A traditionally followed practice prior to elective surgery is to keep the patient fasting for around 12 to 24 hours. This is done to avoid the risk of vomiting and pulmonary aspiration during induction of anesthesia. Prolonged fasting significantly increases patient discomfort, thirst and hunger. It may cause dehydration and acute kidney injury, especially in the older adults, with poor postoperative outcomes. Hence, new guidelines now advocate fast for 2 hours from clear fluids and 6 hours from food for patients undergoing elective surgical procedures.

A multicenter prospective audit was conducted over 2 months to assess preoperative fasting and surgical timing (FaST) in 343 patients undergoing elective and emergency general surgery in the East Midlands region of the United Kingdom. Adherence to guidelines for fasting in patients was also examined. Of the 343 participants, 172 (50%) were males; 266 (78%) underwent elective surgery and 77 participants (22%) had emergency surgery. The median fasting time for clear fluids was 5.8 hours, while it was 16.1 hours for food. Seventy-one (21%) and 250 (73%) participants fasted for more than 12 hours for clear fluids and food, respectively. Most patients undergoing elective surgery fasted for more than 4 hours from clear fluids and more than 12 hours from food. The fasting period was even longer in patients undergoing emergency surgery; more than 12 hours from clear fluids and more than 24 hours from food. The study demonstrated poor compliance with fasting guidelines.

Patients undergoing surgery tended to fast from clear fluids and food for longer durations despite guidelines recommending against prolonged preoperative fasting. The authors suggest that the available data on operative times and theatre efficiency can be used to better plan preoperative fasting in emergency as well as elective surgeries. Explaining the rationale of guidelines to patients and making them part of shared decision making may increase compliance with better outcomes of surgery.

El-Sharkawy AM, et al. Clin Nutr. 2020 Sep 5:S0261-5614(20)30449-0