Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial

The predictive value of chest X-ray for the depth of tracheal intubation in infants

OBJECTIVE

To determine the predictive value of chest X-ray for the depth of tracheal intubation in infants.

METHODS

Basic data of 161 infants under 3 years old was collected. Tracheal length was measured on preoperative chest radiographs to guide intubation depth. Correlation analysis was performed to examine relationships between tracheal length, age, and body weight.

RESULTS

161 cases (male/female = 142/19, no significant difference in sex, p = 0.09) were included, aged from 1 month to 28 months, weight from 2.5 kg to 18.0 kg. The endotracheal intubation depth reached the standard rate was 100 %, with 0 cases of over-deep or over-shallow intubation. Correlation analysis showed that tracheal length was positively correlated with both age and body weight, with stronger correlations observed in infants aged 1-12 months (r = 0.751 for age, r = 0.672 for weight, p < 0.01) compared to those aged 13-28 months (r = 0.672 for age, r = 0.408 for weight, p < 0.01).

CONCLUSION

Direct measurement of tracheal length on routinely performed chest X-rays is simple, feasible and safe, and may be another choice for guiding the depth of tracheal intubation in children.

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

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

Comparison of dynamic versus static ultrasound to confirm endotracheal tube depth

INTRODUCTION

After endotracheal intubation is performed, the location of the endotracheal tube (ETT) is confirmed followed by assessment of ETT depth. Physical examination can be unreliable and chest radiographs can lead to delayed recognition. Ultrasound may facilitate rapid determination of ETT depth at the bedside; however, the ideal technique is unknown.

METHODS

This was a randomized trial comparing the static versus dynamic technique for ETT depth assessment using a cadaver model. The ETT was randomized to correct versus deep placement. Seven physicians blinded to ETT location assessed the location using static (direct visualization of an inflated cuff) versus dynamic (active inflation of the ETT cuff) visualization. Outcomes included diagnostic accuracy, time to identification, and operator confidence with subgroup analyses by physician ultrasound experience.

RESULTS

420 total assessments were performed. The static technique was 99.1% (95% CI 94.8%-100%) sensitive and 97.1% (95% CI 91.9%-99.4%) specific. The dynamic technique was 100% (95% CI 96.7%-100%) sensitive and 100% (95% CI 96.7%-100%) specific. Time to identification was faster for the static technique (6.6 s; 95% CI 5.9-7.4 s) versus the dynamic technique (8.7 s; 95% CI 8.0-9.5 s). Operator confidence was lower for the static technique (4.4/5.0; 95% CI 4.3-4.5) versus the dynamic technique (4.7/5.0; 95% CI 4.6-4.8). There were no differences in the findings when assessed among expert or non-expert sonographers.

CONCLUSION

There was no statistically significant difference in the accuracy of ETT depth identification between the static or dynamic technique. However, utilizing the dynamic technique showed a statistically significant improvement in sonographer confidence and a concomitant increase in time to identification.

Camera-based Respiratory Imaging for Thoracic Asymmetry in Thoracic Surgery Patients

The current tool for assessing thoracic asymmetry of thoracic surgery patients is inappropriate for timely or frequent clinical routines due to its dependency on empirical physical examinations or specialized machines. This study investigates the camera-based respiratory imaging for screening thoracic asymmetry, in an intelligent and convenient way. The respiratory heatmaps are generated based on the respiratory magnitudes, phases and angles extracted from the chest video, and bilateral chest region of interest are compared statistically. Due to the variability of chest respiratory direction, spatial enhancement (SDR and SPCA) algorithms are proposed to magnify the respiratory energy. The proposed framework was validated in a clinical trial involving 31 patients, recorded by a smartphone camera. A high correlation was found between the camera measurements and patients' thoracic status in both the visual imaging and quantified indices. The respiratory imaging of camera shows a clear potential for assessing chest abnormalities of thoracic surgery patients.

[Prehospital emergency anesthesia in adults : Current recommendations for performing prehospital emergency anesthesia based on the recommendations for prehospital emergency anesthesia in adults]

The frequency of prehospital emergency anesthesia in Germany is around 2-3% of all emergency medical missions. The Association of the Scientific Medical Societies of Germany (AWMF) has published guidelines for the implementation of a prehospital emergency anesthesia. The purpose of this article is to highlight important aspects from these guidelines and to present the implementation and special features for specific patient groups. A case study is intended to illustrate that the preclinical setting can provide various facets that make a certain amount of experience and expertise indispensable. The article emphasizes that clear standard situations are not always present and that there are some challenges in the preclinical setting. Therefore, mastering the content of prehospital emergency anesthesia and the manual skills of induction of anesthesia are essential and obligatory for the emergency team.

Strategies to Improve Neonatal Intubation Safety by Preventing Endobronchial Placement of the Tracheal Tube-Literature Review and Experience at a Tertiary Center

Unintended endobronchial placement is a common complication of neonatal tracheal intubation and a threat to patient safety, but it has received little attention towards decreasing its incidence and mitigating associated harms. We report on the key aspects of a long-term project in which we applied principles of patient safety to design and implement safeguards and establish a safety culture, aiming to decrease the rate of deep intubation (beyond T3) in neonates to <10%. Results from 5745 consecutive intubations revealed a 47% incidence of deep tube placement at baseline, which decreased to 10-15% after initial interventions and remained in the 9-20% range for the past 15 years; concurrently, rates of deep intubation at referring institutions have remained high. Root cause analyses revealed multiple contributing factors, so countermeasures specifically aimed at improving intubation safety should be applied before, during, and immediately after tube insertion. Extensive literature review, concordant with our experience, suggests that pre-specifying the expected tube depth before intubation is the most effective and simple intervention, although further research is needed to establish accurate and accepted standards for estimating the expected depth. Presently, team training on intubation safety, plus possible technological advances, offer additional options for safer neonatal intubations.

