the spinous processes have been located, the probe is moved caudally to identify the sacrum, which is seen as a roughly horizontal hyperechoic line. Once the sacrum is identified, the probe is moved cranially, and the first spinous process identified will be L5, with the space caudal to it the L5-S1 interspinous space. The process should be repeated for L4 and the L4-L5 interspinous space, and then center the L4-L5 interspace on the ultrasound screen and draw a line across this space with a skin marker. A line between the L4 and L5 spinous processes is also made, and the intersection between these two lines may represent the optimal site for needle insertion. 

In obese patients the spinous processes can be difficult to see from a midline approach. In these patients a paramedian approach can be used, where the procedure begins at the midline and then the probe is moved laterally 2-3cm until a hyperechoic saw-like pattern is seen, which would represent the articular processes. The probe is then moved caudally as described above to identify the sacrum, and then the specific L5 and L4 articular processes can be identified. The probe is then angled toward the midline to identify the lamina and L5-S1 and L4-L5 interlaminar spaces. Again, a line can be drawn horizontally across the interlaminar space, and then a line can be drawn from the 

#3 Estimate Required Depth for Needle Insertion: Using the paramedian approach described above in technique two, with the transducer in the sagittal plane, identify the posterior complex, which includes the ligamentum flavum, epidural space, and posterior dura. This complex will appear as a hyperechoic linear structure just deep to the lamina, and once identified its distance from the skin surface can be measured. The procedure can also be performed in the transverse plane from technique one, by identifying the desired spinous process and then moving the probe cranially or caudally to visualized the intervertebral space; the posterior complex can then be seen just deep to the lamina and its distance from the skin again measured; this value can be compared to the value obtained from the sagittal approach for a better estimate.

#4 Perform an Ultrasound-Assisted LP: Dynamic ultrasound guidance during the procedure is not recommended as it would require the operator to hold the transducer in their off hand during needle insertion, which would make the procedure unnecessarily complicated. After performing a thorough pre-procedural scan, set the set the probe aside and perform the procedure. 

Discussion: Point of care ultrasound has become an integral part of both emergency and critical care medicine. There are many procedures into which incorporating the use of ultrasound has already become the standard of care, and although this is not currently the case for performing lumbar punctures, it stands to reason that using ultrasound to better identify landmarks of the spine could improve patient outcomes, and thus should be considered a useful skill to learn to incorporate into regular practice. For more information, images corresponding to the procedures described above, and videos, see the original article cited above.

FOCUS exam in the detection of Pulmonary Embolism

Zachary Messina, DO | EM/IM PGY3

The Article:

Daley et al. Increased Sensitivity of FOCUS for PE in ED Patients with Abnormal Vitals. Academic Emergency Medicine. November 2019. Vol 26 (11). 1212-1220.

The Idea:

To determine the sensitivity and specificity of the FOCUS exam as well as each component of the focused cardiac ultrasound (FOCUS) in two subsets of patients with abnormal vital signs.

The Study:

This study is a prospective, blinded, observational multicenter cohort study of two subsets of patients. The study was performed at six academic emergency rooms and involved seven ultrasound-fellowship-trained emergency attendings, three PGY-3 emergency room residents, as well as three third year medical students. The enrollment of the study was determined by a power calculation in place of a timeframe. Patients were placed in one of two groups, either the primary grouping which had a requirement of heart rate of greater than 100 and/or hypotension with systolic blood pressure less than 90 mmHg, or a subgroup which required only heart rate to be greater than 110 beats per minute. All patients were 18 years of age or older and all patients underwent computed tomography with angiography (CTA) of the chest. Prisoners, wards of the state, non-English speaking patients, and those where investigators were not able to obtain any echocardiographic data due to technical challenges were excluded. The goal was to have sonographers perform FOCUS prior to CTA; however, if FOCUS was performed after CTA the sonographers were blinded to the results of the CTA. All personnel in the study underwent standardized training consisting of a brief video and 1-hour didactic session. Two of the three residents also underwent an additional didactic session; the third already had prior experience in collecting ultrasounds. The three medical students underwent a 1-hour didactic session and 1-hour hands-on training session by the third resident as well. The medical students were required to perform 20 FOCUS exams prior to the study initiation to ensure competency. The FOCUS exam consisted of the parasternal long axis, parasternal short axis, apical four chamber, and subxyphoid views with a measurement of TAPSE, visual inspection of right ventricular enlargement, septal flattening, presence of tricuspid regurgitation on color Doppler, or monitoring for McConnell’s sign. If any of these components were present, the FOCUS exam was positive, if all components were absent the FOCUS was negative. TAPSE in this study was defined as <2.0cm instead of the conventional <1.7cm to increase sensitivity at the loss of specificity. Finally, inter-rater reliability was also tested as the site principal investigator by their own review in 104 of 136 patients in the right ventricular components in comparison to the sonographer’s interpretation.

