Effects of Isoflurane versus Propofol for Postoperative Neurocognitive Recovery in Patients Undergoing Surgery under General Anaesthesia: A Randomised Clinical Study

Introduction: Propofol and isoflurane are commonly used in general anaesthesia. Both the drugs are neither neuroprotective nor neurotoxic. In clinical settings, inhaled anaesthetics like isoflurane are frequently used. But, it has been claimed that isoflurane anaesthesia would be a factor inducing cognitive impairment. Propofol is metabolised quickly, primarily in the liver, and its by products are inert. After the initial dose, the half-life of propofol is 2 to 8 minutes, and even with prolonged infusions, propofol promotes quick recovery.

Aim: To evaluate the effects of propofol and isoflurane on postoperative recovery patterns in patients receiving general anaesthesia and to determine how they affect cognitive function and memory.

Materials and Methods: A double-blinded randomised clinical study was conducted at the Department of Anaesthesia, RL Jalappa Hospital and Research Centre, Tamaka, Kolar, Karnataka, India, during the period from January 2022 to March 2022. In the present study, 60 patients of between age 50-90 years were included. Patients were split into two groups: group A received an intravenous infusion of propofol, and group B received isoflurane. Patients in both groups had their cognitive ability and memory tested before surgery. In the present study, baseline Mean Atrial Pressure (MAP), Heart Rate (HR), Pulse Oximetry (SpO2) and Ramsay Sedation score were comparable in both groups. The novel variables, such as surgery types, duration, and medications were evaluated in both groups. Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were assessed one hour before and four hours after surgery. Comparison of a continuous variable across the groups was performed using the Student’s t-test or Mann-Whitney U test, depending on the normality of the distribution. A comparison of categorical variables across the two study groups was made using the Chi-square test. A p-value of <0.05 was considered statistically significant.

Results: Age group of 50-60 years were more in both group A (66.7%), and group B (70%). In Group A, most participants were females (56.7%), and in group B, majority were males (60%). In group A, the postoperative assessment showed a mean MoCA score of 25.6±1.52; in group B postoperative assessment showed a mean MoCA score of 24.17±1.46 with a p-value of 0.001, which was statistically significant. The postoperative assessment showed a mean MMSE score of 26.3±1.58 in group A and in group B, the postoperative assessment showed a mean MMSE score of 24.9±1.4 with a p-value of 0.001, which was statistically significant.

Conclusion: The current results imply that postoperative delirium is more frequently present after isoflurane anaesthesia than after propofol anaesthesia.