Nothing by mouth at midnight: saving or starving? A literature review

Historical use of fasting at midnight before anesthesia and surgery has been based on tradition instead of evidence. Research has challenged this practice and determined consuming clear liquids (e.g., water, apple juice, black tea, black coffee) 2-3 hours before surgery does not increase gastric residual volume or risk for aspiration. Liberal fasting guidelines have been published to support this research; however, there continues to be a disparity between practice and evidence. Metabolic alterations occur in the starved state and current available evidence suggests the use of a carbohydrate-rich clear liquid beverage to stimulate the fed state. The fed state is characterized by insulin secretion that stimulates the storage of macronutrients for fuel and promotes protein synthesis. Implementing this practice may decrease insulin resistance and support immune function. Allowing the patient to consume carbohydrate-rich clear liquid beverages may reduce postoperative nausea and vomiting and improve patient reports of anxiety, hunger, and thirst. This article evaluates the evidence for providing clear liquids and carbohydrate-rich clear liquid beverages to healthy adults undergoing surgery to optimize postoperative recovery.