Blinding practices during acute point-of-care ultrasound research: the BLIND-US meta-research study

Venous congestion in septic shock quantified with point-of-care ultrasound: a pilot prospective multicentre cohort study

PURPOSE

Venous congestion is a pathophysiologic state that can result in organ dysfunction, particularly acute kidney injury (AKI). We sought to evaluate the feasibility of performing a definitive observational study to determine the impact of venous congestion quantified using point-of-care ultrasound (POCUS) in patients with septic shock.

METHODS

We conducted a prospective observational feasibility study at two intensive care units (ICUs). We recruited adult patients with septic shock within 12 hr of ICU admission. Using the validated Venous Excess Ultrasound Score (VEXUS), we quantified venous congestion on day 1 and day 3 of ICU admission. The primary feasibility outcome was successful completion rate of the two VEXUS scores. We performed a survival analysis to quantify the hazard of renal replacement therapy (RRT).

RESULTS

We enrolled 75 patients from January 2022 to January 2023. The success rate of completion for VEXUS scans was 94.5% (95% confidence interval [CI], 89.5 to 97.6). Severe venous congestion was present in 19% (14/75) of patients on ICU admission day 1 and in 16% (10/61) of patients on day 3. Venous congestion on ICU admission may be associated with a higher risk of requiring RRT (unadjusted hazard ratio, 3.35; 95% CI, 0.94 to 11.88; P = 0.06).

CONCLUSIONS

It is feasible to conduct a definitive observational study exploring the association between venous congestion quantified with POCUS and clinical outcomes in patients with septic shock. We hypothesize that venous congestion may be associated with an increased hazard of receiving RRT.

Automated Real-Time Detection of Lung Sliding Using Artificial Intelligence: A Prospective Diagnostic Accuracy Study

BACKGROUND

Rapid evaluation for pneumothorax is a common clinical priority. Although lung ultrasound (LUS) often is used to assess for pneumothorax, its diagnostic accuracy varies based on patient and provider factors. To enhance the performance of LUS for pulmonary pathologic features, artificial intelligence (AI)-assisted imaging has been adopted; however, the diagnostic accuracy of AI-assisted LUS (AI-LUS) deployed in real time to diagnose pneumothorax remains unknown.

RESEARCH QUESTION

In patients with suspected pneumothorax, what is the real-time diagnostic accuracy of AI-LUS to recognize the absence of lung sliding?

STUDY DESIGN AND METHODS

We performed a prospective AI-assisted diagnostic accuracy study of AI-LUS to recognize the absence of lung sliding in a convenience sample of patients with suspected pneumothorax. After calibrating the model parameters and imaging settings for bedside deployment, we prospectively evaluated its diagnostic accuracy for lung sliding compared with a reference standard of expert consensus.

RESULTS

Two hundred forty-one lung sliding evaluations were derived from 62 patients. AI-LUS showed a sensitivity of 0.921 (95% CI, 0.792-0.973), specificity of 0.802 (95% CI, 0.735-0.856), area under the receiver operating characteristic curve of 0.885 (95% CI, 0.828-0.956), and accuracy of 0.824 (95% CI, 0.766-0.870) for the diagnosis of absent lung sliding.

INTERPRETATION

Real-time AI-LUS shows high sensitivity and moderate specificity to identify the absence of lung sliding. Further research to improve model performance and optimize the integration of AI-LUS into existing diagnostic pathways is warranted.

Indications, Clinical Impact, and Complications of Critical Care Transesophageal Echocardiography: A Scoping Review

BACKGROUND

Critical care transesophageal echocardiography (ccTEE) is an increasingly popular tool used by intensivists to characterize and manage hemodynamics at the bedside. Its usage appears to be driven by expanded diagnostic scope as well as the limitations of transthoracic echocardiography (TTE) - lack of acoustic windows, patient positioning, and competing clinical interests (eg, the need to perform chest compressions). The objectives of this scoping review were to determine the indications, clinical impact, and complications of ccTEE.

METHODS

MEDLINE, EMBASE, Cochrane, and six major conferences were searched without a time or language restriction on March 31^st, 2021. Studies were included if they assessed TEE performed for adult critically ill patients by intensivists, emergency physicians, or anesthesiologists. Intraoperative or post-cardiac surgical TEE studies were excluded. Study demographics, indication for TEE, main results, and complications were extracted in duplicate.

RESULTS

Of the 4403 abstracts screened, 289 studies underwent full-text review, with 108 studies (6739 patients) included. Most studies were retrospective (66%), performed in academic centers (84%), in the intensive care unit (73%), and were observational (55%). The most common indications for ccTEE were hemodynamic instability, trauma, cardiac arrest, respiratory failure, and procedural guidance. Across multiple indications, ccTEE was reported to change the diagnosis in 52% to 78% of patients and change management in 32% to79% patients. During cardiac arrest, ccTEE identified the cause of arrest in 25% to 35% of cases. Complications of ccTEE included two cases of significant gastrointestinal bleeding requiring intervention, but no other major complications (death or esophageal perforation) reported.

