Tracheal rapid ultrasound exam (T.R.U.E.) for confirming endotracheal tube placement during emergency intubation

Confirmatory methods for endotracheal tube placement in out-of-hospital settings: A systematic review of the literature

Background

Confirming proper placement of an endotracheal tube (ETT) is important, as accidental misplacements may occur and lead to critical injuries, potentially leading to adverse outcomes. Multiple methods are available for determining the correct ETT placement in prehospital care.

Objective

To assess the accuracy and reliability of the different methods used to confirm endotracheal intubation in prehospital settings.

Methods

A comprehensive literature search was performed in the MEDLINE, EMBASE, Scopus, and Web of Science databases for studies that were published between 1-June-1992 and 12-June-2022 using a combination of predetermined search terms. Studies that met the inclusion criteria were included and assessed for risk of bias using "Risk of Bias in Non-randomized Studies of Intervention" tool.

Results

Of the 1016 identified studies, nine met the inclusion criteria. Capnography and point-of-care ultrasound showed high sensitivity and specificity rates when applied to confirm ETT placement in prehospital care. Other methods including capnometry, colorimetric detectors, ODDs, and auscultation showed varied sensitivity and specificity. Patient comorbidities and device failure contributed to decreased accuracy rates in prehospital care. Capnography was less reliable in distinguishing between endotracheal intubation and right main stem intubation, which is known as a complication in out-of-hospital endotracheal intubation. Point-of-care ultrasound was more accurate and reliable in detecting oesophageal and endobronchial misplacements. ETCO2 monitors, i.e., capnometry and colorimetric detectors, were less reliable in patients with low perfusion states.

Conclusion

This systematic review showed that there is no single method with 100% accuracy in confirming the correct ETT placement and detecting the occurrence of accidental oesophageal or endobronchial misplacements in prehospital care. Further studies with a larger sample size are needed to assess the accuracy of multiple confirmatory methods in prehospital settings.

Deep Learning-Based Localization and Detection of Malpositioned Endotracheal Tube on Portable Supine Chest Radiographs in Intensive and Emergency Medicine: A Multicenter Retrospective Study

OBJECTIVES

We aimed to develop a computer-aided detection (CAD) system to localize and detect the malposition of endotracheal tubes (ETTs) on portable supine chest radiographs (CXRs).

DESIGN

This was a retrospective diagnostic study. DeepLabv3+ with ResNeSt50 backbone and DenseNet121 served as the model architecture for segmentation and classification tasks, respectively.

SETTING

Multicenter study.

PATIENTS

For the training dataset, images meeting the following inclusion criteria were included: 1) patient age greater than or equal to 20 years; 2) portable supine CXR; 3) examination in emergency departments or ICUs; and 4) examination between 2015 and 2019 at National Taiwan University Hospital (NTUH) (NTUH-1519 dataset: 5,767 images). The derived CAD system was tested on images from chronologically (examination during 2020 at NTUH, NTUH-20 dataset: 955 images) or geographically (examination between 2015 and 2020 at NTUH Yunlin Branch [YB], NTUH-YB dataset: 656 images) different datasets. All CXRs were annotated with pixel-level labels of ETT and with image-level labels of ETT presence and malposition.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For the segmentation model, the Dice coefficients indicated that ETT would be delineated accurately (NTUH-20: 0.854; 95% CI, 0.824-0.881 and NTUH-YB: 0.839; 95% CI, 0.820-0.857). For the classification model, the presence of ETT could be accurately detected with high accuracy (area under the receiver operating characteristic curve [AUC]: NTUH-20, 1.000; 95% CI, 0.999-1.000 and NTUH-YB: 0.994; 95% CI, 0.984-1.000). Furthermore, among those images with ETT, ETT malposition could be detected with high accuracy (AUC: NTUH-20, 0.847; 95% CI, 0.671-0.980 and NTUH-YB, 0.734; 95% CI, 0.630-0.833), especially for endobronchial intubation (AUC: NTUH-20, 0.991; 95% CI, 0.969-1.000 and NTUH-YB, 0.966; 95% CI, 0.933-0.991).

CONCLUSIONS

The derived CAD system could localize ETT and detect ETT malposition with excellent performance, especially for endobronchial intubation, and with favorable potential for external generalizability.

Real-Time Tracheal Ultrasound vs. Capnography for Intubation Confirmation during CPR Wearing a Powered Air-Purifying Respirator in COVID-19 Era

This study aimed to compare the accuracy of real-time trans-tracheal ultrasound (TTUS) with capnography to confirm intubation in cardiopulmonary resuscitation (CPR) while wearing a powered air-purifying respirator (PAPR). This setting reflects increased caution due to contagious diseases. This single-center, prospective, comparative study enrolled patients requiring CPR while wearing a PAPR who visited the emergency department of a tertiary medical center from December 2020 to August 2022. A physician performed the TTUS in real time and recorded the tube placement assessment. Another healthcare provider attached waveform capnography to the tube and recorded end-tidal carbon dioxide (EtCO2) after five ventilations. The accuracy and agreement of both methods compared with direct laryngoscopic visualization of tube placement, and the time taken by both methods was evaluated. Thirty-three patients with cardiac arrest were analyzed. TTUS confirmed tube placement with 100% accuracy, sensitivity, and specificity, whereas capnography demonstrated 97% accuracy, 96.8% sensitivity, and 100% specificity. The Kappa values for TTUS and capnography compared to direct visualization were 1.0 and 0.7843, respectively. EtCO2 was measured in 45 (37-59) seconds (median (interquartile range)), whereas TTUS required only 12 (8-23) seconds, indicating that TTUS was significantly faster (p < 0.001). No significant correlation was found between the physician's TTUS proficiency and image acquisition time. This study demonstrated that TTUS is more accurate and faster than EtCO2 measurement for confirming endotracheal tube placement during CPR, particularly in the context of PAPR usage in pandemic conditions.

Ultrasonography Imaging versus Waveform Capnography in Detecting Endotracheal Tube Placement during Intubation at a Tertiary Hospital

Background

There is continued research to find new faster, highly accurate, easily accessible, and portable methods of confirming endotracheal tube position during intubation. A newer modality for visualizing endotracheal tube location is transtracheal or transcricothyroid ultrasonography. The aim of this study was to see if ultrasound machine can also be routinely used for the confirmation of endotracheal tube position in operating theaters along with capnograph.

Methods

The study was observational and prospective, conducted from January 2017 to July 2017. Study locations were at the Tribhuvan University Teaching Hospital and Manmohan Cardiothoracic Vascular and Transplant Center operating rooms. Sample size taken was 95.

