Point-of-care ultrasound for airway management in the emergency and critical care setting.

Airway management is a common procedure within emergency and critical care medicine. Traditional techniques for predicting and managing a difficult airway each have important limitations. As the field has evolved, point-of-care ultrasound has been increasingly utilized for this application. Several measures can be used to sonographically predict a difficult airway, including skin to epiglottis, hyomental distance, and tongue thickness. Ultrasound can also be used to confirm endotracheal tube intubation and assess endotracheal tube depth. Ultrasound is superior to the landmark-based approach for locating the cricothyroid membrane, particularly in patients with difficult anatomy. Finally, we provide an algorithm for using ultrasound to manage the crashing patient on mechanical ventilation. After reading this article, readers will have an enhanced understanding of the role of ultrasound in airway management.

Comparison of dynamic versus static ultrasound to confirm endotracheal tube depth.

INTRODUCTION: After endotracheal intubation is performed, the location of the endotracheal tube (ETT) is confirmed followed by assessment of ETT depth. Physical examination can be unreliable and chest radiographs can lead to delayed recognition. Ultrasound may facilitate rapid determination of ETT depth at the bedside; however, the ideal technique is unknown. METHODS: This was a randomized trial comparing the static versus dynamic technique for ETT depth assessment using a cadaver model. The ETT was randomized to correct versus deep placement. Seven physicians blinded to ETT location assessed the location using static (direct visualization of an inflated cuff) versus dynamic (active inflation of the ETT cuff) visualization. Outcomes included diagnostic accuracy, time to identification, and operator confidence with subgroup analyses by physician ultrasound experience. RESULTS: 420 total assessments were performed. The static technique was 99.1% (95% CI 94.8%-100%) sensitive and 97.1% (95% CI 91.9%-99.4%) specific. The dynamic technique was 100% (95% CI 96.7%-100%) sensitive and 100% (95% CI 96.7%-100%) specific. Time to identification was faster for the static technique (6.6 s; 95% CI 5.9-7.4 s) versus the dynamic technique (8.7 s; 95% CI 8.0-9.5 s). Operator confidence was lower for the static technique (4.4/5.0; 95% CI 4.3-4.5) versus the dynamic technique (4.7/5.0; 95% CI 4.6-4.8). There were no differences in the findings when assessed among expert or non-expert sonographers. CONCLUSION: There was no statistically significant difference in the accuracy of ETT depth identification between the static or dynamic technique. However, utilizing the dynamic technique showed a statistically significant improvement in sonographer confidence and a concomitant increase in time to identification.

Ultrasound for the diagnosis of necrotizing fasciitis: A systematic review of the literature.

BACKGROUND: Necrotizing fasciitis (NF) is a deadly disorder that can be challenging to diagnose on history and examination alone. Point-of-care ultrasound (POCUS) is widely available and has been increasingly used for diagnosing skin and soft tissue infections. We performed a systematic review to determine the accuracy of POCUS for diagnosing NF with subgroup analyses of the accuracy of specific POCUS examination components. METHODS: PubMed, Scopus, CINAHL, LILACS, the Cochrane databases, Google Scholar, and bibliographies of selected articles were assessed for all retrospective, prospective, and randomized control trials evaluating the accuracy of POCUS for diagnosing NF. Data were dual extracted into a predefined worksheet and quality analysis was performed with the QUADAS-2 tool. Data were summarized and an overall summary was completed. RESULTS: We identified three papers (n = 221 patients; 33% NF) that met our inclusion criteria. The overall sensitivity ranged from 85.4%-100% while the specificity ranged from 44.7% to 98.2%. Fluid accumulation along the fascial plane was the most sensitive (85.4%; 95% CI 72.2% - 93.9%), while subcutaneous emphysema was the most specific (100%; 95% CI 92.5% - 100%). CONCLUSIONS: POCUS has good sensitivity and specificity for the diagnosis of NF. POCUS should be considered as an adjunct to the initial clinical decision making for the diagnosis of NF.

Diagnostic accuracy of ultrasound to confirm endotracheal tube depth.

