Comparison of Gastric Volume After 6-hour and 8-hour Fasting in Patient Scheduled for Elective Surgery

Background. Preoperative fasting was a common practice to decrease perioperative aspiration risk. Duration of fasting was proportional to gastric volume. Short fasting duration may increase aspiration risk. However, prolonged perioperative fasting duration may lead to dehydration and hypoglycemia. The protocols of 8 hours preoperative fasting was recommended by American Society of Anesthesiologist (ASA) after a full meal. The meal recognized by ASA to make this guidelines were Western diet that contains more fat. South East Asian (SEA) standard solid meal mainly contains rice and less protein and fats. We hypothesized 6-hours compared with 8-hours fasting was sufficient to provide ideal gastric volume for preoperative fasting after SEA standard solid meal. The objective of this study was to analyze gastric volume after 6-hour and 8-hour of fasting after consumption of SEA standard solid meal on patients scheduled for elective surgery.

Methods This was a cohort study recruiting 37 subjects from January to February 2019. Subjects were patients scheduled for elective non-digestive surgery in Cipto Mangunkusumo Hospital, Jakarta, Indonesia. Inclusion criteria were age between 18 to 60 years old, have no nutritional status disorder, and ASA physical status of 1 or 2. The exclusion criteria were patients with diabetes mellitus, pregnancy, abdominal distention, history of dyspepsia, and intestinal motility disturbances.

Subjects agreed to take part in the research, will be initial examined for obtaining demographic data: age, weight and height, type of surgery to be performed, and preoperative examinations. The subject will start 8 hours of fasting before the surgical planning time. Before fasting, the subjects were given Cipto Mangunkusumo Hospital food standardized nutritional levels. Subjects were given 1 hour to consume the food. Six hours after the standard meal is consumed, an ultrasound examination will be performed in the right lateral decubitus position to obtain ultrasound imaging of the antrum. After that, the subject continued fasting until 8 hours after meal and ultrasound examination was performed using the same technique to obtain images of ultrasound imaging of the antrum. Imaging pictures are taken at the time relaxation of the antrum, between two contractions. The results of this imaging are stored and assessments of antrum craniocaudal (CC) and anteroposterior (AP) diameters were performed by research assistants who don't know when the image was taken. These measurements were used to calculate Cross Sectional Area (CSA) using the formula of CSA=(π×CC×AP)/4. The Gastric Volume (GV) was then calculated with the formula GV=27.0+(14.6×CSA)-(1.28×age).

The primary data obtained was the result of repeated examinations. The analysis was adjusted using the Bonferonni correction factor. Categorical data was analyzed using the McNemar test. The results of data processing are displayed in tabular form. The gastric volume was grouped into sufficient and insufficient with a border value of 1.5ml/kg.