The effect of preoperative anxiety, hormone-induced ovarian stimulation, and prolonged face mask ventilation on gastric antrum size

BACKGROUND: Pulmonary aspiration is a potentially lethal perioperative complication related to gastric size and contents. Several perioperative factors are believed to increase gastric size, while others are less studied. Therefore, this study aimed to investigate the effect of anxiety, hormone-induced ovarian stimulation, and prolonged face mask ventilation (FMV) on gastric size via measuring antral cross-sectional area (CSA) using ultrasound. METHODS: This prospective observational study was conducted in Rabin Medical Center, Israel. We recruited 49 female patients undergoing hormone-induced ovarian stimulation and oocyte retrieval for in-vitro fertilization. Preoperatively, they ranked anxiety level on a visual numeric anxiety score (VNS). In the operation room, pre-and postoperative gastric ultrasound examinations were performed. Anesthesia was induced intravenously, followed by FMV with a peak inspiratory pressure of 15 cm H 2 O. RESULTS: There was no substantial correlation between pre-operative VNS anxiety and antral CSA ( p =0.697). Moreover, the number of follicles, blood estradiol, and progesterone levels did not correlate with antral CSA ( p =0.590, p =0.104, and p =0.511, respectively). The median duration of FMV was 13 minutes [IQR 18 to 8.5] and did not correlate with the antral CSA delta ( p =0.312). CONCLUSIONS: Neither preoperative anxiety nor extensive ovarian stimulation affects gastric size. Moreover, prolonged FMV with a peak inspiratory pressure of 15 cm H2O did not increase the gastric size by insufflation. These findings add to a growing body of literature on this topic. Furthermore, it provides new evidence that FMV is still safe even in a relatively short procedure. TRIAL REGISTRATION: ClinicalTrials.gov (Registration number, NCT04833530; Registration date, 06/04/2021).