The evolution of pre-operative fasting guidelines reflects a broader shift in medical practice toward evidence-based and patient-centered care. Historically, the practice of fasting from midnight before surgery, commonly referred to as “NPO after midnight,” was implemented universally to mitigate the risk of pulmonary aspiration under anesthesia. This rigid approach emerged from early studies linking full stomachs to aspiration, which could lead to life-threatening complications. While effective at reducing aspiration incidents, this traditional guideline imposes significant burdens on patients, often resulting in discomfort, dehydration, and metabolic imbalances. Moreover, research has questioned its necessity, particularly for healthy patients undergoing elective procedures (1). As a result, pre-operative fasting guidelines have undergone evolution to reduce the disruption to patient’s lives and health while maintaining safety.

As research in anesthesiology advanced, the limitations of prolonged fasting became more apparent. Studies demonstrated that the physiological risks associated with extended fasting, such as hypoglycemia and electrolyte imbalance, could outweigh the benefits, particularly for low-risk patients. Evidence showed that clear fluids could be safely consumed up to two hours before surgery without increasing gastric volume or acidity. Similarly, light meals consumed up to six hours prior to anesthesia were deemed safe for many patients. These findings prompted a paradigm shift in fasting practices, with organizations such as the American Society of Anesthesiologists (ASA) issuing updated guidelines in the 1990s and 2000s that adopted these more liberal policies (2).

However, despite pre-operative fasting guidelines’ evolution, their implementation has been inconsistent. Surveys have shown that outdated practices such as “NPO after midnight” persist in many institutions, often due to a lack of awareness among healthcare professionals or logistical challenges in hospital operations. For example, a study revealed that some nurses and anesthetists extended fasting times unnecessarily, sometimes for as long as 29 hours, due to institutional inertia or insufficient policies (3). This disconnect between evidence-based recommendations and clinical practice underscores the need for targeted education and improved communication within the perioperative team.

Beyond shortening fasting periods, recent research has explored innovative approaches to enhance patient outcomes. One notable advancement is the use of carbohydrate-rich beverages consumed a few hours before surgery. These drinks have been shown to reduce perioperative insulin resistance and promote better postoperative recovery without increasing the risk of aspiration. This approach not only minimizes the physiological stress of fasting but also aligns with enhanced recovery after surgery (ERAS) protocols, which emphasize minimizing surgical stress to improve patient outcomes (4).

Despite these advancements, some challenges remain, particularly in high-risk populations. Patients with conditions such as diabetes, gastroesophageal reflux disease, or obesity may require different fasting protocols due to altered gastric emptying rates. Similarly, fasting in emergency surgery settings is often not possible. Research in these areas remains ongoing,

highlighting the complexity of translating generalized guidelines into practice for diverse patient populations (5).

The evolution of pre-operative fasting guidelines is a testament to the dynamic nature of medical science. While traditional “NPO after midnight” practices have largely been replaced by more liberal and evidence-based recommendations, significant work remains to ensure these guidelines are universally adopted. Addressing barriers such as knowledge gaps, institutional inertia, and patient-specific complexities is essential for optimizing perioperative care. As the medical community continues to refine fasting protocols, the goal remains to balance patient safety with comfort and metabolic stability, fostering better outcomes and satisfaction.

References

1. Brady M, Kinn S, Stuart P. Preoperative fasting for adults to prevent perioperative complications. Cochrane Database Syst Rev. 2003;(4):CD004423. doi:10.1002/14651858.CD004423

2. Anderson M, Comrie R. Adopting preoperative fasting guidelines. AORN J. 2009;90(1):73-80. doi:10.1016/j.aorn.2009.01.026

3. Chapman A. Current theory and practice: a study of pre-operative fasting. Nurs Stand. 1996;10(18):33-36. doi:10.7748/ns.10.18.33.s42

4. Søreide E, Eriksson LI, Hirlekar G, et al. Pre-operative fasting guidelines: an update. Acta Anaesthesiol Scand. 2005;49(8):1041-1047. doi:10.1111/j.1399-6576.2005.00781.x

5. Hamid S. Pre-operative fasting – a patient centered approach. BMJ Qual Improv Rep. 2014;2(2):u605.w1252. Published 2014 Jan 5. doi:10.1136/bmjquality.u605.w1252