CONCLUSIONS

The use of ccTEE has been described for the diagnosis and management of a broad range of clinical problems. Overall, ccTEE was commonly reported to offer additional diagnostic yield beyond TTE with a low observed complication rate. Additional high quality ccTEE studies will permit stronger conclusions and a more precise understanding of the trends observed in this scoping review.

Interrater Reliability of Point-of-Care Cardiopulmonary Ultrasound in Patients With Septic Shock: An Analysis of Agreement Between Treating Clinician and Expert Reviewers

BACKGROUND

Cardiopulmonary ultrasound (CPUS) is commonly used to assess cardiac function and preload status in patients with septic shock. However, the reliability of CPUS findings at the point of care is unknown.

OBJECTIVE

To assess interrater reliability (IRR) of CPUS in patients with suspected septic shock between treating emergency physicians (EPs) vs emergency ultrasound (EUS) experts.

METHODS

Single-center, prospective, observational cohort enrolling patients (n = 51) with hypotension and suspected infection. Treating EPs performed and interpreted CPUS for cardiac function parameters (left ventricular [LV] function and right ventricular [RV] function and size) and preload volume parameters (inferior vena cava [IVC] diameter and pulmonary B-lines). The primary outcome was IRR (assessed by Kappa values [κ] and intraclass correlation coefficient [ICC]) between EP and EUS-expert consensus. Secondary analyses examined the effects on IRR of operator experience, respiratory rate, and known difficult views on a Cardiology-performed echocardiogram.

RESULTS

IRR was fair for LV function, κ = 0.37, 95% confidence interval (CI) 0.1-0.64; poor for RV function, κ = -0.05, 95% CI -0.6-0.5; moderate for RV size, κ = 0.47, 95% CI 0.07-0.88; and substantial for B-lines, κ = 0.73, 95% CI 0.51-0.95 and IVC size, ICC = 0.87, 95% CI 0.2-0.99. Involvement of ultrasound-trained faculty was associated with improved IRR of RV size (p = 0.002), but not other CPUS domains.

CONCLUSIONS

Our study demonstrated high IRR for preload volume parameters (IVC size and presence of B-lines), but not for cardiac parameters (LV function and RV function and size) in patients presenting with concern for septic shock. Future research must focus on determining sonographer and patient-specific factors affecting CPUS interpretation in real-time.

Characterizing the biomechanical differences between novice and expert point-of-care ultrasound practitioners using a low-cost gyroscope and accelerometer integrated sensor: A pilot study

INTRODUCTION

Point-of-care ultrasound (POCUS) has become an important diagnostic tool in acute care medicine; however, little is known about the biomechanical differences between novice and expert practitioners.

METHODS

A low-cost ($50 CAD) gyroscope and accelerometer integrated sensor was assembled and affixed to an ultrasound probe. Seventeen participants, nine novices and eight experts, were recruited to perform three abdominal and four cardiac scans on a standardized patient. Participant demographics, time per scan, average acceleration, average angular velocity, decay in acceleration and angular velocity over time, and frequency of probe movements were analyzed. Video capture with blinded video review was scored.

RESULTS

On video review, experts had higher image optimization and acquisition scores for both abdominal and cardiac scans. Experts had shorter scan times for abdominal (7 s vs. 26 s, p = 0.003) and cardiac (11 s vs. 26 s, p < 0.001) scans. There was no difference in average acceleration (g) between novices and experts performing abdominal (1.02 vs. 1.01, p = 0.50) and cardiac (1.01 vs. 1.01, p = 0.45) scans. Experts had lower angular velocity (°/s) for abdominal scans (10.00 vs. 18.73, p < 0.001) and cardiac scans (15.61 vs. 20.33, p = 0.02) There was a greater decay in acceleration over time for experts performing cardiac scans compared to novices (-0.194 vs. -0.050, p = 0.03) but not for abdominal scans or when measuring angular velocity. The frequency of movements (Hz) was higher for novices compared to experts for abdominal (16.68 vs. 13.79, p < 0.001) and cardiac (17.60 vs. 13.63, p = 0.002) scans.

DISCUSSION

This study supports the feasibility of a low-cost gyroscope and accelerometer integrated sensor to quantify the biomechanics of POCUS. It may also support the concept of "window shopping" as a method by which experts obtain abdominal and cardiac views, where sliding is used to find an acoustic window, then smaller rocking and tilting probe movements are used to refine the image.

Point-of-Care Ultrasound for the Trauma Anesthesiologist

Purpose of Review

With advances in technology and availability of handheld ultrasound probes, studies are focusing on the perioperative care of patients, but a limited number specifically on trauma patients. This review highlights recent findings from studies using point of care ultrasound (POCUS) to improve the care of trauma patients.

Recent Findings

Major findings include the use of POCUS to assess volume status of trauma patients upon arrival to measure the major vasculature. Additionally, several studies have advanced the use of POCUS to identify pneumothorax in trauma patients. Finally, the ASA POCUS certification and ASRA expert guidelines are examples of international organizations establishing guidelines for utilization and training of anesthesiologists in the field of POCUS, which will be discussed.

Summary

Despite the COVID-19 pandemic, and considerable resources being diverted to fight this global healthcare crisis, advances are being made in utilization of POCUS to aid the care of trauma patients.