The Role of Airway and Endobronchial Ultrasound in Perioperative Medicine

Correlation of Ultrasound Examination with FOB for Airway Assessment in Burn Patients with Inhalational Injury: A Prospective Observational Study

Aim/background

Fiberoptic bronchoscopy (FOB) is the gold standard for assessing airway involvement in burn patients but is invasive. Ultrasound (USG) has not been previously used to evaluate the airway in burn patients. Our study evaluated the feasibility of using USG to assess airway involvement in inhalational burn injury and correlated its efficacy with FOB.

Materials and methods

This prospective observational study was conducted in the burns intensive care unit (ICU) of a tertiary care hospital. Bedside airway USG was performed to evaluate vocal cord (VC) width for edema and other airway parameters, including tongue thickness, pre-epiglottis space depth, inter-arytenoid distance, epiglottis-to-midpoint of VC, distance between the true VCs, distance between the false VCs, tracheal wall thickness, and tracheal air column width. Fiberoptic bronchoscopy was then performed to assess airway involvement, and findings were correlated with USG at the VC level.

Results

About 51 patients were included. Airway USG assessment was able to predict the VC edema, correlating with FOB findings in 30 patients. Ultrasound showed a sensitivity and specificity of 85.2 and 81.3%, respectively, with a positive and negative predictive value of 90.9 and 72.2%, respectively, for assessing airway edema at the level of VC. The mean right and left VC widths were 21.15 ± 9.52 mm and 22.03 ± 9.52 mm, respectively, in patients with VC edema. The pre-epiglottis space in patients with (n = 33) vs without VC edema (n = 18) was found to be statistically significant (14.5± 5.64 mm vs 10.87 ± 4.36 mm; p = 0.02).

Conclusion

Ultrasound can be used as a reliable, non-invasive bedside predictor of airway involvement in patients with suspected inhalational injury.

How to cite this article

Garg H, Agarwal S, Kumar A, Kumar S, Darlong V, Kashyap L, et al. Correlation of Ultrasound Examination with FOB for Airway Assessment in Burn Patients with Inhalational Injury: A Prospective Observational Study. Indian J Crit Care Med 2025;29(4):314-319.

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.

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.

Airway Ultrasound for Anesthesia and in Intensive Care Patients-A Narrative Review of the Literature

Ultrasound is an everyday diagnostic tool. In anesthesia and intensive care, it has a role as an adjuvant for many procedures, including the evaluation of the airway. Ultrasound airway evaluation can help predict a difficult airway, visualize the proper positioning of an intubation cannula, or evaluate the airway post-intubation. Protocols need to be established for the better integration of ultrasound in the airway evaluation, however until a consensus is reached in this respect, the ultrasound is a reliable aid in anesthesia and intensive care.

A novel online education module to teach clinicians how to correctly identify ultrasonographic features of mediastinal lymph nodes during endobronchial ultrasound

Background

Ultrasonographic features can be used to predict mediastinal lymph node malignancy during endobronchial ultrasonography. Despite the validity of using these features for this purpose, the features are not being widely used in clinical practice. This may be attributable to the absence of educational programs that teach clinicians how to identify the features. To address this knowledge gap, we developed an online educational module to teach clinicians how to correctly interpret ultrasonographic features.

Methods

The module was designed using corrective feedback and test-enhanced learning theories and distributed to clinicians in relevant specialties. The efficacy of the program was determined by comparing the percentages of correctly identified ultrasonographic features as each clinician progressed through the module. Participants were also asked to self-rate their confidence during the module. Analysis of variance was conducted, and a learning curve and descriptive statistics were generated.

Results

Twenty-two of the 29 participants (76%) completed the module. Analysis of variance indicated that the percentage of correctly identified features increased significantly as clinicians completed the module (p = 0.004); this finding is supported by the positive slope of the learning curve. Even though they initially reported some difficulty with identifying certain features, their confidence increased as they progressed through the module. When asked, 86% of participants reported that they found the educational module helpful and 90% reported that they would recommend it to others.

