"Nil per oral after midnight": Is it necessary for clear fluids?

Area of Science:

• Anesthesiology
• Gastroenterology
• Surgical Care

Background:

• Preoperative fasting guidelines aim to minimize gastric volume and acidity to prevent aspiration during anesthesia.
• Recent recommendations favor relaxed fasting policies, allowing clear fluid intake closer to surgery.

Purpose of the Study:

• To evaluate the effect of ingesting 150 ml of water 2 hours before elective surgery on gastric fluid volume and acidity.
• To compare gastric aspirate parameters between patients with standard overnight fasting and those who consumed water preoperatively.

Main Methods:

• Prospective study of 100 ASA I and II patients undergoing elective surgery.
• Random assignment into two groups: overnight fasting (Group I) and 150 ml water intake 2 hours prior (Group II).
• Gastric aspirate volume and pH measured post-intubation via nasogastric tube.

Main Results:

• Significantly lower gastric fluid volume in the water-drinking group (5.5 ± 3.70 ml) compared to the overnight fasting group (17.1 ± 8.2 ml).
• Mean gastric pH values were comparable between the two groups.
• No statistically significant difference in gastric fluid acidity was observed.

Conclusions:

• Ingesting 150 ml of water 2 hours before surgery is safe for patients without aspiration risk.
• This practice leads to a reduced gastric fluid volume, aligning with modernized preoperative fasting protocols.
• Supports the liberalization of clear fluid intake policies prior to anesthesia.