Effects of remote ischemic preconditioning on prognosis in patients with lung injury: A meta-analysis

Objective: A number of trials have shown that remote ischemic preconditioning (RIPC) could reduce lung injury of patients suffering cardiovascular surgery, pulmonary transplantation surgery and thoracic surgery with one-lung ventilation. However, there is still a controversy over the lung protection of RIPC in patients who suffers different types of surgery. We undertook meta-analysis of the randomized controlled trials to evaluate the effect of remote ischemic preconditioning on clinical outcomes of patients with lung injury. Design: Systematic review and meta-analysis. Setting: Perioperative care areas. Patients: Adults and infants suffering cardiovascular surgery with lung injury. Intervention: Remote ischemic preconditioning. Measurements: The literatures were selected complying with the inclusive and exclusive criteria from the following databases as PubMed, Embase, Medline, Chinese Biomedical Literature and Journal Databases, Chinese Academic and VIP journal full-text Databases. Inclusion criteria includes: (1) Human clinical randomized and controlled trial; (2) the article we included is a clinical randomized controlled study; (3) the article discusses the effect of RIPC on lung injury of patients; (4) the primary evaluation indicators of the inclusive studies included postoperative intensive care unit stay time and mechanical ventilation time; (5) published in the form of full text, any language; (6) the type of operation is cardiovascular surgery; (7) there is no serious COPD, ARDS, respiratory failure and other lung diseases. Articles were excluded if they reported none of the outcomes as follows: postoperative intensive care unit stay time and mechanical ventilation time, human clinical controlled trails, pulmonary protection of RIPC, prospective clinical controlled trials. Two independent reviewers screened abstracts and titles, and selected records following full-text review. Software RevMan5.3 and STATA 12.0 were adopted to perform Meta-analysis. Result: The search finally includes10 studies of 708 patients, 352 patients in RIPC group and 356 patients in control group. The baseline characteristics of patients are no differences in two groups (P > 0.05). Compared with control group, RIPC significantly reduced the duration of ICU (P < 0.05) and mechanical ventilation time (P < 0.05) in RIPC group. In addition, the serum TNF-alpha and MDA concentration 24 h after operation in RIPC group are significantly lower than control group (P < 0.05). However, there are no significant differences between RIPC group and control group in terms of serum IL-6, IL-8 concentrations, A-aDO(2), PaO2/FiO(2 )and respiratory index 24 h after operation. Conclusion: RIPC can decrease pulmonary inflammatory responses, reduce the duration of ICU and mechanical ventilation time, and improve the clinical outcomes of patients with lung injury.