Results

In the study, 11 patients had esophageal intubation out of the 95. The accuracy of both ultrasonography and capnography was found to be 96.84%. For ultrasonography, the sensitivity, specificity, along with positive predictive value and negative predictive value were 97.62%, 90.91%, 98.80%, and 83.33%, respectively, while that for capnography were found to be 96.43%, 100%, 100%, and 78.57%, respectively. The kappa value was calculated to be 0.749, which suggested the degree of agreement of result between the methods to be good. Compared to capnography, ultrasonography was found to be significantly faster for the confirmation of endotracheal tube location by 16.36 s (15.70-17.02) (P = 0.011).

Conclusion

Both waveform capnography and ultrasonography were found to be accurate and reliable in confirming endotracheal tube location. The use of ultrasound during intubation can help confirm endotracheal tube location faster and also aid in precision when used along with capnography. Manual bag ventilations are not necessary when confirming endotracheal tube position by ultrasonography and thus may help in preventing aspiration of gastric contents into the lungs of the patient.

Role of point-of-care ultrasound in critical care and emergency medicine: update and future perspective

Point-of-care ultrasound (POCUS) is a rapidly developing technology that has the potential to revolutionize emergency and critical care medicine. The use of POCUS can improve patient care by providing real-time clinical information. However, appropriate usage and proper training are crucial to ensure patient safety and reliability. This article discusses the various applications of POCUS in emergency and critical care medicine, the importance of training and education, and the future of POCUS in medicine.

Cervical ultrasound for endotracheal intubation confirmation in dogs by veterinary students: a cadaveric study

Although endotracheal intubation is usually a simple and fast procedure in dogs, some situations can be challenging and lead to the risk of tube misplacement in the esophagus-a life-threatening complication. Hence, confirming intubation is a cornerstone whenever this procedure is performed. Methods such as direct visualization or capnography present limitations insofar as they may be unreliable or unavailable under some circumstances. Ultrasound has emerged as a promising tool to confirm intubation in medicine. However, so far little research has been done on the subject in veterinary medicine. This study's main goal was to investigate ultrasound performed by veterinary students as a confirmation method for intubation in canine cadavers after a brief training session (25 minutes). A total of 160 exams were performed with a microconvex probe by 20 students in 11 different cadavers on left and right recumbencies. Overall accuracy was 70.6% with a median success rate of 75% and a median time to diagnosis of 25 seconds. The number of correct diagnoses was statistically higher than the wrong ones (p<0.05) without difference between recumbencies. Sensitivity, specificity, and positive and negative predictive values were 72.5%, 68.8%, 69.9%, and 71.4%, respectively. The fastest diagnosis was performed in just 4 seconds, and among the top-performers, one student had 100% accuracy with a mean time to diagnosis of 16.8 seconds, and four students had approximately 88% accuracy. This study showed for the first time that even inexperienced veterinary students can have acceptable accuracy in confirming endotracheal intubation in dogs after a brief training session.

Point-of-Care Ultrasound in Airway Evaluation and Management: A Comprehensive Review

Airway management is a common and critical procedure in acute settings, such as the Emergency Department (ED) or Intensive Care Unit (ICU) of hospitals. Many of the traditional physical examination methods have limitations in airway assessment. Point-of-care ultrasound (POCUS) has emerged as a promising tool for airway management due to its familiarity, accessibility, safety, and non-invasive nature. It can assist physicians in identifying relevant anatomy of the upper airway with objective measurements of airway parameters, and it can guide airway interventions with dynamic real-time images. To date, ultrasound has been considered highly accurate for assessment of the difficult airway, confirmation of proper endotracheal intubation, prediction of post-extubation laryngeal edema, and preparation for cricothyrotomy by identifying the cricothyroid membrane. This review aims to provide a comprehensive overview of the key evidence on the use of ultrasound in airway management. Databases including PubMed and Embase were systematically searched. A search strategy using a combination of the term "ultrasound" combined with several search terms, i.e., "probe", "anatomy", "difficult airway", "endotracheal intubation", "laryngeal edema", and "cricothyrotomy" was performed. In conclusion, POCUS is a valuable tool with multiple applications ranging from pre- and post-intubation management. Clinicians should consider using POCUS in conjunction with traditional exam techniques to manage the airway more efficiently in the acute setting.

Comparison of Upper Airway Ultrasonography With End-Tidal Capnography for the Confirmation of Endotracheal Tube Placement in Patients Requiring General Anesthesia

Introduction End-tidal capnography (EtCO₂) has been the gold standard method for confirmation of endotracheal intubation. Upper airway ultrasonography (USG) is a new promising method for confirming endotracheal tube (ETT) placement and has the potential to become the first-line non-invasive airway assessment tool in the future thanks to widespread POCUS knowledge, greater technology improvements, portability, and availability of ultrasound in the majority of essential areas. Hence our study aimed to compare upper airway USG and EtCO₂ for the confirmation of ETT placement in patients undergoing general anesthesia. Aim To compare the upper airway USG with EtCO₂ for confirmation of ETT placement in patients requiring general anesthesia for elective surgical procedures. The objectives of the study were to compare the time taken for confirmation, and the number of correct identification of tracheal and esophageal intubation by both upper airway USG and EtCO₂. Materials and methods After obtaining institutional ethical committee (IEC) approval, a prospective randomized comparative study involving 150 patients under American Society of Anesthesiologists (ASA) grade I and II requiring endotracheal intubation for elective surgeries under general anesthesia was randomized into two groups, Group U-upper airway USG and Group E-EtCO₂ with 75 patients in each group. ETT placement confirmation was done by upper airway USG in Group U and by EtCO₂ in Group E and the time taken for confirmation of ETT placement and correct identification of esophageal and tracheal intubation by USG and EtCO₂ was noted. Results The demographic details among both groups were statistically insignificant. Upper airway USG had a faster average confirmation time of 16.41 seconds when compared to EtCO₂ which took an average confirmation time of 23.56 seconds. In our study, upper airway USG was able to identify esophageal intubation with 100% specificity. Conclusion Upper airway USG can be a reliable method and can be employed as a standard method for confirmation of ETT location in patients undergoing elective surgeries under general anesthesia when compared to EtCO₂.

The Role of Thoracic Ultrasound for Diagnosis of Diseases of the Chest Wall, the Mediastinum, and the Diaphragm-Narrative Review and Pictorial Essay

The diagnostic capabilities of ultrasound extend far beyond the evaluation of the pleural space and lungs. Sonographic evaluation of the chest wall is a classic extension of the clinical examination of visible, palpable, or dolent findings. Unclear mass lesions of the chest wall can be differentiated accurately and with low risk by additional techniques such as color Doppler imaging, contrast-enhanced ultrasound, and, in particular, ultrasound-guided biopsy. For imaging of mediastinal pathologies, ultrasound has only a complementary function but is valuable for guidance of percutaneous biopsies of malignant masses. In emergency medicine, ultrasound can verify and support correct positioning of endotracheal tubes. Diaphragmatic ultrasound benefits from the real-time nature of sonographic imaging and is becoming increasingly important for the assessment of diaphragmatic function in long-term ventilated patients. The clinical role of thoracic ultrasound is reviewed in a combination of narrative review and pictorial essay.

