Effect of Unexpected Prolonged Fasting on Patients Undergoing Elective Surgery under Spinal Anaesthesia: An Observational Study

Abstract

Introduction: Preoperative fasting is a standard practice aimed at minimising the risk of pulmonary aspiration during surgery. However, patients often experience prolonged fasting periods beyond the recommended duration due to unanticipated delays in the operating theatre, communication failures between teams, inadequate preoperative planning and other factors. Aim: To investigate the effects of unexpectedly prolonged fasting on intraoperative and postoperative parameters in patients undergoing elective surgery under spinal anaesthesia. Materials and Methods: This prospective observational study was conducted from October 2023 to June 2024 at the Department of Anaesthesiology, Dr. D.Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. The study included 70 patients undergoing elective surgery under spinal anaesthesia. Patients were divided into two groups: Group A (AM group, n=35), scheduled for surgery between 8:00 AM and 12:00 PM and Group B (PM group, n=35), scheduled for surgery after 12:00 PM or with delayed surgeries. Intraoperative parameters, including Mean Arterial Pressure (MAP), Heart Rate (HR), oxygen saturation (SpO2) and random blood glucose levels, were recorded at specific time points. Postoperative outcomes, such as nausea, vomiting and random blood glucose levels, were also assessed. Continuous and discrete variables were summarised as mean±SD and median, while categorical variables were presented as frequencies and percentages. Associations between categorical variables were tested using Pearson’s Chi-square or Fisher’s-exact test, with p-values<0.05 considered statistically significant. Results: The PM group exhibited higher preoperative random blood glucose levels (102.3±18.7 mg/dL) compared to the AM group (89.2±12.5 mg/dL). Postoperative nausea and vomiting were observed in 5 (14.3%) patients in the AM group and 11 (31.4%) patients in the PM group. Both groups showed a gradual decrease in MAP and HR from the preoperative period to 30 minutes after spinal anaesthesia administration, with slightly higher values noted in the PM group. No significant differences in SpO2 were observed between the groups. Conclusion: Unexpected prolonged fasting before elective surgery under spinal anaesthesia may contribute to higher preoperative blood glucose levels and an increased risk of postoperative nausea and vomiting. These findings underscore the importance of adhering to preoperative fasting guidelines and exploring potential strategies to minimise prolonged fasting periods, such as carbohydrate loading or allowing clear fluids closer to surgery.

Keywords

• elective surgical procedures
• intraoperative complications
• preoperative care
• respiratory aspiration