Secondary confirmation of endotracheal tube position by ultrasound image

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.

Ultrasound assessment of endotracheal tube depth in neonates: a prospective feasibility study

OBJECTIVE

To examine the reliability of a novel ultrasound (US) method for assessment of endotracheal tube (ETT) position in neonates.

DESIGN

Prospective, observational, single-centre, feasibility study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Term and preterm neonates requiring endotracheal intubation.

INTERVENTION

US measurement of the ETT tip to right pulmonary artery (RPA) distance was used to determine ETT position according to one-fourth to three-fourths estimated tracheal length for weight. US demonstration of pleural sliding and diaphragmatic movement was also assessed. Chest radiography (CXR) was performed following each intubation.

MAIN OUTCOME MEASURES

Agreement between US assessment of ETT tip position and CXR served as the gold standard. Sensitivity, specificity, positive and negative predictive values for each US method and correlation between ETT tip to RPA distance on US, and ETT tip to carina distance on CXR were assessed.

RESULTS

Forty-two US studies were performed on 33 intubated neonates. US evaluation of ETT-RPA distance identified 100% of ETTs positioned correctly: 77% deep and 80% high, demonstrating strong agreement with CXR (kappa=0.822). Sensitivity was 78%, specificity 100%, positive predictive value 100% and negative predictive value 86%. US ETT-RPA distance strongly correlated with CXR ETT-carina distance (r=0.826). No significant agreement was found between CXR and US assessment of pleural sliding and diaphragmatic movement. No adverse events were encountered during US scans.

CONCLUSION

US evaluation of ETT-RPA distance demonstrated excellent accuracy for determining ETT position in neonates compared with CXR. More research is needed to support its feasibility in clinical settings.

A Scoping Review of Ultrasonographic Techniques in the Evaluation of the Pediatric Airway

Point-of-care ultrasound is making rapid advancements in pediatrics, and ultrasonographic assessment of the airway is being employed in many specialties such as the pediatric, cardiac, and neonatal intensive care units, emergency department, pulmonary clinic, and the perioperative setting. This scoping review provides a technical description of image acquisition and interpretation, accompanying ultrasound images of the hallmark airway applications in pediatrics, and supporting evidence when available. We describe and illustrate ultrasound-determined endotracheal tube (ETT) sizing, ETT placement and depth confirmation, vocal fold assessment, prediction of post-extubation stridor, difficult laryngoscopy prediction, and cricothyrotomy guidance. This review aims to provide the descriptions and images necessary to learn and apply these skills at the point of care in the pediatric patient.

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.

Diagnostic Value of Epigastric Ultrasound and Suprasternal Notch Ultrasound in Comparison with Standard Capnography in Confirmation of Endotracheal Tube Placement after Intubation

Background

Endotracheal intubation is the basic method of providing a safe cross-sectional airway area and the incorrect placement can be dangerous and causes complications. So this study aimed to access the diagnostic value of color Doppler epigastric ultrasound and linear probe suprasternal notch ultrasound in comparison with standard capnography in confirmation of endotracheal tube (ETT) placement after intubation.

Materials and Methods

This diagnostic value study was conducted on 104 patients requiring intubation who were referred to the Emergency Department. After the intubation, color Doppler epigastric ultrasound and suprasternal notch ultrasound as well as the standard capnography were used to confirm the placement ETT.

Results

The sensitivity and specificity of color Doppler epigastric ultrasound were 97.96% and 100%, for suprasternal notch ultrasound were 98.98% and 66.67%, and for combination of the both methods were 96.94% and 100% respectively that showed the significant diagnostic value in the confirmation of ETT placement (P < 0.001). The mean of elapsed time to confirm the ETT placement by the standard capnography method (17.95 ± 2.45 s) was significantly more than the two methods of epigastric ultrasound (10.38 ± 4.65 s) and suprasternal notch ultrasound (5.08 ± 4.45 s) as well as the combined method with the mean of 15.46 ± 8.31 s (P < 0.001).

Conclusion

The results of this study showed that although ultrasound is a potentially accurate, fast, and reliable method to confirm the endotracheal tube placement, but suprasternal notch ultrasound is considered to be a more appropriate diagnostic technique due to its higher sensitivity and less detection time compared to epigastric ultrasound and combined method.

Diagnostic value of pleural ultrasound to refine endotracheal tube placement in pediatric intensive care unit

AIM

To assess the diagnostic performance of a simplified lung point-of-care ultrasound (POCUS) to confirm the correct positioning of an endotracheal tube (ETT) in a pediatric intensive care unit (PICU) used to chest radiography (CXR), and to compare the time to obtain the ETT position between POCUS and CXR.

METHODS

We conducted a single-center prospective study in critically ill children requiring urgent endotracheal intubation. Esophageal tube malposition was first avoided using auscultation and end-tidal CO2. The ETT position was assessed with CXR and lung POCUS using the lung sliding sign on a pleural window. All of the investigators had to read guidelines and received 1-h training on the technical aspects of lung sliding. The primary objective was the accuracy of POCUS in confirming correct nonselective endotracheal intubation as compared with CXR.

RESULTS

A total of 71 patients were included from December 2016 to November 2018. CXR identified proper nonselective ETT placement in 43 of 71 (61%) patients, while the rate for selective intubation was 39%. The sensitivity and specificity of POCUS as compared with CXR were 77% and 68%, respectively. Median time to POCUS was significantly shorter than CXR (2 min to perform POCUS, 10 min to obtain radiographs, p<10-4).

