Point-of-care ultrasound (POCUS) of the upper airway. Can J Anaesth. 2018;65:473-484. [PMID: 29349733 DOI: 10.1007/s12630-018-1064-8]

Airway and Thoracic Ultrasound

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

The Difficult Airway in Patients with Cancer

PURPOSE OF REVIEW

The goal of this review is to provide an overview of difficult airway management in the cancer population.

RECENT FINDINGS

Difficult airways can be unanticipated; however, several anatomical and physiological features may predict difficult airway management, with several specific for the cancer patient population. New technologies and techniques for airway management, including non-invasive oxygenation, and even the utilization of ECMO, have led to better outcomes and decreased morbidity. Furthermore, the incorporation of multidisciplinary airway teams has helped reduce morbidity associated with predicted and known difficult airways. Cancer patients may exhibit or develop anatomic and physiologic features that may predispose them to difficulty with airway management. As our technologies for airway management continue to advance, as well as further commitment to more interdisciplinary collaboration, difficult airway management in the cancer population will continue to become safer.

Tracheal Ultrasound for Diagnosis of Tracheal Cartilaginous Sleeve in Patients with Syndromic Craniosynostosis

OBJECTIVE

The aim of this study was to assess the utility of ultrasound (US) imaging for diagnosis of abnormal tracheal morphology, such as tracheal cartilaginous sleeves (TCS), in patients with syndromic craniosynostosis (SC).

STUDY DESIGN

Age-matched cohort study.

SETTING

Tertiary pediatric hospital.

METHODS

Two age-matched cohorts were identified: patients with SC and known TCS based upon airway endoscopy and normal controls without tracheal pathology. Enrolled patients underwent awake US of the neck which were randomized and reviewed by blinded pediatric radiologists and rated on presence or absence of normal tracheal cartilage morphology and visualization or nonvisualization of a tracheostomy tube. Fisher's exact test was used to assess pooled data. Fleiss' Kappa (κ) was calculated to assess inter-rater reliability.

RESULTS

Ten patients were included in each cohort. Control patients were gender and age-matched to TCS patients with a mean difference of 3.7 months (±3.9 months). Across all raters, cartilage type was correctly identified in 93% (95% confidence interval [CI]: 84%-98%) and tracheostomy visualization in 97% (95% CI: 89%-99%). The sensitivity and specificity for detection of abnormal cartilage pathology was 87% and 100%, respectively. Inter-rater reliability for cartilage assessment was κ = 0.88 (95% CI: 0.67-1.00, P < .05) and 0.83 (95% CI: 0.58-1.00, P < .05) for tracheostomy presence.

CONCLUSION

This study demonstrated that tracheal US is a feasible, accurate screening tool for TCS, and can be successfully performed non-sedated in patients up to 18 years of age, both with and without tracheostomy tubes in place.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part II

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Bedside Ultrasound: The Silent Guardian for Upper Airway Assessment and Management

Ultrasound evaluation of the upper airway has emerged as an essential instrument for clinicians, offering real-time assessment that can help to guide interventions and improve patient outcomes. This review aims to provide health care providers with a practical approach to performing ultrasound evaluation of the upper airway, covering basic physics relevant to upper airway ultrasound, the identification of key anatomical structures, and elucidating its various clinical applications, such as prediction of difficult airway, confirmation of endotracheal intubation, and guidance for surgical airway procedures and airway blocks. We also discuss evidence-based training programs, limitations, and future directions of ultrasound imaging of the upper airway.

Training Requirements in Point-of-Care Ultrasonography of the Upper Airway: A Feasibility Study

OBJECTIVES

Point-of-care ultrasonography of the upper airway can be a useful supplement to conventional pre-anesthetic clinical evaluations. However, the reliability of such examinations is highly operator-dependent and proper training in sonoanatomy and ultrasound operational skills are required. The objective of this study aims to assess the minimum training requirements for applying a predefined upper airway scanning protocol in healthy volunteers by anesthesia trainees.

METHODS

Twenty-two healthy volunteer members of the Operating Room staff participated in the study. A predefined scanning protocol that included the identification of specific structures (hyoid bone, vocal cords, thyrohyoid membrane/epiglottis/pre-epiglottic space, cricothyroid membrane, and thyroid gland), as well as the performance of specific measurements (distance from the hyoid bone to skin, anterior commissure to skin, epiglottis to skin, and thyroid isthmus to skin) was taught in a single-day training course. The trainees' competence was assessed after multiple scanning repetitions performed over a week. Mixed effects regression models were applied for the trainee-instructor differences in all ultrasound measurements.

RESULTS

Cricothyroid membrane visualization had the lowest success rate (88%). Trainee-instructor differences were statistically significant for hyoid bone-to-skin (P < .001) and epiglottis-to-skin distances (P = .016). Measurement of the distance from the epiglottis to the skin required more scanning repetitions to achieve minimum deviance compared with other measurements. Ten or fewer scanning repetitions were sufficient to achieve minimum deviance for all four measurements.

