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Clinical and physiological consequences of preoxygenation using high-flow nasal oxygen in emergency anaesthesia

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posted on 2024-09-03, 01:48 authored by Albin SjöblomAlbin Sjöblom

Emergency anaesthesia is usually performed using a rapid sequence induction technique. The incidence of desaturation during rapid sequence induction is high, and preoxygenation prolongs the safe apnoea time. Apnoeic oxygenation using high-flow nasal oxygen can maintain adequate oxygenation in non-obese and pulmonary healthy patients for half an hour. High-flow nasal oxygen has also been shown to achieve a preoxygenation efficacy comparable to a traditional, tight-fitting facemask. Therefore, high-flow nasal oxygen has been proposed as a preoxygenation technique during rapid sequence induction, with a potential benefit being a seamless transition to apnoeic oxygenation. This thesis has investigated high-flow nasal oxygen during rapid sequence induction in various high-risk patient populations, aiming to explore its effectiveness in avoiding oxygen desaturation and the potential limitations of the technique.

Study I explored high-flow nasal oxygen as preoxygenation among patients undergoing emergency surgical procedures. High-flow nasal oxygen did not decrease the incidence of desaturation during induction of anaesthesia compared to a traditional facemask. The frequency of regurgitation did not differ between the groups, and no differences in the incidence of desaturation were seen comparing office hours and on-call hours. The facemask group had higher end-tidal oxygen levels immediately following intubation.

Study II investigated parturients, a population known to tolerate apnoea poorly. We therefore examined the use of high-flow nasal oxygen during induction of anaesthesia in pregnant women. All women in our cohort maintained well-oxygenated, and no patient showed signs of regurgitation. More parturients preoxygenated with high-flow nasal oxygen had end-tidal oxygen levels above 70% immediately following intubation compared to those preoxygenated with a facemask. This may indicate a greater oxygen reserve and superior conditions to maintain oxygen saturation during prolonged apnoea. Larger, randomised trials are needed to confirm our results.

Pre-hospital data have shown a high incidence of desaturation in trauma patients undergoing emergency anaesthesia. In study III, investigating trauma patients in need of in-hospital emergency anaesthesia, we could not detect any differences in the number of patients desaturating < 93% if preoxygenation was performed with high-flow nasal oxygen compared to a traditional facemask. Using high-flow nasal oxygen did not increase the incidence of adverse events, although these results are limited by the size of the population. Anaesthetists assessed preoxygenation with high-flow nasal oxygen as easier compared to a traditional facemask which could be valuable given the stressful clinical situation.

In this thesis, we also propose a new technique for preoxygenation. In study IV, we have shown that using a standard nasal cannula, at high flow rates, generates a preoxygenation efficacy comparable to a traditional facemask and high-flow nasal oxygen, although at the expense of impaired comfort. Since the standard nasal cannula is inexpensive, user-friendly and available globally, it could constitute an option when alternative methods are lacking.

In summary, preoxygenation using high-flow nasal oxygen has shown to be a feasible method to use during rapid sequence induction in various high-risk populations, equally effective as a traditional facemask in avoiding oxygen desaturation. Potential benefits are anaesthetists assessed ease, high patient comfort and a smooth transition to apnoeic oxygenation. This thesis demonstrated no increased risks of using high-flow nasal oxygen compared to a traditional facemask, although these results are limited by the size of our populations and need to be further explored. Finally, this thesis proposes a new method for preoxygenation, using a standard nasal cannula. Even though it impairs comfort, it could serve as an option when alternative methods are lacking.

List of scientific papers

I. Preoxygenation using high-flow nasal oxygen vs. tight facemask during rapid sequence induction. Albin Sjöblom, Jacob Broms, Magnus Hedberg, Åse Lodenius, Anders Furubacke, Ragnar Henningsson, Andreas Wiklund, Sabine Nabecker, Lorenz Theiler, Malin Jonsson Fagerlund. Anaesthesia. 2021;76(9):1176-1183.
https://doi.org/10.1111/anae.15426

II. Preoxygenation using high-flow nasal oxygen in parturients undergoing caesarean section in general anaesthesia – a prospective, multicentre, pilot study. Albin Sjöblom, Magnus Hedberg, Sofia Johansson, Ragnar Henningsson, Ioannis Soumpasis, Hannah Lafrenz, Daniel Törnberg, Åse Lodenius, Malin Jonsson Fagerlund. Acta Anaesthesiologica Scandinavica. 2023; 67(8):1028-1036.
https://doi.org/10.1111/aas.14264

III. Preoxygenation using high-flow nasal oxygen versus tight facemask in trauma patients during emergency anaesthesia - a prospective before-and-after study. Albin Sjöblom, Magnus Hedberg, Anders Gille, Andres Guerra, Vilde Aanesen, IdaMaria Forsberg, Malin Jonsson Fagerlund. [Submitted]

IV. Comparison of preoxygenation using a tight facemask, humidified high-flow nasal oxygen and a standard nasal cannula - a volunteer, randomised, crossover study. Albin Sjöblom, Magnus Hedberg, Ida-Maria Forsberg, Frida Hoffman, Malin Jonsson Fagerlund. [Submitted]

History

Defence date

2023-12-08

Department

  • Department of Physiology and Pharmacology

Publisher/Institution

Karolinska Institutet

Main supervisor

Jonsson Fagerlund, Malin

Co-supervisors

Hedberg, Magnus; Forsberg, Ida-Maria

Publication year

2023

Thesis type

  • Doctoral thesis

ISBN

978-91-8017-124-3

Number of supporting papers

4

Language

  • eng

Original publication date

2023-11-10

Author name in thesis

Sjöblom, Albin

Original department name

Department of Physiology and Pharmacology

Place of publication

Stockholm

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