Evaluation of the endotracheal tube cuff pressure resulting from four different methods of inflation in dogs.

OBJECTIVE

To evaluate the endotracheal tube cuff pressure achieved by four different inflation methods.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Eighty client owned dogs.

METHODS

After anaesthesia induction, endotracheal intubation was performed using plastic or silicone tubes. A clinician unaware of tube type inflated the cuff by simple digital palpation (method A), thereafter the cuff was deflated and inflated again by a second clinician who tried to reproduce a previously learned cuff pressure of between 19 and 24 mmHg (method B). During method C the cuff was inflated to the minimum occlusive volume at an airway pressure of 20 cm H(2) O, and in method D the cuff was incrementally deflated until an audible air leak could be heard from the oral cavity at an airway pressure of 25 cm H(2) O. For all the methods, an operator recorded the actual cuff pressure obtained using a manometer. Heart rate, respiratory rate and mean arterial pressure were monitored throughout the procedure.

RESULTS

The mean inflation pressure for plastic tubes was 56 ± 28 mmHg for method A, 20 ± 9 mmHg for method B, 35 ± 32 mmHg for method C and 46 ± 39 mmHg for method D. Pressures using silicone tubes were significantly higher than for plastic tubes, the mean registered pressures being 79 ± 39, 33 ± 16, 77 ± 50 and 92 ± 56 mmHg for methods A, B, C and D.

CONCLUSIONS AND CLINICAL RELEVANCE

None of the methods evaluated in this study can be considered effective for inflating the endotracheal tube cuff to within the optimal range when using silicone tubes. Direct measurement of the cuff pressure with a manometer is therefore recommended.