An in vitro study of the compliance of paediatric tracheal tube cuffs and tracheal wall pressure

Cuff volume-pressure curves and cuff pressure-tracheal wall pressure relationships were investigated in eight brands of currently available cuffed, paediatric tracheal tubes with internal diameters of 5.0 mm. Cuff volume-pressure curves were measured with the cuff unrestricted and with the cuff placed within a tracheal model with wall pressure measurements. With the tracheal tube cuffs, unrestricted cuff compliance at 20 cmH(2)O cuff pressure varied between 0.06 and 0.3 ml x cmH(2)O(-1). With the cuff restricted within the model trachea, all tracheal tube cuffs became considerably less compliant (0.01-0.09 ml x cmH(2)O(-1)). We found tracheal wall pressure was similar to the cuff pressure as long as the resulting cuff diameter was sufficiently large freely to drape the inner tracheal wall. We found that, regardless of whether a higher or lower compliant tube cuff was used, cuff hyperinflation uniformly resulted in potentially compromised tracheal mucosal blood flow; cuff pressure monitoring using cuff pressure limitation is therefore strongly recommended.