The Perioperative Glycemic Level of Nondiabetic Patients – A Mixed-method Study Based on American Society of Anesthesiologists Fasting Guidelines and Actual Fasting Times

BACKGROUND: Traditional "nil per oral after midnight" fasting practices often result in unnecessarily prolonged fasting before surgery, which may adversely affect metabolic stability and patient comfort. Updated American Society of Anesthesiologists (ASA) guidelines recommend shorter, evidence-based fasting durations; however, adherence remains inconsistent in many healthcare settings. OBJECTIVES: This study aimed to assess the association between actual preoperative fasting duration and perioperative blood glucose levels in nondiabetic patients, to determine the prevalence of perioperative hypoglycemia and hyperglycemia in relation to ASA fasting guideline compliance, to evaluate patient-reported symptoms such as thirst, tiredness, and anxiety in relation to fasting duration, and to qualitatively explore patients' perceptions of prolonged fasting and its psychological effects. MATERIALS AND METHODS: A mixed-method, prospective observational study was conducted among 130 nondiabetic adult patients (ASA I and II) undergoing elective surgeries under general anesthesia. Fasting durations for solids and clear fluids were recorded and compared with ASA recommendations. Capillary blood glucose was measured preoperatively and postoperatively using a standardized glucometer. Quantitative data were analyzed using Chi-square and t-tests to assess associations between fasting duration and glycemic status. RESULTS: The mean fasting duration was 8.7 ± 1.2 h for solids and 3.4 ± 0.7 h for clear fluids, exceeding ASA recommendations in 27.7% of patients. The mean preoperative blood glucose was significantly lower in patients fasting beyond recommended duration (79.8 ± 9.5 mg/dL) compared to those within guidelines (93.4 ± 8.1 mg/dL, P < 0.001). Mild hypoglycemia (