CONCLUSIONS

At least 10 scanning repetitions of a pre-defined upper airway scanning protocol can be used as the minimum standard for training.

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.

Tracheal Mirror Image Artifact in Patients With Normal and Pathologic Tracheas

Ultrasonography is gaining popularity as a diagnostic imaging modality for airway pathology. Tracheal ultrasound (US) has several nuances that are important for clinicians, including imaging artifacts, which can be mistaken for pathology. Tracheal mirror image artifacts (TMIAs) occur when the US beam is reflected back to the transducer in a nonliner direction or with multiple timesteps. It has previously been believed that the convexity of the tracheal cartilage prevents mirror image artifacts, but in reality, the air column acts as an acoustic mirror and causes TMIA. We describe a cohort of patients with both normal and pathologic tracheas, all of whom have TMIA on the tracheal US. These artifacts are important to recognize, especially as the airway US becomes more commonplace.

Ultrasound-Assisted Management for Tracheal Intubation in the Patient with Tracheal Diverticulum

Tracheal diverticulum (TD) is a rare disease. Due to the worldwide pandemic of COVID-19, the increase of routine preoperative chest CT examination has led to a higher detection rate of TD. Although TD is very rare, it is one of the reasons for difficult intubation and difficult ventilation. Improper treatment can cause severe airway emergencies such as diverticulum tearing, tracheal rupture, and subcutaneous or mediastinal emphysema. Unfortunately, there are few studies on TD, especially in perioperative airway and anesthesia management. This paper reports a case of TD found by preoperative chest CT examination who required tracheal intubation under general anesthesia. For the first time, ultrasound was used to confirm the position of tracheal tube and TD, and good results were achieved. This attempt provides a new idea and method for airway management in patients with TD.

Insights into the Use of Point-of-Care Ultrasound for Diagnosing Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a sleeping disorder caused by complete or partial disturbance of breathing during the night. Existing screening methods include questionnaire-based evaluations which are time-consuming, vary in specificity, and are not globally adopted. Point-of-care ultrasound (PoCUS), on the other hand, is a painless, inexpensive, portable, and useful tool that has already been introduced for the evaluation of upper airways by anesthetists. PoCUS could also serve as a potential screening tool for the diagnosis of OSA by measuring different airway parameters, including retropalatal pharynx transverse diameter, tongue base thickness, distance between lingual arteries, lateral parapharyngeal wall thickness, palatine tonsil volume, and some non-airway parameters like carotid intima-media thickness, mesenteric fat thickness, and diaphragm characteristics. This study reviewed previously reported studies to highlight the importance of PoCUS as a potential screening tool for OSA.

Vocal cord dysfunction/inducible laryngeal obstruction-2022 Melbourne Roundtable Report

Vocal cord dysfunction/inducible laryngeal obstruction (VCD/ILO), is a common condition characterized by breathlessness associated with inappropriate laryngeal narrowing. Important questions remain unresolved, and to improve collaboration and harmonization in the field, we convened an international Roundtable conference on VCD/ILO in Melbourne, Australia. The aims were to delineate a consistent approach to VCD/ILO diagnosis, appraise disease pathogenesis, outline current management and model(s) of care and identify key research questions. This report summarizes discussions, frames key questions and details recommendations. Participants discussed clinical, research and conceptual advances in the context of recent evidence. The condition presents in a heterogenous manner, and diagnosis is often delayed. Definitive diagnosis of VCD/ILO conventionally utilizes laryngoscopy demonstrating inspiratory vocal fold narrowing >50%. Computed tomography of the larynx is a new technology with potential for swift diagnosis that requires validation in clinical pathways. Disease pathogenesis and multimorbidity interactions are complex reflecting a multi-factorial, complex condition, with no single overarching disease mechanism. Currently there is no evidence-based standard of care since randomized trials for treatment are non-existent. Recent multidisciplinary models of care need to be clearly articulated and prospectively investigated. Patient impact and healthcare utilization can be formidable but have largely escaped inquiry and patient perspectives have not been explored. Roundtable participants expressed optimism as collective understanding of this complex condition evolves. The Melbourne VCD/ILO Roundtable 2022 identified clear priorities and future directions for this impactful condition.

Point-of-care ultrasound-guided submucosal paclitaxel injection in tracheal stenosis model

Background and Objectives

Transcutaneous point-of-care ultrasound (POCUS) is a good tool to monitor the trachea in many clinical practices. The aim of our study is to verify the feasibility of POCUS-guided submucosal injection as a potential drug delivery method for the treatment of tracheal stenosis.

