Influence of temperature on tracheal tube cuff pressure during cardiac surgery

Background: Lateral wall pressure may cause tracheal injury by affecting tr acheal capillary blood flow. Damage to the trachea is less severe when late ral wall pressure exerted by the endotracheal tube cuff does not exceed the mean capillary perfusion pressure of the mucosa. The purpose of this study was to determine the effects of hypothermic and normothermic cardiopulmona ry bypass (CPB) on tracheal tube cuff pressure dynamics. Methods: Twenty-two patients were studied during normothermic CPB (pulmonar y artery blood temperature in the CPB period between 36 and 35 degrees C), and 22 patients during hypothermic CPB (pulmonary artery temperature in the CPB period between 32 and 28 degrees C). A Mallinckrodt Medical Lo-Contour (TM) Murphy tracheal tube, with high-volume, low-pressure cuff was used wit hout lubricant. Intracuff pressure FCP) was recorded at end-expiration befo re, during and after cardiopulmonary bypass. Results: ITCP measurements were different between groups during CPB at aort ic cross-clamping (13.9+/-0.8 mmHg in the normothermic group versus 11.3+/- 0.4 mmHg in the hypothermic group, P<0.05), and respectively during CPB aft er aortic declamping (15.3+/-0.8 mmHg and 12.6+/-0.8 mmHg, P<0.05) and afte r CPB at the end of surgery (16.8+/-0.7 mmHg and 18.6+/-0.3 mmHg, P<0.05). Conclusion: We conclude that the ITCP is higher in normothermic CPB than in hypothermic CPB; however, the clinical significance of this observation ne eds further investigation.