Postoperative Assessment of Cognitive Dysfunction in Patients Undergoing Transurethral resection of the Prostate under Spinal Anaesthesia: A Prospective Cohort Study

Abstract

Introduction: Postoperative Cognitive Dysfunction (POCD) is a common disorder following surgery that threatens the quality of patients’ lives. POCD is closely associated with perioperative factors such as age, physical state, surgery duration, anaesthesia method, intraoperative hypotension, and infection. Among these factors, age is the only long-term risk factor for POCD. The relationship between anaesthesia depth and the incidence of POCD is debatable. Aim: To assess POCD in patients undergoing Transurethral Resection of the Prostate (TURP) and to examine the association between the duration of surgery and serum sodium levels with cognitive dysfunction. Materials and Methods: A prospective observational study was conducted at the Department of Anesthesiology, PES Institute of Medical Sciences and Research, Kuppam, Andhra Pradesh, India, from January 2020 to June 2021. The study included 100 patients aged over 60 years who were scheduled for TURP surgery under Spinal Anaesthesia. The Mini-Mental State Examination (MMSE) test was performed in the preoperative holding area, and the results were recorded. A decline in cognitive function was defined as a loss of 2 or more points on the MMSE test compared to the preoperative value. Serum sodium levels and MMSE scores were measured before surgery. Serum sodium levels and MMSE scores were also recorded after the 1st hour and 6th hour postoperatively. The data were entered into MS Excel 2007 and analysed using Statistical Package for Social Sciences (SPSS) version 20.0. Results: In the present study, out of 100 subjects, the majority of patients (33%) belonged to the age group of 66-70 years, and most of the study subjects (79%) were classified as American Society of Anesthesiologists (ASA) II status, followed by ASA III status. The mean age of the study participants was 69.3 years. The mean duration of surgery was 45.6 minutes. A statistically significant difference (p<0.05) was observed when comparing the mean serum sodium levels before surgery (138.1±1.5 mmol/L) with those at the 1st hour postoperatively (135.9±1.6 mmol/L) and 6th hour postoperatively (134.4±1.4 mmol/L). The mean MMSE score before surgery and at the 1st hour and 6th hour postoperatively was the same (27.6±0.8), and there was no statistically significant difference between them. The MMSE score did not vary with the serum sodium levels, and this difference was not statistically significant (p>0.05). Conclusion: In the present study, patients undergoing TURP procedures under spinal anaesthesia did not exhibit any POCD, despite a considerable drop in serum sodium levels. It is worth noting that all patients were asymptomatic.