The Findings:

First, 143 patient’s underwent CTA during the study, but seven were excluded. Three were due to technically difficult FOCUS exams, and only four were due to non-English speaking language barrier. There were 136 patients enrolled during the study, 37 had a pulmonary embolism on CTA. Of these 37 patients, six were hypotensive, 28 were normotensive with at least one right ventricular component identified, and three were normotensive without any component identified. In the comparison of FOCUS versus CTA in patients who had a PE, the following data apply. In the primary group of patients (n = 136), the sensitivity of FOCUS was 92% (95% CI = 78-98%). Of the right ventricular components, TAPSE of <2.0cm was the most sensitive at 88% (95% CI = 72-97%), and in comparison the TAPSE value of <1.7cm was at 67% (95% CI = 48-82%). The other components ranged from a sensitivity of 35% to 51%. The overall specificity of FOCUS was 64% (95% CI = 53-73%), with the McConnell’s sign component being most specific at 99% (95% CI = 94-100%). The other components ranged from 64% to 93% in specificity. 

In the subgroup of patients with a heart rate of >110 (n = 98), the sensitivity of FOCUS for PE was 100% (95% CI = 88-100%), with the most sensitive component being TAPSE of <2.0cm, which was 93% sensitive (95% CI = 75-99%). The sensitivity of TAPSE at <1.7cm was 77% (95% CI = 56-91%). The other components ranged in sensitivity from 36% to 57%. FOCUS specificity in this subgroup was 63% overall (95% CI = 51-74%), the most specific being the McConnell’s sign at 100% specificity (95% CI = 95-100%). The other components ranged from 63% to 93% in specificity. 

Finally, inter-rater reliability for whether the FOCUS exam was positive or negative by two separate sonographers was 1.0 (95% CI = 0.31 to 1.0). Of the individual components, TAPSE had a kappa statistic of 0.61 (95% CI = 0.31 to 1.0), septal flattening had 0.88 (95% CI = 0.69 to 1.0), right ventricular enlargement had 0.89 (95% CI = 0.7 to 1.0), McConnell’s sign had 0.89 (95% CI = 0.7 to 1.0), and tricuspid regurgitation was 0.81 (95% CI = 0.64 to 1.0). 

Limitations of this study:

From the study set-up, one of the three residents performing ultrasound was more experienced. To offset this, additional training was provided to the other residents in hopes this would bridge any gap in experience. In addition, the three medical students were all third year and inexperienced in ultrasound. While their data was also compiled into the resident data, there was concern for inaccuracy given inexperience. This was attempted to be compensated for in additional training and the performance of 20 FOCUS exams prior to the study initiation. These limitations may lead to the acceptance of incorrect data, however, this was demonstrated in terms of Kappa statistics.

In terms of data collection, nine patients had missing data for TAPSE, two for right ventricular enlargement, two for septal flattening, two for McConnell’s sign, and 60 for tricuspid regurgitation. There was also unintentional unblinding of two patients in the study to the sonographer. These limitations may primarily cause the unintentional underestimation of sensitivity or overestimation of specificity in the data collected. 

Finally, the study was created using a statistical power, which may cause bias, however, the power was meant to limit the width of sensitivity to no greater than 20%. Selection bias may also confound these data in terms of the exclusion of patients; however, the number of patients excluded was kept to a minimum.

The Takeaway:

The FOCUS exam in patients with abnormal vital signs may help to significantly lower the likelihood of pulmonary embolism in most patients who are suspected of having a pulmonary embolism. This was especially true in patients with a heart rate of >110 beats per minute. Further study with an unpowered cohort is needed to determine of FOCUS can exclude PE.