Materials and methods

The inner wall of the trachea was monitored via a bronchoscope during the POCUS-guided submucosal injection of methylene blue in fresh ex vivo porcine trachea to evaluate the distribution of methylene blue. The feasibility and eficacy of POCUS-guided submucosal injection were evaluated in a tracheal stenosis rabbit model. Animals were divided into sham group, tracheal stenosis group, and treatment group. Ten days after the scraping of the tracheal mucosa or sham operation, POCUS-guided submucosal injection of paclitaxel or saline was performed. Seven days after the submucosal injection, the trachea was assessed by cervical computed tomography (CT) scan and ultrasound.

Results

The distribution of methylene blue in trachea proved the technical feasibility of POCUS-guided submucosal injection. CT evaluation revealed that the tracheal stenosis index and the degree of tracheal stenosis increased significantly in the stenosis group, while POCUS-guided submucosal injection of paclitaxel partially reversed the tracheal stenosis. POCUS-guided submucosal injection of paclitaxel also decreased the lamina propria thickness and collagen deposition in the stenosed trachea.

Conclusion

POCUS-guided submucosal paclitaxel injection alleviated tracheal stenosis induced by scraping of the tracheal mucosa. POCUS-guided submucosal injection might be a potential method for the treatment of tracheal stenosis.

Current status of point of care ultrasonography for the perioperative care of trauma patients

PURPOSE OF REVIEW

The incorporation of point of care ultrasound into the field of anesthesiology and perioperative medicine is growing at rapid pace. The benefits of this modality align with the acuity of patient care and decision-making in anesthetic care of a trauma patient.

RECENT FINDINGS

Cardiac ultrasound can be used to diagnose cardiac tamponade or investigate the inferior vena cava to assess volume status in patients who may suffer from hemorrhagic shock. Thoracic ultrasound may be used to rapidly identify pneumothorax or hemothorax in a patient suffering chest wall trauma. In addition, investigators are exploring the utility of ultrasonography in traumatic airway management and elevated intracranial pressure. In addition, the utility of gastric ultrasound on trauma patients is briefly discussed.

SUMMARY

Incorporation of point of care ultrasound techniques into the practice of trauma anesthesiology is important for noninvasive, mobile and expeditious assessment of trauma patients. In addition, further large-scale studies are needed to investigate how point of care ultrasound impacts outcomes in trauma patients.

Airway ultrasound for patients anticipated to have a difficult airway: Perspective for personalized medicine

Airway ultrasound allows for precise airway evaluation, particularly for assessing the difficult airway and the potential for front of neck access. Many studies have shown that identification of the cricothyroid membrane by airway ultrasound is more accurate than digital palpation. However, no reports to date have provided clinical evidence that ultrasound identification of the cricothyroid membrane increases the success rate of cricothyroidotomy. This is a narrative review which describes patients with difficult airways for whom airway ultrasound may have been useful for clinical decision making. The role of airway ultrasound for the evaluation of difficult airways is summarized and an approach to the use of ultrasound for airway management is proposed. The goal of this review is to present practical applications of airway ultrasound for patients predicted to have a difficult airway and who undergo cricothyroidotomy.

Point-of-Care Ultrasound: A Moving Picture Is Worth a Thousand Tests

The effective utilization of point-of-care ultrasound may decrease the utilization of conventional diagnostic modalities. This review describes the various pathologies that can be effectively and rapidly identified with point-of-care cardiac, lung, abdominal, vascular airway, and ocular ultrasonography.

Point-of-care ultrasound use in emergencies: what every anaesthetist should know

Point-of-care ultrasound has been embraced by anaesthetists as an invaluable tool for rapid diagnosis of haemodynamic instability, to ensure procedural safety and monitor response to treatments. Increasingly available, affordable and portable, with emerging evidence of improved patient outcomes, point-of-care ultrasound has become a valuable tool in the emergency setting. This state-of-the-art review describes the feasibility of point-of-care ultrasound practice, training and maintenance of competence. It also describes the many uses of point-of-care ultrasound for the anaesthetist and describes the most salient point-of-care ultrasound views for anaesthetic emergencies including: undifferentiated shock; hypoxemia; and trauma. Procedural safety is also discussed in addition to relevant important governance aspects. Cardiac function should be assessed using the parasternal long axis, parasternal short basal/mid-papillary/apical, apical four chamber and subcostal four chamber views, and should include a visual estimation of global left ventricular ejection fraction. Other cardiovascular conditions that can be identified using point-of-care ultrasound include: pericardial effusion; cardiac tamponade; and pulmonary embolism. Pulmonary emergency conditions that can be diagnosed using point-of-care ultrasound include pneumothorax; pleural effusion; and interstitial syndrome. The extended focused assessment with sonography for trauma examination may of value in patients who are hypotensive in order to identify intra-abdominal haemorrhage, pneumothoraces and haemothoraces.

