Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Study Objectives

Endotracheal intubation is a common intervention in critical care patients undergoing Helicopter Emergency Medical Services (HEMS) transportation.  Measurement of endotracheal tube (ETT) cuff pressures is not common practice in patients referred to our service.  Animal studies have demonstrated an association between the pressure of the ETT cuff on the tracheal mucosa and decreased blood flow leading to mucosal ischemia and scarring.  Cuff pressures greater than 30 cmH₂O impede mucosal capillary blood flow.  Multiple prior studies have recommended 30 cmH₂O as the maximum safe cuff inflation pressure.  This study sought to evaluate the inflation pressures in ETT cuffs of patients presenting to HEMS.

Methods

We enrolled a convenience sample of patients presenting to UMass Memorial LifeFlight who were intubated by the sending facility or Emergency Medical Services (EMS) agency.  Flight crews measured the ETT cuff pressures using a commercially available device.  Those patients intubated by the flight crew were excluded from this analysis as the cuff was inflated with the manometer to a standardized pressure.  Crews logged the results on a research form and the data were analyzed using Microsoft Excel and an online statistical analysis tool.

Results

We analyzed data for 55 patients.  There was a mean age of 57 years (range 18-90).  The mean ETT cuff pressure was 70 (95% CI, 61-80) cmH₂O.  The mean lies 40 cmH₂O above the maximum accepted value of 30 cmH₂O (p<0.0001).  Eighty-four percent (84%) of patients encountered had pressures above the recommended maximum.  The most frequently recorded pressure was >120 cmH₂O, the maximum pressure on the analog gauge.

Conclusion

Patients presenting to HEMS after intubation by the referral agency (EMS or hospital) have ETT cuffs inflated to pressures that are, on average, more than double the recommended maximum.  These patients are at risk for tracheal mucosal injury and scarring from decreased mucosal capillary blood flow.  Hospital and EMS providers should use ETT cuff manometry to ensure that they inflate ETT cuffs to safe pressures.