Position Classification of the Endotracheal Tube with Automatic Segmentation of the Trachea and the Tube on Plain Chest Radiography Using Deep Convolutional Neural Network

Background: This study aimed to develop an algorithm for multilabel classification according to the distance from carina to endotracheal tube (ETT) tip (absence, shallow > 70 mm, 30 mm ≤ proper ≤ 70 mm, and deep position < 30 mm) with the application of automatic segmentation of the trachea and the ETT on chest radiographs using deep convolutional neural network (CNN). Methods: This study was a retrospective study using plain chest radiographs. We segmented the trachea and the ETT on images and labeled the classification of the ETT position. We proposed models for the classification of the ETT position using EfficientNet B0 with the application of automatic segmentation using Mask R-CNN and ResNet50. Primary outcomes were favorable performance for automatic segmentation and four-label classification through five-fold validation with segmented images and a test with non-segmented images. Results: Of 1985 images, 596 images were manually segmented and consisted of 298 absence, 97 shallow, 100 proper, and 101 deep images according to the ETT position. In five-fold validations with segmented images, Dice coefficients [mean (SD)] between segmented and predicted masks were 0.841 (0.063) for the trachea and 0.893 (0.078) for the ETT, and the accuracy for four-label classification was 0.945 (0.017). In the test for classification with 1389 non-segmented images, overall values were 0.922 for accuracy, 0.843 for precision, 0.843 for sensitivity, 0.922 for specificity, and 0.843 for F1-score. Conclusions: Automatic segmentation of the ETT and trachea images and classification of the ETT position using deep CNN with plain chest radiographs could achieve good performance and improve the physician’s performance in deciding the appropriateness of ETT depth.

Detecting Endotracheal Tube and Carina on Portable Supine Chest Radiographs Using One-Stage Detector with a Coarse-to-Fine Attention

In intensive care units (ICUs), after endotracheal intubation, the position of the endotracheal tube (ETT) should be checked to avoid complications. The malposition can be detected by the distance between the ETT tip and the Carina (ETT–Carina distance). However, it struggles with a limited performance for two major problems, i.e., occlusion by external machine, and the posture and machine of taking chest radiographs. While previous studies addressed these problems, they always suffered from the requirements of manual intervention. Therefore, the purpose of this paper is to locate the ETT tip and the Carina more accurately for detecting the malposition without manual intervention. The proposed architecture is composed of FCOS: Fully Convolutional One-Stage Object Detection, an attention mechanism named Coarse-to-Fine Attention (CTFA), and a segmentation branch. Moreover, a post-process algorithm is adopted to select the final location of the ETT tip and the Carina. Three metrics were used to evaluate the performance of the proposed method. With the dataset provided by National Cheng Kung University Hospital, the accuracy of the malposition detected by the proposed method achieves 88.82% and the ETT–Carina distance errors are less than 5.333±6.240 mm.

Optimising endotracheal length in adult cats: a retrospective CT study

OBJECTIVES

The aim of this study was to determine the maximal endotracheal insertion length by measuring the larynx to carina (L-C) distance by means of CT. An additional objective was to establish certain anatomical landmarks to optimise the process of endotracheal intubation (ETI).

METHODS

Head, neck and thoracic CT images from adult cats at a single referral hospital between 2013 and 2020 were retrospectively evaluated. After standardising and identifying key markers (larynx, carina and first rib) the L-C, larynx to first rib (L-1R) and first rib to carina (1R-C) distances were measured.

RESULTS

Forty-five adult cats were enrolled in the study, from which a total of nine different breeds were identified. The L-C distance was 14.3 ± 1.1 cm. This was longer in male (14.7 ± 1.1 cm) than in female cats (13.5 ± 0.7 cm). The first rib (1R) was 8.8 ± 0.7 cm from the larynx and the mean 1R-C distance was 5.4 ± 0.7 cm. The carina was found within the fifth intercostal space in 93.3% (n = 42) of the cats.

CONCLUSIONS AND RELEVANCE

The process of ETI in adult cats may be guided by using the L-C and L-1R distance for a maximal and optimal endotracheal tube introduction, respectively. In addition, the maximal insertion length may be guided by estimating the position of the carina parallel to the fifth intercostal space.

Lung Ultrasound to Assess One Lung Ventilation: A Pediatric Case Series

Objectives: One lung ventilation (OLV) is the preferred ventilation technique for thoracoscopy as it provides a better exposure of the operative field and grants the protection of the healthy lung. Preoperative evaluation of lung exclusion is necessary and different methods are available. In recent years lung ultrasound (US) gained popularity and its use for monitoring the endotracheal tube position is widely reported. The existing evidence on adults addresses lung US as effective, yet only few data are available in children. Therefore, we present our experience with lung US as verification method for pediatric OLV. Methods: All patients undergoing OLV for video-assisted thoracoscopic surgery from January 2019 to May 2021 and for whom lung exclusion was confirmed through lung US were involved. Lung exclusion was considered effective when absence of lung motion and presence of lung pulse were encountered. When lung US did not match these criteria, repositioning of the endobronchial device followed by US verification was performed. When lung US met the exclusion criteria surgery was started and direct thoracoscopic observation was used to verify lung exclusion. Results: A total of 20 patients, accounting for 22 procedures, were involved. Absence of lung motion and presence of lung pulse were assessed in the operative-side lung for all patients. Lung exclusion was confirmed through thoracoscopy. Postoperative lung US proved the reappearance of lung motion in the previously excluded lung. Conclusions: In our center experience lung US resulted to be a safe, effective, and time-saving verification method for OLV. Further studies are needed to define its sensitivity and specificity.

