Nil Per Os in the Emergency Department: A Quantitative Study on Fasting Before Presumptive Emergency Surgery

Nil per os is a common precautionary practice in emergency departments for patients with suspected need for emergency surgery. However, this practice may lead to prolonged fasting periods, which can negatively affect patient outcomes. This study aimed to evaluate the necessity and appropriateness of nil per os for patients in the emergency department.

A retrospective quantitative observational study was conducted, analyzing 41,983 patient visits from 2 emergency departments in 2023. The study focused on surgical, orthopedic, and neurological chief complaints, where nil per os was commonly implemented. We assessed the negative predictive value of emergency surgery within specified time intervals (<6 hours and <12 hours after arrival) solely based on time from arrival in combination with surgical priorities, chief complaints, and triage priorities according to the Rapid Emergency Triage and Treatment System.

Among the 41,983 included patients, 6.1% (n = 2561) underwent emergency surgery. The negative predictive value for emergency surgery within the specified time intervals was highest for Rapid Emergency Triage and Treatment System priorities 3, 4, and 5 (>99%), indicating a very low likelihood of emergency surgery within 6 to 12 hours for these patients. Rapid Emergency Triage and Treatment System priority 1 had the lowest negative predictive value, approximately 80% to 90%.

The study indicates that the routine practice of nil per os upon arrival at the emergency department is often unwarranted, particularly for those not classified as Rapid Emergency Triage and Treatment System priority 1. These findings highlight the need for updated guidelines to ensure that nil per os protocols are issued based on a clear medical necessity, thereby minimizing unnecessary fasting and its associated risks.