The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

EFFECT OF MEAN AIRWAY PRESSURE ON INTRACUFF ENDOTRACHEAL TUBE CUFF PRESSURE IN AN ARTIFICIAL AIRWAY MODEL.

Sacha P. Broccard1, Sara K. Green2, William M. LeTourneau3; 1Lafayette College, Easton, PA; 2Saint Paul College, St. Paul, MN; 3Fairview Southdale Hospital, Edina, MN

Background: Endotracheal tube (ETT) cuff pressure ideally should be kept within an optimal range (20-30 cmH2O) to seal the trachea during positive pressure ventilation. Cuff pressures too low will allow for pharyngeal content migration below the ETT cuff and a possible volume loss during ventilation. Conversely, an ETT cuff pressure too high may compromise capillary circulation and damage the airway mucosa. Changes in ventilatory strategy may affect mean airway pressure (mPaw) and also native intracuff ETT cuff pressures (Pcuff). The purpose of this study was assessing to what extent mPaw alters Pcuff in an artifical airway model. Method: The artificial airway consisted of a 30 mL syringe with an inner diameter of 2.5 cm into which an ETT were introduced for testing. We studied 2 different ETT types (barrel-shaped and taper-shaped cuff). Pcuff was adjusted to 12, 20, 28 and 36 cm H2O prior to application of positive pressure ventilation. Ventilation using a conventional mechanical ventilator (CMV) and a high frequency oscillator ventilator (HFOV) were used to generate a mPaw of 12, 24 and 36 cmH2O for each native Pcuff condition and nadir and peak Pcuff were recorded and mean Pcuff calculated for 4 different sets of the 2 types of ETT studied. Results: Overall results demonstrated that mPaw significantly affects native Pcuff. The extent by which mPaw affects native Pcuff appears however, to be independent of the type of ETT studied (barrel-shaped and taper-shaped cuffs) and how mPaw is generated (CMV vs. HFOV). We also found that the effects of mPaw on native Pcuff varies, with the augmented Pcuff being the greatest for low native Pcuff and minimal for high native Pcuff (Figure 1). Conclusion: The results of this study demonstrate the dynamic nature of ETT cuff pressure measurement and the potential for ventilatory strategy to affect native Pcuff. Our results suggest the need to either continuously monitor Pcuff or measure it whenever a major change in ventilatory strategy affecting mPaw is implemented or during circuit disconnects to maintain a safe ETT cuff pressure to avoid complications. Our results need now to be confirmed in vivo. Sponsored Research - None