Determining Carina and Clavicular Distance-Dependent Positioning of Endotracheal Tube in Critically Ill Patients: An Artificial Intelligence-Based Approach

Early and accurate prediction of endotracheal tube (ETT) location is pivotal for critically ill patients. Automatic and timely detection of faulty ETT locations from chest X-ray images may avert patients' morbidity and mortality. Therefore, we designed convolutional neural network (CNN)-based algorithms to evaluate ETT position appropriateness relative to four detected key points, including tracheal tube end, carina, and left/right clavicular heads on chest radiographs. We estimated distances from the tube end to tracheal carina and the midpoint of clavicular heads. A DenseNet121 encoder transformed images into embedding features, and a CNN-based decoder generated the probability distributions. Based on four sets of tube-to-carina distance-dependent parameters (i.e., (i) 30-70 mm, (ii) 30-60 mm, (iii) 20-60 mm, and (iv) 20-55 mm), corresponding models were generated, and their accuracy was evaluated through the predicted L1 distance to ground-truth coordinates. Based on tube-to-carina and tube-to-clavicle distances, the highest sensitivity, and specificity of 92.85% and 84.62% respectively, were revealed for 20-55 mm. This implies that tube-to-carina distance between 20 and 55 mm is optimal for an AI-based key point appropriateness detection system and is empirically comparable to physicians' consensus.

Use of Electronic Auscultation in Full Personal Protective Equipment to Detect Ventilation Status in Selective Lung Ventilation: A Randomized Controlled Trial

Chest auscultation is the first procedure performed to detect endotracheal tube malpositioning but conventional stethoscopes do not conform to the personal protective equipment (PPE) protocol during the COVID-19 pandemic. This double-blinded randomized controlled trial evaluated the feasibility of using ear-contactless electronic stethoscope to identify endobronchial blocker established selective lung ventilation, simulating endobronchial intubation during thoracic surgery with full PPE. Conventional and electronic auscultation was performed without and with full PPE, respectively, of 50 patients with selective lung ventilation. The rates of correct ventilation status detection were 86 and 88% in the conventional and electronic auscultation groups (p = 1.00). Electronic auscultation revealed a positive predictive value of 87% (95% CI 77 to 93%), and a negative predictive value of 91% (95% CI 58 to 99%), comparable to the results for conventional auscultation. For detection of the true unilateral lung ventilation, the F1 score and the phi were 0.904 and 0.654, respectively for conventional auscultation; were 0.919 and 0.706, respectively for electronic auscultation. Furthermore, the user experience questionnaire revealed that the majority of participant anesthesiologists (90.5%) rated the audio quality of electronic lung sounds as comparable or superior to that of conventional acoustic lung sounds. In conclusion, electronic auscultation assessments of ventilation status as examined during thoracic surgery in full PPE were comparable in accuracy to corresponding conventional auscultation assessments made without PPE. Users reported satisfactory experience with the electronic stethoscope.

[Evaluation of the Endotracheal Tube by Ultrasound in Neonates]

The reliable evaluation of a correctly placed endotracheal tube is an essential challenge in neonatology. Point-of-care ultrasound is an emerging method to address this concern with the following advantages: less time-consuming, no exposure to radiation, less staff-intensive, and high tolerability by the patients. This article focuses on the evaluation of the clinical application of point-of-care ultrasound to examine the position of the endotracheal tube with regard to visualization, consistency compared to the chest X-ray, and the level of training to obtain sufficient results. We identified nine studies relevant to these questions. The visualization of the endotracheal tube by using point-of-care ultrasound is highly effective. The assessment of a correctly placed endotracheal tube is comparable to the results of a chest X-ray. The technique is suitable for any examiner with previous ultrasound experience. Future applications such as emergency intubations, implementation in the standard care of extremely low birth weight preterm babies, and use in low-resource settings could be promising. This article offers a practical guideline to promote the level of awareness and the clinical application.