CONCLUSION

Pleural ultrasound, although faster than CXR, appears to be inadequate for identifying selective ETT after urgent intubation in a PICU less accustomed to this kind of ultrasound. In this heterogeneous and fragile population, timely POCUS may remain useful at the bedside as compared with auscultation, aiming at guiding optimal ETT placement and reducing respiratory complications, provided by trained physicians.

Unmasking the Lung Pulse for Detection of Endobronchial Intubation

The ultrasound lung pulse for detecting endobronchial intubation was first described in 2003 in the only study to date assessing its accuracy. It refers to rhythmic movement of the visceral pleura along the stationary parietal pleura as cardiac vibrations transmit through a motionless, airless lung. Compared to delayed visualization on chest radiography, this artifact immediately detects physiologic atelectasis. There is a scarcity of studies assessing the lung pulse, while several others that encountered this artifact did not even identify it. The lung pulse is useful for immediate detection of endobronchial intubation, but it remains unrecognized and underused by physicians.

Point-of-Care Ultrasound for Pediatric Endotracheal Tube Placement Confirmation by Advanced Practice Transport Nurses

OBJECTIVE

This study aimed to identify which point-of-care ultrasound (POCUS) techniques and sonographic signs were reliably acquired and interpreted by transport nurses for the confirmation of endotracheal tube placement in children.

METHODS

We developed and assessed a multimodal POCUS training curriculum for transport nurses that evaluated 5 sonographic signs using 3 scanning techniques.

RESULTS

Twenty-one transport nurses were enrolled in the curriculum. The mean scores (95% confidence interval [CI]) of the knowledge test were 82% (95% CI, 63%-93%), 88% (95% CI, 68%-95%), and 74% (95% CI, 53%-87%) for tracheal, lung, and hemidiaphragmatic scans, respectively. For the simulation image evaluation, 94% (95% CI, 77%-99%) of tracheal scan images, 97% (95% CI, 81%-99%) of lung scan images, and 88% (95% CI, 69%-96%) of hemidiaphragmatic scan images were determined clinically useful. For the pediatric intensive care unit image evaluation, 100% (95% CI, 86%-100%) of tracheal scan images, 100% (95% CI, 86%-100%) of lung scan images, and 79% (95% CI, 59%-91%) of hemidiaphragmatic scan images were determined clinically useful. A tracheal dilation sign was rarely captured by POCUS.

CONCLUSION

Transport nurses can acquire POCUS skills to confirm endotracheal tube placement in children. A combination of a double trachea sign, a lung sliding sign, and a lung pulse sign could be a feasible POCUS approach.

Endotracheal Tube Placement Confirmation with Bedside Ultrasonography in the Pediatric Intensive Care Unit: A Validation Study

Critically ill patients who are intubated undergo multiple chest X-rays (CXRs) to determine endotracheal tube position; however, other modalities can save time, medical expenses, and radiation exposure. In this article, we evaluated the validity and interrater reliability of ultrasound to confirm endotracheal tube (ETT) position in patients. A prospective study was performed on intubated patients with cuffed ETTs. The accuracy of ultrasound to confirm correct ETT placement in 92 patients was 97.8%. Sensitivity, positive predictive value, and agreement of 97.7, 93.3, and 91.3% were found on comparing ultrasound to CXR findings. Ultrasound is feasible, reliable, and has good interrater reliability in assessing correct ETT position in children.

Point-of-Care Ultrasound for Intubation Confirmation of COVID-19 Patients

The novel coronavirus disease of 2019 (COVID-19) is associated with significant morbidity and mortality, as well as large numbers of patients requiring endotracheal intubation. While much of the literature has focused on the intubation technique, there is scant discussion of intubation confirmation. Herein, we discuss the limitations of traditional confirmatory approaches, summarize the literature supporting a role for point-of-care ultrasound in this application, and propose an algorithm for intubation confirmation among COVID-19 patients.

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.

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.

Lung ultrasound in the diagnosis of neonatal respiratory failure prior to patient transport

PURPOSE

Lung ultrasound (LUS) at the point-of-care is a new method that is increasingly used in neonatology. The aim of this study was to determine the utility of the addition of LUS prior to the interhospital transport of neonates with respiratory failure.

METHODS

LUS was performed on 50 newborns with respiratory failure prior to transport to a tertiary neonatal intensive care unit. We analyzed the performance of LUS for diagnosing the cause of respiratory failure, the concordance between LUS, chest X-ray (CXR) and final clinical diagnosis, and the impact of LUS on clinical decision making before transport.

RESULTS

LUS sensitivity for the diagnosis of respiratory distress syndrome was 91.3% (95%CI: 70.5-98.5%), and specificity was 92.6% (95%CI: 74.2-98.7%), whereas sensitivity and specificity of CXR were 69.6% (95%CI: 47.0-85.9%) and 81.5% (95%CI: 61.2-92.9%), respectively. For the recognition of pneumothorax (PTX) LUS had a sensitivity of 83.3% (95%CI: 36.5-99.1%) and a specificity of 100% (95%CI: 89.9-100%). For CXR, sensitivity was 16.7% (95%CI: 0.01-63.5%) and specificity was 97.7% (95%CI: 86.4-99.9%). The agreement between LUS and CXR in diagnosing the cause of respiratory failure was substantial (κ of 0.57 [95%CI: 0.40-0.74]) and the agreement between LUS and the final clinical diagnosis was very good (κ of 0.86 [95%CI: 0.74-0.98]). In 42% of the patients, a LUS examination prior to transport indicated the need for endotracheal tube repositioning or PTX decompression.