Applications of Airway Ultrasound for Endotracheal Intubation in Pediatric Patients: A Systematic Review

Endotracheal intubation is a challenging procedure for pediatric patients. Airway ultrasound as a new technology is suitable for aiding this process, but its diagnostic value remains unclear. We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and the Chinese biomedical literature database to summarize specific applications of airway ultrasound in each step of endotracheal intubation in pediatric patients. Diagnostic accuracy and 95% confidence interval were used as outcomes. In total, 33 studies (6 randomized controlled trials and 27 diagnostic studies) with 1934 airway ultrasound examinations were included. Population included neonates, infants, and older children. Airway ultrasound could be used to determine the endotracheal tube size and confirm endotracheal intubation and intubation depth; the diagnostic accuracy for all these factors was 23.3-100%, 90.6-100%, and 66.7-100%, respectively. Furthermore, the accuracy of airway ultrasound in predicting endotracheal tube size was consistently higher than traditional methods, such as height formula, age formula, and the width of the little finger. In conclusion, airway ultrasound has unique advantages for confirming successful endotracheal intubation in pediatric patients, and it may become an effective auxiliary tool in this field. There is a need to develop a unified airway ultrasound protocol to conduct clinical trials and practice in the future.

Diagnostic accuracy of point-of-care ultrasound compared to standard-of-care methods for endotracheal tube placement in neonates

INTRODUCTION

Point-of-care ultrasound (POCUS) is a valuable tool to determine endotracheal tube (ETT) placement; however, few studies have compared it with standard confirmation methods. We evaluated the diagnostic accuracy of POCUS and time-to-interpretation for correct identification of tracheal versus esophageal intubations compared to a composite of standard-of-care methods in neonates.

METHODS

A cross-sectional study was conducted in the Neonatal Intensive Care Unit (NICU) at Aga Khan University Hospital Karachi, Pakistan. All required intubations were performed as per NICU guidelines. The clinical team simultaneously determined the ETT placement using standard-of-care methods (auscultation, colorimetric capnography, and chest X-ray) by POCUS. In addition, the clinical team was blinded to the POCUS images. Timings were recorded for each method by independent study staff.

RESULTS

A total of 348 neonates were enrolled in the study. More than half (58%) of intubations were in an emergency scenario. POCUS user interpretation showed 100% sensitivity and 94% specificity using an expert as the reference standard. We found a 99.4% agreement (Kappa: 0.96; p < 0.001). Diagnostic accuracy of POCUS compared with at least two standard-of-care methods demonstrated 99.7% sensitivity, 91% specificity, and 98.9% agreement (Kappa:0.93; p < 0.001). The median time required for POCUS interpretation was 3.0 (interquartile range [IQR] 3.0-4.0) seconds for tracheal intubation. The time recorded for auscultation and capnography was 6.0 (IQR 5.0-7.0) and 3.0 (IQR 3.0-4.0), respectively.

CONCLUSION

POCUS is a rapid and reliable method of identifying ETT placement in neonates. Early and correct identification of airway management is critical to save lives and prevent mortality and morbidity.

Airway Ultrasound in Critically Ill Patients: A Narrative Review

Airway assessment and management have a central role in critical care medicine. Airway ultrasound can help us evaluate the anatomy, facilitate interventions such as intubation in difficult airways and tracheostomy, prevent post-extubation complications, and diagnose dysphagia. In this review, we will summarize the current use of ultrasound in airway assessment and management in critically ill patients.

Point-of-Care Ultrasound Curriculum for Endotracheal Tube Confirmation for Pediatric Critical Care Transport Team Through Remote Learning and Teleguidance

OBJECTIVE

Point-of-care ultrasound (POCUS) is used to manage patients in real time. This study aimed to teach pediatric critical care team members to use POCUS for endotracheal tube (ETT) placement confirmation. A secondary aim was to assess the feasibility of a remote curriculum for this purpose.

METHODS

The Kern 6-step approach was used. The curriculum involved virtual didactics, asynchronous learning modules, and remote hands-on sessions using teleguidance with the Butterfly IQ+ probe, Butterfly Network, Inc, Guilford, CT. Participants learned direct and indirect methods of ETT placement confirmation and were directed to practice independently. Outcomes included attitudes and satisfaction, knowledge and skills acquisition and retention, and the use of POCUS on shift.

RESULTS

Ten participants completed the curriculum. The average knobology and quiz scores improved by 29.3% and 20.8%, respectively. Improvement was sustained at re-evaluation. Seven of 10 participants performed independent scans. At the 3-month reassessment, most demonstrated mastery of thoracic scans. All required prompting for satisfactory tracheal scans. All felt positively toward POCUS and the remote curriculum.

CONCLUSION

Pediatric critical care team members acquired and retained knowledge and skills for POCUS basics and ETT placement confirmation through a remote curriculum. Participants were satisfied with the course. Further studies are needed to reassess longer-term knowledge and skill retention and the effects on patient outcomes.

Mapping Trends and Hotspots Regarding the Use of Ultrasound in Emergency Medicine: A Bibliometric Analysis of Global Research

Objective: Diagnostic tools in emergency medicine have been widely studied. As a non-invasive and quick tool, ultrasound plays a role in the field of emergency medicine. Thus, it is significant to understand the global scientific output of this topic. An analysis of publications on the use of ultrasound in emergency medicine over the past decade was performed and summarized to track the current hotspots and highlight future directions.

Methods: Globally relevant publications on ultrasound in emergency medicine from 2009 to 2020 were extracted from the Web of Science collection database. VOSviewer software and CiteSpace were employed to visualize and predict the trends in the research on the topic.

Results: The overall volume of global publications is on the rise; furthermore, the United States published the most publications in this field and had the most citations and H-index. University of California at San Francisco in the United States has most publications in terms of institutions. The American Journal of Emergency Medicine published the most papers related to ultrasound in emergency medicine in terms of journals. Pulmonary embolism was once the main research direction, and importantly, “point-of-care ultrasound” was determined to be a new research hotspot.

Conclusion: Altogether, the number of publications on ultrasound in emergency medicine will rise in the future. In addition, the findings reported here shed new light on the major progress on ultrasound in emergency medicine, which may be mutually cooperative in various fields. Moreover, this bibliometric study provides further indications for the topic of “point-of-care ultrasound”.

