Cuff compliance of pediatric and adult cuffed tracheal tubes: an experimental study

Tracheal mucosal damage related to tracheal intubation has been widely described in pediatric and adult patients. High volume-low pressure cuffs (HVLPC) are being advertised as safe to avoid this particularly unpleasant complication. Compliances of these supposed pediatric and adult HVLPC are not mentioned by manufacturers and still remain unknown.

The compliance of HVLPC was measured in vitro and defined as the straight portion of the pressure-volume curve. Cuff pressure was measured after incremental 0.1 ml filling volumes of air for sizes 3.0-8.0 of internal diameter of Rüsch and Mallinckrodt tracheal tubes. Compliances were assessed in air and in a rigid tube. The filling volume to achieve a 25-mmHg intracuff pressure was also measured.

In air, each 0.1 ml step almost linearly increased cuff pressure by 1 mmHg (size 8.0) to 9 mmHg (size 3). In air, the volume needed to maintain a cuff pressure < 25 mmHg was small for sizes 3-5.5 (0.35-2 ml). The 25 mmHg inflated cuff volume and compliance were decreased within a rigid tube, especially for adult sizes. In a rigid tube simulating a trachea, the compliances of almost every Rüsch tracheal tube were statistically higher than those of the Mallinckrodt.

We conclude that the tested tracheal tube cuffs have low compliance and cannot be defined as high volume-low pressure.