Gastric emptying is not prolonged in obese patients

Obesity is associated with a poor anesthetic risk, in part because of the greater aspiration rates. A greater gastric residue and lower stomach pH have been implicated. The relationship of obesity to gastric emptying is ill-defined. with contradicting reports stating shorter, similar, and longer times compared with nonobese subjects. The aim of the present study was to compare gastric emptying in obese and nonobese subjects at a university hospital.

A total of 19 obese (body mass index [BMI] >40 kg/m(2)) and 20 nonobese (BMI <30 kg/m(2)) subjects underwent a standardized scintigraphic gastric emptying study. The participants consumed a standard semisolid, technetium-99m-labeled meal. Images were acquired immediately and 1, 2, and 4 hours after meal completion. The interval to evacuate one half of the counts measured at meal completion) and retention (the percentage of counts in stomach at each measurement point) were recorded.

The mean age and BMI was 35 years and 45 kg/m(2) in the obese and 44 years and 26 kg/m(2) in the nonobese group, respectively. No differences were found between the 2 groups regarding gastric emptying. Regression analysis showed no statistical association between the BMI and gastric emptying, including multivariate analysis, considering BMI, age, and gender.

A scintigraphy test of a labeled meal was used to evaluate gastric emptying in obese and nonobese subjects. In accordance with other published data, no significant difference was found between the 2 groups. The anesthetic risks in the obese should be attributed to factors other than delayed gastric emptying (i.e., anatomic variation, increased rates of hiatal hernia and reflux).