Screening Performance Characteristics of Ultrasonography in Confirmation of Endotracheal Intubation; a Systematic Review and Meta-analysis

Introduction:

Recent studies have suggested that point-of-care ultrasonography can be used for confirming the placement of endotracheal tube. This systematic review and meta-analysis aimed to investigate the sensitivity and specificity of ultrasonography for confirming endotracheal tube placement.

Methods:

In this meta-analysis, systematic search of the previous published papers investigating the diagnostic accuracy of ultrasonography for confirmation of endotracheal tube placement was performed. Seven electronic databases, including PubMed, Scopus, Google Scholar, EBSCO, EMBASE, Web of Science, and Cochrane Database were searched up to July 2021, for all relevant articles published in English on this topic. Meta-DiSc version 1.4 software was used for statistical analysis.

Results:

The estimated pooled sensitivity and specificity of ultrasonography for confirmation of endotracheal tube location were 0.98 (95% CI: 0.98–0.99) and 0.94 (95% CI 0.91–0.96), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 5.94 (95% CI 4.41–7.98) and 0.03 (95% CI: 0.02-0.04), respectively. The diagnostic odds ratio of ultrasonography was 281.47 and the area under hierarchical summary receiver operating characteristic (HSROC) revealed an appropriate accuracy of 0.98.

Conclusion:

Ultrasonography has high diagnostic accuracy and can be used as a promising tool for confirmation of endotracheal tube placement, especially in critically ill patients or when capnography is not available, or its result is equivocal.

Measurement of the subglottic diameter of the trachea and its distance from the skin by ultrasonography in children

OBJECTIVE

To investigate the relationship between age, sex, height, weight and body mass index (BMI) by measuring the subglottic diameter of the trachea (SDT) and its distance to the skin by ultrasonography (US) in children.

METHODS

This prospective study included a total of 234 children, 104 girls and 134 boys, with ages ranging from 3 to 17 years. Demographic data including sex, age, height, weight and BMI were recorded. The SDT and its distance to the skin was measured with a 14L5 high-frequency surface transducer. The correlation of SDT and its distance to the skin with basic descriptive data was investigated. Statistical analyses used were Mann-Whitney U, Kruskal-Wallis and Spearman correlation tests.

RESULTS

No significant difference was found among the median SDT and distance of the trachea from the skin values for boys (10.85 mm) and girls (11.15 mm) (p = 0.58). The distance of the trachea from the skin was greater in girls (5.5 mm) than in boys (4.75 mm) (p = 0.009). Median SDT values were 9.4 mm, 11.2 mm, and 13.35 mm in age groups 1, 2, and 3, respectively. There were highly significant strong positive correlations between SDT with age (p = 0.001, r = 0.78), height (p = 0.001, r = 0.76), and weight (p = 0.001, r = 0.70), and a highly significant moderate positive correlation between SDT with BMI (p = 0.001, r = 0.43). Median distance values of the trachea from the skin were 4.6 mm, 5.2 mm, and 6.2 mm in age groups 1, 2, and 3, respectively. There were moderate positive correlations between distance of the trachea from the skin with age (p = 0.001, r = 0.41), height (p = 0.001, r = 0.42), weight (p = 0.001, r = 0.53), and BMI (p = 0.001, r = 0.54).

CONCLUSION

US is an accurate, safe, inexpensive, non-invasive and accessible method for objective evaluation of SDT and its distance to the skin. There is a positive correlation between age, height, weight, and BMI with SDT and its distance to the skin in healthy children.

The Use of POCUS to Manage ICU Patients With COVID-19

Since the advent of SARS-CoV-2, the virus that causes COVID-19, clinicians have had to modify how they provide high-value care while mitigating the risk of viral spread. Routine imaging studies have been discouraged due to elevated transmission risk. Patients who have been diagnosed with COVID-19 often have a protracted hospital course with progression of disease. Given the need for close follow-up of patients, we recommend the use of ultrasonography, particularly point-of-care ultrasound (POCUS), to manage patients with COVID-19 through their entire ICU course. POCUS will allow a clinician to evaluate and monitor cardiac and pulmonary function, as well as evaluate for thromboembolic disease, place an endotracheal tube, confirm central venous catheter placement, and rule out a pneumothorax. If a patient improves sufficiently to perform weaning trials, POCUS can also help evaluate readiness for ventilator liberation.

Assessing the accuracy of ultrasound measurements of tracheal diameter: an in vitro experimental study

Background

Recent studies indicate that ultrasound can detect changes in tracheal diameter during endotracheal tube (ETT) cuff inflation. We sought to assess the accuracy of ultrasound measurement of tracheal diameter, and to determine the relationship between tracheal wall pressure (TWP), cuff inflation volume (CIV), and the degree of tracheal deformation.

Methods

Our study comprised two parts: the first included 45 porcine tracheas, the second 41 porcine tracheas. Each trachea was intubated with a cuffed ETT, which was connected to an injector and the manometer via a three-way tap. The cuff was inflated and the cuff pressure recorded before and after intubation. The tracheal diameter was measured using ultrasound. This included three separate measurements: outer transverse diameter (OTD), internal transverse diameter (ITD), and anterior tracheal wall thicknesses (ATWT). A precision electronic Vernier caliper was also used to measure tracheal diameter. We calculated TWP and the percentage change of tracheal diameter. The Bland–Altman method, linear regression, and locally weighted regression (LOESS) were used to analyze the data.

Results

There were strong correlation and agreement for OTD (r = 0.97, P < 0.001) and ITD (r = 0.90, P < 0.001) as measured by ultrasound and by precision electronic Vernier caliper, but a poor correlation for ATWT (r = 0.58, P < 0.001). There was a strong correlation between the percentage change of OTD (OTD%, r = 0.75, P < 0.001) and CIV, the percentage change of ITD (ITD%, r = 0.77, P < 0.001) and CIV, TWP (r = 0.75, P < 0.001) and CIV. And a strong correlation was also found between TWP and OTD% (r = 0.84, P < 0.001), TWP and ITD% (r = 0.84, P < 0.001).

Conclusions

Use of ultrasound to measure OTD and ITD is accurate, but is less accurate for ATWT. There is a close correlation between OTD%, ITD%, CIV and TWP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01398-3.

Ultrasound for assessment and follow-up of airway stenosis

BACKGROUND

Ultrasound is a reliable tool for airway assessment and management. We evaluated the accuracy of Ultrasound in the pre-procedure planning and follow-up evaluation of patients undergoing airway stenting for benign upper airway stenosis.

METHODS

This was a retrospective single center study on patients with benign upper airway stenosis treated with airway stenting. Ultrasound evaluated the characteristics of the stenosis (distance from vocal folds, diameter and length) before treatment and any complications after treatment; these results were then statistically compared with those obtained by computed tomography, taking the endoscopy as the reference method.

