Ketamine's impact on mood after day-case surgery and its relation to obesity: a randomised controlled trial in women undergoing fractional curettage.

Background: Several studies have shown that ketamine has an effect on mood and depression in the perioperative context; however, little is known about ketamine's effect on patients' emotional recovery after day-case surgery. We aimed to examine whether a single subanaesthetic dose of ketamine could improve acute mood in patients shortly following fractional curettage.

Methods: One hundred forty women from 202 consecutive fractional curettage patients were enrolled in this randomised, double-blind placebo-controlled single-centre trial. In addition to propofol and fentanyl anaesthesia, subjects were randomly assigned to receive a single dose of iv ketamine 0.5 mg/kg (ketamine group) or saline (control group). The main objective of this study was to analyse the total mood score between the two groups by using the Profile of Mood States (POMS) questionnaire performed before and 120 min after the procedure and to evaluate the impact of menstrual status and obesity on the total mood score among patients in the ketamine and control groups, as well as in the entire study group separately. Pain, haemodynamic changes, sedation levels, and adverse medication effects were all studied as secondary outcomes.

Results: After surgery, both the ketamine and control groups showed a statistically significant decline in the total mood scores, although there were no apparent differences between the groups. Separate multiple linear regression analyses among ketamine group patients revealed that the presence of obesity was inversely related to total mood scores after surgery.

Conclusions: Our study showed that compared with the patients in the control group, a single subanaesthetic intravenous dosage of ketamine did not improve the total mood scores of patients in the ketamine group, as measured by the POMS questionnaire. On the other hand, obesity was an independent predictor of improvement in total mood scores among patients who received 0.5 mg/kg ketamine. Further studies are needed to evaluate the relationship between ketamine, obesity and patients' emotional recovery after surgery.

Trial Registration: This randomised controlled double-blind trial was retrospectively registered at ClinicalTrials.gov (trial number: NCT05752110; date of registration: 02/03/2023).