Growth and globalization of point-of-care ultrasound publications in emergency medicine.

OBJECTIVES: Since the introduction of point-of-care ultrasound (POCUS) in emergency medicine (EM), the applications, indications, and training for POCUS have grown. POCUS training in EM residency is standard and POCUS fellowships are common. We sought to quantify and characterize changes in POCUS publications over time with a scoping review of the literature METHODS: We conducted a structured keyword search of high impact EM journals according to 2019 journal citation reports and other journals publishing POCUS studies between 2000-2019. Two abstractors recorded whether the publication was POCUS related, the type of publication, and author affiliation by department and country. We included studies with at least one author affiliated with a department of EM. Agreement between abstractors was tested. RESULTS: The number of POCUS-related publications grew from a mean of 8.8 publications/year 2000-2004 to 134.8 publications/year from 2015-2019. The most common publication type was case reports or series (44%). The proportion of publications from outside the United States (US) decreased over time. Between 2000 and 2004 89% of publications came from authors affiliated with US institutions; from 2015-2019 this had decreased to 64%. Agreement between abstractors was excellent (Cohen's k = 0.89) CONCLUSIONS: POCUS publications increased substantially between 2000-2019. The most common type of publication was a case report, which was consistent throughout the study period. Authorship from outside the US increased. Publications yielding high-quality evidence from observational or controlled studies represented a low proportion of the total number of studies.

Ultrasound-Guided Serratus Anterior Plane Block (SAPB) Improves Pain Control in Patients With Rib Fractures.

OBJECTIVES: The serratus anterior plane block (SAPB) is an ultrasound-guided compartment block; limited data suggest that it can decrease pain in patients with rib fractures or chest wall pain. We sought to determine the effect of SAPB on pain and incentive spirometry (IS) maximal vital capacity in adult patients with rib fractures. METHODS: We enrolled a prospective sample of adult patients with at least two unilateral rib fractures who were being admitted for pain control. SAPB was performed by trained emergency physicians. Patients reported pain on an 11-point Numeric Rating Scale at rest and during IS, before, 15, and 60 minutes after SAPB. RESULTS: Mean pain scores decreased by 1.8 (SD 2.17, 95% confidence interval [CI]: 0.79-2.81) at 15 minutes and 2.5 (SD 2.69, 95% CI: 1.24-3.76) at 60 minutes. Compared to pre-block pain scores during IS, mean pain scores decreased by 1.95 (SD 1.99, 95% CI: 1.02-2.88) at 15 minutes and 2.4 (SD 2.42, 95% CI: 1.27-3.53) at 60 minutes. Mean maximum vital capacity increased by 232 mL (SD 406, 95% CI: 36-427) at 60 minutes. Zero SAPB-attributable complications were identified in the 24 hours post-enrollment. CONCLUSIONS: In patients with multiple rib fractures, SAPB reduced pain scores at rest and during IS, and increased maximal vital capacity. The SABP may be a safe and effective modality for pain control in trauma patients with multiple rib fractures.

Carotid artery velocity time integral and corrected flow time measured by a wearable Doppler ultrasound detect stroke volume rise from simulated hemorrhage to transfusion.

OBJECTIVE: Doppler ultrasonography of the common carotid artery is used to infer stroke volume change and a wearable Doppler ultrasound has been designed to improve this workflow. Previously, in a human model of hemorrhage and resuscitation comprising approximately 50,000 cardiac cycles, we found a strong, linear correlation between changing stroke volume, and measures from the carotid Doppler signal, however, optimal Doppler thresholds for detecting a 10% stroke volume change were not reported. In this Research Note, we present these thresholds, their sensitivities, specificities and areas under their receiver operator curves (AUROC). RESULTS: Augmentation of carotid artery maximum velocity time integral and corrected flowtime by 18% and 4%, respectively, accurately captured 10% stroke volume rise. The sensitivity and specificity for these thresholds were identical at 89% and 100%. These data are similar to previous investigations in healthy volunteers monitored by the wearable ultrasound.

Carotid Doppler Measurement Variability in Functional Hemodynamic Monitoring: An Analysis of 17,822 Cardiac Cycles.

Carotid Doppler ultrasound is used as a measure of fluid responsiveness, however, assessing change with statistical confidence requires an adequate beat sample size. The coefficient of variation helps quantify the number of cardiac cycles needed to adequately detect change during functional hemodynamic monitoring. DESIGN: Prospective, observational, human model of hemorrhage and resuscitation. SETTING: Human physiology laboratory at Mayo Clinic. SUBJECTS: Healthy volunteers. INTERVENTIONS: Lower body negative pressure. MEASUREMENTS AND MAIN RESULTS: We measured the coefficient of variation of the carotid artery velocity time integral and corrected flow time during significant cardiac preload changes. Seventeen-thousand eight-hundred twenty-two cardiac cycles were analyzed. The median coefficient of variation of the carotid velocity time integral was 8.7% at baseline and 11.9% during lowest-tolerated lower body negative pressure stage. These values were 3.6% and 4.6%, respectively, for the corrected flow time. CONCLUSIONS: The median coefficient of variation values measured in this large dataset indicates that at least 6 cardiac cycles should be averaged before and after an intervention when using the carotid artery as a functional hemodynamic measure.

