Measuring tracheal tube cuff pressures--tool and technique.

A three-part study identified factors essential to accurate determination of pressure exerted against the lateral wall of the trachea by three types of endotracheal tube cuffs. Part I compared 31 mercury sphygmomanometer measurements of tracheal cuff pressures to those of pressure-sensitive aneroid Portex manometer during simulated intubation and found 99.28% of mercury manometer readings accurate to within 2 mm Hg of Portex readings. Part II demonstrated that cuff compliance (i.e., the distensibility of the cuff material) influences such pressure determinations. Part III compared two methods of obtaining tracheal cuff pressure readings with the mercury sphygmomanometer during simulated intubation. Accurate measurement was made only with a stopcock system that simultaneously opened to the cuff, the manometer, and the inflator syringe and when a separate cuff distensibility factor was used in the computation.