A randomized trial of sevoflurane versus desflurane on the quality of recovery following knee arthroscopy

Aims: To identify whether the quality of recovery over time is affected by sevoflurane versus desflurane when used as the primary anaesthetic for knee arthroscopy surgery. Significance: Quality of recovery is an emerging field within anaesthesia of great importance. Although large outcome studies are very important in anaesthesia, there is a changing focus from “mortality and morbidity studies”, to quality of recovery. The reason is that the frequency of mortality is now very low with the result that few interventions will further reduce mortality. Very large numbers are required to demonstrate any improvements in surgery and anaesthesia when mortality is used as an outcome. However early data on the PQRS as well as clinical reports indicate that the quality of recovery is often poor in many patients, and yet these are not identified by the treating anaesthetist. There are implications for the individual patient, for the practice of anaesthesia, and for the community (such as safe return to work or to driving). Knee arthroscopy is often performed as an outpatient (day) procedure, and therefore may be perceived as “minor surgery”. However, for some patients the quality of recovery including cognitive decline may be more profound than would be expected from brief peripheral surgery. The role of the anaesthetic agent may have an important influence on this recovery. It is frequently assumed by anaesthetists that anaesthetics from the same class should produce similar effects when administered for a brief anaesthetic, but there are insufficient data to validate that assumption. This study will help anaesthetists to choose the anaesthetic that is best for their patients undergoing brief surgery. Hypothesis: The null hypothesis is that there is no difference in recovery in all domains measured using the PQRS, in patients undergoing knee arthroscopy under general anaesthesia with either sevoflurane or desflurane as the primary anaesthetic Methods: A parallel group, randomised trial with 1:1 allocation ratio will be conducted in adult patients undergoing arthroscopy, where the intervention is to receive sevoflurane or desflurane as the primary anaesthetic agent. Quality of recovery will be measured using the Post-operative Quality of Recovery Scale (PQRS), at baseline (preoperative), 15 and 40 minutes, one and three days, and three months following surgery. Patients who are unable to complete the PQRS due to language limitations, or who will receive regional anaesthesia will be excluded. Recovery is defined as “return to baseline values or better” for each of the survey questions and is dichotomised to recovered or not recovered. Recovery is grouped within domains (physiological, emotive, nociceptive, cognitive, and activities of daily living, with a sixth domain of self-assessment). The primary endpoint will be the incidence of recovery for all domains (not including self-assessment) on the third day after surgery. Based on a pilot study performed at the Epworth Hospital, we estimate the ability to detect a clinically important difference with 150 patients in each group. Guidelines for other aspects of patient care including co-induction agents, antiemetics, and post-operative analgesics will be issued to reduce variability between patients. Likely benefits: There are pharmacological differences between sevoflurane and desflurane that make them more or less attractive to the anesthetist. Desflurane, should provide for earlier and more complete recovery then sevoflurane, but sevoflurane is an easier drug to administer due to a lower incidence of airway irritability. There are very few data investigating quality of recovery with these two drugs beyond emergence and PACU care. This study will provide data into whether there are longer-term differences in the quality of recovery between these two drugs.