Monotherapy Anticoagulation to Expedite Home Treatment of Patients Diagnosed With Venous Thromboembolism in the Emergency Department: A Pragmatic Effectiveness Trial.

BACKGROUND: The objective was to test if low-risk emergency department patients with vitamin K antagonist (venous thromboembolism [VTE]; including venous thrombosis and pulmonary embolism [PE]) can be safely and effectively treated at home with direct acting oral (monotherapy) anticoagulation in a large-scale, real-world pragmatic effectiveness trial. METHODS: This was a single-arm trial, conducted from 2016 to 2019 in accordance with the Standards for Reporting Implementation Studies guideline in 33 emergency departments in the United States. Participants had newly diagnosed VTE with low risk of death based upon either the modified Hestia criteria, or physician judgment plus the simplified PE severity index score of zero, together with nonhigh bleeding risk were eligible. Patients had to be discharged within 24 hours of triage and treated with either apixaban or rivaroxaban. Effectiveness was defined by the primary efficacy and safety outcomes, image-proven recurrent VTE and bleeding requiring hospitalization >24 hours, respectively, with an upper limit of the 95% CI for the 30-day frequency of VTE recurrence below 2.0% for both outcomes. RESULTS: We enrolled 1421 patients with complete outcomes data, including 903 with venous thrombosis and 518 with PE. The recurrent VTE requiring hospitalization occurred in 14/1421 (1.0% [95% CI, 0.5%-1.7%]), and bleeding requiring hospitalization occurred in 12/1421 (0.8% [0.4%-1.5%). The rate of severe bleeding using International Society for Thrombosis and Haemostasis criteria was 2/1421 (0.1% [0%-0.5%]). No patient died, and serious adverse events occurred in 2.5% of venous thrombosis patients and 2.3% of patients with PE. Medication nonadherence was reported by patients in 8.0% (6.6%-9.5%) and was associated with a risk ratio of 6.0 (2.3-15.2) for VTE recurrence. Among all patients diagnosed with VTE in the emergency department during the period of study, 18% of venous thrombosis patients and 10% of patients with PE were enrolled. CONCLUSIONS: Monotherapy treatment of low-risk patients with venous thrombosis or PE in the emergency department setting produced a low rate of bleeding and VTE recurrence, but may be underused. Patients with venous thrombosis and PE should undergo risk-stratification before home treatment. Improved patient adherence may reduce rate of recurrent VTE. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03404635.

Inferring the Frank-Starling Curve From Simultaneous Venous and Arterial Doppler: Measurements From a Wireless, Wearable Ultrasound Patch.

The Frank-Starling relationship is a fundamental concept in cardiovascular physiology, relating change in cardiac filling to its output. Historically, this relationship has been measured by physiologists and clinicians using invasive monitoring tools, relating right atrial pressure (P ra) to stroke volume (SV) because the P ra-SV slope has therapeutic implications. For example, a critically ill patient with a flattened P ra-SV slope may have low P ra yet fail to increase SV following additional cardiac filling (e.g., intravenous fluids). Provocative maneuvers such as the passive leg raise (PLR) have been proposed to identify these "fluid non-responders"; however, simultaneously measuring cardiac filling and output via non-invasive methods like ultrasound is cumbersome during a PLR. In this Hypothesis and Theory submission, we suggest that a wearable Doppler ultrasound can infer the P ra-SV relationship by simultaneously capturing jugular venous and carotid arterial Doppler in real time. We propose that this method would confirm that low cardiac filling may associate with poor response to additional volume. Additionally, simultaneous assessment of venous filling and arterial output could help interpret and compare provocative maneuvers like the PLR because change in cardiac filling can be confirmed. If our hypothesis is confirmed with future investigation, wearable monitors capable of monitoring both variables of the Frank-Starling relation could be helpful in the ICU and other less acute patient settings.

Diagnostic characteristics of 11 formulae for calculating corrected flow time as measured by a wearable Doppler patch.

