Anaesthesia is provided to hundreds of millions of people each year with remarkable safety.1 However, a key concern of patients undergoing general anaesthesia is the potential experience of awareness.2 Young females are at increased risk of awareness under anaesthesia compared to males, as demonstrated in our meta-analysis.3 An implication of this may be that female patients are relatively under-dosed compared to males. Alternatively, this increased risk of awareness in females may arise from an influence of sex hormones on the pharmacokinetics and pharmacodynamics of anaesthetic agents.
Critically, the foremost way to reduce this risk of awareness is to increase the dose of anaesthesia. Stakeholder engagement has revealed that a limitation to adjusting dosing in females is concern that greater doses is associated with more adverse events and poorer quality of recovery. There is a lack of data to establish if deeper anaesthesia is non-inferior than lighter anaesthesia in young patients (as it is in older patients4).
In this randomised controlled blinded non-inferiority trial, we will address a critical lack of knowledge about (1) quality of recovery following anaesthesia in young females and (2) the influence of sex hormones on anaesthetic dosing.
1 Higham H, Baxendale B. Br J Anaesth 2017; 119: i106-i14
2 Rowley P, Boncyk C, Gaskell A, et al. Br J Anaesth 2017; 118: 486-8
3 Braithwaite H. MEDRXIV 2023: 287147
4 Short TG, Campbell D, Frampton C, et al. Lancet 2019; 394: 1907-14
Dr Hannah Braithwaite, Dr Elise Butler, Ms Kaitlyn Kramer, Royal Prince Alfred Hospital, NSW; Professor Robert Sanders, Dr Tom Payne, University of Sydney, NSW; Dr Amy Lawrence, Concord General Repatriation Hospital, NSW; Dr Ben Moran, Gosford Hospital, NSW.
The project was awarded A$70,000 funding through the ANZCA research grants program for 2025.