title: Prolonged preoperative fasting in elective surgical patients: why should we reduce it?
abstract: Despite the abundance of evidence to the contrary, 6-8 hours of total preoperative fasting is still considered essential by many surgeons and anesthesiologists, based on the strength of old concepts. Patients frequently end up fasting for 12 hours or more because of delays and changes in operating room schedules. The metabolic response to long fasting leads to intensification of the organic response occurring after trauma, which is mainly manifested as increased insulin resistance, an acute-phase response, and loss of lean body mass. In fact, there has not been any evidence indicating that a shorter fast of 2-3 hours, which includes oral clear or carbohydrate (CHO)-rich (12.5% carbohydrates, 50 kcal/100 mL) fluids, results in an increased risk of aspiration, regurgitation, or related morbidity compared with the standard policy of "nil by mouth after midnight." In addition, preoperative treatment with CHO-rich fluids may reduce postoperative discomfort and, for patients undergoing major abdominal surgery, may decrease the duration of postoperative hospitalization. New formulas for preoperative oral fluids containing amino acid or protein such as glutamine or whey protein are also potential candidates for early preoperative treatment and merit further study.
authors: José Eduardo de Aguilar-Nascimento, Department of Surgery, Federal University of Mato Grosso, Rodovia Helder Cândia 2755, Condomínio Country,15, 78048-150; Cuiabá-MT, Brazil. Email: aguilar@terra.com.br.
authors: Gunther Peres
authors: GP
authors: Pimenta
authors: José Eduardo
authors: JE
authors: de Aguilar-Nascimento
mesh_terms: D004040:Dietary Carbohydrates / Q000008:administration & dosage; D005215:Fasting; D005973:Glutamine / Q000008:administration & dosage; D006801:Humans; D007333:Insulin Resistance; D008894:Milk Proteins / Q000008:administration & dosage; D009325:Nausea / Q000378:metabolism / Q000517:prevention & control; D011182:Postoperative Care; D011183:Postoperative Complications / Q000517:prevention & control*; D011184:Postoperative Period; D017410:Practice Guidelines as Topic; D011300:Preoperative Care / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D014839:Vomiting / Q000378:metabolism / Q000517:prevention & control; D000067816:Whey Proteins; D014947:Wounds and Injuries / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D008894:Milk Proteins; D000067816:Whey Proteins; D005973:Glutamine
keywords: acute-phase proteins; carbohydrates; fasting; glutamine; insulin resistance; preoperative care; trauma; whey protein