Effect of changing direction of PEEP ladder on individualized PEEP determination and pulmonary complications in patients undergoing endoscopic surgery with Trendelenburg position

ObjectiveTo compare the effects of changing direction of positive end-expiratory pressure(PEEP) ladder and the duration of each PEEP level on the determination of individualized PEEP, pulmonary dynamic compliance and oxygenation in patients undergoing endoscopic surgery with Trendelenburg position.

MethodsSixty patients scheduled for endoscopic colorectal surgery under general anesthesia were randomly divided into increasing group and decreasing group, with 30 cases in each group.PEEP increased from 0 cmH₂O to 16 cmH₂O in the increasing group and decreased from 16 cmH₂O to 0 cmH₂O in the decreasing group, and the change gradient of PEEP in all patients was 2 cmH₂O.The end-expiratory dynamic pulmonary compliance(Cdyn) displayed on anesthesia machine at 1 min and 2 min under each PEEP level during the change of PEEP was recorded, and the PEEP at the maximum Cdyn was determined as the individualized PEEP.During the change of PEEP, if the invasive mean arterial pressure decreased more than 10% of the basic level, deoxyepinephrine was given to maintain the hemodynamic stability.

ResultsThere was no significant difference in the number of patients who needed to be given deoxyepinephrine in the process of maintaining hemodynamic stability between the two groups(P>0.05).There was no significant difference in PaO₂/FiO₂ between the two groups before and after PEEP ladder(P>0.05), there was no significant difference in PaO₂/FiO₂ before and after PEEP ladder in the increasing group(P>0.05), but PaO₂/FiO₂ after PEEP ladder was higher than that before PEEP ladder in the decreasing group(P < 0.05).There was no significant difference in the individualized PEEP obtained by maintaining PEEP for 1 min and 2 min between the two groups(P>0.05).When the PEEP level was 12, 14, 16 cmH₂O at 1 min maintenance time and the PEEP level was 8, 10, 12, 14 cmH₂O at 2 min maintenance time, the Cdyn value in decreasing group was significantly higher than that in increasing group(P < 0.01).

ConclusionsIn patients undergoing endoscopic surgery with Trendelenburg position, the stepwise increase or decrease of PEEP has the same effect on the determination of individualized PEEP and circulation, and there was no significant difference between each PEEP level at 1 min or 2 min.However, the effect of PEEP decrease on lung recruitment in the process of PEEP ladder change is more effective and faster than that of PEEP increase.