BACKGROUND: Change of the corrected flow time (Ftc) is a surrogate for tracking stroke volume (SV) in the intensive care unit. Multiple Ftc equations have been proposed; many have not had their diagnostic characteristics for detecting SV change reported. Further, little is known about the inherent Ftc variability induced by the respiratory cycle. MATERIALS AND METHODS: Using a wearable Doppler ultrasound patch, we studied the clinical performance of 11 Ftc equations to detect a 10% change in SV measured by non-invasive pulse contour analysis; 26 healthy volunteers performed a standardized cardiac preload modifying maneuver. RESULTS: One hundred changes in cardiac preload and 3890 carotid beats were analyzed. Most of the 11 Ftc equations studied had similar diagnostic attributes. Wodeys' and Chambers' formulae had identical results; a 2% change in Ftc detected a 10% change in SV with a sensitivity and specificity of 96% and 93%, respectively. Similarly, a 3% change in Ftc calculated by Bazett's formula displayed a sensitivity and specificity of 91% and 93%. FtcWodey had 100% concordance and an R2 of 0.75 with change in SV; these values were 99%, 0.76 and 98%, 0.71 for FtcChambers and FtcBazetts, respectively. As an exploratory analysis, we studied 3335 carotid beats for the dispersion of Ftc during quiet breathing using the equations of Wodey and Bazett. The coefficient of variation of Ftc during quiet breathing for these formulae were 0.06 and 0.07, respectively. CONCLUSIONS: Most of the 11 different equations used to calculate carotid artery Ftc from a wearable Doppler ultrasound patch had similar thresholds and abilities to detect SV change in healthy volunteers. Variation in Ftc induced by the respiratory cycle is important; measuring a clinically significant change in Ftc with statistical confidence requires a large sample of beats.

ACR Appropriateness Criteria® Placenta Accreta Spectrum Disorder.

Placenta accreta spectrum disorder (PASD) is the current terminology recommended by the International Federation of Obstetrics and Gynecology (FIGO) and should replace terms such as abnormally adherent/invasive placenta or morbidly adherent placenta. PASD refers to a variety of potential clinical complications, which may result from abnormal placental implantation. More specifically, placenta accreta refers to a defect in the decidua basalis where the chorionic villi adhere directly to the myometrium with trophoblastic invasion. Accurate antenatal diagnosis is needed to plan for an appropriate delivery strategy at an experienced center in order to reduce maternal and potential fetal morbidity and mortality. Obtaining radiologic and clinical data when PASD is first suspected can play a significant role in formulating an appropriate delivery strategy. Depending on the clinical risk factors and initial imaging findings, transabdominal ultrasound of the pregnant uterus with duplex Doppler and transvaginal ultrasound as needed are the most appropriate imaging procedures. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Penetrating Trauma-Lower Abdomen and Pelvis.

Lower urinary tract injury is most commonly the result of blunt trauma but can also result from penetrating or iatrogenic trauma. Clinical findings in patients with a mechanism of penetrating trauma to the lower urinary tract include lacerations or puncture wounds of the pelvis, perineum, buttocks, or genitalia, as well as gross hematuria or inability to void. CT cystography or fluoroscopy retrograde cystography are usually the most appropriate initial imaging procedures in patients with a mechanism of penetrating trauma to the lower urinary tract. CT of the pelvis with intravenous contrast, pelvic radiography, fluoroscopic retrograde urethrography, and CT of the pelvis without intravenous contrast may be appropriate in some cases. Arteriography, radiographic intravenous urography, CT of the pelvis without and with intravenous contrast, ultrasound, MRI, and nuclear scintigraphy are usually not appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

WAMAMI: emergency physicians can accurately identify wall motion abnormalities in acute myocardial infarction.

OBJECTIVE: The ability to identify wall motion abnormalities may be useful for emergency clinicians, but is not typically evaluated in point-of-care echocardiograms. We sought to determine if emergency physicians with basic training in emergency echocardiography could identify regional wall motion abnormalities (RWMA) in patients admitted with ST-elevation myocardial infarction (STEMI). METHODS: We prospectively enrolled patients with admitted with STEMI. Resident physicians with basic training in emergency ultrasound, blinded to other patient data, performed a point-of-care echocardiogram to evaluate for RWMA. If present, they also recorded the suspected territory of the RWMA. We calculated test performance characteristics and compared the agreement between point-of-care and comprehensive echocardiogram for RWMA and territory. RESULTS: 75 patients with STEMI were enrolled, and 62% had a RMWA. RWMA were identified with excellent test performance characteristics (sensitivity 88% (95% CI 75-96); specificity 92% (95% CI 75-99)). There was substantial agreement between the point-of-care echocardiogram and reference standard (K = 0.79; 95% CI: 0.64-0.94). CONCLUSIONS: Emergency physicians with core training in point-of-care echocardiography can accurately identify RMWA.

Test performance of point-of-care ultrasound for gastric content.

OBJECTIVE: We sought to determine test performance characteristics of emergency physician ultrasound for the identification of gastric contents. METHODS: Subjects were randomized to fast for at least 10 h or to consume food and water. A sonologist blinded to the patient's status performed an ultrasound of the stomach 10 min after randomization and oral intake, if applicable. The sonologist recorded their interpretation of the study using three sonographic windows. Subsequently 2 emergency physicians reviewed images of each study and provided an interpretation of the examination. Test performance characteristics and inter-rater agreement were calculated. RESULTS: 45 gastric ultrasounds were performed. The sonologist had excellent sensitivity (92%; 95% CI 73%-99%) and specificity (85%; 95% CI 62%-92%). Expert review demonstrated excellent sensitivity but lower specificity. Inter-rater agreement was very good (κ = 0.64, 95%CI 0.5-0.78). CONCLUSION: Emergency physician sonologists were sensitive but less specific at detecting stomach contents using gastric ultrasound.