Conclusion

Participating clinicians were receptive to the interactive educational module. It enhances clinician skill and confidence in interpreting ultrasonographic features. The results of this study provide the foundation needed to test the validity of the educational module in clinical settings and to further explore clinician preferences for educational programs.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Objective Assessment of Postoperative Swallowing Difficulty Through Ultrasound in Patients Undergoing Thyroidectomy

Swallowing discomfort is a common postoperative complaint in patients undergoing thyroidectomy. Contraction of the strap muscles might cause resistance to elevation of the laryngotracheal unit, and downward movement of the laryngotracheal unit may lead to swallowing discomfort. However, few studies have evaluated the mechanism related to limited laryngotracheal elevation after thyroidectomy. We aimed to objectively verify the presence of postoperative impaired laryngotracheal elevation through ultrasound evaluation in patients undergoing thyroidectomy and evaluate its relationship with limitation of laryngotracheal elevation. This is a prospective clinical study. Among patients undergoing hemithyroidectomy and total thyroidectomy, the patients who were followed up for ≥ 6 months were selected (N = 40). Ultrasound evaluation was done preoperatively and at 1, 3, and 6 months postoperatively. Laryngotracheal movement was recorded and the length of elevation was measured. Symptom after thyroidectomy was evaluated through swallowing-related items of thyroidectomy-related voice questionnaire. Ultrasound evaluation verified the presence of limited laryngotracheal elevation postoperatively in patients undergoing thyroidectomy. After thyroidectomy, the swallowing-related score was significantly increased, and was recovered time-dependently at 1 month. Laryngotracheal elevation showed significant decrease after thyroidectomy. The symptom score of swallowing was significantly correlated with the length of laryngotracheal elevation. Post-thyroidectomy ultrasound evaluation verified that laryngotracheal elevation was significantly impaired. Presence of adhesion between the laryngotracheal unit and the superficial soft tissue was the probable cause of the limitation at 6 months after thyroidectomy. The length of laryngotracheal elevation was related to the symptom score of swallowing after thyroid surgery.

Determining the amount of training needed for competency of anesthesia trainees in ultrasonographic identification of the cricothyroid membrane

Background

Airway guidelines recommend the use of ultrasound to localize the cricothyroid membrane prior to airway manipulation in difficult airways. In this study, we aimed to determine the amount of training anesthesia trainees would need to achieve competence in bedside ultrasound to identify the cricothyroid membrane.

Methods

This is a prospective non-randomized cohort study in the Department of Anesthesia at Mount Sinai Hospital (Toronto, Ontario, Canada). Following institutional ethics approval, six anesthesia trainees consisting of four residents and two fellows underwent a 2-h training session on neck ultrasound to identify neck landmarks and the cricothyroid membrane. The trainees had no previous airway ultrasound experience. One-two weeks later, each trainee performed consecutive neck ultrasound scans on 20 healthy volunteers to identify the cricothyroid membrane. Cumulative sum (CUSUM) learning curves were constructed for each trainee. Primary outcome was the number of ultrasound examinations required to achieve competence, defined as 90% success rate in a series of 20 ultrasound scans. Secondary outcomes were the overall success rate, the time (sec.) required to perform the task, and 3-month skills assessment.

Results

CUSUM analysis showed four trainees achieved competence with a mean [range] success rate of 94.0% [90–100%] and a median [range] number of attempts of 14 [9–18]. Two trainees did not achieve competence, but obtained a success rate of 75.0 and 80.0% each. Overall (number of attempts) success rate was 88.3% (106/120) with a mean (SD) time of 36.9 (9.0) sec. Three months after training, ultrasound of five consecutive neck scans showed a mean success rate of 86.7% (26/30) and mean (SD) time of 47.7 (16.0) sec.

Conclusions

After a short 2-h training session, most anesthesia trainees (n = 4/6) achieved competence in ultrasound-identification of the cricothyroid membrane with less than 20 scans in a mean time less than 60 s., and that they remain reasonably competent 3 months later. The learning curve for ultrasound identification of the cricothyroid membrane seems to be short even without prior airway ultrasound experience.