The impact of perioperative fasting on metabolic status in elective caesarean section patients

Abstract

Background: Obstetric patients exhibit ‘accelerated starvation’, increasing the risk of ketoacidosis. Fasting guidelines aim to reduce pulmonary aspiration, but prolonged preoperative starvation may cause metabolic disturbances. This study aimed to assess the relationship between fasting duration and the incidence of metabolic disturbances. Methods: We conducted a prospective observational study of patients undergoing elective caesarean section at Harry Gwala Regional Hospital. Fasting duration was recorded via questionnaire. Preoperative venous bicarbonate, base excess, glucose and ketone levels were measured to determine the incidence of metabolic disturbances before anaesthesia. Results: We recruited 107 patients. Of which, 30% were acidotic (base excess less than −3). The acidotic group had a longer starvation time than the non-acidotic group (mean starvation time 14.8 h [standard deviation [s.d.] 2.68, 95% confidence interval [CI] 13.8–15.7] versus 12.75 h [s.d. 3.18, 95% CI 11.8–13.2]; p < 0.01). Ketosis occurred in 32% of patients and was associated with longer starvation times (p < 0.01). Conclusion: Starvation periods exceeded recommendations and were associated with metabolic disturbances, including acidosis, hypoglycaemia and elevated ketones in elective caesarean patients. Adherence to fasting guidelines should be reinforced, and patients with extended starvation require further assessment. Future research should focus on optimising fasting durations and improving compliance with established guidelines. Contribution: This study demonstrates the metabolic impact of extended preoperative fasting periods in elective caesarean sections. Findings reinforce the need for quality improvement programmes to reduce prolonged fasting periods in the perioperative period.