RESULTS

Twenty-seven patients were evaluated. Ultrasound was significantly correlated with endoscopy and computed tomography scan measurements as distance of stenosis from vocal folds (r=0.88; p<0.001 and r=0.87; p<0.001, respectively); diameter of the stenosis (r=0.97; p<0.001 and r=0.97; p<0.001, respectively); and length of the stenosis (r=0.97; p<0.001 and r=0.97; p<0.001, respectively). Four out of 27 (15%) patients presented complications after treatment as stent migration (n=2; 7%); stent obstruction (n=1; 4%), and granulation of vocal fold (n=1; 4%). All complications but granulation of vocal fold were correctly depicted by Ultrasound and Computed Tomography without significant difference in comparison to endoscopy (p=0.87) CONCLUSIONS: Ultrasound is a promising tool in assessment of airway stenosis and follow-up of patients after stenting; it may be routinely used in adjunction to computed tomography and/or endoscopy in this setting, if our results are corroborated by future larger study.

Ultrasonography for airway management

Ultrasonography (USG) allows a new approach to the airway in anaesthesia and intensive care. USG visualises the airway from the mouth to the lungs. By exploring the entire airway, USG proposes new criteria (1) to assess the risk of difficult laryngoscopy, (2) to anticipate the management of a difficult airway, (3) to confirm the position of the endotracheal tube (ETT), and (4) to confirm that the lungs are effectively ventilated. Intraoperatively, USG may also help to resolve acute ventilatory problems such as pneumothorax, delayed selective bronchial intubation after patient positioning (Trendelenburg, prone or lateral position) or acute pulmonary oedema.

Ultrasound for Intubation Confirmation: A Randomized Controlled Study among Emergency Medicine Residents

Confirmation of endotracheal tube (ETT) placement during intubation is a critical skill for emergency medicine (EM) residents; airway ultrasonography has been suggested as an accessible and accurate method of ETT confirmation. Here, we investigated the accuracy with which EM residents could identify ETT location in cadavers using different ultrasound modes. EM attendings intubated either the trachea or the esophagus of a cadaver, and blinded residents identified ETT position using either B-mode or B-mode plus color Doppler. Residents correctly identified ETT location in 1075 of 1203 trials (89.4%); performance improved with post-graduate year (residents in post-graduate year 3 had 97.8% accurate identifications). There were 556 (91.7%) correct identifications made with B-mode and 519 (86.9%) with B-mode plus color Doppler (p value = 0.007); thus, accuracy did not improve with addition of color Doppler to B-mode. Further research is needed on the efficacy of different ultrasound modes in confirming ETT placement in live intubations.

Evaluation of real-time tracheal ultrasound versus colorimetric capnography as a point of care tool for confirmation of endotracheal intubation: a randomized controlled study

Background

Endotracheal intubation is essential for optimal airway control during general anesthesia or resuscitation of critically ill patients. Misplacement of the endotracheal tube (ETT) can lead to devastating, preventable morbidity and mortality. Colorimetric carbon dioxide detectors are considered a simplistic mainstream capnography that contains a pH-sensitive chemical marker that is prone to color change with ventilation. Real-time tracheal ultrasound allows for the dynamic observation of tube passage through the trachea or the esophagus, providing immediate confirmation of placement prior to any ventilation attempts with reported sensitivity/specificity of 100% for adult patients in the operating room.

We aimed to compare two different techniques (tracheal real-time ultrasound vs colorimetric capnography) as point of care tools for confirmation of correct endotracheal tube position.

Results

This study carried out on eligible seventy patients undergoing general anesthesia. Patients were divided randomly and equally into two groups (35 patients each). Group A in which patients’ ETT position was confirmed by real-time tracheal ultrasound and group B in which patients’ ETT position was confirmed by colorimetric capnography. Comparing both groups according to their diagnostic performance for detecting the correct position of the ETT inserted showed the diagnostic sensitivity, specificity, and accuracy of real-time tracheal ultrasound vs colorimetric capnography (93.8%, 66.7%, and 91.4% VS 97%, 50%, and 94.3% respectively). Although there were higher sensitivity and accuracy of colorimetric capnography than real-time tracheal ultrasound, the p value between the two groups was 0.462.

Conclusion

Both tools are fast, effective, reliable, and accurate with many advantages and few disadvantages including the need for training on ultrasound practice and air-filled stomach in colorimetric capnography. However, these disadvantages can be easily overruled and the benefits from both tools overweigh their disadvantages.

[Ultrasound in the management of the critically ill patient with SARS-CoV-2 infection (COVID-19): narrative review]

The clinical picture of SARS-CoV-2 infection (COVID-19) is characterized in its more severe form, by an acute respiratory failure which can worsen to pneumonia and acute respiratory distress syndrome (ARDS) and get complicated with thrombotic events and heart dysfunction. Therefore, admission to the Intensive Care Unit (ICU) is common. Ultrasound, which has become an everyday tool in the ICU, can be very useful during COVID-19 pandemic, since it provides the clinician with information which can be interpreted and integrated within a global assessment during the physical examination. A description of some of the potential applications of ultrasound is depicted in this document, in order to supply the physicians taking care of these patients with an adapted guide to the intensive care setting. Some of its applications since ICU admission include verification of the correct position of the endotracheal tube, contribution to safe cannulation of lines, and identification of complications and thrombotic events. Furthermore, pleural and lung ultrasound can be an alternative diagnostic test to assess the degree of involvement of the lung parenchyma by means of the evaluation of specific ultrasound patterns, identification of pleural effusions and barotrauma. Echocardiography provides information of heart involvement, detects cor pulmonale and shock states.

Narrative review of ultrasound in the management of the critically ill patient with SARS-CoV-2 infection (COVID-19): clinical applications in intensive care medicine

The clinical picture of SARS-CoV-2 infection (COVID-19) is characterized in its more severe form, by an acute respiratory failure which can worsen to pneumonia and acute respiratory distress syndrome (ARDS), and get complicated with thrombotic events and heart dysfunction. Therefore, admission to the Intensive Care Unit (ICU) is common.

Ultrasound, which has become an everyday tool in the ICU, can be very useful during COVID-19 pandemic, since it provides the clinician with information which can be interpreted and integrated within a global assessment during the physical examination. A description of some of the potential applications of ultrasound is depicted in this document, in order to supply the physicians taking care of these patients with a adapted guide to the intensive care setting.

Some of its applications since ICU admission include verification of the correct position of the endotracheal tube, contribution to safe cannulation of lines, and identification of complications and thrombotic events. Furthermore, pleural and lung ultrasound can be an alternative diagnostic test to assess the degree of involvement of the lung parenchyma by means of the evaluation of specific ultrasound patterns, identification of pleural effusions and barotrauma. Echocardiography provides information of heart involvement, detects cor pulmonale and shock states.

