Uso da ultrassonografia para avaliação do volume gástrico residual no pré-operatório de pacientes obesos

Abstract

Obesity is currently one of the major public health problems in the world and the number of obese patients undergoing general anesthesia is growing. The risk of gastric contents aspiration while under anesthesia is considered major to these patients and its consequences are extremely severe. OBJECTIVES Evaluate gastric ultrasound to calculate residual gastric volume after obese patients’ preoperative long fasting. MATERIALSAND METHODS A prospective study was conducted in a tertiary public hospital involving 41 obese patients (BMI ≥ 35 kg/m2), referred to bariatric surgery. Gastric volume got in ultrasound and aspirated on direct vision during upper gastrointestinal endoscopy were compared and the last was compared to gastric contents pH and fasting period. RESULTS Ultrasound did not appear as a good method to assess gastric volume in obese patients, probably because of the large gastric dimensions presented by obese patients and the bad signal transmission through abundant adipose tissue. There was no relation between pH and gastric volume. Fasting period lower than 700 minutes associated with large gastric volumes. CONCLUSION Our results suggest the necessity to adapt the formula to calculate gastric volume in obese patients through ultrasound, taking mainly into account an index to fix the cross-sectional area of gastric antrum. Furthermore, there was no connection between weight and residual gastric volume increase.