Preoperative fasting - "nihil per os" a difficult myth to break down: a randomized controlled study

For several years the scientific anaesthesia societies declared a preoperative fast of 6 hours for solid foods and 2 hours for clear liquids before elective surgical interventions to be sufficient. The aim of this study is to identify the extent of the gap that exists between the preoperative fasting time required and that actually encountered in operating rooms.

The safety and clinical applicability of a reduction of the preoperative fasting time was investigated through the use of oral solutions enriched with maltodextrin and their effects on the pre- and postoperative well-being that this may have on patients who are candidates for elective abdominal surgery. The study was conducted in two successive phases (I and II) and patients divided into two groups (A and B).

Clinical practice is slow to change, in fact, in our study the duration of fasting was an average of 19 hours for solids and 13 hours for liquids. The duration of the fasting did not show differences in the various surgical departments, demonstrating that it is a transversal practice and is not only limited to abdominal surgery in which the utility of fasting would theoretically be greater. Among Group patients A, the fasting time for liquids was about 9 hours. This shows that the time is certainly shorter but not much different when compared to the fasting time for liquids in group B which was on average 14 hours. It is important how difficult it is to achieve good compliance from patients when trying to reduce the time of preoperative fasting based on scientific evidence that is now well established.

The use of carbohydrate-enriched drinks up to 2 hours after induction of anaesthesia appears to be a safe procedure. The use of these solutions reduces the catabolic response to surgery and contributes to maintaining a pre-operative state of well-being by reducing feelings of hunger and thirst and the state of preoperative anxiety.