Deep learning for anatomical interpretation of video bronchoscopy images

Anesthesiologists commonly use video bronchoscopy to facilitate intubation or confirm the location of the endotracheal tube; however, depth and orientation in the bronchial tree can often be confused because anesthesiologists cannot trace the airway from the oropharynx when it is performed using an endotracheal tube. Moreover, the decubitus position is often used in certain surgeries. Although it occurs rarely, the misinterpretation of tube location can cause accidental extubation or endobronchial intubation, which can lead to hyperinflation. Thus, video bronchoscopy with a decision supporting system using artificial intelligence would be useful in the anesthesiologic process. In this study, we aimed to develop an artificial intelligence model robust to rotation and covering using video bronchoscopy images. We collected video bronchoscopic images from an institutional database. Collected images were automatically labeled by an optical character recognition engine as the carina and left/right main bronchus. Except 180 images for the evaluation dataset, 80% were randomly allocated to the training dataset. The remaining images were assigned to the validation and test datasets in a 7:3 ratio. Random image rotation and circular cropping were applied. Ten kinds of pretrained models with < 25 million parameters were trained on the training and validation datasets. The model showing the best prediction accuracy for the test dataset was selected as the final model. Six human experts reviewed the evaluation dataset for the inference of anatomical locations to compare its performance with that of the final model. In the experiments, 8688 images were prepared and assigned to the evaluation (180), training (6806), validation (1191), and test (511) datasets. The EfficientNetB1 model showed the highest accuracy (0.86) and was selected as the final model. For the evaluation dataset, the final model showed better performance (accuracy, 0.84) than almost all human experts (0.38, 0.44, 0.51, 0.68, and 0.63), and only the most-experienced pulmonologist showed performance comparable (0.82) with that of the final model. The performance of human experts was generally proportional to their experiences. The performance difference between anesthesiologists and pulmonologists was marked in discrimination of the right main bronchus. Using bronchoscopic images, our model could distinguish anatomical locations among the carina and both main bronchi under random rotation and covering. The performance was comparable with that of the most-experienced human expert. This model can be a basis for designing a clinical decision support system with video bronchoscopy.

Comparison of clinical methods to diagnose pediatric endobronchial intubation-A randomized controlled trial

Background and Aims:

Diagnosing accurate placement of the tip of the endotracheal tube is crucial in pediatric practice. This study was conducted to find out the efficacy of five clinical methods to ascertain the tube position by a resident anesthesiologist.

Material and Methods:

This was a randomized crossover study conducted in a research institute. Fifty pediatric patients were enrolled. All patients were randomly allocated to tracheal (group T) or bronchial group (group B). The five clinical methods which were evaluated include the auscultation, observation of chest movements, bag compliance, tube depth, and capnography. In group T, the tube was placed in the trachea and later positioned in bronchus (assisted by fiberoptic bronchoscopy). The vice versa was done in group B. In each position, a single test followed by all tests was performed and after the change of position, the same single test followed by all tests was performed. Correct and incorrect diagnoses by tests in detecting tube positions were made and their sensitivity and odds ratio were estimated.

Results:

The tube depth and combination of all tests detected endobronchial intubation with a sensitivity of 88% and 97%, respectively, which is more than that of auscultation (70%) and observation (55%). Evaluation of the difference in agreement level of tube depth to detect tube-position showed the odds ratio of 2.28 (0.17–30.95) for detecting endobronchial intubation.

Conclusion:

We observed that the tube-depth was better than the other individual tests in diagnosing endobronchial intubation in pediatric patients. However, its efficacy is lesser than that of performing all clinical tests together.

Risk factors and outcomes of unrecognised endobronchial intubation in major trauma patients

Background

Emergency tracheal intubation during major trauma resuscitation may be associated with unrecognised endobronchial intubation. The risk factors and outcomes associated with this issue have not previously been fully defined.

Methods

We retrospectively analysed adult patients admitted directly from the scene to the ED of a single level 1 trauma centre, who received either prehospital or ED tracheal intubation prior to initial whole-body CT from January 2008 to December 2019. Our objectives were to describe tube-to-carina distances (TCDs) via CT and to assess the risk factors and outcomes (mortality, length of intensive care unit stay and mechanical ventilation) of patients with endobronchial intubation (TCD <0 cm) using a multivariable model.

Results

We included 616 patients and discovered 26 (4.2%) cases of endobronchial intubation identified on CT. Factors associated with an increased risk of endobronchial intubations were short body height (OR per 1 cm increase 0.89; 95% CI 0.84 to 0.94; p≤0.001), a high body mass index (OR 1.14; 95% CI 1.04 to 1.25; p=0.005) and ED intubation (OR 3.62; 95% CI 1.39 to 8.90; p=0.006). Eight of 26 cases underwent tube thoracostomy, four of whom had no evidence of underlying chest injury on CT. There was no statistically significant difference in mortality or length of stay although the absolute number of endobronchial intubations was small.

Conclusions

Short body height and high body mass index were associated with endobronchial intubation. Before considering tube thoracostomy in intubated major trauma patients suspected of pneumothorax, the possibility of unrecognised endobronchial intubation should be considered.

Accuracy of pediatric advanced life support method for predicting the depth of endotracheal tube in Indonesian children

BACKGROUND The pediatric advanced life support (PALS) method can predict the depth of endotracheal tube (ETT) in pediatric patients easily, but it has limitations due to variations in the children’s characteristics, especially the racial consideration. This study compared the accuracy of ETT depth prediction based on the PALS methods in Indonesian children. METHODS Patients aged 0–12 years, who underwent elective surgery with oral intubation, were recruited consecutively based on their ages: 0–24 months and 25 months–12 years for this cross-sectional study in Cipto Mangunkusumo Hospital, Jakarta, Indonesia from June to August 2014. Bland–Altman analysis was used to compare the two measurement methods: PALS method to predict the ETT depth accuracy and auscultation method to confirm the position of the ETT. Furthermore, correlation analysis was done to examine the relationship of age, weight, height, and ETT internal diameter with ETT depth. RESULTS 50 patients were recruited in each group. Bland–Altman test of ETT depth in the 0–24 months age group showed a 1.18 cm mean difference from confirmation using the auscultation method (limits of agreement −0.71 to 3.08). The 25 months–12 years age group showed a 1.11 cm mean difference with limits of agreement were −0.95 to 3.17 from confirmation using the auscultation method. Age and weight had the strongest correlation value to ETT depth in the 25 months–12 years age group (R2 = 62.3%). CONCLUSIONS The PALS method is inaccurate for predicting ETT depth in Indonesian children aged 0–12 years old compared with the auscultation method.

