Modulating postoperative insulin resistance by preoperative carbohydrate loading.

The concept of preoperative overnight fasting was challenged and proved to have no benefits over allowing patients to drink clear fluids up until 2 h before surgery. This led to changes in the guidelines for preoperative fasting in many countries around the world. This concept has more recently been developed further. Mounting evidence indicates that instead of being operated in the traditional overnight fasted state, undergoing surgery in the carbohydrate-fed state has many clinical benefits. Many of these clinical effects can be related to reduced postoperative insulin resistance by preoperative carbohydrate loading. This article summarises the present understanding of the mechanisms behind the positive clinical effects and gives an overview of the information available regarding the clinical effects of this treatment. Finally, the article summarises the most recently published national guidelines on preoperative fasting routines where preoperative carbohydrates are recommended for use before a major surgery. These are to be considered for all patients allowed to drink clear fluids and undergoing elective surgery.