Improving the C-MAC video laryngoscopic view when applying cricoid pressure by allowing access of assistant to the video screen.

Cricoid pressure, as part of rapid sequence induction, may on occasion worsen laryngoscopic views and intubating conditions. We investigated whether allowing the assistant applying cricoid pressure to view the video laryngoscope screen would improve the laryngoscopic views compared to when they were blinded to the video screen. Laryngoscopy using the C-MAC video laryngoscope was performed in 51 patients undergoing elective general anaesthesia. Photographs were recorded sequentially under the following conditions: A) cricoid pressure by an assistant unable to see the video monitor, and B) cricoid pressure optimised by an assistant able to see the video monitor. These photographs were analysed offline by assessors blinded to whether the photo was obtained with blinded or non-blinded cricoid pressure application. Subjectively, 41% of views were improved when the assistant applying cricoid pressure was able to see the C-MAC screen, compared to those unable to see the screen. The view was unchanged in 45%, but initially worsened in 14%. These findings suggest that assistants applying cricoid pressure when a C-MAC is used should have access to the video image, but must also respond to requests for change from the person performing the intubation.