CONCLUSION

LUS may be a reliable imaging technique for differentiating the causes of respiratory failure before neonatal transport. Use of LUS may optimize the care of infants during transport.

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.

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.

[Ultrasound guided airway access]

Ultrasound has increasingly growing applications in anesthesia. This procedure has proven to be a novel, non-invasive and simple technique for the upper airway management, proving to be a useful tool, not only in the operating room but also in the intensive care unit and emergency department. Indeed, over the years mounting evidence has showed an increasing role of ultrasound in airway management. In this review, the authors will discuss the importance of ultrasound in the airway preoperative assessment as a way of detecting signs of difficult intubation or to define the type and/or size of the endotracheal tube as well as to help airway procedures such as endotracheal intubation, cricothyrotomy, percutaneous tracheal intubation, retrograde intubation as well as the criteria for extubation.

Accuracy of Real-time Intratracheal Bedside Ultrasonography and Waveform Capnography for Confirmation of Intubation in Multiple Trauma Patients

Background:

A secure airway and effective ventilation are key components of advanced life support, and misplacement of endotracheal tube (ETT) can lead to morbidity in multiple trauma patients. The purpose of this study was to investigate the accuracy of ultrasound in diagnosis of direction for tracheal intubation.

Materials and Methods:

This descriptive-analytical study was conducted on 100 traumatic patients requiring intubation in 2016 in the Emergency Department of Al-Zahra and Kashani Medical Education Centers in Isfahan. Surface probe was placed transversally in the front of the neck at the top of the suprasternal notch, and the position of trachea was specified by front of comet-tail artifact which is the contour between hyperechoic air–mucosa (A–M) and a posterior reverberation artifact. Intubation accuracy by capnography was investigated, and the results were recorded in each patient's profile. Tracheal sonography was done during placement, or as soon as, the ETT has been embedded. The scanning time was minimized and it was carried out in total time of 10 s.

Results:

The diagnosis of intubation accuracy indicated that it was successful in 94 individuals (94%) and unsuccessful in 6 ones (6%). Intubation accuracy in 93 people (93%) was confirmed, and inaccuracy of intubation in 7 people (7%) was diagnosed. Ultrasound sensitivity in diagnosis of intubation accuracy was 97.9% (92.94) with 83.3% (5.6%) specificity. The positive and negative predictive values were 98.9% (92.93) and 71.4% (5.7%) respectively.

Conclusion:

Ultrasound method has high sensitivity and specificity to determine the correct placement of the tracheal tube, and it can be implemented as a reliable method given the acceptable positive and negative predictive values.

Point-of-care ultrasound in pediatric anesthesiology and critical care medicine

Ultrasound has increasingly become a clinical asset in the hands of the anesthesiologist and intensivist who cares for children. Though many applications for ultrasound parallel adult modalities, children as always are not simply small adults and benefit from the application of ultrasound to their management in various ways. Body composition and size are important factors that affect ultrasound performance in the child, as are the pathologies that may uniquely afflict children and aspects of procedures unique to this patient population. Ultrasound simplifies vascular access and other procedures by visualizing structures smaller than those in adults. Maturation of the thoracic cage presents challenges for the clinician performing pulmonary ultrasound though a greater proportion of the thorax can be seen. Moreover, ultrasound may provide unique solutions to sizing the airway and assessing it for cricothyroidotomy. Though cardiac ultrasound and neurosonology have historically been performed by well-developed diagnostic imaging services, emerging literature stresses the utility of clinician ultrasound in screening for pathology and providing serial observations for monitoring clinical status. Use of ultrasound is growing in clinical areas where time and diagnostic accuracy are crucial. Implementation of ultrasound at the bedside will require institutional support of education and credentialing. It is only natural that the pediatric anesthesiologist and intensivist will lead the incorporation of ultrasound in the future practice of these specialties.

Ultrasonography for endotracheal tube position in infants and children

Ultrasonography (US) has been shown to be effective for verifying endotracheal tube (ETT) position in adults but has been less studied in infants and children. We review the literature regarding US for ETT positioning in the pediatric population. A literature search was conducted using the Ovid and MEDLINE databases with search terms regarding US relating to ETT intubation and positioning in infants and children. Most studies in neonates and infants used the midsagittal suprasternal view. Studies reported >80% visualization of the ETT tip by US, and US interpretation of the ETT position correlated with the XR position in 73-100% of cases. Studies of older children used the suprasternal views, substernal views, and mid-axillary intercostal views. US appears comparable to XR and capnography in determining ETT position in this population.

CONCLUSION

US for ETT verification appears to be well tolerated in infants and children and may augment determination of proper ETT position in combination with other ETT verification modalities. Further studies are needed regarding technique and training. What is Known: • Point-of-care ultrasonography is realizing increased availability and use in several pediatric specialties. • Ultrasonography has been shown to be effective for verifying ETT position in adults but have been less studied in infants and children. What is New: • Ultrasonography for endotracheal tube verification appears to be well tolerated in infants and children. • Ultrasonography may augment determination of proper endotracheal tube position in combination with other verification modalities such as radiography and capnography in the pediatric population.

