Tracheal intubation in microgravity: a simulation study comparing direct laryngoscopy and videolaryngoscopy†

Abstract

Background: The risk of severe medical and surgical events during long-duration spaceflight is significant. In space, many environmental and psychological factors may make tracheal intubation more difficult than on Earth. We hypothesised that, in microgravity, tracheal intubation may be facilitated by the use of a videolaryngoscope compared with direct laryngoscopy. Methods: In a non-randomised, controlled, cross-over simulation study, we compared intubation performance of novice operators and experts, using either a direct laryngoscope or a videolaryngoscope, in weightlessness and in normogravity. The primary outcome was the success rate of tracheal intubation. Time to intubation and the confidence score into the success of tube placement were also recorded. Results: When novices attempted to intubate the trachea in microgravity, the success rate of tracheal intubation using a videolaryngoscope was significantly higher (20/25 [80%]; 95% confidence interval [CI], 64.3e95.7 vs eight/20 [40%]; 95% CI, 18.5e61.5; P¼0.006), and intubation time was shorter, compared with using a direct laryngoscope. In normogravity, the success rate of tracheal intubation by experts was significantly higher than that by novices (16/ 20 [80%]; 95% CI, 62.5e97.5 vs seven/25 [28%]; 95% CI, 10.4e45.6; P¼0.001), but in microgravity, there was no significant difference between the experts and novices (19/20 [95%]; 95% CI, 85.4e100 vs 20/25 [80%]; 95% CI, 64.3e95.7; P¼0.113). Higher confidence scores were achieved with videolaryngoscopy compared with direct laryngoscopy by both experts and novices in both microgravity and normogravity. Conclusions: Videolaryngoscopy was associated with higher intubation success rate and speed, and higher confidence for correct tube placement by novice operators in microgravity, and as such may represent the best technique for advanced airway management during long-duration spaceflight.

Time to ventilation and success rate of airway devices in microgravity: A randomized crossover manikin‐trial using an underwater setting

“…There are currently four randomized controlled trials (RCT) published 16 describing simulations of airway management in simulated microgravity [12][13][14]17 (Table 4). Three of the RCT studies simulated microgravity with parabolic flight [12][13][14] and one RCT study utilized an underwater neutral buoyancy setup. 17 Additionally, Starck et al compared the time that was required to perform endotracheal tube intubation (ETI) by experts vs novices as well as their success rates.…”

“…17 Additionally, Starck et al compared the time that was required to perform endotracheal tube intubation (ETI) by experts vs novices as well as their success rates. 12 This study was designed to test the airway devices under different gravity conditions, without the influence of the participant's clinical or diving experience. Therefore, and in contrast with Groemer et al or Rabitsch et al, all participants were anaesthesiologists with certified diving experience (Table 2).…”

“…In the Starck study, the mannequin and the endoscopist were restrained to the floor of the aircraft throughout the study, and the endoscopist was allowed to maintain the laryngoscope in their hand prior to the beginning of the intubation attempt. 12 In the first phase of an emergency, restraining the patient is time consuming and not always possible, eg in the International Space Station (ISS). 10 And as one might expect, the time to first ventilation was significantly shorter in the normogravity-segment (control group) for all devices except the non-significant faster placement of the LM.…”

“…Recent trials comparing airway devices in microgravity mainly took part during parabolic flight 12‐14 . This setting has the significant limitation that the time for each trial is limited to approximately 21 seconds and, therefore, might be too short to complete airway management.…”

“…10 Against this backdrop, trials with simulated microgravity offer a useful alternative.Recent trials comparing airway devices in microgravity mainly took part during parabolic flight. [12][13][14] This setting has the significant limitation that the time for each trial is limited to approximately 21 seconds and, therefore, might be too short to complete airway management. Several trials utilizing parabolic flight used a setting How to cite this article: Warnecke T, Dauth L, Ahlbäck A, et al Time to ventilation and success rate of airway devices in microgravity: A randomized crossover manikin-trial using an underwater setting.…”