Effect of Applying Cuff Air Leak Pressure as Intraoperative Cuff Pressure on Postoperative Complications

Once the intra-cuff pressure is measured and recorded, the cuff will be deflated by drawing the air 0.5ml per step with each step lasting 3 breaths until a leak, in which a 10% reduction in expiratory volume over the inspiratory tidal volume, is detected.Cuff will then be reinflated until the expiratory tidal volume reaches the inspiratory tidal volume and the discrepancy between the inspiratory and expiratory tidal volume is less than 10 percent. If the intra-cuff pressure applied by the anesthesia care team is inadequate and the discrepancy between the inspiratory and expiratory tidal volume is 10% or greater, the cuff will be further inflated with air 0.5ml per step with each step lasting 3 breaths until it reaches Pcr. This Pcr will be maintained during the entire anesthesia time until extubation.During the course of surgery, if any leak is detected, the cuff will be re-inflated by 0.5ml of air until the leak is not detectable.

Pcr is obtained just as it is done in the intervention group. The cuff will then be reinsufflated to the actual cuff pressure the care team initially chose. The care team will be blinded to the measured critical cuff pressures and hence will maintain the usual level of intracuff pressure in the control group during the entire anesthesia time.