The Tracheal Accordion and the Position of the Endotracheal Tube

The purpose of this review is to, first, determine the static factors that affect the length of the human trachea across different populations and, second, to investigate whether or not there are dynamic factors that cause the length of the human trachea to vary within the same individual. We also investigated whether these changes in tracheal length within the same individual are significant enough to increase the risk of endobronchial intubation or accidental extubation. A PubMed/MEDLINE and a Web of Science database English-language literature search was conducted in May 2016 with relevant keywords and MeSH terms when available. We found that gender, extremes of age, patient height, postsurgical changes and co-existing disease are static patient factors that affect the length of the human trachea. Dynamic clinical changes that occur under anaesthesia, including Trendelenburg position, head and neck flexion and extension, paralysis of the diaphragm and pneumoperitoneum, cause the trachea to act as an accordion, decreasing and increasing its length. The length of the human trachea in both awake and anaesthetised and paralysed patients is a critical consideration in preventing both endobronchial intubation and tracheal extubation. It is clear from the literature that tracheal length varies widely across populations and, additionally, with the dynamic clinical changes that occur under anaesthesia, the trachea acts as an accordion decreasing and increasing its length within the same individual. Knowledge of the magnitude of the change in tracheal dimensions in response to these factors is an important clinical consideration.

Lung Sliding Identification Is Less Accurate in the Left Hemithorax

OBJECTIVES

The aim of our study was to compare the accuracy of lung sliding identification for the left and right hemithoraxes, using prerecorded short US sequences, in a group of physicians with mixed clinical and US training.

METHODS

A total of 140 US sequences of a complete respiratory cycle were recorded in the operating room. Each sequence was divided in two, yielding 140 sequences of present lung sliding and 140 sequences of absent lung sliding. Of these 280 sequences, 40 were randomly repeated to assess intraobserver variability, for a total of 320 sequences. Descriptive data, the mean accuracy of each participant, as well as the rate of correct answers for each of the original 280 sequences were tabulated and compared for different subgroups of clinical and US training. A video with examples of present and absent lung sliding and a lung pulse was shown before testing.

RESULTS

Two sessions were planned to facilitate the participation of 75 clinicians. In the first group, the rate of accurate lung sliding identification was lower in the left hemithorax than in the right (67.0% [interquartile range (IQR), 43.0-83.0] versus 80.0% [IQR, 57.0-95.0]; P < .001). In the second group, the rate of accurate lung sliding identification was also lower in the left hemithorax than in the right (76.3% [IQR, 42.9-90.9] versus 88.7% [IQR, 63.1-96.9]; P = .001). Mean accuracy rates were 67.5% (95% confidence interval, 65.7-69.4) in the first group and 73.1% (95% confidence interval, 70.7-75.5) in the second (P < .001).

CONCLUSIONS

Lung sliding identification seems less accurate in the left hemithorax when using a short US examination. This study was done on recorded US sequences and should be repeated in a live clinical situation to confirm our results.

Reliability of Ultrasonography in Confirming Endotracheal Tube Placement in an Emergency Setting

Background and Objectives:

Over the past few years, ultrasonography is increasingly being used to confirm the correct placement of endotracheal tube (ETT). In our study, we aimed to compare it with the traditional clinical methods and the gold standard quantitative waveform capnography. Two primary outcomes were measured in our study. First was the sensitivity and specificity of ultrasonography against the other two methods to confirm endotracheal intubation. The second primary outcome assessed was the time taken for each method to confirm tube placement in an emergency setting.

Methods:

This is a single-centered, prospective cohort study conducted in an emergency department of a tertiary care hospital. We included 100 patients with indication of emergency intubation by convenient sampling. The intubation was performed as per standard hospital protocol. As part of the study protocol, ultrasonography was used to identify ETT placement simultaneously with the intubation procedure along with quantitative waveform capnography (end-tidal carbon dioxide) and clinical methods. Confirmation of tube placement and time taken for the same were noted by three separate health-care staffs.

Results and Discussion:

Out of the 100 intubation attempts, five (5%) had esophageal intubations. The sensitivity and specificity of diagnosis using ultrasonography were 97.89% and 100%, respectively. This was statistically comparable with the other two modalities. The time taken to confirm tube placement with ultrasonography was 8.27 ± 1.54 s compared to waveform capnography and clinical methods which were 18.06 ± 2.58 and 20.72 ± 3.21 s, respectively. The time taken by ultrasonography was significantly less.

Conclusions:

Ultrasonography confirmed tube placement with comparable sensitivity and specificity to quantitative waveform capnography and clinical methods. But then, it yielded results considerably faster than the other two modalities.

Bedside Ultrasound for Tracheal Tube Verification in Pediatric Emergency Department and ICU Patients: A Systematic Review

OBJECTIVES

Improper placement of the tracheal tube during intubation can lead to dangerous complications, and bedside ultrasound has been proposed as a method of quickly and accurately identifying tube placement. Recent studies in adults have found it to be accurate, but its applicability in pediatric patients is unclear. This systematic review aims to describe the current available data on the accuracy and feasibility of bedside ultrasound for tracheal tube placement in children.

DATA SOURCES

OVID MEDLINE and EMBASE.

STUDY SELECTION

Available articles on bedside neck or lung/diaphragm ultrasound for confirmation of tracheal tube placement in children through December 2015.