Evaluation of Endotracheal Tube Depth in the Out-of-Hospital Setting

Introduction Endobronchial intubation is a known complication of endotracheal intubation with significant associated morbidity and a reported incidence of up to 15%. In the out-of-hospital setting, paramedics must rely on bedside techniques to confirm appropriate endotracheal tube (ETT) depth. The present real-world practices of paramedics have not been described in this regard. Methods A multi-point survey was distributed to paramedics within the state of Pennsylvania. Participants were scored on the basis of their use of techniques to confirm ETT depth with the highest sensitivity to exclude endobronchial intubation. Results Four-hundred nine (409) responses from 111 emergency medical services (EMS) agencies were recorded. Participants were found to evaluate endotracheal tube depth via auscultation of bilateral breath sounds (91.7% of participants), visualization of the endotracheal tube as it advances 1-2 cm beyond the vocal cords (82.9%), observation of symmetrical chest rise (80.0%), and by securing the ETT at 21 and 23 cm at the incisors for women and men (18.6%). Experienced paramedics were more likely to use the 21/23 cm rule (p=0.039). Participants did not employ the cumulative use of these techniques (p < 0.001) as per a method that has been previously described to exclude endobronchial intubation with 100% sensitivity. Conclusion These data suggest that paramedics are not presently employing the most sensitive techniques to exclude endobronchial intubation. An educational initiative and protocol update may be beneficial.

Portable Chest Radiography Immediately after Post-Cardiac Surgery; an Essential Tool for the Early Diagnosis and Treatment of Atelectasis: a Case Report

Atelectasis after endobronchial intubation (ETT) is a known complication of general anesthesia. In-bed auscultation of lungs and use of the 21/23 rule are the two suggestive, but not reliable, methods for the early detection of this event; however, none of them guarantees its prevention. The portable chest radiograph (CXR) is a simple, quick method to detect atelectasis and proper placement of the endotracheal tube in the intensive care unit (ICU). A case of postsurgical, ICU-admitted patient was presented in the report, demonstrating left (LT) lung atelectasis in immediate portable CXR without any evidence of respiratory or hemodynamic abnormality. Portable CXR showed that the tip of the endotracheal tube was located in the lumen of the right main bronchus, leading to LT lung total atelectasis. After repositioning of ETT to the lumen of the trachea, atelectasis was disappeared in early follow-up CXR.

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.

Lung sonography can improve the specificity of determination of left-sided double-lumen tracheal tube position in both novices and experts: a randomised prospective study

Objective

Lung sonography can be helpful to determine the position of a left-sided double-lumen tube (DLT). However, clinical experience is required for correct assessment. We investigated whether lung sonography can improve the diagnostic efficacy of determining the DLT position in novices and experts.

Methods

In this randomised prospective clinical study, 88 patients were allocated to two groups using auscultation or lung sonography for initial assessment of the DLT position. In each group, two repeated assessments were performed; the first was performed by a novice, and the second was performed by an expert. The final DLT position was confirmed by fibre-optic bronchoscopy. The primary outcome was the diagnostic efficacy (including overall accuracy, sensitivity, and specificity) in confirming the DLT position.

Results

In both the novices and experts, the specificity of determining the DLT position was significantly higher with lung sonography than auscultation (60.0% vs. 21.7% and 66.7% vs. 37.5%, respectively). Additionally, the predictability of an incorrect position was similar between the novices and experts using lung sonography (area under the curve of 0.665 and 0.690, respectively).

Conclusions

Lung sonography can improve the diagnostic efficacy of detecting an incorrect DLT position in both novices and experts.

Use of Handheld Point-of-Care Ultrasound in Emergency Airway Management

Emergency airway management (EAM) is associated with a high rate of complications, morbidity, and mortality. Handheld point-of-care ultrasound shows promise as an emerging technology to facilitate rapid screening for difficult laryngoscopy, identify the cricothyroid membrane for potential cricothyroidotomy, and assess for increased aspiration risk, as well as provide confirmation of proper endotracheal tube positioning. This review summarizes the available evidence for the use of point-of-care ultrasound in EAM, provides an algorithm to facilitate its incorporation into existing EAM practice to improve patient safety, and serves as a framework for future validation studies.

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.

Airway ultrasound: Point of care in children-The time is now

BACKGROUND

Point-of-care ultrasonography of the airway is becoming a first-line noninvasive adjunct assessment tool of the pediatric airway. It is defined as a focused and goal-directed portable ultrasonography brought to the patient and performed and interpreted on the spot by the provider. Successful use requires a thorough understanding of airway anatomy and ultrasound experience.

AIMS

To outline the many benefits, and some limitations, of airway ultrasonography in the clinical and perioperative setting.

MATERIALS AND METHODS

Expert review of the recent literature.

RESULTS

Ultrasound assessment of the airway may provide the clinician with valuable information that is specific to the individual airway static and dynamic anatomy of the patient. Ultrasound can help identify vocal cord dysfunction and pathology, assess airway size, predict the appropriate diameter of endotracheal and tracheostomy tubes, differentiate tracheal from esophageal intubation, localize the cricothyroid membrane for emergency airway access and identify tracheal rings for US-guided tracheostomy. Ultrasonography is also a great tool for the intraoperative diagnosis of a pneumothorax, the visualization of the movement of the diaphragms, and quantifying the amount of gastric content. Ultrasonography signs, tips, and pearls that allow these diagnoses are highlighted. The major disadvantage of ultrasonography remains interobserver variability, and operator dependence, as it requires specific training and experience.

