Optimization of Ultrasound Transducer Positioning for Endotracheal Tube Placement Confirmation in Cadaveric Model

Airway and Thoracic Ultrasound

Airway and thoracic ultrasound applications can provide critical information to improve patient safety for procedures and management of pulmonary conditions. Emergency physicians should utilize airway ultrasound in the preparation for an anatomically and/or physiologically difficult airway, which may include site demarcation for surgical airway planning. Thoracic ultrasound is useful in the prompt evaluation of a dyspneic patient. This article underscores the crucial role of airway and thoracic ultrasound in emergency medicine, emphasizing its utility for assessing difficult airways, planning surgical airways, and promptly evaluating dyspneic patients.

Point-of-Care Ultrasonography to Confirm Endotracheal Tube Placement: A Review for the Emergency Nurse Practitioner

Ensuring correct placement of the endotracheal tube (ETT) during intubation is an important step to avoid complications. Appropriate placement of the ETT can be challenging and, if done incorrectly, can lead to complications such as hypoxemia, atelectasis, hyperinflation, barotrauma, cardiovascular instability, end organ damage, and even death. Although several procedures exist to help assess ETT confirmation, all have limitations, are not always reliable, and vary in their degree of accuracy. Point-of-care ultrasound (POCUS) has emerged as a useful tool in the emergency department for quick diagnosis and treatment of many emergency conditions (Gonzalez et al., 2020). The purpose of this paper is to describe a systematic approach for the emergency nurse practitioner to use POCUS to assess proper endotracheal placement and the positioning within the trachea based on prior studies that compare this modality to traditional ones.

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.

Transtracheal ultrasonographic confirmation of endotracheal intubation using I-gel and an endotracheal tube introducer

BACKGROUND

This study aimed to investigate the efficacy of transtracheal ultrasonography in confirming the placement of an endotracheal tube introducer during endotracheal intubation using the I-gel supraglottic airway as a guide.

METHODS

In this prospective study, endotracheal intubation using an endotracheal tube introducer through the I-gel was performed in patients with return of spontaneous circulation after I-gel insertion for out-of-hospital cardiac arrest. The introducer placement was assessed by the occurrence of hyperechoic artifacts within the trachea or esophagus in transtracheal ultrasonography. Results of ultrasonography were confirmed by waveform capnography in the case of tracheal artifacts and direct visualization by laryngoscopy in the case of esophageal artifacts.

RESULTS

One hundred and six patients were enrolled in this study. In transtracheal ultrasonography, artifacts of introducer in the trachea and esophagus were observed in 80 (75.5%) and 26 (24.5%) patients, respectively. Transtracheal ultrasonography in identifying the placement of introducers revealed a sensitivity of 100% (95% CI 95.4 to 100), specificity of 96.3% (95% CI 81.0 to 99.9), a PPV of 98.7% (95% CI 92.0 to 99.8), and a NPV of 100% (95% CI 94.8 to 99.9).

CONCLUSION

Transtracheal ultrasonography is an accurate method for identifying introducer placement during endotracheal intubation using an endotracheal tube introducer through the I-gel.

Ultrasound for airway management: An evidence-based review for the emergency clinician

BACKGROUND

Airway management is a common procedure performed in the Emergency Department with significant potential for complications. Many of the traditional physical examination maneuvers have limitations in the assessment and management of difficult airways. Point-of-care ultrasound (POCUS) has been increasingly studied for the evaluation and management of the airway in a variety of settings.

OBJECTIVE

This article summarizes the current literature on POCUS for airway assessment, intubation confirmation, endotracheal tube (ETT) depth assessment, and performing cricothyroidotomy with an emphasis on those components most relevant for the Emergency Medicine clinician.

DISCUSSION

POCUS can be a useful tool for identifying difficult airways by measuring the distance from the skin to the thyrohyoid membrane, hyoid bone, or epiglottis. It can also predict ETT size better than age-based formulae. POCUS is highly accurate for confirming ETT placement in adult and pediatric patients. The typical approach involves transtracheal visualization but can also include lung sliding and diaphragmatic elevation. ETT depth can be assessed by visualizing the ETT cuff in the trachea, as well as using lung sliding and the lung pulse sign. Finally, POCUS can identify the cricothyroid membrane more quickly and accurately than the landmark-based approach.

CONCLUSION

Airway management is a core skill in the Emergency Department. POCUS can be a valuable tool with applications ranging from airway assessment to dynamic cricothyroidotomy. This paper summarizes the key literature on POCUS for airway management.

Confirmation of endotracheal tube placement using disposable fiberoptic bronchoscopy in the emergent setting

BACKGROUND

Patients intubated in the prehospital setting require quick and definitive confirmation of endotracheal (ET) tube placement upon arrival to the emergency department (ED). Direct and adjunct strategies exist, but each has limitations and there is no definitive gold standard. The utility of bronchoscopy in ED intubation has been studied, but scant literature exists on its use for ET tube confirmation. This study aims to assess effectiveness, ease and speed with which ET tube placement can be confirmed with disposable fiberoptic bronchoscopy.

METHODS

Emergency medicine residents recruited from a 3-year urban residency program received 5 minutes of active learning on a simulation mannequin using a disposable, flexible Ambu aScope interfaced with a monitor. With residents blinded, the researcher randomly placed the ET tube in the trachea, esophagus or right mainstem. Residents identified ET tube position by threading the bronchoscope through the tube and viewing distal anatomy. Each resident underwent 4 trials. Accuracy, speed and perceptions of difficulty were measured.

RESULTS

Residents accurately identified the location of the ET tube in 88 out of 92 trials (95.7%). The median time-to-guess was 7.0 seconds, IQR (5.0-10.0). Average perceived difficulty was 1.6 on a scale from 1-5 (1 being very easy and 5 being very difficult). No tubes were damaged or dislodged.

CONCLUSION

While simulation cannot completely replicate the live experience, fiberoptic bronchoscopy appears to be a quick and accurate method for ET tube confirmation. Further studies directly comparing this novel approach to established practices on actual patients are warranted.

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.