Computed Tomography Imaging of the Larynx for Diagnosis of Vocal Cord Dysfunction

BACKGROUND: Vocal cord dysfunction/inducible laryngeal obstruction (VCD/ILO) is characterized by breathlessness and often mimics or accompanies severe asthma. The disorder occurs intermittently, and the diagnosis is established by using laryngoscopy. Dynamic computed tomography (CT) imaging of the larynx at low-radiation doses has the potential to provide an alternative method to make the diagnosis of VCD/ILO. METHODS: We report two case series: in series A, laryngoscopy (diagnostic standard) and CT imaging of the larynx were each performed within 1 hour of each other (n=31), and in series B, the procedures were performed on separate days 4 to 6 weeks apart (n=72). Diagnosis of VCD/ILO by laryngoscopy used conventional criteria, and diagnosis by CT imaging was based on vocal cord narrowing in excess of a validated normal threshold. In each series, we evaluated the accuracy of CT imaging of the larynx to establish a diagnosis of VCD/ILO compared with laryngoscopy. RESULTS: In series A, the sensitivity of CT imaging of the larynx was 53.8%, and specificity was 88.9%; in series B, the sensitivity of CT imaging of the larynx was 76.2%, and specificity was 93.3%. At a disease prevalence of 30% (which was known to be the case in our clinic), the positive predictive value was 67.5% in series A and 83% in series B. Negative predictive values were 81.8% and 90.1% in series A and B, respectively, and false-positive rates were 11.1% and 6.7%. CONCLUSIONS: When the population prevalence was assumed to be 30%, low-dose CT imaging of the larynx detected VCD/ILO with negative predictive values greater than 80% in both series settings and agreed with each other within 9 percentage points. Positive predictive values for laryngeal CT imaging varied substantially between the settings of the two case series. (Supported by Monash Lung and Sleep Institute and Grant APP ID 1198362 and others.)

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.

Point-of-care ultrasound in the head and neck region

Point-of-care ultrasound (POCUS) in the head and neck region plays a particularly significant role in the diagnosis and treatment of upper airway stenosis, swelling, and painful diseases in the neck, and in the evaluation of swallowing function. Therefore, it should be performed in various medical settings beyond the boundaries of the clinical department such as general medicine, emergency medicine, anesthesiology, orthopedics, and pediatrics. The target diseases are salivary gland disease, lymph node disease, pharyngeal disease, laryngeal disease, esophageal disease, thyroid disease, and dysphagia and dyspnea due to various causes. Head and neck POCUS is an extremely useful diagnostic method for both patients and doctors, and its use is expected to become more widespread in the future.

The value of multiparameter combinations for predicting difficult airways by ultrasound

Background

Based on the upper airway anatomy and joint function parameters examined by ultrasound, a multiparameter ultrasound model for difficult airway assessment (ultrasound model) was established, and we evaluated its ability to predict difficult airways.

Methods

A prospective case-cohort study of difficult airway prediction in adult patients undergoing elective surgery with endotracheal intubation under general anesthesia, and ultrasound phantom examination for difficult airway assessment before anesthesia, including hyomental distance, tongue thickness, mandibular condylar mobility, mouth opening, thyromental distance, and modified Mallampati tests, was performed. Receiver operating characteristic (ROC) curve analysis was used to evaluate the effectiveness of the ultrasound model and conventional airway assessment methods in predicting difficult airways.

Results

We successfully enrolled 1000 patients, including 51 with difficult laryngoscopy (DL) and 26 with difficult tracheal intubation (DTI). The area under the ROC curve (AUC) for the ultrasound model to predict DL was 0.84 (95% confidence interval [CI]: 0.82–0.87), and the sensitivity and specificity were 0.75 (95% CI: 0.60–0.86) and 0.82 (95% CI: 0.79–0.84), respectively. The AUC for predicting DTI was 0.89 (95% CI: 0.87–0.91), and the sensitivity and specificity were 0.85 (95% CI: 0.65–0.96) and 0.81 (95% CI: 0.78–0.83), respectively. Compared with mouth opening, thyromental distance, and modified Mallampati tests, the ultrasound model predicted a greater AUC for DL (P < 0.05). Compared with mouth opening and modified Mallampati tests, the ultrasound model predicted a greater AUC for DTI (P < 0.05).

Conclusions

The ultrasound model has good predictive performance for difficult airways.

Trial registration

This study is registered on chictr.org.cn (ChiCTR-ROC-17013258); principal investigator: Jianling Xu; registration date: 06/11/2017).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01840-0.

Airway Ultrasound in Critically Ill Patients: A Narrative Review

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

Preanesthetic Evaluation and Preparation for Neurosurgical Procedures: An Indian Perspective

Background A questionnaire-based survey was conducted to determine the preanesthetic evaluation (PAE) practices among the members of the Indian Society of Neuroanesthesiology and Critical Care (ISNACC). The survey aimed to assess the current clinical practice of PAE and optimization of neurosurgical patients in India.