CONCLUSION

Although it is not standard of care yet, there is significant potential for the integration of ultrasound technology into the routine care of the airway.

A Formula for Estimating the Appropriate Tube Depth for Intubation

An estimation of the appropriate tubing depth for fixation is helpful to prevent inadvertent endobronchial intubation and prolapse of cuff from the vocal cord. A feasible estimation formula should be established. We measured the anatomical length of the upper-airway tract through the oral and nasal pathways on cephalometric radiographs and tried to establish the estimation formula from the height of the patient. The oral upper-airway tract was measured from the tip of the incisor to the vocal cord. The nasal upper-airway tract was measured from the tip of the nostril to the vocal cord. The tracts were smoothly traced by using software. The length of the oral upper-airway tract was 13.2 ± 0.8 cm, and the nasal upper-airway tract was 16.1 ± 0.9 cm. We found no gender difference ( p > .05). The correlations between the patients' height and the length of the oral and nasal upper-airway tracts were 0.692 and 0.760, respectively. We found that the formulas (height/10) - 3 (in cm) for oral upper-airway and (height/10) + 1 (in cm) for nasal upper-airway tract are the simple fit estimation formulas. The average error and standard deviation of the estimated values from the measured values were 0.50 ± 0.66 cm for the oral tract and 0.39 ± 0.63 cm for the nasal tract. Thus, considering the length of the intubation marker of each product (DM), we would like to propose the length of tube fixation as (height/10) + 1 + DM for nasal intubation and (height/10) - 3 + DM for oral intubation. In conclusion, the estimation formulas of (height/10) - 3 + DM and (height/10) + 1 + DM for oral and nasal intubation, respectively, are within almost 1 cm error in most cases.

Effects of tracheal intubation and tracheal tube position on regional lung ventilation: an observational study

Anaesthesia and positive pressure ventilation cause ventral redistribution of regional ventilation, potentially caused by the tracheal tube. We used electrical impedance tomography to map regional ventilation during anaesthesia in 10 patients with and without a tracheal tube. We recorded impedance data in subjects who were awake, during bag-mask ventilation, with the tracheal tube positioned normally, rotated 90° to each side and advanced until in an endobronchial position. We recorded the following measurements: ventilation of the right lung (proportion, %); centre of ventilation (100% = entirely ventral); global inhomogeneity (0% = homogenous); and regional ventilation delay, an index of temporal heterogeneity. We compared the results using Student's t-tests. Relative to subjects who were awake, anaesthesia with bag-mask ventilation reduced right-sided ventilation by 5.6% (p = 0.002), reduced regional ventilation delay by 1.6% (p = 0.025), and moved the centre of ventilation ventrally from 51.4% to 58.2% (p = 0.0001). Tracheal tube ventilation caused a further centre of ventilation increase of 1.3% (p = 0.009). With the tube near the carina, right-sided ventilation increased by 3.2% (p = 0.031) and regional ventilation delay by 2.8% (p = 0.049). Tube rotation caused a 1.6% increase in right-sided ventilation compared with normal position (p = 0.043 left and p = 0.031 right). Global inhomogeneity remained mostly unchanged. Ventral ventilation with positive pressure ventilation occurred with bag-mask ventilation, but was exacerbated by a tracheal tube. Tube position influenced ventilation of the right and left lungs, while ventilation overall remained homogenous. Tube rotation in either direction resulted in ventilation patterns being closer to when awake than either bag-mask ventilation or a normally positioned tube. These results suggest that even ideal tube positioning cannot avoid the ventral shift in ventilation.

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.

A controlled trial to investigate whether the orientation of the bevel and angle of approach determine the side of endobronchial intubation in an adult manikin

One of the commonest complications of endotracheal intubation occurs when the tip of the endotracheal tube passes distal to the carina and enters one of the main bronchi. The perioperative practitioner may observe high airway pressures, hypoxia or even pneumothorax. The most common reason given for the high incidence of right endobronchial intubation is that the right main bronchus comes off the trachea at a more acute angle from the midline. We sought, however, to explore two other factors which may explain this phenomenon – the angle of the tube’s bevel and its trajectory of approach. We conducted a prospective controlled trial in which doctors from our department intubated the trachea of an adult manikin in three distinct sets using standard tube, reversed tubes and reversed laryngoscope blades. We found that the angle of the bevel and trajectory of approach determines the side of endobronchial intubation in an adult manikin.

Is prehospital endobronchial intubation a risk factor for subsequent ventilator associated pneumonia? A retrospective analysis

More than half of patients under mechanical ventilation in the intensive care unit (ICU) are field-intubated, which is a known risk factor for ventilator associated pneumonia (VAP). We assessed whether field endobronchial intubation (EBI) is associated with the development of subsequent VAP during the ICU stay. This retrospective, nested case-control study was conducted in a cohort of field-intubated patients admitted to an ICU of a teaching hospital during a three-year period. Cases were defined as field-intubated patients with EBI and controls corresponded to field-intubated patients with proper position of the tracheal tube on admission chest X-ray. Primary endpoint was the development of early VAP. Secondary endpoints included the development of early ventilator associated tracheo-bronchitis, late VAP, duration of mechanical ventilation, length of stay and mortality in the ICU. A total of 145 patients were studied (mean age: 54 ± 19 years; men: 74%). Reasons for field intubation were predominantly multiple trauma (49%) and cardiorespiratory arrest (38%). EBI was identified in 33 patients (23%). Fifty-three patients (37%) developed early or late VAP. EBI after field intubation was associated with a nearly two-fold increase of early VAP, though not statistically significant (30% vs. 17%: p = 0.09). No statistically significant difference was found regarding secondary outcomes. The present study suggests that inadvertent prehospital EBI could be associated with a higher incidence of early-onset VAP. Larger studies are required to confirm this hypothesis. Whether strategies aimed at decreasing the incidence and duration of EBI could reduce the incidence of subsequent VAP remains to be determined.