DATA EXTRACTION

Two reviewers screened studies for eligibility and abstracted data independently. The quality of selected articles was evaluated using Quality Assessment of Diagnostic Accuracy Studies statement.

DATA SYNTHESIS

A total of nine articles were identified: one study using neck ultrasound, two using lung/diaphragmatic ultrasound, one with both, and five studies looking at direct visualization of the tracheal tube tip met our inclusion criteria. There were 81 intubations evaluated using neck ultrasound, 214 intubations evaluated using diaphragmatic or pleural sliding, and 165 intubations evaluated for feasibility of bedside ultrasound in visualizing tracheal tube tip placement. The sensitivities of transtracheal ultrasound for intubation were overall high ranging from 0.92 to 1.00 with excellent specificities at 1.00. For lung ultrasound, the sensitivities for tracheal placement versus esophageal placement were high at 1.00, but only one study reported esophageal intubations and had a specificity of 1.00. When assessing the appropriate tracheal tube depth for tracheal intubations using lung ultrasound, the sensitivities ranged from 0.91 to 1.00 with specificities ranging from 0.5 to 1.0. Regarding feasibility of direct visualization of tracheal tube tip, visualization ranged from 83% to 100%.

CONCLUSION

Bedside ultrasound has been described to be feasible in determining tracheal tube placement in several small single center studies and could be a useful adjunct tool in confirming tracheal tube placement in critically ill pediatric patients, but further studies are needed to assess its accuracy in a randomized multicenter setting.

Sonographic detection of tracheal or esophageal intubation: A cadaver study

Background:

The correct position of the endotracheal tube is confirmed by various modalities, most of which are not entirely reliable. Ultrasound is now increasingly available to anesthesiologists in the operating theater and is an attractive alternative. To investigate the usefulness of sonography in identifying the correct tracheal tube position in human cadavers.

Materials and Methods:

Endotracheal tubes placed randomly into trachea or esophagus was identified with a linear ultrasound probe placed transversely just above the suprasternal notch by a single anesthesiologist.

Results:

Of the 100 intubations performed at random, 99 were correctly identified to give a sensitivity of 100% and a specificity of 97.9%.

Conclusion:

Sonography is a useful technique to identify correct position of the tracheal tube.

A prospective comparative study to evaluate the utility of lung ultrasonography to improve the accuracy of traditional clinical methods to confirm position of left sided double lumen tube in elective thoracic surgeries

Background and Aims:

Traditional clinical methods like auscultation or inspection have been found to be inaccurate in confirmation of double-lumen tube (DLT) position. Lung ultrasonography (USG) reliably identifies the tidal movement (lung sliding) and the collapse of the lung (lung pulse). We intended to check whether the accuracy of clinical methods can be improved by the addition of USG in confirmation of left DLT (LDLT) position.

Methods:

A single centred, prospective, comparative study was conducted involving 70 patients undergoing thoracic surgeries requiring the use of LDLT. The patients were assigned to Group A - where LDLT position was assessed by using clinical methods alone, and Group B - where LDLT position was assessed by USG and clinical methods. The correct position was predicted when USG demonstrated the absence of lung sliding and the presence of lung pulse on the operative side, the presence of lung sliding on non-operative side, along with normal airway pressures and oxygenation. The final verification of LDLT position was done by direct observation of lung isolation by one surgeon who was blinded to the method of confirmation. Contingency tables were drawn to calculate sensitivity, specificity, positive predictive value, negative predictive value and accuracy of each method.

Results:

Compared to clinical methods alone, addition of lung USG improved sensitivity (75% vs. 88%), specificity (18% vs. 75%) and accuracy (57% vs. 85%) for correct prediction of LDLT position.

Conclusion:

USG is a useful addition to the armamentarium of anaesthesiologist for the confirmation of LDLT position.

Ultrasonography for confirmation of endotracheal tube placement: a systematic review and meta-analysis

OBJECTIVE

This study aimed to undertake a systematic review and meta-analysis to summarize evidence on the diagnostic value of ultrasonography for the assessment of endotracheal tube placement in adult patients.

METHODS

The major databases, PubMed, EMBASE, and the Cochrane Library, were searched for studies published from inception to June 2014. We selected studies that used ultrasonography to confirm endotracheal tube placement. The search was limited to human studies, and had no publication date or country restrictions. Exclusion criteria included case reports, comments, reviews, guidelines and animal studies. Two reviewers extracted and verified the data independently. We summarized test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random effect models. Meta-regression analysis was performed to explore the source of heterogeneity. The methodological quality of individual studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool.

RESULTS

A total of 12 eligible studies involving adult patients and cadaveric models were identified from 1488 references. For detection of esophageal intubation, the pooled sensitivity was 0.93 (95% CI: 0.86-0.96) and the specificity was 0.97 (95% CI: 0.95-0.98). The area under the summary ROC curve was 0.97 (95% CI: 0.95-0.98). The positive and negative likelihood ratios were 26.98 (95% CI: 19.32-37.66) and 0.08 (95% CI: 0.04-0.15), respectively.

CONCLUSIONS

Current evidence supports that ultrasonography has high diagnostic value for identifying esophageal intubation. With optimal sensitivity and specificity, ultrasonography can be a valuable adjunct in this aspect of airway assessment, especially in situations where capnography may be unreliable.

