Pre-oxygenation--how long?

Abstract

Pre-oxygenation was studied in 12 fit volunteers and 20 patients using an oxygen flow of 8 litres/minute delivered from a standard anaesthetic machine via a Magill or Bain breathing attachment. End-tidal nitrogen concentrations of 4% or less were achieved within 3 minutes; the fastest times were achieved using the Magill breathing system when the reservoir bag was filled with oxygen prior to application to the face. Gas-tight fits of face masks on patients were found to be essential.