Assessment of effectiveness of cricoid pressure in preventing gastric insufflation during bag and mask ventilation: A randomized controlled trial

BACKGROUND: Rapid sequence induction and intubation (RSII) with application of “Cricoid pressure” and avoidance of “facemask ventilation” (FMV) is believed to minimize the risk of pulmonary aspiration of gastric contents during general anesthesia. However, some patients may be at risk of developing hypoxemia and may benefit from FMV during RSII. The purpose of this study was to assess the effectiveness of “cricoid pressure” in preventing gastric insufflation during FMV using gastric ultrasonography. MATERIALS AND METHODS: Eighty-four adult patients were randomized to receive cricoid pressure (CP) or no cricoid pressure (NCP), during FMV after induction of general anesthesia. Gastric antral cross-sectional area (CSA) was measured with ultrasonography before and after FMV in supine and right lateral decubitus positions (LDP). Appearance of “comet tail” artifacts created by acoustic shadows of gas in the gastric antrum was noted. RESULTS: The incidence of insufflation indicated by “comet tail” artifacts during FMV was lower in group CP (17 vs 71%; P < 0.001). The lowest P(aw) at which gastric insufflation occurred was higher in group CP (20 vs 14 cmH(2)O). The change in mean gastric antral CSA was significantly lower in group CP than in group NCP in supine (0.02 vs 0.36 cm(2), P = 0.012) and right LDP (0.03 vs 0.67 cm(2), P < 0.001). CONCLUSION: Cricoid pressure is effective in preventing gastric insufflation during FMV at P(aw) less than 20 cmH(2)O. Observation of comet tail artifacts in gastric antrum along with measurement of change in antral CSA on ultrasound examination is a feasible and reliable method to detect gastric insufflation.