Beta blockers for acute traumatic brain injury: a systematic review and meta-analysis.
Traumatic brain injury (TBI) is associated with a systemic hyperadrenergic state. Through activation of beta adrenoreceptors, catecholamines may induce hypermetabolism and increase both cardiac and cerebral oxygen demands. We conducted a systematic review to appraise the available evidence examining the safety and efficacy of beta blockers in patients with acute TBI. We systematically searched CENTRAL, MEDLINE, EMBASE and the reference lists of relevant articles from database inception until March 19, 2013. The outcomes assessed were in-hospital mortality, functional outcome and quality of life. Common adverse effects of beta blockers were examined including clinically significant hypotension, bradycardia, bronchospasm and congestive heart failure. Data on study outcomes and quality were abstracted in duplicate. The results were summarized descriptively and quantitatively. One randomized controlled trial was found with a high risk of bias. Eight retrospective cohort studies were found with a moderate risk of bias; however, only four of these studies were identified as unique after excluding overlapping cases. The cohort studies reported mortality outcomes; however, none of these included studies assessed functional outcomes or quality of life. Meta-analysis on the cohort studies (n = 4,782 patients) demonstrated that exposure to beta blockers after TBI was associated with a reduction in the adjusted odds of in-hospital mortality by 65 % (pooled adjusted odds ratio 0.35; 95 % CI 0.27-0.45). The current body of evidence is suggestive of a benefit of beta blockers following TBI. However, methodologically sound randomized controlled trials are indicated to confirm the efficacy of beta blockers in patients with TBI.