Point of care Ultrasonography in the Diagnosis of Retinal Detachment, Vitreous Hemorrhage, and Vitreous Detachment in the Emergency Department

Danica Zold, DO MPH  | EM/FM PGY4

Article: 

Lahham S, Shniter I, Thompson M, et al. Point-of-Care Ultrasonography in the Diagnosis of Retinal Detachment, Vitreous Hemorrhage, and Vitreous Detachment in the Emergency Department. JAMA Network Open. Published online April 12, 20192(4):e192162. doi:10.1001/jamanetworkopen.2019.216

Objective:

To determine if Emergency medicine physicians can use POCUS for early and accurate identification of retinal detachment, vitreous hemorrhage, and vitreous detachment. 

Importance: 

Early detection and distinction among these 3 common ocular diagnoses, helps lead to proper disposition of patients, faster treatment and therefore prevention of potential permanent vision loss. 

Study:

A prospective, observational, multicenter, diagnostic study was performed across 2 academic and 2 county EDs in southern CA from Feb 2016- April 2018. The study enrolled a total of 225 patients with ocular symptoms and concern for retinal detachment, vitreous detachment or vitreous hemorrhage (blurry vision, vision loss, flashers, floaters); 18 years or older, without concern for ocular trauma or globe rupture. 

Ocular POCUS was performed by 75 Emergency medicine attendings, residents (PGY1-4) and PA’s of variable experience. They were given a 30 minute lecture and 30 minute hands on scanning lesson for the key US findings associated with each of the 3 diseases. 

Both the POCUS scanners and ophthalmologists were blind to one another’s findings, however physicians were not blind to the patient, their histories or other evident physical exam findings. Patients underwent ocular POCUS evaluation followed by ophthalmologic evaluation. Diagnoses were compared, with the definitive correct diagnosis determined by ophthalmologist evaluation.

Findings:

• Of the 4 sites involved in the study, the prevalence of ocular disease was found to 36%.

• Of the 225 patients, ophthalmologists diagnosed 20.8% with retinal detachment. Ocular POCUS correctly diagnosed 46 of these 47 patients, resulting in 96.9% sensitivity. POCUS correctly ruled out retinal detachment in 156 of the 176 cases, resulting in 88.1% specificity. 

• Ophthalmologists diagnosed 24% of patients with vitreous hemorrhage. Ocular POCUS diagnosed 46 of these 54 patients correctly, resulting in 81.9% sensitivity and 82.3% specificity. 

• Ophthalmologists diagnosed 15% of the patients with vitreous detachment. Although ocular POCUS was only able to identify 19 of the 34 patients correctly, leading to a 42.5% sensitivity, POCUS was able to rule out vitreous detachment in 178 of the 190 negative cases, resulting in 96.0% specificity. 

• Overall, POCUS has a >90% negative predictive value for all 3 of these ocular diseases. It appears however, that emergency medicine providers are best at ocular POCUS when diagnosing retinal detachment, with a 99% NPV, 64.5% PPV, and 90.6% accuracy.

Take Home Points:

• EM providers using ocular POCUS are better at successfully ruling in the disease then definitively ruling out.

• Ocular POCUS should not replace the role of an ophthalmologist, however EM practitioners can use POCUS as an adjunct to help accurately and reliably identify retinal detachment, vitreous hemorrhage, and vitreous detachment with statistical significance, expediting care and treatment for ocular disease in the Emergency room.

Pre-hospital lung ultrasound for cardiac heart failure and COPD: is it worthwhile?

Jacob Finkle, DO | EM PGY 4 

The Article:  “Pre-hospital lung ultrasound for cardiac heart failure and COPD: is it worthwhile?” Mirko Zanatta* , Piero Benato, Sigilfredo De Battisti, Concetta Pirozzi, Renato Ippolito and Vito Cianci. Zanatta et al. Crit Ultrasound J (2018) 

The Idea 

Ultrasound is a known and proven useful commodity in the Emergency Department. It’s ability to rapidly diagnose and decrease length of stay in the Emergency Department is proven. Pre-hospital US is considered one of the top five research priorities according to the opinion of consensus meeting of a European expert panel to identify which US examinations can be reliably transferred to the pre hospital setting. Lung US has the ability to rapidly identify the lung profile - the identification of, interstitial edema, pleural effusions and the diagnosis of pneumothorax. Given that a rapid two point technique is often sufficient to rule in or rule out lung pathology, the use of Lung US could be extremely useful in the pre-hospital setting. 