Methods An online questionnaire was designed by the working group of ISNACC and circulated among its active members. Response to individual questions was considered significant if 50% or more respondents concurred. The survey questions to which less than 50% of respondents concurred were identified as inconclusive results.

Results Out of 438 active ISNACC members, 218 responded. Responses were obtained from various parts of the country. The majority of participants were practicing neuroanesthesiology. Questions asked were regarding clinical assessment, preoperative optimization, prognostication, and airway management in neurosurgery. More than 50% of practitioners acceded to most of the questions; however, the percentage of responses varied across different questions (50–100%). The questions related to preoperative duplex scanning in chronically immobilized patients, preoperative cognitive testing, and risk stratification during neurosurgical procedures received an inconclusive response (< 50%).

Conclusion The survey highlights the variable PAE practices perused by ISNACC members across the country. A guideline for uniform PAE practices may help to enhance research and improve perioperative care.

Comparative study of the reliability of ultrasound to confirm the position of endotracheal tube with cuff inflated with saline versus air

Aim: To compare the reliability of transtracheal ultrasound to confirm the endotracheal tube position with saline versus air inflated cuff. Methods: This was a prospective randomized cadaveric study. Four techniques were randomized: endotracheal tube in the trachea with air or saline inflated cuff, and endotracheal tube in the esophagus with air or saline inflated cuff. The investigator used the Mcgrath to randomly place the endotracheal tube in the trachea or in the esophagus with saline or air inflated cuff. During the first series of measurements, nine residents performed transtracheal ultrasound with linear transducer placed transversely at the suprasternal notch. They were recorded with a cut off fixed to 30 seconds, and a questionnaire was completed by the residents after each transtracheal ultrasound in order to report where the endotracheal tube is positioned according to them. The second series followed the same protocol and included three residents who had participated in the first series. The primary outcome was the success rate in determining the position of the endotracheal tube. Results: In the first series, the success rate was 46.5%. In the second series, the success rate was 72.9%. There was no significant difference between cuff inflated with saline and air (p = 1.00). The overall mean time required was 20.6 s (95% CI 13.0–28.2 s). Based on an empirical data set, transtracheal ultrasound had a sensitivity of 62.2%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 26.08%. Conclusion: This investigation shows that regardless of the contents of the endotracheal tube cuff, the use of transtracheal ultrasound to confirm the position of endotracheal tube reports disappointing results.

Correlation of airway ultrasonography and laryngoscopy findings in adults with subglottic stenosis: a pilot study

PURPOSE

Ultrasonography of the airway has potential as an alternative, non-invasive, method to monitor patients with subglottic stenosis in an outpatient setting. This prospective, interventional, double-blinded study aimed to correlate ultrasound-based and laryngoscopy-based subglottic stenosis assessment in adults.

METHODS

The study was conducted between July 2020 and March 2021 at a tertiary referral center. Consecutive adult patients with subglottic stenosis were evaluated using airway ultrasonography 1 day prior to scheduled laryngoscopy. The radiologist was blinded to the preoperative endoscopic findings, and the primary surgeon was blinded to the ultrasonographic measurements. The intraoperative subglottic diameter was defined as the outer diameter of an endotracheal tube passing through the subglottis without producing an air leak.

RESULTS

Sixteen patients (11 females; age range, 17-66 years; mean = 44.06, SD = 12.79) were included. The ultrasonographic subglottic diameter ranged from 5.20 mm to 8.00 mm (mean = 6.24 mm, SD = 0.90). In 15 of 16 patients, the diameter difference between the ultrasonographic and intraoperative measurements ranged from -0.80 mm to 0.30 mm (mean = -0.20 mm, SD = 0.35). However, patient 6 had a difference of - 2.10 mm between the two measurements, which was attributed to thick laryngotracheal secretions interfering with the ultrasonographic air shadow. Data analysis of all 16 patients showed a statistically significant correlation between the readings obtained by the two techniques (r = 0.84, P = 0.000051).

CONCLUSION

This study found a significant correlation between ultrasonography-based and laryngoscopy-based subglottic stenosis assessment in adult patients. It provides a basis for an alternative and potentially reliable method to monitor patients with subglottic stenosis.

Basic ultrasound head-to-toe skills for intensivists in the general and neuro intensive care unit population: consensus and expert recommendations of the European Society of Intensive Care Medicine

Purpose

To provide consensus, and a list of experts’ recommendations regarding the basic skills for head-to-toe ultrasonography in the intensive care setting.

Methods

The Executive Committee of the European Society of Intensive Care (ESICM) commissioned the project and supervised the methodology and structure of the consensus. We selected an international panel of 19 expert clinicians–researchers in intensive care unit (ICU) with expertise in critical care ultrasonography (US), plus a non-voting methodologist. The panel was divided into five subgroups (brain, lung, heart, abdomen and vascular ultrasound) which identified the domains and generated a list of questions to be addressed by the panel. A Delphi process based on an iterative approach was used to obtain the final consensus statements. Statements were classified as a strong recommendation (84% of agreement), weak recommendation (74% of agreement), and no recommendation (less than 74%), in favor or against.

