Tracheal tube cuff pressure during cardiac surgery using cardiopulmonary bypass

To determine the effects of cardiopulmonary bypass (CPB) ontracheal cuff pressure, we have measured intracuff pressure(ICP) in 29 consecutive patients undergoing cardiac surgerywith CPB. Premedication comprised hyoscine and, after inductionof anaesthesia with diazepam and fentanyl, followed by vecuronium,the trachea was intubated using a Portex Profile tracheal tube.Anaesthesia was maintained with high-dose fentanyl and 100%oxygen. ICP was measured with a transducer and the ICP was adjustedto 20 mm Hg. CPB was used with mild to deep hypothermia andblood-gas tensions were regulated according to alpha-stat (temperatureuncorrected) pH management. Before CPB, ICP was significantlyreduced from the mean baseline value of 20 (SEM 0.2) to 16.7(0.6) mm Hg (P < 0.01). ICP changed significantly duringCPB, decreasing to 8.0 (1.0) mm Hg before rewarming {P <0.01 vs immediately before CPB) and increasing to 17.0 (0.6)mm Hg after the start of rewarming (P < 0.01 vs before rewarming).After CPB, ICP did not differ significantly from that immediatelybefore CPB. We conclude that the decrease in ICP during thehypothermic phase of CPB may protect the tracheal mucosa againsthypotensive ischaemic injury. (Br. J. Anaesth. 1995; 74: 283–286)