Simulator-based ultrasound training for identification of endotracheal tube placement in a neonatal intensive care unit using point of care ultrasound

BACKGROUND

Simulators are an extensively utilized teaching tool in clinical settings. Simulation enables learners to practice and improve their skills in a safe and controlled environment before using these skills on patients. We evaluated the effect of a training session utilizing a novel intubation ultrasound simulator on the accuracy of provider detection of tracheal versus esophageal neonatal endotracheal tube (ETT) placement using point-of-care ultrasound (POCUS). We also investigated whether the time to POCUS image interpretation decreased with repeated simulator attempts.

METHODS

Sixty neonatal health care providers participated in a three-hour simulator-based training session in the neonatal intensive care unit (NICU) of Aga Khan University Hospital (AKUH), Karachi, Pakistan. Participants included neonatologists, neonatal fellows, pediatric residents and senior nursing staff. The training utilized a novel low-cost simulator made with gelatin, water and psyllium fiber. Training consisted of a didactic session, practice with the simulator, and practice with intubated NICU patients. At the end of training, participants underwent an objective structured assessment of technical skills (OSATS) and ten rounds of simulator-based testing of their ability to use POCUS to differentiate between simulated tracheal and esophageal intubations.

RESULTS

The majority of the participants in the training had an average of 7.0 years (SD 4.9) of clinical experience. After controlling for gender, profession, years of practice and POCUS knowledge, linear mixed model and mixed effects logistic regression demonstrated marginal improvement in POCUS interpretation over repeated simulator testing. The mean time-to-interpretation decreased from 24.7 (SD 20.3) seconds for test 1 to 10.1 (SD 4.5) seconds for Test 10, p < 0.001. There was an average reduction of 1.3 s (β = - 1.3; 95% CI: - 1.66 to - 1.0) in time-to-interpretation with repeated simulator testing after adjusting for the covariates listed above.

CONCLUSION

We found a three-hour simulator-based training session had a significant impact on technical skills and performance of neonatal health care providers in identification of ETT position using POCUS. Further research is needed to examine whether these skills are transferable to intubated newborns in various health settings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03533218 . Registered May 2018.

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.

Differences Between Esophageal and Tracheal Intubation Ultrasound View Proficiency: An Educational Study of Novice Prehospital Providers

Objectives

Airway ultrasound is now possible in the prehospital setting due to advances in ultrasound equipment portability. We questioned how well prehospital providers without prior experience could determine both esophageal and tracheal placement of an endotracheal tube in cadavers after a brief training course in ultrasound. 

Methods

This educational prospective study at the Simulation Center in Mayo Clinic Jacksonville Florida enrolled 50 prehospital providers. Demographic and practice background information was obtained through surveys. Each participant performed a baseline ultrasound to determine endotracheal tube placement in a cadaver that was randomly assigned to an esophageal or tracheal intubation. Participants then repeated the randomized testing after a 15-minute tutorial. Before and after overall accuracy as well as proportions of correct identification of esophageal and tracheal intubations were determined and compared using standard binomial proportion and McNemar’s tests.

Results 

None of the participants had prior experience of performing airway ultrasound. Baseline group scores were 60% (CI 45%-74%) for overall accuracy (n=50), 55% (CI 32%-76%) for correct identification of an esophageal intubation, and 64% (CI 44%-81%) for correct tracheal detection. Baseline scores were not significantly different from standard binomial distributions. Post-test scores were 82% (CI 69%-91%) for overall accuracy, 96% (CI 80%-100%) for esophageal intubation detection, and 66.7% (CI 45%-84%) for tracheal intubation detection, with corresponding binomial p-values of <0.001, <0.001, and 0.15. P-values for McNemar’s paired test for combined overall accuracy, correct esophageal detection, and correct tracheal detection were 0.04, 0.02, and 0.62, respectively.

Conclusions

Prehospital participants without prior ultrasound experience demonstrated significant gains in airway ultrasound proficiency after a limited introductory course. Post-training score increases were largely due to a notable increase in correct esophageal intubation detection rates. Learners did not make significant progress in correctly identifying a tracheal intubation. Airway ultrasound educational design may benefit from added emphasis on the potentially more difficult to recognize tracheal intubation view.

Pediatrician performed point-of-care ultrasound for the detection of ingested foreign bodies: case series and review of the literature

PURPOSE

Foreign body (FB) ingestions represent a common problem in children. History and physical examination are commonly not enough to diagnose a foreign body ingestion; therefore, conventional radiography is routinely used to detect them. Point-of-care ultrasound is widely used in the emergency department for several diagnostic applications but there are few articles describing the possibility to use point-of-care ultrasound to detect ingested foreign bodies, and the necessary training to get competent in this application. The main objective of this paper is to illustrate the use of point-of-care ultrasound (POCUS) to detect ingested foreign bodies. The secondary objective is to describe a limited training, necessary for emergency pediatricians, to obtain this skill.

METHODS

This is a case series of eight pediatric patients who presented to the pediatric Emergency Department (ED), with suspected ingestion of FB, and were assessed with POCUS. Physician sonographers were two pediatricians and three residents in pediatrics working in two Italian Pediatric EDs. All sonographers participated in a 2-day POCUS workshop which included the most common pediatric POCUS applications.

RESULTS

POCUS, performed by emergency pediatricians who participated to a limited training, allowed to always identify the foreign bodies ingested.

CONCLUSIONS

We demonstrate that an appropriate and limited training allows pediatric emergency physicians to correctly identify foreign body in the esophagus or stomach. Point-of-care ultrasound in foreign body ingestion in the Emergency Department may allow to prioritize the escalation of care in children and it can contribute to reduce the time to endoscopic management when needed.

Ultrasound is a reliable and faster tool for confirmation of endotracheal intubation compared to chest auscultation and capnography when performed by novice anaesthesia residents - A prospective controlled clinical trial

Background

Anesthesia trainee may initially take longer time to intubate and unintentionally place the endotracheal tube (ETT) in the esophagus. The present study determined if ultrasound is the fastest method of confirmation of correct placement of ETT compared to capnography, and chest auscultation in trainees.

Methods

First year anesthesia residents performed intubation in 120 patients recruited after ethical clearance and informed consent. Time to visualize flutter in trachea, double trachea sign, time to appearance of first and sixth capnography, and time to execute chest auscultation was noted.

Results

Ultrasonography was statistically fastest method to determine endotracheal intubation (36.50 ± 15.14 seconds) vs unilateral chest auscultation (50.29 ± 15.50 seconds) vs bilateral chest auscultation (51.90 ± 15.98 seconds) vs capnography first waveform (53.57 ± 15.97 seconds) vs capnography sixth waveform (61.67 ± 15.88 seconds).

