Effect of combined remote ischemic preconditioning and postconditioning on pulmonary function in valvular heart surgery

Background: The aim of this study was to evaluate the lung-protective effect of combined remote ischemic preconditioning (RIPCpre) and postconditioning (RIPCpost ) in patients undergoing complex valvular heart surgery. Methods: In this randomized, placebo-controlled, double-blind trial, 54 patients were assigned to an RIPCpre plus RIPCpost group or a control group (1:1). Patients in the RIPCpre plus RIPCpost group received three 10-min cycles of right-side lower-limb ischemia of 250 mm Hg at both 10 min after anesthetic induction and weaning from cardiopulmonary bypass. The primary end point was to compare postoperative Pa_O2/F_IO2. Secondary end points were to compare pulmonary variables, incidence of acute lung injury, and inflammatory cytokines. Results: In both groups, Pa_O2/F_IO2 at 24 h postoperation was significantly decreased compared with each corresponding baseline value. However, intergroup comparisons of pulmonary variables, including Pa_O2/F_IO2 and incidence of acute lung injury, revealed no significant differences. Serum levels of IL-6, IL-8, IL-10, and tumor necrosis factor-α were all significantly increased in both groups compared with each corresponding baseline value, without any significant intergroup differences. There were also no significant differences in transpulmonary gradient of IL-6, IL-10, and tumor necrosis factor- a between the groups. Conclusions: RIPC pre plus RIPCpost as tested in this randomized controlled trial did not provide significant pulmonary benefit following complex valvular cardiac surgery. Trial registry: ClinicalTrials.gov; No.: NCT01427621; URL: www.clinicaltrials.gov.