Airway devices for awake tracheal intubation in adults: a systematic review and network meta-analysis

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.

Fibreoptic intubation: a commitment to an indispensable technique

Recent evidence has shown that fibreoptic intubation is still an indispensable technique for safe management of predicted difficult airways, despite the implementation of new technologies such as videolaryngoscopy. It is therefore our obligation as anaesthesia societies and as practicing anaesthetists to offer this technique to our patients in clearly designated situations.

Incidence, causes, and management of failed awake fibreoptic intubation-A retrospective study of 833 procedures

Awake fibreoptic intubation has been considered a gold standard in the management of the difficult airway. However, failure may cause critical situations. The aim of this study was to investigate the incidence and causes of failed awake fibreoptic intubation at a tertiary care hospital. The study was conducted at St. Olav University Hospital in Trondheim, Norway. Problems occurring during anaesthesia are routinely recorded in the electronic anaesthesia information system (Picis Clinical Solutions Inc.), including difficult intubations. We applied text search on all anaesthesia records between 2011 and 2021 and identified 833 awake fibreoptic intubations. The anaesthesia records were examined to identify failed awake fibreoptic intubations, the cause of failure and how the airway ultimately was secured. Among 233,938 patients who received anaesthesia, 90,397 received tracheal intubation and 833 received awake fibreoptic intubation. Twenty-nine of the procedures failed. In nine patients the failure caused loss of airway control with desaturation and hypoventilation. The major causes of failure were dislodged tube after induction of general anaesthesia (n = 8), patient distress (n = 5), tube not able to pass (n = 5), and airway bleeding (n = 3). The situations were primarily solved using direct laryngoscopy, with or without bougie, or with video laryngoscopy. Tracheostomy was performed in four patients. Awake fibreoptic intubation failed in 3.5% of patients, most often due to dislocation, problems passing the tracheal tube, or patient discomfort. The failure rate was higher than in previous studies.

Airway nerve blocks for awake tracheal intubation: A meta-analysis of randomized control trials and trial sequential analysis

STUDY OBJECTIVE

This systematic review and meta-analysis aimed to assess the superiority of airway nerve blocks versus airway anesthesia without nerve blocks for awake tracheal intubation (ATI).

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

SETTING

All studies that assessed the superiority of airway anesthesia technique for awake tracheal intubation were searched in PubMed, Web of Science, Cochrane Library, Ovid Medline, Embase and Chinese databases (including China National Knowledge Infrastructure, Wanfang database, and VIP databases) and trial registry databases from their inception to December 2022.

PATIENTS

Adult patients included in randomized controlled trials comparing airway anesthesia with or without airway nerve blocks for ATI.

INTERVENTIONS

Airway nerve (including superior laryngeal nerve, glossopharyngeal nerve, or recurrent laryngeal nerve) blocks for ATI.

MEASUREMENTS

The primary outcome was the intubation time. Secondary outcomes were quality of intubating conditions (including patient reaction to placement of the flexible scope and tracheal tube, coughing and gagging, and patient satisfaction) and overall complications during ATI.

MAIN RESULTS

Fourteen articles with 658 patients were identified for analysis. When compared with airway anesthesia without nerve blocks, airway nerve blocks significantly reduced intubation time (standardized mean difference [SMD] -2.57, 95% CI -3.59- -1.56, p < 0.00001), improved anesthesia quality of ATI with higher no reaction to placement of the flexible scope and tracheal tube (relative risk [RR] 9.87; 95% CI 4.10-23.75, p < 0.00001), lower cough or gag reflex during intubation (RR 0.35, 95% CI 0.27-0.46, p < 0.00001), higher excellent patient satisfaction rate (RR 1.88, 95% CI 1.05-3.34, p = 0.03), and lower overall complications (RR 0.29, 95% CI 0.19-0.45, p < 0.00001). The overall quality of evidence was moderate.

CONCLUSIONS

Based on current published evidence, airway nerve blocks provide better airway anesthesia quality for ATI with a shorter intubation time, better intubation conditions including higher no reaction to placement of the flexible scope and tracheal tube, lower cough or gag reflex during intubation, higher excellent patient satisfaction, and lower overall complications.

A learning curve of a novel multimodal endotracheal intubation assistant device for novices in a simulated airway: a prospective manikin trial with cumulative sum method

BACKGROUND

Awake fiberoptic intubation is conventionally performed in anticipated difficult airways. However, obstruction by secretions and sputum makes it challenging for novices. A prototype of a novel multimodal endotracheal intubation assistant device (MEIAD) was developed for an indication of airway according to end-tidal carbon dioxide (ETCO₂) and image. At the tip, 4 sampling tubes collected ETCO₂ concentration. The airway direction is located according to an advanced algorithm based on 4 directions' concentrations. It assists awake intubation, especially with unclear view field. The objective was to analyze the learning curve of MEIAD for novices on a manikin by cumulative sum method (CUSUM) and evaluate the utility.

METHODS

A total of 16 novice residents with less than 2-year clinical experience were enrolled. After instruction, each individual exercised 40 insertions with MEIAD on a difficult airway simulation. Insertion success (defined as a visualization of the carina within 120 seconds), insertion time (the time from when the guiding scope entered the nasal cavity to the carina was visible), and self-confidence score (subjective score with a numerical rating scale from 0 to 10) were recorded. The acceptable and unacceptable failure rates of CUSUM were set as 15% and 30%, respectively. The exercises were divided into 2 phases (phase 1: 1-20, phase 2: 21-40) for further evaluation. All continuous data were expressed by median (IQR, interquartile ranges) and analyzed using Mann-Whitney test. All categorical variables were expressed as percentages and compared by the χ² test.

RESULTS

Among the 16 residents, 15 were able to cross the lower decision boundary in an average of 21.27±9.51 attempts using the novel device. The insertion time [24.0 (17.0-42.0) vs. 17.5 (14.0-28.0) seconds, P<0.001] and success rate (88.4% vs. 97.5%, P<0.001) were improved with increased experience. The confidence score was significantly improved from 2.5 (1.3-4.0) to 7.0 (7.0-8.0).

CONCLUSIONS

MEIAD showed a satisfactory learning curve and efficacy on the manikin for novices. However, as a small exploratory manikin trial, the results cannot be replicated in clinical practice. MEIAD is expected to be further improved and potential to be an alternative device for difficult airways.