Prevalence and factors predictive of full stomach in elective and emergency surgical patients: a prospective cohort study

Background. This prospective observational study sought to assess the rate of full and empty stomach in elective and emergency patients and to determine the factors associated with full stomach. Methods. Non-premedicated patients were consecutively included between May 2014 and October 2014. Ultrasound examination of the gastric antrum was performed by an operator blinded to the history of the patient. It included measurement of the antral cross-sectional area, performed in the supine position with the head of the bed elevated to 45 degrees, and qualitative assessment of the gastric antrum, performed in both semirecumbent and right lateral decubitus positions. Full stomach was defined by the appearance of any gastric content in both positions (Grade 2). Empty stomach was defined either by empty antrum in both positions (Grade 0) or by empty antrum in the semirecumbent position only (Grade 1) with measured antral area<340mm(2). The combination of Grade 1 and antral area>340mm(2) defined intermediate stomach. Logistic regression analyses were performed for the identification of factors associated with full stomach. Results. Four hundred and forty patients were analysed. The prevalence of full stomach was 5% (95% confidence interval: 2-9) in elective patients and 56% (95% confidence interval: 50-62) in emergency patients (P<0.0001). Obesity, diabetes mellitus, emergency surgery, and preoperative consumption of opiates were independent factors predictive of full stomach. Conclusions. The results suggest that preoperative ultrasound assessment of gastric content should be performed in all emergency patients, and in elective patients with identified predictive factors for full stomach.