slow positive end-expiratory pressure titration during general anesthesia with muscle paralysis improves lung function without compromising hemodynamic stability in preschool children: a randomized control clinical trial

Background: mechanical ventilation impairs oxygenation and increases intrapulmonary shunt. positive end-expiratory pressure (peep) slows derecruitment, improves lung function but can compromise hemodynamics. objectives: to asses slow peep titration effect on intrapulmonary shunt, oxygenation and hemodynamics in preschool children on mechanical ventilation under general anesthesia. methods: this was a single tertiary care center an open-label, randomized parallel group controlled clinical trial. study included 70 children, 3 - 7 years, asa i and ii, under general anesthesia for non-cardiothoracic surgery. children were randomly allocated either to receive peep titration 5 - 11 cmh2 o 20 minutes before the end of anesthesia (intervention group) or to be ventilated until the end of anesthesia with constant positive end-expiratory pressure of 3 cmh2 o (control group). main outcome measures were changes in oxygenation index (pao2 /fio2 ) and alveolar-arterial gradient (p(a-a)o2 ) between and within groups and changes in systolic blood pressure (sbp), mean arterial pressure (map) and heart rate (hr) in interventional group during peep trial. results: seventy children were recruited and analyzed. p(a-a)o2 and pao2 /fio2 improved in interventional group comparing to control as consequence of peep titration (∆pao2 /fio2 -30.3 vs. 0.52; p < 0.001; ∆p(a-a)o2 6.7 vs. -1.0; p < 0.001) and within interven- tional group before and after peep titration (pao2 /fio2 522.0 vs. 552.3; p < 0.01; p(a-a)o2 20.1 vs. 13.3; p < 0.001). hypotension and bradycardia were not documented. conclusions: slow peep titration up to 11 cmh2 o improves oxygenation, reduces intrapulmonary shunt without causing hemody- namic instability in preschool children during general anesthesia.