Results

This consensus produced a total of 74 statements (7 for brain, 20 for lung, 20 for heart, 20 for abdomen, 7 for vascular Ultrasound). We obtained strong agreement in favor for 49 statements (66.2%), 8 weak in favor (10.8%), 3 weak against (4.1%), and no consensus in 14 cases (19.9%). In most cases when consensus was not obtained, it was felt that the skills were considered as too advanced. A research agenda and discussion on training programs were implemented from the results of the consensus.

Conclusions

This consensus provides guidance for the basic use of critical care US and paves the way for the development of training and research projects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00134-021-06486-z.

Submental Ultrasound Is Effective in Predicting Difficult Mask Ventilation but Not in Difficult Laryngoscopy

The goal of this study was to determine the utility of submental ultrasound parameters in distinguishing difficult airway management from easy airway management. Forty-one adult patients who underwent elective surgery under general anesthesia with endotracheal intubation from March to December 2018 were included. We used submental ultrasound to measure tongue base thickness (TBT) in the midsagittal plane and the distance between lingual arteries (DLA) in the transverse dimension. The primary outcome was difficult laryngoscopy, and the secondary outcome was difficult mask ventilation. Receiver operating characteristic curve analysis and logistic regression revealed no correlation between difficult laryngoscopy and SMUS measurements. Nevertheless, patients with difficult mask ventilation had significantly higher TBT (p = 0.009) and longer DLA (p = 0.010). After adjustment of confounding factors, increased TBT (>69.6 mm) was the sole independent predictor of difficult mask ventilation. The results indicated that SMUS is effective in predicting difficult mask ventilation but not difficult laryngoscopy.

Utility of ultrasound evaluation of I-Gel® placement in children: An observational study

BACKGROUND

Ultrasound is not widely used to evaluate optimal supraglottic airway positioning even though it could potentially be used to identify and correct problem areas.

AIMS

We evaluated a new ultrasound scoring method to identify the position of the supraglottic airway and detect the location of air leaks during ventilation in pediatric patients.

METHODS

Using a prospective observational study design, we enrolled 90 pediatric patients of ASA physical status I-III scheduled for elective surgery under general anesthesia. After anesthesia induction, patients were assigned to a noncorrection group or a correction group after their first ultrasound evaluation. Noncorrection group comprised patients with tolerable I-Gel positioning based on ultrasound evaluation and no problems with clinical parameters, while the correction group comprised patients with I-Gel mispositioning based on ultrasound.

RESULTS

After the first ultrasound evaluation, 61 patients did not need I-Gel correction (noncorrection group), while 29 patients needed I-Gel correction (correction group) and underwent a second ultrasound evaluation. Airway sealing pressure and total ultrasound score showed a negative correlation (r = -.845, p < .001). The area under the receiver operating curve for total ultrasound score was 0.97 (95% confidence interval, 0.94-0.99; p < .001). In the correction group, ultrasound score and ventilation parameters improved after correction based on ultrasound evaluation.

CONCLUSIONS

Ultrasound scores were negatively correlated with airway sealing pressure in pediatric patients. Ultrasound evaluation is useful for detecting misplacement of the I-Gel and can be a useful tool for correction.

The Role of Lung Ultrasound in the Management of the Critically Ill Neonate-A Narrative Review and Practical Guide

Lung ultrasound makes use of artifacts generated by the ratio of air and fluid in the lung. Recently, an enormous increase of research regarding lung ultrasound emerged, especially in intensive care units. The use of lung ultrasound on the neonatal intensive care unit enables the clinician to gain knowledge about the respiratory condition of the patients, make quick decisions, and reduces exposure to ionizing radiation. In this narrative review, the possibilities of lung ultrasound for the stabilization and resuscitation of the neonate using the ABCDE algorithm will be discussed.

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

Background

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

Perioperative Point-of-Care Ultrasound Use by Anesthesiologists

Point-of-Care ultrasound (POCUS) is the bedside utilization of ultrasound, in real-time, to aid in the diagnosis and treatment of patients. Image acquisition from POCUS utilization by anesthesiologists involves the assessment of multiple organs in different perioperative situations. POCUS can be utilized to enhance clinical decision-making in a variety of perioperative situations due to its ability to assess endotracheal tube placement, cardiac function, pulmonary function, aspiration risk, hemodynamics, vascular access, and nerve visualization for regional procedures. The mounting clinical evidence for the value of POCUS in perioperative settings, its growing affordability, and its low associated risks are responsible for the nationwide movement across many anesthesiology residency programs to increase the focus on perioperative ultrasound training. The purpose of this review is to present to current anesthesiologists and anesthesiology trainees, a broad discussion regarding the diverse utility and importance of POCUS in perioperative settings.