Conclusion

When teaching endotracheal intubation to novice anesthesia residents using conventional direct laryngoscopy, ultrasonography is the fastest method to confirm correct ETT placement compared to capnograph and chest auscultation. Mentor can guide trainee to direct ETT towards trachea and can promptly detect esophageal intubation by double trachea sign.

Tracheal, Lung, and Diaphragmatic Applications of M-Mode Ultrasonography in Anesthesiology and Critical Care

Today, proficiency in cardiopulmonary ultrasound is considered essential for anesthesiologists and critical care physicians. Conventional 2-dimensional images, however, do not permit optimal characterization of specific conditions (eg, diaphragmatic paralysis, major atelectasis, and pneumothorax) that may have relevant clinical implications in critical care and perioperative settings. By contrast, M-mode (motion-based) ultrasonographic imaging modality offers the highest temporal resolution in ultrasonography; this modality, therefore, can provide important information in ultrasound-driven approaches performed by anesthesiologists and intensivists for diagnosis, monitoring, and procedural guidance. Despite its practicability, M-mode has been progressively abandoned in echocardiography and is often underused in lung and diaphragmatic ultrasound. This review describes contemporary applications of M-mode ultrasonography in the practice of critical care and perioperative medicine. Information presented for each clinical application includes image acquisition and interpretation, evidence-based clinical implications in critically ill and surgical patients, and main limitations. The article focuses on tracheal, lung, and diaphragmatic ultrasound. It reviews tracheal ultrasound for procedural guidance during endotracheal intubation, confirmation of correct tube placement, and detection of esophageal intubation; lung ultrasound for the confirmation of endotracheal and endobronchial (selective) intubation and for the diagnosis of pneumothorax, alveolar-interstitial syndrome (cardiogenic v noncardiogenic pulmonary edema), pulmonary consolidation (pneumonia v major atelectasis) and pleural effusion; and diaphragmatic ultrasound for the diagnosis of diaphragmatic dysfunction and prediction of extubation success.

A novel training simulator for portable ultrasound identification of incorrect newborn endotracheal tube placement - observational diagnostic accuracy study protocol

Background

Endotracheal tube (ETT) placement is a critical procedure for newborns that are unable to breathe. Inadvertent esophageal intubation can lead to oxygen deprivation and consequent permanent neurological impairment. Current standard-of-care methods to confirm ETT placement in neonates (auscultation, colorimetric capnography, and chest x-ray) are time consuming or unreliable, especially in the stressful resuscitation environment. Point-of-care ultrasound (POCUS) of the neck has recently emerged as a powerful tool for detecting esophageal ETTs. It is accurate and fast, and is also easy to learn and perform, especially on children.

Methods

This will be an observational diagnostic accuracy study consisting of two phases and conducted at the Aga Khan University Hospital in Karachi, Pakistan. In phase 1, neonatal health care providers that currently perform standard-of-care methods for ETT localization, regardless of experience in portable ultrasound, will undergo a two-hour training session. During this session, providers will learn to detect tracheal vs. esophageal ETTs using POCUS. The session will consist of a didactic component, hands-on training with a novel intubation ultrasound simulator, and practice with stable, ventilated newborns. At the end of the session, the providers will undergo an objective structured assessment of technical skills, as well as an evaluation of their ability to differentiate between tracheal and esophageal endotracheal tubes. In phase 2, newborns requiring intubation will be assessed for ETT location via POCUS, at the same time as standard-of-care methods. The initial 2 months of phase 2 will include a quality assurance component to ensure the POCUS accuracy of trained providers. The primary outcome of the study is to determine the accuracy of neck POCUS for ETT location when performed by neonatal providers with focused POCUS training, and the secondary outcome is to determine whether neck POCUS is faster than standard-of-care methods.

Discussion

This study represents the first large investigation of the benefits of POCUS for ETT confirmation in the sickest newborns undergoing intubations for respiratory support.

Trial registration

ClinicalTrials.gov Identifier: NCT03533218. Registered May 2018.

Diagnostic Accuracy of a 3-Point Ultrasound Protocol to Detect Esophageal or Endobronchial Mainstem Intubation in a Pediatric Emergency Department

OBJECTIVES

The aim of this study was to evaluate the diagnostic accuracy of the 3-point approach with ultrasonography for confirming endotracheal tube (ETT) placement in pediatric patients.

METHODS

This was a prospective study conducted at a tertiary care center in Japan between March 2014 and March 2016. Children aged 0 to 18 years requiring endotracheal intubation in our emergency department (ED) who underwent ultrasonography for confirming ETT placement were enrolled. Patients who had already undergone a tracheotomy or intubation before arrival at our ED or who had severe neck injuries hindering ultrasonography were excluded. Quantitative capnography and portable chest x-ray imaging were used as the reference standard for the confirmation of proper ETT placement. The main outcome was the diagnostic accuracy of the 3-point approach with ultrasonography for detecting inappropriate ETT placement.

RESULTS

In total, 68 patients were enrolled. The median age was 17 months (interquartile range, 8-40), and 51.4% were males. Three (4.4%) and 7 (10.3%) patients had esophageal and endobronchial mainstem intubation, respectively. The patients received emergency intubation due to a dysfunction of the central nervous system (45.6%) or respiratory failure (22.0%). The sensitivity and specificity of esophageal versus tracheal intubation was 100% (95% confidence interval [CI], 54.9%-100.0%) and 100% (95% CI, 97.9%-100.0%), respectively, whereas for endobronchial mainstem intubation versus tracheal intubation, the sensitivity and specificity was 85.7% (95% CI, 56.7%-96.0%) and 98.3% (95% CI, 94.8%-99.5%), respectively. Agreement between the reviewers was high (kappa coefficient, 0.78).

CONCLUSION

The 3-point approach with ultrasonography was a feasible method for detecting esophageal and endobronchial mainstem intubation in pediatric patients.

Effectiveness of limited airway ultrasound education for medical students: a pilot study

Objective

The point-of-care ultrasound of the airway (POCUS-A) is a useful examination method but there are currently no educational programs for medical students regarding it. We designed a POCUS-A training curriculum for medical students to improve three cognitive and psychomotor learning domains: knowledge of POCUS-A, image acquisition, and image interpretation.

Methods

Two hours of training were provided to 52 medical students in their emergency medicine (EM) rotation. Students were evaluated for cognitive and psychomotor skills before and immediately after the training. The validity measures were established with the help of six specialists and eight EM residents. A survey was administered following the curriculum.

