The Effects of Fasting Status on the Relative Risk of Pulmonary Aspiration in Acute Care Surgery Patients

Abstract

Acute care surgery patients are often unfasted at the time of surgery, presenting a unique opportunity to study the effects of fasting on the risk of pulmonary aspiration. We aimed to determine the relative risk of aspiration in patients who were fasted at the time of surgery according to guidelines versus those in an unfasted state. A retrospective chart review of 100 patients who underwent appendectomy (n = 76) or exploratory laparotomy (n = 24) was conducted at a single institution in 2016-2017. Using the American Society of Anesthesiologists (ASA) Practice Guidelines for Preoperative Fasting, patients were stratified into study and control groups according to whether they were unfasted (nothing by mouth for <8 hours prior to surgery) or fasted (nothing by mouth for >8 hours prior to surgery). Data controlled for patients' age, sex, body mass index (BMI), most recent hemoglobin A1c, presence of gastroesophageal reflux disease (GERD), and presence of hiatal hernia. Of the 76 patients who underwent appendectomy, 15% were unfasted with a total of 0 aspiration events (P < .001). Of the 24 patients who underwent exploratory laparotomy, 42% were unfasted with a total of 0 aspiration events (P < .001). This yields a relative risk of pulmonary aspiration of 1.0 (absolute risk of 0) in both the study and control groups. In an acute care surgery population including patients who were not fasted according to guidelines, there was no increase in the risk of pulmonary aspiration. Epidemiological study; Level III.