Relationship between cuffpressure of endotracheal tube and temperature on patients under cardiopulmonary bypass anesthesia and its clinical significance

Abstract

Objective Investigating the relationship between the cuff-pressure of endotracheal tube and temperature on patients under CPB anesthesia and explore its clinical significance. Methods This is a prospective clinical study with randomly selected cases. Forty patients undergoing selective surgery under CPB anesthesia with tracheal intubation were randomly divided into 2 groups(n=20): 25 cmH2O(1 cmH2O=0.098 kPa) as initial cuff-pressure of endotracheal tube(group A) and 30 cmH2O as initial cuff-pressure(group B). The pressure of the tracheal tube cuff was recorded at different temperature points during cooling and warming. Meanwhile, CPB time, circulatory arrest time, postoperative mechanical ventilation time, postoperative hospitalization days and respiratory complications were recorded. Results There was no statistical difference between groups concerning age, sex, BMI, CPB time, circulatory arrest time, postoperative mechanical ventilation time, postoperative hospitalization days and respiratory complications(P>0.05). The pressure of the tracheal tube cuff during cooling and warming was significantly different with that at initial temperature(P<0.05). When the temperature dropped to 28 ℃, the decreased percentages were(17.8±9.9)% and (24.2±7.2)% respectively(P<0.05). The pressure was significantly higher in group B than in group A at the same temperature points(P<0.05). Conclusions For patients under CPB anesthesia, hypothermia will significantly reduce the cuff-pressure of endotracheal tube. In clinical practice, both 25 cmH2O and 30 cmH2O used as the pressure of the tracheal tube cuff are safe. Key words: Endotracheal tube; Cuff-pressure; Cardiopulmonary bypass