Airway management: Overview

Abstract
Background: Supraglottic jet ventilation (SJV) is used during flexible bronchoscopy to improve oxygenation, but its impact on overall lung ventilation is unclear. Thoracic electrical impedance tomography (EIT) offers real-time monitoring of respiratory function.

Methods: This prospective pilot study enrolled patients undergoing flexible bronchoscopy. End-expiratory lung impedance (EELI) changes from baseline (ΔEELI) were measured at baseline (T0), oxygenation with Wei nasal jet (WNJ) (T1), SJV (T2), during bronchoscopy (T3), and post-bronchoscopy (T4). The primary outcome was ΔEELI at T2 vs. T3. Secondary outcomes included ΔEELI at other time points, ventilation distribution (ventral vs. total lung, ROIventral), hemodynamics, oxygen saturation (SpO2) at each point, and adverse events.

Results: Among 27 patients, 5 experienced transient desaturation (no laryngeal mask ventilation needed). ΔEELI and SpO2 significantly decreased from T2-T3 (ΔEELI: -2.65, 95% CI -4.27 to -1.02, p < 0.001; SpO2: -2.5%, 95% CI -4.7 to -0.3%, p < 0.001). Conversely, ΔEELI and SpO2 significantly increased from T1-T2 (ΔEELI: 1.84, 95% CI 1.02-2.66, p < 0.001; SpO2: 3.3%, 95% CI 1.3-5.2%, p < 0.001), with ROIventral rising from 43.7 to 60.4% (16.6% increase, 95% CI 4.4-28.9%, p < 0.001).

Conclusions: While SJV did not prevent the negative effects of bronchoscopy on lung ventilation and oxygenation, it maintained adequate SpO2. Pre-bronchoscopy SJV improved these measures, but shifted ventilation towards ventral lung regions compared to WNJ oxygenation.

Trial registration: Chinese Clinical Trial Registry (URL: Chictr.org.cn), Identifier: ChiCTR2100050285. Date of registration: Aug 25th, 2021.

Abstract
Introduction: Patients living with obesity present specific challenges for airway management. They have been overrepresented repeatedly in studies looking at complications associated with airway management. Whilst generic airway guidelines offer assistance, there are no evidence-based guidelines specific to this group of patients to support safe and effective airway management.

Methods: An expert multidisciplinary working party was convened on behalf of the Society of Obesity and Bariatric Anaesthesia to conduct this work. A systematic review was performed and was followed by a three-round Delphi process.

Results: Forty-three recommendations are made which cover a number of key areas of practice including: pre-assessment; planning; peroxygenation; tracheal intubation; supraglottic airway devices; tracheal extubation; training; and organisational responsibilities.

Discussion: It is hoped the recommendations made will improve the safety and efficacy of airway management in patients living with obesity. They are not intended to replace current airway management guidelines.

Keywords: airway; guidelines; obesity; tracheal intubation.

Abstract
Introduction: Children with difficult airways are at high risk of complications. Alternative techniques to direct laryngoscopy for tracheal intubation include videolaryngoscopy, flexible bronchoscopy and the hybrid technique of simultaneous videolaryngoscopy and flexible bronchoscopy. This analysis aimed to compare the first-attempt success of each technique and assess the complications associated with difficult paediatric intubations in a quaternary paediatric institution.

Methods: The electronic health records of a single quaternary paediatric hospital were searched to identify anaesthesia encounters involving difficult paediatric intubation. This was defined either by the Pediatric Difficult Intubation Registry criteria or as tracheal intubation requiring ≥ 3 attempts. Primary outcomes were the first-attempt success rate and incidence of complications with each tracheal intubation technique.

Results: From April 2019 to January 2024, 559 encounters involving difficult tracheal intubation were identified. First-attempt success was highest for the hybrid technique (70/94, 74.5%) compared with videolaryngoscopy (143/235, 60.9%, p = 0.020) or direct laryngoscopy (19/190, 10.0%, p < 0.001). The hybrid technique was used to rescue 19/27 (70.4%) encounters where videolaryngoscopy alone was unsuccessful and was successful in all these encounters. Eighty-six (15.4%) encounters had at least one complication. The complication rate was significantly higher for patients weighing < 10 kg (45/184, 24.5%) compared with those weighing ≥ 10 kg (41/375, 10.9%, p < 0.001). The hybrid technique was associated with a lower incidence of complications (5/94, 5.3%) compared with videolaryngoscopy (33/235, 14.0%, p = 0.025) or direct laryngoscopy (41/190, 21.6%, p < 0.001).

Discussion: In children with difficult tracheal intubation, the hybrid technique was associated with a higher first-attempt success rate compared with videolaryngoscopy alone or direct laryngoscopy. Consideration should be given to the hybrid technique as a first-line approach when difficult tracheal intubation is anticipated and when there is a failed attempt with either direct laryngoscopy or videolaryngoscopy.

Abstract
Before completion of this study, there was insufficient evidence demonstrating the superiority of videolaryngoscopy compared with direct laryngoscopy for elective tracheal intubation. We hypothesised that using videolaryngoscopy for routine tracheal intubation would result in higher first-pass tracheal intubation success compared with direct laryngoscopy. In this multicentre randomised trial, 2092 adult patients without predicted difficult airway requiring tracheal intubation for elective surgery were allocated randomly to either videolaryngoscopy with a Macintosh blade (McGrath™) or direct laryngoscopy. First-pass tracheal intubation success was higher with the McGrath (987/1053, 94%), compared with direct laryngoscopy (848/1039, 82%); absolute risk reduction (95%CI) was 12.1% (10.9-13.6%). This resulted in a relative risk (95%CI) of unsuccessful tracheal intubation at first attempt of 0.34 (0.26-0.45; p < 0.001) for McGrath compared with direct laryngoscopy. Cormack and Lehane grade ≥ 3 was observed more frequently with direct laryngoscopy (84/1039, 8%) compared with McGrath (8/1053, 0.7%; p < 0.001) No significant difference in tracheal intubation-associated adverse events was observed between groups. This study demonstrates that using McGrath videolaryngoscopy compared with direct laryngoscopy improves first-pass tracheal intubation success in patients having elective surgery. Practitioners may consider using this device as first choice for tracheal intubation.