Ultrasonography for airway management

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

Successful endotracheal intubation using i-gel supraglottic airway device and ultrasonography in a patient with bedside cervical traction: A case report

We report a case of successful endotracheal intubation using i-gel and ultrasonography without a laryngoscope in a patient with a bedside cervical traction device. A 57-year-old man was referred to the emergency department because of quadriparesis following a motor vehicle accident, who was confirmed to have cervical dislocation with spinal cord compression. For ventilation support, the i-gel rescue airway device was placed to secure the patient airway temporarily. Then, an endotracheal tube was passed through the stem of the i-gel while observing the optimal tube position with ultrasonography. This case showed that ultrasonography can be used for early confirmation of endotracheal tube placement into the trachea via the i-gel.

American Society of Regional Anesthesia and Pain Medicine expert panel recommendations on point-of-care ultrasound education and training for regional anesthesiologists and pain physicians-part II: recommendations

Point-of-care ultrasound (POCUS) is a critical skill for all regional anesthesiologists and pain physicians to help diagnose relevant complications related to routine practice and guide perioperative management. In an effort to inform the regional anesthesia and pain community as well as address a need for structured education and training, the American Society of Regional Anesthesia and Pain Medicine Society (ASRA) commissioned this narrative review to provide recommendations for POCUS. The recommendations were written by content and educational experts and were approved by the guidelines committee and the Board of Directors of the ASRA. In part II of this two-part series, learning goals and objectives were identified and outlined for achieving competency in the use of POCUS, specifically, airway ultrasound, lung ultrasound, gastric ultrasound, the focus assessment with sonography for trauma exam, and focused cardiac ultrasound, in the perioperative and chronic pain setting. It also discusses barriers to POCUS education and training and proposes a list of educational resources. For each POCUS section, learning goals and specific skills were presented in the Indication, Acquisition, Interpretation, and Medical decision-making framework.

Use of Airway Ultrasound in Infants With Unexpected Subglottic Stenosis During Anesthesia Induction: A Case Report

Point-of-care ultrasound has been integrated into airway management because it allows for rapid and noninvasive assessments. We present 2 cases of unexpected subglottic stenosis in infants during induction of anesthesia. Intubation failed even with endotracheal tubes that were small for patients' age. Airway ultrasound was used to measure the subglottic airway diameters, which were 2.0 and 3.0 mm in first and second cases, respectively. The severity of subglottic stenosis in the first case was grade III, requiring emergent tracheostomy. In conclusion, airway ultrasound helps to assess possibility of intubation and plan further airway management in children with unexpected difficult airway.

Point-of-Care Ultrasound (POCUS) for the Cardiothoracic Anesthesiologist

Point-of-Care Ultrasound (POCUS) is a valuable bedside diagnostic tool for a variety of expeditious clinical assessments or as guidance for a multitude of acute care procedures. Varying aspects of nearly all organ systems can be evaluated using POCUS and, with the increasing availability of affordable ultrasound systems over the past decade, many now refer to POCUS as the 21^st-century stethoscope. With the current available and growing evidence for the clinical value of POCUS, its utility across the perioperative arena adds enormous benefit to clinical decision-making. Cardiothoracic anesthesiologists routinely have used portable ultrasound systems for nearly as long as the technology has been available, making POCUS applications a natural extension of existing cardiothoracic anesthesia practice. This narrative review presents a broad discussion of the utility of POCUS for the cardiothoracic anesthesiologist in varying perioperative contexts, including the preoperative clinic, the operating room (OR), intensive care unit (ICU), and others. Furthermore, POCUS-related education, competence, and certification are addressed.

Unplanned hospital admission after ambulatory surgery: a retrospective, single cohort study

PURPOSE

We estimated the rate of unplanned hospital and intensive care unit (ICU) admissions following ambulatory surgery centre (ASC) procedures, and identified factors associated with their occurrence.

METHODS

This retrospective cohort included adult patients who underwent ASC procedures within a large community practice from January 2010 to December 2014. Patients were categorized into two groups: unplanned postoperative hospital/ICU admission within 24 hr of procedure or uneventful discharge. Demographics, comorbidities, anesthesia type, procedure type, procedure group, and ASC facility were assessed.

