Use of a Liquid Diet Before Anesthesia

The use of a liquid diet prior to anesthesia has become an area of interest to improve patient comfort while managing safety risks. Historically, patients have been required to fast from solids for at least six hours and from clear liquids for two hours prior to anesthesia. This fasting was intended to reduce the risk of pulmonary aspiration by minimizing gastric contents that could be regurgitated during anesthesia induction. However, recent research has questioned whether prolonged fasting is always necessary and suggested that allowing patients to continue a liquid diet up to one hour before anesthesia and surgery may be both safe and beneficial for patients (1).

Studies have shown that a more liberal fluid intake policy, allowing clear liquids closer to the time of surgery, can reduce common patient discomforts such as preoperative thirst and anxiety without significantly increasing the risk of aspiration. In particular, a study by He et al. (2024) evaluated patients who were allowed to consume clear liquids up to one hour prior to surgery. These patients reported a decrease in preoperative thirst and anxiety, and experienced a reduced incidence of postoperative nausea and vomiting (PONV) compared to those who adhered to stricter fasting guidelines. This not only suggests potential benefits for patient comfort and well-being but may also improve recovery and reduce complications such as PONV, which are commonly observed in the postoperative period (2).

Physiologically, clear fluids are known to leave the stomach quickly – typically within two hours – so the risk of aspiration is generally low if fluids are consumed any time earlier than the hour before surgery. Research in pediatric patients, who have smaller stores of energy and water in their body, has shown that shortening the fasting period can improve patient comfort without increasing the risk of aspiration, a finding that has encouraged similar studies in adults. The results of a recent study by Bove et al. (2024) showed that patients who followed a more liberal fluid intake protocol did not have a significantly increased incidence of adverse events, even in surgeries involving complex gastrointestinal procedures (3).

Liberalizing fluid fasting guidelines offers additional benefits in terms of operational efficiency and patient compliance. Shorter fasting periods reduce the likelihood of patient non-compliance and can simplify preoperative instructions, making it easier for patients to adhere to preoperative protocols. In addition, hospitals benefit from more flexible surgical scheduling, as surgeries are less likely to be delayed or postponed due to extended fasting issues. However, some caution is warranted when implementing liberal fluid policies. Patients with certain medical conditions, such as gastroparesis or high aspiration risk, may still require a more restrictive approach. A randomized, double-blind study by Holte et al. (2007) highlighted the need for individualized fluid management, particularly in complex or high-risk cases. However, in the general surgical population, the liberal fluid approach has shown considerable promise and warrants further investigation and wider adoption in appropriate candidates (4).

Evolving research supports that allowing a liquid diet up to 1 hour prior to anesthesia may improve patient comfort, reduce complications such as PONV, and enhance the overall surgical experience without a significant increase in aspiration risk. As research adds to these findings,

liberal fluid fasting policies may become a central component of patient-centered care in the perioperative setting, balancing safety with improved patient satisfaction.

References

1. Joshi GP, LaMasters T, Kindel TL. Preprocedure care of patients on glucagon-like peptide-1 receptor agonists: a multisociety clinical practice guidance. Anesthesiology. Published online October 29, 2024. doi:10.1097/ALN.0000000000005231

2. He J, Wang Z, Yu X, Su Y, Hong M, Zhu K. Promoting application of enhanced recovery after surgery protocols during perioperative localized abdominal and thoracic neuroblastomas. Pediatr Surg Int. 2024;40(1):286. Published 2024 Nov 2. doi:10.1007/s00383-024-05884-w

3. De Siena M, Gualtieri L, Bove V, et al. Impenetrable abdomen: a case report of endoscopic sleeve gastroplasty performed in patient with huge paramedian laparocele. Obes Surg. Published online October 26, 2024. doi:10.1007/s11695-024-07536-3

4. Holte K, Foss NB, Andersen J, et al. Liberal or restrictive fluid administration in fast-track colonic surgery: a randomized, double-blind study [published correction appears in Br J Anaesth. 2008 Feb;100(2):284]. Br J Anaesth. 2007;99(4):500-508. doi:10.1093/bja/aem211