Transtracheal ultrasound for verification of endotracheal tube placement: a systematic review and meta-analysis

PURPOSE

Early confirmation of endotracheal tube placement is of paramount importance to prevent hypoxia and its catastrophic consequences. Despite certain limitations, capnography is considered the gold standard to evaluate the proper placement of an endotracheal tube. Ultrasound is a novel tool with some definitive advantages over capnography. It enables a real-time view and can be performed quickly; furthermore, it is independent of pulmonary blood flow and does not require lung ventilation. In this review, we aimed to evaluate the diagnostic accuracy of transtracheal ultrasound in detecting endotracheal intubation.

SOURCE

We completed an extensive search of MEDLINE®, EMBASE™, The Cochrane Library, KoreaMed, LILACS, OpenGrey, and the World Health Organization International Clinical Trials Registry from their inception to September 4, 2014. The studies that met the inclusion criteria were pooled and a meta-analysis was conducted.

PRINCIPAL FINDINGS

Eleven studies and 969 intubations were included in the final analysis. Eight studies and 713 intubations were performed in emergency situations and the others were carried out in elective situations. Transtracheal ultrasonography's pooled sensitivity and specificity with 95% confidence intervals (CIs) were 0.98 (95% CI 0.97 to 0.99) and 0.98 (95% CI 0.95 to 0.99), respectively. In emergency scenarios, transtracheal ultrasonography showed an aggregate sensitivity and specificity of 0.98 (95% CI 0.97 to 0.99) and 0.94 (95% CI 0.86 to 0.98), respectively.

CONCLUSION

Transtracheal ultrasound is a useful tool to confirm endotracheal intubation with an acceptable degree of sensitivity and specificity. It can be used in emergency situations as a preliminary test before final confirmation by capnography.

Utility of ultrasound in the ICU

PURPOSE OF REVIEW

Use of ultrasound in the acute care setting has become more common in recent years. However, it still remains underutilized in the perioperative management of critical patients. In this review, we aim to increase the awareness of ultrasound as an important diagnostic modality that can be used in the perioperative period to improve patient care. Our main focus will be in describing the diagnostic uses of ultrasound to identify cardiac, pulmonary, airway and vascular diseases commonly encountered in acute care settings.

RECENT FINDINGS

We find that ultrasound can be used in a quick fashion to assess a haemodynamically unstable patient. Protocols are available to use ultrasound as a part of cardiopulmonary resuscitation. Ultrasound can help in deciding fluid vs. pressor treatment by evaluating the inferior vena cava and other cardiac structures.Lung ultrasound can not only help in diagnosing pneumothoracies and effusions but also look at lung recruitment and diaphragmatic movement, hence can aid in deciding extubation strategies. This modality can be utilized for confirmation of endotracheal tube.Recent interest in axillary vein cannulation with ultrasound guidance has gained some momentum.

SUMMARY

This article covers the recent developments and literature available on point of care ultrasound and its utilization in the perioperative period. We have not covered some other important uses of ultrasound such as abdominal examination looking at the aorta and other abdominal organs. This was beyond the scope of this article.

Sonographic confirmation of intubation: comparison of 3 methods in a pig model

OBJECTIVES

Several recent studies have investigated methods to confirm endotracheal tube (ETT) placement with sonography, using diaphragmatic movement, lung sliding, and transtracheal visualization of the ETT. To our knowledge, no studies have directly compared these 3 methods. This study aimed to directly compare the test characteristics of these 3 methods to determine ETT placement. Additionally, we compared the time required to complete the sonographic examination and the performers' confidence in their findings.

METHODS

We conducted a prospective randomized single-blinded study. Twenty-five recently euthanized pigs were intubated either in the esophagus or trachea, for a total of 50 intubations. Each of the 3 sonographic methods of intubation confirmation was performed by sonographers of different skill levels. Sonographic findings, the time to findings, and confidence in findings were recorded.

RESULTS

A total of 150 sonographic examinations were performed. There were no significant differences in the sensitivity, specificity, positive predictive value, negative predictive value, or accuracy for correct ETT placement between the 3 methods of intubation confirmation. On average, the transtracheal and thoracic methods were faster (12.5 and 14.0 seconds, respectively) than the diaphragmatic method (21.0 seconds; P < .01). There were no significant differences in operator confidence between the confirmation methods.

CONCLUSIONS

All 3 methods for determining ETT placement had similar test characteristics. Transtracheal and thoracic sonography were faster than diaphragmatic sonography for determining ETT placement in pigs.

Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae

OBJECTIVES

To create a state-of-the-art overview of the new and expanding role of ultrasonography in clinical decision-making, intervention and management of the upper and lower airways, that is clinically relevant, up-to-date and practically useful for clinicians.

METHODS

This is a narrative review combined with a structured Medline literature search.

RESULTS

Ultrasonography can be utilised to predict airway difficulty during induction of anaesthesia, evaluate if the stomach is empty or possesses gastric content that poses an aspiration risk, localise the essential cricothyroid membrane prior to difficult airway management, perform nerve blocks for awake intubation, confirm tracheal or oesophageal intubation and facilitate localisation of tracheal rings for tracheostomy. Ultrasonography is an excellent diagnostic tool in intraoperative and emergency diagnosis of pneumothorax. It also enables diagnosis and treatment of interstitial syndrome, lung consolidation, atelectasis, pleural effusion and differentiates causes of acute breathlessness during pregnancy. Patient safety can be enhanced by performing procedures under ultrasound guidance, e.g. thoracocentesis, vascular line access and help guide timing of removal of chest tubes by quantification of residual pneumothorax size.