Results

Cognitive skill significantly improved after the training (38.7±12.4 vs. 91.2±7.7) and there was no significant difference between medical students and EM residents in posttest scores (91.2±7.7 vs. 90.8±4.6). The success rate of overall POCUS-A performance was 95.8%. The students were confident to perform POCUS-A on an actual patient and strongly agreed to incorporate POCUS-A training in their medical school curriculum.

Conclusion

Cognitive and psychomotor skills of POCUS-A among medical students can be improved via a limited curriculum on EM rotation.

Getting to know a familiar face: Current and emerging focused ultrasound applications for the perioperative setting

Ultrasound technology is available in many pediatric perioperative settings. There is an increasing number of ultrasound applications for anesthesiologists which may enhance clinical performance, procedural safety, and patient outcomes. This review highlights the literature and experience supporting focused ultrasound applications in the pediatric perioperative setting across varied disciplines including anesthesiology. The review also suggests strategies for building educational and infrastructural systems to translate this technology into clinical practice.

A New Formula for Confirmation of Proper Endotracheal Tube Placement with Ultrasonography

Background:

Endotracheal intubation is an important procedure in critical care and emergency medicine settings. Optimal depth of the tube placement has been a serious concern because of several complications associated with its malposition.

Objective:

The aim of the current study was to find a new formula to estimate the proper endotracheal tube depth when using ultrasonography or lighted stylet device in order to increase the accuracy of determining Endotracheal tube (ETT) depth and decrease the side effects of ETT misplacement.

Method:

Patients older than 18 years of age admitted to Imam emergency department who needed tracheal intubation were included. Tube’s length at the angle of the mouth while the tube passed the suprasternal notch, ETT depth after insertion and the distance from ETT’s tip to carina were recorded. Ultrasonography and portable chest x-ray were used as tools for measuring these lengths.

Results:

A total number of 91 patients including 55 men and 36 women were eligible for inclusion in the study. Not placing the tube at proper depth was considered as the failure of intubation. This failure rate was 9.9% in the standard method which would have been 1.1% if our proposed formula was used.

Conclusion:

The findings of this study suggest that the use of this new formula may help in predicting the proper intubation tube placement. Further studies are warranted to confirm these findings.

Accuracy of ultrasound for endotracheal intubation between different transducer types

INTRODUCTION

Ultrasound has been increasingly utilized for the identification of endotracheal tube (ETT) location after an intubation attempt, particularly among patients in cardiac arrest. However, prior studies have varied with respect to the choice of transducer and no studies have directly compared the accuracy between transducer types. Our study is the first to directly compare the accuracy of ETT confirmation between the linear and curvilinear transducer.

METHODS

This study was performed in a cadaver lab using three different cadavers chosen to represent varying neck circumferences. Cadavers were randomized to tracheal or esophageal intubation. Blinded sonographers assessed the location of the ETT using either a linear or curvilinear transducer in an alternating sequence. Accuracy of sonographer identification, time to identification, and operator confidence were assessed.

RESULTS

Four hundred and five assessments were performed with 198 (48.9%) tracheal and 207 (51.1%) esophageal intubations. The linear transducer was 98% (95% CI 95.1% to 99.2%) accurate. The curvilinear transducer was 95% (95% CI 91.1% to 97.3%) accurate. The mean time to identification was significantly lower with the linear transducer [7.46 s (95% CI 6.23 to 8.7 s)] as compared with the curvilinear transducer [11.63 s (95% CI 9.05 to 14.2 s)]. The mean operator confidence was significantly higher with the linear transducer [4.84/5.0 (95% CI 4.76 to 4.91)] than with the curvilinear transducer [4.44/5.0 (95% CI 4.3 to 4.57)]. All operators preferred the linear transducer over the curvilinear transducer.

CONCLUSION

The diagnostic accuracy of ultrasound for ETT confirmation did not significantly differ between ultrasound transducer types, but the curvilinear transducer was associated with a longer time to confirmation and lower operator confidence. Further studies are needed to determine if the accuracy would change with more novice providers or in specific patient populations.

Real-time Tracheal Ultrasound for the Confirmation of Endotracheal Intubations in the Intensive Care Unit: An Observational Study

OBJECTIVES

Current methods to confirm endotracheal tube (ETT) placement have varying degrees of effectiveness and time to completion. We aimed to study the accuracy of real-time tracheal ultrasound (US) to confirm ETT placement in the intensive care unit (ICU) setting.

METHODS

This work was a prospective study completed at 2 academic tertiary care centers. Patients in the adult ICU requiring emergent intubation were enrolled in the trial. During the intubation process, a US team performed a tracheal US examination to determine, in real time, whether the ETT was placed into the trachea or the esophagus.

RESULTS

A total of 75 patients were enrolled in the study and were available for analysis. There were 12 (16%) esophageal intubations and 63 (84%) tracheal intubations. One hundred percent of the tracheal intubations and 83% of the esophageal intubations were correctly identified. The positive and negative predictive values of US to detect an esophageal intubation were 100% and 97%, respectively.

CONCLUSIONS

Tracheal US can be highly accurate in identifying the location of the ETT, in real time, in ICU patients undergoing emergent intubation. Although our study shows a great potential of real-time US use during emergent intubations, larger studies would be needed to further evaluate the accuracy of this technique.

Confirmation of placement of endotracheal tube - A comparative observational pilot study of three ultrasound methods

Background and Aims

Confirmation of endotracheal tube (ETT) position is necessary to ensure proper ventilation. The present study was conducted with the aim to compare the efficacy of three ultrasonographic (USG) techniques in terms of time taken for confirmation of ETT position. The time taken by each USG technique was also compared with that for auscultation and capnography. The ability of the three USG techniques to identify tracheal placement of ETT was evaluated in all patients.

Material and Methods

Ninety adult American Society of Anesthesiologists (ASA) I/II patients requiring general anaesthesia with tracheal intubation were randomised into three groups (n = 30 each) depending upon the initial USG transducer position used to confirm tracheal placement of ETT: group T (tracheal), group P (pleural) and group D (diaphragm). The time taken for confirmation of tracheal placement of ETT by USG, auscultation and capnography was recorded for each of the groups. Subsequently, USG confirmation of ETT placement was performed with the other two USG techniques in all patients.

Results

The time taken for USG in group T was significantly less (3.8 ± 0.9 s) compared to group P (12.1 ± 1.6 s) and group D (13.8 ± 1.7 s); P < 0.001. USG was significantly faster than both auscultation and capnography in group T (P < 0.001), whereas in group P and group D, USG took longer time compared to auscultation (P = 0.014 and P < 0.001, respectively) but lesser time than capnography (P < 0.001 in both groups).

Conclusion

USG is a rapid technique for identification of ETT placement. All the three USG techniques are reliable in identifying the tracheal placement of ETT.