INTRODUCTION: Endotracheal intubation is commonly performed in the Emergency Department. Traditional measures for estimating and confirming the endotracheal tube (ETT) depth may be inaccurate or lead to delayed recognition. Ultrasound may offer a rapid tool to confirm ETT depth at the bedside. METHODS: This was a randomized trial assessing the diagnostic accuracy of ultrasound to confirm ETT depth. Three cadavers were intubated in a random sequence with the ETT placed high (directly below the vocal cords), middle (2 cm above the carina), or deep (ETT at the carina). Seven blinded sonographers assessed the depth of the ETT using ultrasound. Outcomes included diagnostic accuracy of sonographer identification, time to identification, and operator confidence based upon ETT location. A subgroup analysis was performed to assess diagnostic accuracy by operator confidence. RESULTS: 441 total assessments were performed (154 high, 154 middle, and 133 deep ETT placements). Overall accuracy was 84.8% (95% CI 81.1% to 88.0%). When placed high, ultrasound was 82.5% sensitive (95% CI 75.5% to 88.1%) and 92.3% specific (95% CI 88.6% to 95.1%) with a mean time to identification of 15.3 s (95% CI 13.6-17.0) and a mean operator confidence of 3.9/5.0 (95% CI 3.7-4.1). When the ETT was placed in the middle, ultrasound was 83.8% sensitive (95% CI 77.0% to 89.2%) and 92.3% specific (95% CI 88.6% to 95.1%) with a mean time to identification of 16.7 s (95% CI 14.6-18.8) and a mean operator confidence of 3.7/5.0 (95% CI 3.5-3.9). When the ETT was placed deep, ultrasound was 88.0% sensitive (95% CI 81.2% to 93.0%) and 92.2% specific (95% CI 88.6% to 94.6%) with a mean time to identification of 19.0 s (95% CI 17.3-20.7) and a mean operator confidence of 3.4/5.0 (95% CI 3.2-3.6). Sonographers were significantly more accurate when they reported a higher confidence score. CONCLUSION: Ultrasound was moderately accurate for identifying the ETT location in a cadaveric model and was more accurate when sonographers felt confident with their visualization. Future research should determine the accuracy of combining transtracheal ultrasound with lung sliding and other modifications to improve the accuracy.

Comparison of saline versus air for identifying endotracheal intubation with ultrasound.

INTRODUCTION: After intubation has been performed, it is important to rapidly confirm the correct location of the endotracheal tube (ETT). Multiple techniques have been described, each with different limitations. Ultrasound has been increasingly recognized as an alternate modality for identifying the ETT location. However, it can be challenging to visualize the air-filled ETT cuff. Saline insufflation of the ETT cuff has been suggested to improve visualization of the ETT but data are limited. Our study sought to compare the diagnostic accuracy of air versus saline ETT cuff inflation on the diagnostic accuracy of intubation. METHODS: This was a randomized trial comparing air versus saline cuff inflation using a cadaver model. Adult cadavers were intubated in a random sequence with respect to both the location of intubation (i.e., tracheal vs esophageal) and air versus saline. Blinded sonographers assessed the location of the ETT using the static technique. Outcomes included accuracy of sonographer identification, time to identification, and operator confidence. RESULTS: 480 total assessments were performed. When using air, ultrasound was 95.8% sensitive (95% CI 90.5% to 98.6%) and 100% specific (95% CI 97.0% to 100%) with a mean time to confirmation of 8.5 s (95% CI 7.6 s to 9.4 s) and a mean operator confidence of 4.32/5.0 (95% CI 4.21 to 4.42). When using saline, ultrasound was 100% sensitive (95% CI 97.0% to 100%) and 100% specific (95% CI 97.0% to 100%) with a mean time to confirmation of 6.3 s (95% CI 5.9 s to 6.8 s) and a mean operator confidence of 4.52/5.0 (95% CI 4.44 to 4.60). CONCLUSION: There was no statistically significant difference between air versus saline for intubation confirmation. However, saline was associated with fewer false negatives. Additionally, time to confirmation was faster and operator confidence was higher with the saline group. Further studies should determine if the outcomes would change with more novice sonographers or in specific patient populations.

