Improving Success of Orotracheal Intubation by Novice Operators in Microgravity with Video-Laryngoscopy

Abstract

Background: The risk of severe medical and surgical events during long-duration spaceflight is significant. Orotracheal intubation, which may be required for a range of medical and surgical conditions, is a technically challenging procedure, especially in novice hands. We hypothesized that the procedure may be facilitated by the use of a video-laryngoscope (VL), and compared intubation success rates of experts and novices under normogravity or simulated microgravity in parabolic flights. Methods: Six subjects (3 experts and 3 novices) performed 180 orotracheal intubations on a mannequin, with half during simulated microgravity and half on the ground (normogravity condition). Half of the attempts used direct laryngoscopy (DL) and half VL. The primary outcome was intubation success rate. We also recorded intubation time and the confidence score into the success of tube placement. Findings: Using DL, the intubation success rate was higher in experts than novices regardless of gravity condition. The success rate for intubation with VL was significantly higher for experts than novices in normogravity (80% versus 28%, p<0·001), but not in microgravity (95% versus 80%, p=0·14). When novices used VL in microgravity, intubation success rates (80% versus 40%, p<0·006) were higher and intubation time shorter than when using DL. Better confidence scores were achieved with VL compared with DL. Interpretation: VL 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. Funding: This work was supported by the French National Space Agency (CNES). Declaration of Interest: The authors declare that they have no competing interest. The medical equipment was graciously made available by their respective manufacturers. Ethical Approval: This study was authorized by the CNES ethical committee. All participants were volunteers and provided written informed consent for the research