RESULTS

Of the 211,389 patients included, there were 211,147 uneventful discharges (99.89%) and 242 unplanned hospital admissions (0.11%), of which 75 were ICU admissions (0.04%). The multivariable logistic regression model for hospital admission showed an increased risk associated with age > 50 yr (odds ratio [OR], 1.53); American Society of Anesthesiologists (ASA) physical status (III vs II: OR, 1.45; IV vs II: OR, 1.88), comorbidity (chronic obstructive pulmonary disease: OR, 2.63; diabetes mellitus: OR, 1.62; transient ischemic attack: OR, 2.48) procedure (respiratory: OR, 2.92; digestive: OR, 2.66; musculoskeletal system: OR, 2.53), anesthetic management (general anesthesia [GA] and peripheral nerve block vs GA: OR, 1.79), and ASC facility (189BB: OR, 2.29; 30E9A: OR, 7.41; and BD21F: OR, 1.69). The multivariable logistic regression model for ICU admission showed increased risk of unplanned ICU admission associated with ASA physical status (ASA III vs II: OR, 3.0; ASA IV vs II: OR, 8.52), procedure (musculoskeletal system: OR, 2.45), and ASC facility (00E6C: OR, 3.14; 189BB: OR, 2.77; 30E9A: OR, 2.59; and BD21F: OR, 3.71).

CONCLUSION

While a small percentage of adult patients who underwent ASC procedures required unplanned hospital admission (0.07%), approximately one-third of these admissions were to the ICU (0.04%). Facility was at least as strong a predictor of hospital admission as the patient- and/or procedure-specific variables.

Unplanned hospital admission after ambulatory surgery: a retrospective, single cohort study

PURPOSE

We estimated the rate of unplanned hospital and intensive care unit (ICU) admissions following ambulatory surgery centre (ASC) procedures, and identified factors associated with their occurrence.

METHODS

This retrospective cohort included adult patients who underwent ASC procedures within a large community practice from January 2010 to December 2014. Patients were categorized into two groups: unplanned postoperative hospital/ICU admission within 24 hr of procedure or uneventful discharge. Demographics, comorbidities, anesthesia type, procedure type, procedure group, and ASC facility were assessed.

RESULTS

Of the 211,389 patients included, there were 211,147 uneventful discharges (99.89%) and 242 unplanned hospital admissions (0.11%), of which 75 were ICU admissions (0.04%). The multivariable logistic regression model for hospital admission showed an increased risk associated with age > 50 yr (odds ratio [OR], 1.53); American Society of Anesthesiologists (ASA) physical status (III vs II: OR, 1.45; IV vs II: OR, 1.88), comorbidity (chronic obstructive pulmonary disease: OR, 2.63; diabetes mellitus: OR, 1.62; transient ischemic attack: OR, 2.48) procedure (respiratory: OR, 2.92; digestive: OR, 2.66; musculoskeletal system: OR, 2.53), anesthetic management (general anesthesia [GA] and peripheral nerve block vs GA: OR, 1.79), and ASC facility (189BB: OR, 2.29; 30E9A: OR, 7.41; and BD21F: OR, 1.69). The multivariable logistic regression model for ICU admission showed increased risk of unplanned ICU admission associated with ASA physical status (ASA III vs II: OR, 3.0; ASA IV vs II: OR, 8.52), procedure (musculoskeletal system: OR, 2.45), and ASC facility (00E6C: OR, 3.14; 189BB: OR, 2.77; 30E9A: OR, 2.59; and BD21F: OR, 3.71).

CONCLUSION

While a small percentage of adult patients who underwent ASC procedures required unplanned hospital admission (0.07%), approximately one-third of these admissions were to the ICU (0.04%). Facility was at least as strong a predictor of hospital admission as the patient- and/or procedure-specific variables.

Multiple trauma management in mountain environments - a scoping review : Evidence based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MedCom). Intended for physicians and other advanced life support personnel

Background

Multiple trauma in mountain environments may be associated with increased morbidity and mortality compared to urban environments.

Objective

To provide evidence based guidance to assist rescuers in multiple trauma management in mountain environments.

Eligibility criteria

All articles published on or before September 30th 2019, in all languages, were included. Articles were searched with predefined search terms.

Sources of evidence

PubMed, Cochrane Database of Systematic Reviews and hand searching of relevant studies from the reference list of included articles.

Charting methods

Evidence was searched according to clinically relevant topics and PICO questions.

Results

Two-hundred forty-seven articles met the inclusion criteria. Recommendations were developed and graded according to the evidence-grading system of the American College of Chest Physicians. The manuscript was initially written and discussed by the coauthors. Then it was presented to ICAR MedCom in draft and again in final form for discussion and internal peer review. Finally, in a face-to-face discussion within ICAR MedCom consensus was reached on October 11th 2019, at the ICAR fall meeting in Zakopane, Poland.

Conclusions

Multiple trauma management in mountain environments can be demanding. Safety of the rescuers and the victim has priority. A crABCDE approach, with haemorrhage control first, is central, followed by basic first aid, splinting, immobilisation, analgesia, and insulation. Time for on-site medical treatment must be balanced against the need for rapid transfer to a trauma centre and should be as short as possible. Reduced on-scene times may be achieved with helicopter rescue. Advanced diagnostics (e.g. ultrasound) may be used and treatment continued during transport.