The Study 

The study was a case controlled study in the pre hospital emergency setting in Italy performed between January 2016 and December 2016. The area included a major emergency department with 35,000 visits and a minor emergency department with 6,000 visits. Each of these hospitals had an emergency physician led advanced life support ambulance. The larger hospital’s ambulance contained a portable US sonosite. The smaller hospital was the control. The inclusion criteria was severe dyspnea as prevalent symptom most likely caused by CHF or COPD exacerbation and pulse oximetry was required to be less than 90%. The exclusion criteria were other causes of respiratory failure and patients less than 18 years old. Lung US was performed after clinical exam with a rapid two point technique in the upper anterior and basal lateral areas. The type of lung profile was recorded as type A - dry lung or type B - wet lung and the presence was noted as well. An interstitial syndrome was defined by the presence of > 3 B lines between two ribs in two or more regions bilaterally. The convex probe was used using the same US device. Sometimes a linear probe was used. In hospital assessment included a PE, lab work, blood gas, CXR, US, cardiac ECHO, and IVC evaluation. The in-hospital lung US was blinded with respect to the pre-hospital one and was performed early upon arrival. The study aimed to evaluate the feasibility of pre-hosptial lung US and improvement of both pharmacological and oxygen administration in the ambulance and of the blood gases analysis at arrival to the ED. The hospitalization rate and time spent in the ED between the two groups was also evaluated. 

The Findings 

A total of 30 patients were recruited affected by non traumatic respiratory failure. There were 12 subjects whose respiratory failure were caused by CHF and 18 by COPD who underwent US management. This was compared to 30 other subjects managed without ultrasound. The characteristics of the groups were all similar in terms of age, gender, type of respiratory failure, and pulse ox value. Pre hospital lung US was accurate for identifying the correct lung profile. B lines had a high sensitivity (100%) and specificity (94.4%), a high PPV and NPV (92.3 and 100%) for CHF. Pleural effusions diagnosis was not as accurate as B lines for CHF - sensitivity 83%, specificity 58.3 %, PPV 75%, NPV 70%. The number of patients who received an appropriate pharmacological treatment was higher in the US group, especially in those who were diagnosed with lung group A - dry lung indicating non cardiogenic cause of respiratory failure. The mean dose of furosemide was significantly lower than those in the non US group and those diagnosed with lung group B - wet lung the mean dosage of furosemide was large than the US group. Steroid administration was comparable between A and B lung groups. CPAP was used more in patients with an A profile and employed more in the US group. Blood gases analysis was not significantly different between the groups, nor were there any significant differences between the other lab work. The hospitalization rate was comparable between the 2 groups, however there was a reduction in overall time spent in the ED by the US group but the data didn ot reach a full statistical significance. 

The Takeaway 

Ultrasound in the pre-hospital setting has great potential and utility. Specifically relating to lung US it is easy and feasible. The learning curve is rapid. The differentiation between COPD and CHF can easily be made with the use of US and can help shed light on the etiology of the undifferentiated respiratory distress, potentially decrease harmful doses of non indicated medications in the field and reduce overall time spent in the ED. The study was small but promising, however larger studies should be performed to establish use of US in the pre hospital setting. 

Ultrasound Criteria for Early Diagnosis of Nonviable Pregnancies

Sarah Lurvey, DO | EM PGY3

The article:  Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester. Doubilet et al. (2014). NEJMI 369(15): 1443-1451

The Idea:

The stakes are high in this assessment because a false positive diagnosis of a nonviable pregnancy means termination of a viable pregnancy, which is more detrimental than a false negative in which case a diagnosis of a nonviable pregnancy is delayed likely by only a few days, assuming this is a hemodynamically stable patient who is being followed medically. The criteria therefore need a specificity of as close to 100% as possible.

