Orotracheal tube intracuff pressure initially and during anesthesia including nitrous oxide

Certified Registered Nurse Anesthetists (CRNA) have an ethical obligation to assure the safety of the anesthetized patient. Maintenance of orotracheal tube intra-cuff pressure (IcP) in a range preventing aspiration and avoiding tracheal ischemia is one way to enhance patient safety. Currently, no standardized method of cuff inflation and IcP maintenance is used in anesthesia practice. In addition, nitrous oxide (N2O) has the ability to diffuse into and inflate a cuff. Rate of N2O induced cuff inflation in vivo, has not been clearly delineated in the current literature. This study measured IcP initially, and over time during an anesthetic including 50% to 70% N2O. The sample consisted of 44 adult subjects intubated orally. Cuff inflation technique was identified and initial IcPs were recorded. IcP was then adjusted to 19 mm Hg and was continuously monitored until increasing to 25 mm Hg. A variety of cuff inflation methods were observed none of which consistently achieved an initial IcP within the target range of 19 to 25 mm Hg. IcP rose from 19 to 25 mm Hg in all cases during N2O administration. Elapsed time for the IcP increase ranged from 2 to 52 minutes (mean = 12.34, median = 8 minutes). During anesthesia with 50% to 70% N2O, IcP will increase from initial safe levels to ischemia producing levels. Devices and approaches designed to limit N2O induced IcP increase have been described, however only direct IcP monitoring has been shown to assure safe initial and ongoing IcP.