The Effect of Prolonged Face Mask Ventilation on Gastric Insufflation: A Prospective Observational Study

Background: Pulmonary aspiration is a potentially lethal perioperative complication that can be precipitated by gastric insufflation. Face mask ventilation (FMV), a ubiquitous anesthetic procedure, can cause gastric insufflation. FMV with an inspiratory pressure of 15 cm H20 provides the best balance between adequate pulmonary ventilation and a low probability of gastric insufflation. There is no data about the effects of FMV > 120 seconds. Objectives: To investigate the effect of prolonged FMV on gastric insufflation. Methods: We conducted a prospective observational study at a tertiary medical center with female patients who underwent oocyte retrieval surgery under general anesthesia FMV. Pre- and postoperative gastric ultrasound examinations measured the gastric antral cross-sectional area to detect gastric insufflation. Pressure-controlled FMV with an inspiratory pressure of 15 cm H20 was continued from the anesthesia induction until the end of the surgery. Results: The study comprised 49 patients. Baseline preop-erative gastric ultrasound demonstrated optimal and good image quality. All supine measurements were feasible. The median duration of FMV was 13 minutes (interquartile range 9-18). In the postoperative period, gastric insufflation was detected in only 2 of 49 patients (4.1%). There was no association between the duration of FMV and delta gastric antral cross-sectional area (-0.01; 95% confidence interval -0.04 to 0.01, P= 0.31). Conclusions: Pressure-controlled FMV with an inspiratory pressure of 15 cm H20 carries a low incidence of gastric insufflations, not only as a bridge to a definitive airway but as an alternative ventilation method for relatively short procedures in selective populations. IMAJ 202A; 26: 24-29.