Influence of airway pressure on minimum occlusive endotracheal tube cuff pressure.

OBJECTIVE

To examine the in vivo relationship between peak inflation pressure and the minimum occlusive pressure of a "high-volume, low-pressure" endotracheal tube cuff that may in some circumstances promote tracheal ischemic complications.

DESIGN

Prospective, clinical study.

SETTING

Surgical suite in a university hospital.

PATIENTS

Fifteen patients undergoing mechanical ventilation and general anesthesia for surgery.

INTERVENTIONS

After the regularly assigned anesthesia personnel established adequate general anesthesia, the investigator deflated and then reinflated the endotracheal tube cuff until tracheal seal was reestablished by auscultation. Peak inflation pressure and minimum occlusive pressure were determined using fluid-filled transducers to simultaneously record airway pressure just proximal to the endotracheal tube and cuff pressure via the pilot tube.

MEASUREMENTS AND MAIN RESULTS

Peak inflation pressure ranged from 12.1 to 43.7 mm Hg, and was associated with a minimum occlusive pressure of 2.2 to 39.7 mm Hg. Minimum occlusive pressure increased linearly over the range of measured peak inflation pressure values (r2 = .85, p < .001).

CONCLUSIONS

Knowledge of the linear relationship between peak inflation pressure and minimum occlusive pressure can help the clinician identify patients who may be at risk for cuff-induced tracheal ischemic complications, such as tracheoesophageal fistula and tracheal stenosis. In our series, a cuff pressure of 25 mm Hg corresponded to a peak inflation pressure of 35.3 mm Hg (48 cm H2O). Patients with higher peak inflation pressures may be at risk for ischemic tracheal injury, despite proper cuff inflation techniques.