Does therapeutic hypothermia reduce mortality and improve neurological outcome in severe tbi? A systematic review study

Abstract

Introduction: Traumatic Brain Injury (TBI) is the leading cause of death and permanent disability in young populations in Africa. In Tanzania, 74% of patients with TBI are due to motor traffic accidents with overall mortality of 13% with 80% occurring in ICU. Despite adequate resuscitation, severe TBI patients tend to have poor outcome which is mostly caused by secondary insult leading to neurological damage to brain. Prophylactic Therapeutic Hypothermia (TH) has shown promising outcome in treating Severe Traumatic Brain Injury (STBI). Objectives/Aims: Examine whether TH reduces mortality caused by secondary injury and improves neurological outcome. Methods: Searches involved various data bases in review: CINAHIL, MEDLINE, EMBASE, Cochrane library and Google Scholar. Data were searched using MeSH terms and Boolean operators were used. Results: A meta-analysis conducted Sichuan Hospital shows that patient treated with moderate TH has significantly less mortality in Asian population. Another study involving patients with TBI in adults using TH was associated with 19% reduction in risk of death and 22% reduction in poor neurological outcome. Discussion: It has been shown that TH reduced the risk of mortality and poor neurologic outcome in adults with TBI. 18 trials evaluating mortality as one outcome, showed that TH was associated with mortality reduction p.=0.0004 and significant reduction in poor outcome p.=0.00001. The effectiveness of TH was determined by early application of cooling (within 6hrs of injury) in the Emergency Room and continuation in the ICU. Decreased death and good neurological outcome were determined by duration of cooling, depth (32⁰C-34⁰C) and frequency of re-warming (1⁰C/4hrs). Conclusion: Hypothermia reduces ICP, decrease cerebral metabolic demand, decrease disruption of blood brain barrier and inhibit inflammatory cascades that leads to reperfusion injury.