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.

Ideal Length of Oral Endotracheal Tube for Critically Ill Intubated Patients in an Asian Population: Comparison to Current Western Standards

Background

Endotracheal (ET) intubation is used to maintain the airway patency of patients during mechanical ventilation and is inserted at a particular depth into the trachea through the nose, mouth, or through an incision in the neck. The aim of our study was to validate the ideal length of an oral endotracheal tube (ETT) in the Asian population compared to Western standards.

Methods

Patient records with an oral ETT inserted between April 2011 and June 2015 in the Intensive Care Unit (ICU) of a hospital were retrospectively analyzed. The key variables included demographics, height, and ideal body weight of the patient, length of the oral ETT, and chest X-rays. Statistical analyses were performed using R software (https://cran.r-project.org/).

Results

There were 876 incidences of oral cuffed ETT insertions in 708 adult patients ≥ 18 years of age. The median ETT depth in all the ethnic groups (Chinese, Malay, Indians, and others) was 22 cm. The median depth of oral ETTs was 22 cm in males and 21 cm in females as compared to Western standards (males: P < 0.0001; females: P = 0.93). In ICU patients intubated with an ETT at an acceptable distance from the carina (2 - 5 cm), the median ETT depth was different in males (P < 0.0001) but was similar in females (P = 0.87).

Conclusion

We suggest that males and females in the Asian population, especially in South East Asia, should have their ETTs secured at the corner of mouth by at least 1 cm less in comparison to the Western population (22 cm in males and 20 cm in females).

[Performance of prehospital emergency anesthesia and airway management : An online survey]

BACKGROUND

The goal of rapid sequence induction (RSI) in cases of emergency situations is to secure the airway as quickly as possible to prevent pulmonary aspiration of gastric contents; however, the technique itself is not standardized. For example, the choice of drugs, application of cricoid pressure and the patient position remain controversial. A survey of emergency medical services (EMS) physicians throughout Germany was carried out to assess the different RSI techniques used and with respect to complying with the national guidelines for emergency airway management anesthesia and local standard operating procedures (SOP).

MATERIAL AND METHODS

Between 1 April 2017 and 31 May 2017, EMS medical directors in Germany were contacted and asked to distribute a 28-question online questionnaire to local EMS physicians. Of the questions 26 were multiple choice and 2 with plain text. After 6 weeks an e‑mail reminder was sent. In addition, the survey was distributed via social media to EMS physicians.

RESULTS

In total the survey was opened 2314 times and 1074 completed responses were received (completion rate 46%). Most of the participants were male (78%) and anesthesiologists (70%) and only one quarter had a local SOP for RSI. The most frequently used muscle relaxant was succinylcholine (62%) and over half of the participants reported using cricoid pressure (57%). There was a distinction between the specialist disciplines in the selection of drugs. Propofol was used most by anesthesiologists, while the others still used etomidate on a larger scale. Nearly 100% could fall back on supraglottic devices (one third laryngeal mask, two thirds laryngeal tube) but only 32.8% with the recommended esophageal drainage. A video laryngoscope was available to 51% of all EMS physicians surveyed.

CONCLUSION

The results of the survey demonstrate heterogeneity in RSI techniques used by EMS physicians in Germany. Medical equipment and safe care practices, such as labeling of syringes varied considerably between different service areas. The recommendations of the S1 national guidelines on emergency airway management and anesthesia should be adhered to together with the implementation of local SOPs.

Effect of one-lung ventilation on end-tidal carbon dioxide during cardiopulmonary resuscitation in a pig model of cardiac arrest

Unrecognized endobronchial intubation frequently occurs after emergency intubation. However, no study has evaluated the effect of one-lung ventilation on end-tidal carbon dioxide (ETCO₂) during cardiopulmonary resuscitation (CPR). We compared the hemodynamic parameters, blood gases, and ETCO₂ during one-lung ventilation with those during conventional two-lung ventilation in a pig model of CPR, to determine the effect of the former on ETCO₂. A randomized crossover study was conducted in 12 pigs intubated with double-lumen endobronchial tube to achieve lung separation. During CPR, the animals underwent three 5-min ventilation trials based on a randomized crossover design: left-lung, right-lung, or two-lung ventilation. Arterial blood gases were measured at the end of each ventilation trial. Ventilation was provided using the same tidal volume throughout the ventilation trials. Comparison using generalized linear mixed model revealed no significant group effects with respect to aortic pressure, coronary perfusion pressure, and carotid blood flow; however, significant group effect in terms of ETCO₂ was found (P < 0.001). In the post hoc analyses, ETCO₂ was lower during the right-lung ventilation than during the two-lung (P = 0.006) or left-lung ventilation (P < 0.001). However, no difference in ETCO₂ was detected between the left-lung and two-lung ventilations. The partial pressure of arterial carbon dioxide (PaCO₂), partial pressure of arterial oxygen (PaO₂), and oxygen saturation (SaO₂) differed among the three types of ventilation (P = 0.003, P = 0.001, and P = 0.001, respectively). The post hoc analyses revealed a higher PaCO₂, lower PaO₂, and lower SaO₂ during right-lung ventilation than during two-lung or left-lung ventilation. However, the levels of these blood gases did not differ between the left-lung and two-lung ventilations. In a pig model of CPR, ETCO₂ was significantly lower during right-lung ventilation than during two-lung ventilation. However, interestingly, ETCO₂ during left-lung ventilation was comparable to that during two-lung ventilation.

