Tran A, et al. - The efficacy and safety of permissive hypotension were assessed in adult trauma patients with hemorrhagic shock. Findings suggest that for patients with hemorrhagic injury, permissive hypotension might offer a survival benefit over conventional resuscitation. Furthermore, it might reduce blood loss and blood product utilization.

Methods

• The MEDLINE and EMBASE databases were searched from inception to May 2017 for randomized controlled trials comparing permissive hypotension vs conventional resuscitationfollowing traumatic injury.
• Preoperative and intraoperative resuscitation strategies were included.
• Thirty-day or in-hospital mortality was assessed as the primary outcome.
• Blood product utilization, estimated blood loss and in-hospital complications were included as secondary outcomes.
• They performed pooling with a random-effects model.

Results

• Seven hundred and twenty-two abstracts were screened, from these five randomized trials evaluating 1,158 patients were included. 
• In the intervention arms, blood pressure targets varied from systolic BP 50 mm Hg to 70 mm Hg or mean arterial pressure of 50 mm Hg or higher as compared to systolic BP 65 mm Hg to 100 mm Hg or mean arterial pressure of 65 or higher in the control arms.
• Only patients with penetrating injury were evaluated by two studies while the remaining three additionally included blunt injuries.
• In terms of 30-day or in-hospital mortality, 4 trials suggested a survival benefit with hypotensive resuscitation, although 3 studies were insufficiently powered to find statistical significance.
• Due to poor protocol reporting and lack of blinding, studies were of poor to moderate quality.
• Researchers noted the pooled odds ratio of 0.70 (95% confidence interval, 0.53–0.92), suggesting a survival benefit for permissive hypotension.
• Furthermore, the patients received fewer blood products and had lesser estimated blood loss.