CONCLUSIONS

Ultrasonography used in conjunction with hands-on management of the upper and lower airways has multiple advantages. There is a rapidly growing body of evidence showing its benefits.

TEACHING POINTS

• Ultrasonography is becoming essential in management of the upper and lower airways. • The tracheal structures can be identified by ultrasonography, even when unidentifiable by palpation. • Ultrasonography is the primary diagnostic approach in suspicion of intraoperative pneumothorax. • Point-of-care ultrasonography of the airways has a steep learning curve. • Lung ultrasonography allows treatment of interstitial syndrome, consolidation, atelectasis and effusion.

[Usefulness of bedside ultrasound compared to capnography and X-ray for tracheal intubation]

OBJECTIVES

The aim of this study was to assess the usefulness of bedside ultrasound compared to capnography and X-ray for endotracheal intubation in children and newborns.

MATERIALS AND METHODS

Hemodynamically stable children intubated in pedriatric and neonatal intensive care unit were included. Endotracheal tube insertion was checked after every intubation attempt by tracheal ultrasound and capnography simultaneously. The endotracheal tube insertion depth was then checked by assesment of lung sliding by thoracic ultrasound. Thereafter, Chest X-ray was performed and interpreted as usual. Time to perform each technique was recorded.

RESULTS

The study included 31 intubations in 26 patients (15 in PICU and 16 in NICU). There were no statistically significant differences between tracheal ultrasound and capnography or between thoracic ultrasound and x-ray in identifying the correct endotracheal intubation and assessment of endotracheal tube insertion depth, respectively. Sensibility and specificity of ultrasound compared to capnography was 92% and 100%, and 100% and 75% compared to X-ray. Ultrasound was significantly slower compared to capnography [12 (4-16) vs 6 (3-12) seconds; P<.001] and significantly quicker compared to X-ray [0.22 (0.17-0.40) vs. 20 (17-25) minutes, P<.001].

CONCLUSIONS

Ultrasound appears to be as effective as capnography, although slower, for identifying endotracheal intubation. Ultrasound may be useful in clinical situations, such as cardiopulmonary resuscitation where capnography is less reliable. Ultrasound is as effective and quicker than X-ray for assessment of endotracheal tube insertion depth, and it may contribute to decrease the routine use of X-ray after tracheal intubation.

Bedside US imaging in multiple trauma patients. Part 1: US findings and techniques

OBJECTIVES

The aim of this review article is to present the current views and visions of the role of ultrasound (US) in the management of patients with multiple trauma. The article is divided into two parts. Part 1 (US findings and techniques) will mainly deal with the technical aspects of US imaging in trauma patients and is written also for educational purposes. Part 2 (pathophysiology and US imaging in trauma patients) will deal with integration of US in the clinical and pathophysiological management of multiple trauma patients.

METHODS

A non-systematic review of the literature through PubMed search (restricted to the last 10 years) of original articles and review articles.

RESULTS

80 publications were selected for Part 1. Of these 80 articles, the author selected 50 according to personal criteria on the basis of their innovative or original contents (48 original articles and 2 literature review articles); 19 articles were furthermore extracted from the references of the selected publications. The information extracted from these 69 publications was organized into sections dealing with different fields of applications of US imaging in multiple trauma patients.

CONCLUSIONS

US imaging in trauma has evolved from the initial use, i.e., early diagnosis of peritoneal effusion (focused abdominal sonography for trauma), to a wider use known as resuscitative ultrasonography, and is today considered as an extension of physical examination to implement a more effective approach to clinical problems and increase the timeliness and safety of interventions.

Secondary confirmation of endotracheal tube position by diaphragm motion in right subcostal ultrasound view

Aims:

To assess the sensitivity and specificity of right subcostal ultrasound view to confirm correct endotracheal tube intubation (ETT).

Materials and Methods:

In this prospective study, apneic or paralyzed patients who had an indication of intubation were selected. Intubation and ventilation with bag were performed by the skilled third-year emergency medicine residents. The residents, following a brief training course of ultrasonography, interpreted the diaphragm motion, and identified either esophageal or tracheal intubation. The confirmation of ETT placement was done by the sonographer. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for tracheal versus esophageal intubation.

Results:

A total of 57 patients aged 59 ± 5 who underwent ETT insertion were studied. Thirty-four of them were male (60%). Ultrasound correctly identified 11 out of 12 esophageal intubations for a sensitivity of 92% (95% CI = 62-100), but misidentified one esophageal intubation as tracheal. Sonographers correctly identified 43 out of 45 (96%) tracheal intubations for a specificity of 96% (95% CI = 85-99), but misdiagnosed two tracheal intubations as esophageal.

Conclusions:

This study suggests that diaphragm motion in right subcostal ultrasound view is an effective adjunct to diagnose ETT place in patients undergoing intubation in emergency department.

Electrical impedance tomography for verification of correct endotracheal tube placement in paediatric patients: a feasibility study

BACKGROUND

Endotracheal tubes (ETTs) are frequently used in paediatric anaesthesia. Correct placement is crucial. The aim of this study was to evaluate electrical impedance tomography (EIT) for guiding and confirmation of paediatric ETT placement. In a retrospective analysis of stored EIT data, distribution of ventilation between left and right lung was used to verify correct paediatric ETT placement.