Point-of-care ultrasound versus auscultation in determining the position of double-lumen tube

This study was designed to assess the accuracy of point-of-care ultrasound in determining the position of double-lumen tubes (DLTs).A total of 103 patients who required DLT intubation were enrolled into the study. After DLTs were tracheal intubated in the supine position, an auscultation researcher and ultrasound researcher were sequentially invited in the operating room to conduct their evaluation of the DLT. After the end of their evaluation, fiberscope researchers (FRs) were invited in the operating room to evaluate the position of DLT using a fiberscope. After the patients were changed to the lateral position, the same evaluation process was repeated. These 3 researchers were blind to each other when they made their conclusions. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were obtained by statistical analysis.When left DLTs (LDLTs) were used, the accuracy of ultrasound (84.2% [72.1%, 92.5%]) was higher than the accuracy of auscultation (59.7% [45.8%, 72.4%]) (P < .01). When right DLTs (RDLTs) were used, the accuracy of ultrasound (89.1% [76.4%, 96.4%]) was higher than the accuracy of auscultation (67.4% [52.0%, 80.5%]) (P < .01). When LDLTs were used in the lateral position, the accuracy of ultrasound (75.4% [62.2%, 85.9%]) was higher than the accuracy of auscultation (54.4% [40.7%, 67.6%]) (P < .05). When RDLT were used, the accuracy of ultrasound (73.9% [58.9%, 85.7%]) was higher than the accuracy of auscultation (47.8% [32.9%, 63.1%]) (P < .05).Assessment via point-of-care ultrasound is superior to auscultation in determining the position of DLTs.

The Airway and Lungs

Extremely useful and relevant information can be obtained when analysing the position assumed by patients with dyspnoea. Relief of breathlessness in a sitting or standing position compared to the recumbent position is referred to as orthopnoea. While increased venous return in the supine patient is well tolerated in individuals with a preserved heart function, this leads to pulmonary venous congestion, an increase in interstitial lung water and a subsequent reduction of lung capacities with resultant shortness of breath in patients with impaired heart function. Accordingly, patients with heart failure prefer to sit upright (e.g. supporting their back with pillows to achieve a maximum upright position) (Fig. 5.1). Conversely, placing the patient into a supine position may be used as a stress test to exclude respiratory distress due to heart failure or (pulmonary) fluid overload. A history of paroxysmal nocturnal dyspnoea characterized by repeated awakening due to breathlessness while sleeping in the recumbent position is a typical symptom of heart failure.

Examination of Patients in the Intensive Care Unit

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Careful examination of the intensive care unit (ICU) patient remains essential because it is the only way (among many examples) to detect the purulence around intravenous lines, the warmth of an infected joint, the purpuric skin lesions of septic emboli, the wheezing of bronchospasm, the neck stiffness of meningitis, or the absent doll’s-eyes of cerebellar stroke.

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The modified early warning score accurately identifies a patient’s risk of hospital mortality.

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In patients with shock, several findings have diagnostic value. For example, the absence of warm hands decreases the probability of septic shock, the presence of elevated venous pressure and crackles increases the probability of cardiogenic shock, and the presence of a pulse pressure increment after passive leg elevation increases the probability of hypovolemic shock.

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The findings of cool limbs, prolonged capillary refill times, and mottling of the limbs (i.e., blotchy or lacelike pattern of dusky discoloration) all increase the probability of reduced cardiac output and a worse prognosis.

Guidelines for the management of tracheal intubation in critically ill adults

These guidelines describe a comprehensive strategy to optimize oxygenation, airway management, and tracheal intubation in critically ill patients, in all hospital locations. They are a direct response to the 4^th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society, which highlighted deficient management of these extremely vulnerable patients leading to major complications and avoidable deaths. They are founded on robust evidence where available, supplemented by expert consensus opinion where it is not. These guidelines recognize that improved outcomes of emergency airway management require closer attention to human factors, rather than simply introduction of new devices or improved technical proficiency. They stress the role of the airway team, a shared mental model, planning, and communication throughout airway management. The primacy of oxygenation including pre- and peroxygenation is emphasized. A modified rapid sequence approach is recommended. Optimal management is presented in an algorithm that combines Plans B and C, incorporating elements of the Vortex approach. To avoid delays and task fixation, the importance of limiting procedural attempts, promptly recognizing failure, and transitioning to the next algorithm step are emphasized. The guidelines recommend early use of a videolaryngoscope, with a screen visible to all, and second generation supraglottic airways for airway rescue. Recommendations for emergency front of neck airway are for a scalpel-bougie-tube technique while acknowledging the value of other techniques performed by trained experts. As most critical care airway catastrophes occur after intubation, from dislodged or blocked tubes, essential methods to avoid these complications are also emphasized.