Diagnosing a nonviable pregnancy involves physicians in many levels of training across many specialties, making widely used criteria difficult to establish, and current criteria are the product of only small studies.

The Study:

A review of the existing studies to differentiate diagnostic criteria for a nonviable pregnancy to establish criteria that near 100% specificity for nonviable pregnancy as opposed to merely suspicious for nonviable pregnancy. This includes a review of the use of hCG and pelvic ultrasonography in women with an IUP of uncertain viability or pregnancy of unknown location.

Inclusion criteria for these tests are a positive serum pregnancy test with a positivity threshold over 5mIU/ml, and a trans-vaginal assessment of the uterus, adnexa, evaluation for free fluid or a mass high in the pelvis which must be performed by physicians or providers overseen by credentialed physicians and images reviewed by US credentialed physicians, using equipment that can adequately see structures in the first trimester of pregnancy.

The Findings:

Trans-vaginal US Findings Diagnostic for Pregnancy Failure in IUP of Uncertain Viability:

• Crown rump length ≥7mm and no heartbeat

• Mean sac diameter of  ≥25mm and no embryo

• Absence of embryo heartbeat ≥2 weeks after a scan with a gestational sac without a yolk sac

• Absence of embryo heartbeat ≥11 days after a scan with a gestational sac and yolk sac

Ruling out a viable IUP in a woman with a pregnancy of unknown location:

• With ultrasonography demonstrating no intrauterine collection and normal adnexa:

  • hCG ≥3000 without anything visualized on US is most likely a nonviable IUP rather than an ectopic pregnancy, it’s generally appropriate to get one more  hCG and US before terminating this pregnancy.

  • Anything less than hCG 3000 could very well be a viable IUP, do not take action. No single measurement of hCG can differentiate between ectopic and IUP, viable or not.

The Takeaway: hCG of ectopic pregnancies is extremely variable, often <1000, and hCG levels are not predictive of ectopic pregnancy rupture. Therefore in a woman with a positive hCG and clinical suspicion of ectopic pregnancy—trans-vaginal ultrasonography is always indicated.

A Prospective, Multicenter Evaluation of Point-of-care Ultrasound for Small-bowel Obstruction in the Emergency Department.

Jackie Anderson, DO | PGY3

The Article: Becker, B. A., Lahham, S., Gonzales, M. A., Nomura, J. T., Bui, M. K., Truong, T. A., . . . Kehrl, T. (2019). A Prospective, Multicenter Evaluation of Point-of-care Ultrasound for Small-bowel Obstruction in the Emergency Department. Academic Emergency Medicine. doi:10.1111/acem.13713

Study Question: 

• How accurate is ER POCUS in identifying SBO as compared to abdominal CT?

Methods/Study Design:

• Prospective, multicenter, observational study

• Occurred between July 2014 and May 2017

• ER POCUS interpreted at bedside by ER physician (attending, fellow, PGY2, PGY3) in real-time; also interpreted retrospectively by an expert reviewer after CT results were available; all reviewers were blinded

• POCUS performed with curvilinear probe

• Patients were evaluated for SBO if attending was concerned based on presentation and symptoms; patients who did not receive abdominal CT were excluded

• Criteria used to diagnose SBO on POCUS: small bowel dilation >= 25mm, abnormal peristalsis

• Criteria used to support SBO diagnosis on POCUS: transition point, intraperitoneal fluid, bowel wall edema (no specific measurement cutoff was used)

Results:

• 217 patients with overall SBO prevalence of 42.9%

• POCUS: sensitivity 88%, specificity 54%

• Expert review: sensitivity 89%, specificity 82%

• POCUS: 11 false negative, 57 false positives when compared to CT

Strengths/Limitations:

• All reviewers were blinded

• ER POCUS performers had no prior training in SBO evaluations

• ER POCUS classified as “indeterminate” was determined to be positive for SBO; CT interpretations of “ileus vs. SBO” were determined to be positive for SBO

• Different machines and performers were used among three hospitals with different patient populations 

Authors’ Conclusion:

• ER POCUS is moderately sensitive for SBO and less specific

Relevance to EM:

• Opportunity for initial evaluation vs waiting for PO contrast and CT scan

• Scanners with specific training performed better