Clinically Induced Hypothermia in the Management of Severe Head Injury:
A Review of the Evidence
1. Title Page
9. i) Inclusion & Exclusion Criteria
10. ii) Limitations of Search
11. iii) Critical Framework
12-26. Critical Review of the Data
13. i) Study Aims & Design
19. ii) Sampling & Controls
25. iii) Results
32. i) Implications for Practice
42. Appendix 1) – The Four Stages of Research
43. Appendix 2) – Database Search (Hard Copy Only)
44-49. Appendix 3) – Example (1) Using the CASP Framework
Evidently, in clinical practice this is not always the case as although many studies have confirmed hypothermia’s ICP lowering effects not all of them have been able to significantly support the above statement. Some researchers even rebutted the use of hypothermia in their studies reporting that its use increases the incidence of complications.
To assess the conflicting evidence, a full systematic literature review was performed using a number of database search engines and nine studies were carefully selected for critical analysis.
Examination of the literature demonstrated a lack of substantial evidence was available that supported the use of therapeutic hypothermia in order to improve the outcome of severely brain injured patients. Despite several small single centre studies concluding that subsets of patients may have an improved outcome. Conversely two large multicentre studies dismissed hypothermia as beneficial, to the extent that the studies were terminated early by patient safety and monitoring boards.
This review has offered some explanations to the diverse results, in doing so it has explored the reported complications and assessed their impact on cancelling out any benefits that clinical hypothermia may offer. It is concluded that many of these related complications can be avoided if pre-empted. However, more research is still required to confirm whether hypothermia would be advantageous. Nevertheless, the information gained from this study has greatly helped the author in managing patients that have suffered a severe head injury.
Head injury is a common and serious health problem, documented as a leading cause of death and disability in individuals below the age of 44 in the Western world (Sahuquillo 2007). It is a major source of severe and long lasting morbidity, often requiring lifelong nursing care. Although pre-hospital mortality remains high, improvements in transportation (including air ambulances), resuscitation, brain imaging and surgical intervention have challenged clinicians to maintain survival in individuals that may have previously died, ultimately testing them to achieve a good quality of life in the post head injured patient. (Sahuquillo 2007).
Brain injury is normally thought of in terms of primary and secondary insults. First published in the 1970’s this remains a useful concept as it differentiates between the unavoidable irreversible primary injury and the potentially avoidable secondary one (Adams 1977). Primary brain injury occurs immediately at the time of injury, whereas secondary injury is a cascade of events that contributes to intracranial hypertension resulting in a reduction in cerebral perfusion pressure and ischaemia (Marmarou 1991). The cerebral perfusion pressure (CPP) is determined by the Monro-Kellie hypothesis. In closed head injuries, the skull has a fixed volume and the pressure within it is determined by the equilibrium between the CPP, the mean arterial...