Transnasal humidified rapid insufflation ventilatory exchange for pre-oxygenation and apnoeic oxygenation during rapid sequence induction

Introduction

Rapid sequence induction (RSI) in the ICU, emergency department (ED) and operating room (OR) carries the risk of hypoxemia if laryngoscopy is prolonged especially in high-risk patients. Bag and mask pre-oxygenation is normally used to extend the apnoea time; however, arterial desaturation may still rapidly occur. Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) is a new technique that provides modest CPAP during pre-oxygenation and crucially also continuous oxygenation of the pharyngeal space throughout the apnoeic period. In elective surgery, THRIVE provides apnoea times as long as 60 minutes due to apnoeic oxygenation [1]. We report the first implementation of THRIVE with emergency patients into the ICU, ED and OR.

Methods

Following training a THRIVE system was installed in each location either as a fixed system on the anaesthetic machine (OR) or a mobile solution on a wheeled stand (ICU, ER). This was a simplified Optiflow system (Fisher and Paykel, New Zealand) consisting of a high-flow rotameter, a reusable humidifier, a reusable circuit and a disposable nasal interface. Anaesthetists of all grades were encouraged to use THRIVE (60 l/minute) prior to and during all high-risk intubations. Prospective data of pre and post intubation SpO₂ and time to intubate were collected. Anaesthetists were interviewed on acceptability of the technique.

Results

There were 62 RSI intubations using THRIVE (ICU and ED = 30; OR = 33). Difficult airway equipment used in 36 cases (videolaryngoscopy in 23). Mean apnoea time was 118 seconds (30 to 480 seconds), with a median SpO₂ fall of 1% (0 to 33%). There was no correlation between arterial desaturation and apnoeic time. OR cases had a mean apnoea of 113 seconds with a median SpO₂ fall of 0% (0 to 13%). ICU and ED cases had a mean apnoea time of 119 seconds and median SpO₂ fall of 1% (0 to 33%). THRIVE was universally readily accepted. Reasons cited included: simplification of pre-oxygenation (hands free) and increased confidence. Six outlying arterial desaturation events suggested poor airway maintenance at induction or use in particularly high-risk patients. Many anaesthetists reinstituted THRIVE following extubation in selected patients (for example, obesity). No complications occurred during implementation.

Conclusion

We conclude that THRIVE provides a convenient, safe and easy to implement technique for pre-oxygenation and apnoeic oxygenation during laryngoscopy.