METHODS

Left and right lung ventilation was studied by EIT in 18 paediatric patients (median age: 53 months) requiring anaesthesia and endotracheal intubation. EIT was recorded before induction of anaesthesia, during mask ventilation, during ETT placement (including deliberate mainstem intubation), and after ETT repositioning according to the formula: ETT intubation depth (cm) = 3× ETT internal diameter (mm) or the mainstem intubation method (withdrawing the ETT 2 cm). Final ETT position was confirmed by fluoroscopy.

RESULTS

Following deliberate mainstem intubation, distribution of ventilation to the right lung was unequivocally demonstrated by EIT. Homogeneous distribution of ventilation between left and right lung monitored with EIT correlated in each patient with correct endotracheal ETT placement. The distribution of left and right lung ventilation differed significantly (P < 0.05) between the initial two-lung ventilation and subsequent right one-lung ventilation, and between right one-lung and subsequent two-lung ventilation according to auscultation and the final ETT position, respectively. In one patient, ETT was misplaced within the oesophagus which was also obvious from the EIT record.

CONCLUSION

This study demonstrates that EIT enables non-invasive recognition of correct ETT placement. Homogeneous right-left-lung ventilation is an indicator for correct ETT placement.

Real-time tracheal ultrasonography for confirmation of endotracheal tube placement during cardiopulmonary resuscitation

OBJECTIVE

This study aimed to evaluate the accuracy of tracheal ultrasonography for assessing endotracheal tube position during cardiopulmonary resuscitation (CPR).

METHODS

We performed a prospective observational study of patients undergoing emergency intubation during CPR. Real-time tracheal ultrasonography was performed during the intubation with the transducer placed transversely just above the suprasternal notch, to assess for endotracheal tube positioning and exclude esophageal intubation. The position of trachea was identified by a hyperechoic air-mucosa (A-M) interface with posterior reverberation artifact (comet-tail artifact). The endotracheal tube position was defined as endotracheal if single A-M interface with comet-tail artifact was observed. Endotracheal tube position was defined as intraesophageal if a second A-M interface appeared, suggesting a false second airway (double tract sign). The gold standard of correct endotracheal intubation was the combination of clinical auscultation and quantitative waveform capnography. The main outcome was the accuracy of tracheal ultrasonography in assessing endotracheal tube position during CPR.

RESULTS

Among the 89 patients enrolled, 7 (7.8%) had esophageal intubations. The sensitivity, specificity, positive predictive value, and negative predictive value of tracheal ultrasonography were 100% (95% confidence interval [CI]: 94.4-100%), 85.7% (95% CI: 42.0-99.2%), 98.8% (95% CI: 92.5-99.0%) and 100% (95% CI: 54.7-100%), respectively. Positive and negative likelihood ratios were 7.0 (95% CI: 1.1-43.0) and 0.0, respectively.

CONCLUSIONS

Real-time tracheal ultrasonography is an accurate method for identifying endotracheal tube position during CPR without the need for interruption of chest compression. Tracheal ultrasonography in resuscitation management may serve as a powerful adjunct in trained hands.

A feasibility study on bedside upper airway ultrasonography compared to waveform capnography for verifying endotracheal tube location after intubation

Background

In emergency settings, verification of endotracheal tube (ETT) location is important for critically ill patients. Ignorance of oesophageal intubation can be disastrous. Many methods are used for verification of the endotracheal tube location; none are ideal. Quantitative waveform capnography is considered the standard of care for this purpose but is not always available and is expensive. Therefore, this feasibility study is conducted to compare a cheaper alternative, bedside upper airway ultrasonography to waveform capnography, for verification of endotracheal tube location after intubation.

Methods

This was a prospective, single-centre, observational study, conducted at the HRPB, Ipoh. It included patients who were intubated in the emergency department from 28 March 2012 to 17 August 2012. A waiver of consent had been obtained from the Medical Research Ethics Committee. Bedside upper airway ultrasonography was performed after intubation and compared to waveform capnography. Specificity, sensitivity, positive and negative predictive value and likelihood ratio are calculated.

Results

A sample of 107 patients were analysed, and 6 (5.6%) had oesophageal intubations. The overall accuracy of bedside upper airway ultrasonography was 98.1% (95% confidence interval (CI) 93.0% to 100.0%). The kappa value (Κ) was 0.85, indicating a very good agreement between the bedside upper airway ultrasonography and waveform capnography. Thus, bedside upper airway ultrasonography is in concordance with waveform capnography. The sensitivity, specificity, positive predictive value and negative predictive value of bedside upper airway ultrasonography were 98.0% (95% CI 93.0% to 99.8%), 100% (95% CI 54.1% to 100.0%), 100% (95% CI 96.3% to 100.0%) and 75.0% (95% CI 34.9% to 96.8%). The likelihood ratio of a positive test is infinite and the likelihood ratio of a negative test is 0.0198 (95% CI 0.005 to 0.0781). The mean confirmation time by ultrasound is 16.4 s. No adverse effects were recorded.

Conclusions

Our study shows that ultrasonography can replace waveform capnography in confirming ETT placement in centres without capnography. This can reduce incidence of unrecognised oesophageal intubation and prevent morbidity and mortality.

Trial registration

National Medical Research Register NMRR11100810230.