What are the echocardiographic findings of acute right ventricular strain that suggest pulmonary embolism?

INTRODUCTION: Pulmonary embolism (PE) is a potentially fatal disease encountered in the hospital setting. Prompt diagnosis and management can improve outcomes and survival. Unfortunately, a PE may be difficult to diagnose in a timely manner. Point-of-care ultrasound (POCUS) can assist in the evaluation for suspected PE by assessing for acute right ventricular strain. Physicians should thus be aware of these echocardiographic findings. OBJECTIVE: This manuscript will review ten echocardiographic findings of right ventricular strain that may suggest a diagnosis of PE. It will provide a description of each finding along with the associated pathophysiology. It will also summarize the literature for the diagnostic utility of echocardiography for this indication, while providing reference parameters where applicable. Along with labeled images and video clips, the review will then illustrate how to evaluate for each of the ten findings, while offering pearls and pitfalls in this bedside evaluation. DISCUSSION: The ten echocardiographic findings of right ventricular strain are: increased right ventricle: left ventricle size ratio, abnormal septal motion, McConnell's sign, tricuspid regurgitation, elevated pulmonary artery systolic pressure, decreased tricuspid annular plane systolic excursion, decreased S', pulmonary artery mid-systolic notching, 60/60 sign, and speckle tracking demonstrating decreased right ventricular free wall strain. CONCLUSIONS: Physicians must recognize and understand the echocardiographic findings and associated pathophysiology of right ventricular strain. In the proper clinical context, these findings can point toward a diagnosis of PE and thereby lead to earlier initiation of directed management.

Comparison of Static versus Dynamic Ultrasound for the Detection of Endotracheal Intubation.

INTRODUCTION: In the emergency department setting, it is essential to rapidly and accurately confirm correct endotracheal tube (ETT) placement. Ultrasound is an increasingly studied modality for identifying ETT location. However, there has been significant variation in techniques between studies, with some using the dynamic technique, while others use a static approach. This study compared the static and dynamic techniques to determine which was more accurate for ETT identification. METHODS: We performed this study in a cadaver lab using three different cadavers to represent variations in neck circumference. Cadavers were randomized to either tracheal or esophageal intubation in equal proportions. Blinded sonographers then assessed the location of the ETT using either static or dynamic sonography. We assessed accuracy of sonographer identification of ETT location, time to identification, and operator confidence. RESULTS: A total of 120 intubations were performed: 62 tracheal intubations and 58 esophageal intubations. The static technique was 93.6% (95% confidence interval [CI] [84.3% to 98.2%]) sensitive and 98.3% specific (95% CI [90.8% to 99.9%]). The dynamic technique was 92.1% (95% CI [82.4% to 97.4%]) sensitive and 91.2% specific (95% CI [80.7% to 97.1%]). The mean time to identification was 6.72 seconds (95% CI [5.53 to 7.9] seconds) in the static technique and 6.4 seconds (95% CI [5.65 to 7.16] seconds) in the dynamic technique. Operator confidence was 4.9/5.0 (95% CI [4.83 to 4.97]) in the static technique and 4.86/5.0 (95% CI [4.78 to 4.94]) in the dynamic technique. There was no statistically significant difference between groups for any of the outcomes. CONCLUSION: This study demonstrated that both the static and dynamic sonography approaches were rapid and accurate for confirming ETT location with no statistically significant difference between modalities. Further studies are recommended to compare these techniques in ED patients and with more novice sonographers.

Ultrasound-Guided Peripheral Intravenous Line Placement: A Narrative Review of Evidence-based Best Practices.

Peripheral intravenous line placement is a common procedure in emergency medicine. Ultrasound guidance has been demonstrated to improve success rates, as well as decrease complications and pain. This paper provides a narrative review of the literature focusing on best practices and techniques to improve performance with this procedure. We provide an evidence-based discussion of preparation for the procedure, vein and catheter selection, multiple techniques for placement, and line confirmation.