Caregivers and Resident Doctors' Perceptions of Preoperative Fasting in Children

Historically, adults and children who undergo elective surgery remain fasting in the preoperative period, for the purposes of avoiding bronchial aspiration of the gastric contents during general anesthesia. The determination of preoperative fasting has taken on importance only in 1946, when Mendelson established a relationship between pulmonary aspiration during labor and general anesthesia. Stemming from other studies, such concept has been expanded to elective surgery and 25 ml were set as the maximum threshold of the gastric content to thus reduce the hazards of aspiration pneumonia.

The fasting time prescribed is still the subject of several investigations. For decades it has been established that patients should not feed on solids or ingest liquids over a period of 8 to 12 hours prior to surgery.

The guidelines are well set in connection with the rules of fasting, with aims at making the instructions constant throughout different services worldwide. In 2011, the American and the European guidelines became more permissive and determined as safe the 2 hours for liquids devoid of residue, 4 hours for breast milk, 6 hours for infant formula and non-human milk, 6 hours for light meals, and 8 hours for full meals. In accordance with the American guideline, liquids devoid of residue are: water, fruit juice with no pulp, carbohydrate-based beverages, tea with no residue, and black coffee, but those examples are not extensive. Gelatin is solid prior to intake, but it is found in a liquid state inside the stomach and, therefore, it is regarded as a liquid devoid of residue. Yet, in spite of the non-human milk's being a liquid material, it features a gastric emptying time which is similar to that of the non-fat solids. A light meal is characterized by toast and liquids devoid of residue, whilst a full meal includes food that is fried or which contains a high level of fat.

Currently, many directives (American Society of Anaesthesiologists - ASA; Norwegian National Consensus Guideline - NNCG; Association of Anaesthetists of Great Britain and Ireland - AAGBI) recommend liquids devoid of residue until two hours prior to the anesthetic induction for elective surgery in healthy children. The particular benefit of the oral intake of fluids includes a lower incidence of deleterious effects, such as thirst, irritation, crying, hypoglycemia, and dehydration. The preservation of the intravascular volume improves the hemodynamic conditions during the induction of inhalation anesthesia and facilitates the vascular access.

Even though the old instruction of "nothing by mouth after midnight" is in a process of being replaced by shorter periods of fasting, both surgeons and anesthesiologists still deem the traditional fast indispensable and have trouble with implementing the new norms, either by uncertainty before the possibility of the catastrophic consequences of pulmonary aspiration, or by lack of update on the subject. That matter generates mistakes in the rendering of information by the health professionals. Combined with the unawareness of the guardians in respect of the risk of bronchial aspiration and the anxiety in relation to the fasting, there is a result of difficulty in abidance by the proper preoperative fasting.

The minority of the guardians understands the real importance of the preoperative fasting and, many times, food regarded as "harmless" is offered during the period of fasting. Likewise, the guardians provide improper information in order to maintain the surgical procedure, with no regard for the correct observance of the fasting. That way, countless pediatric elective surgeries are canceled, deriving in psychological, social, and economic implications. The correction of these flaws will allow for the anesthetic procedure to take place in a more secure manner, with the proper observance of the fasting period and with the least possible trauma to the child.