Introduction
Hypothermia is a term used about a condition in which the body’s core temperatures falls below those needed for normal body functions and metabolism. This is often regarded as unfavourable to human wellbeing. Recent studies in the medical field have revealed that induced hypothermia may prove valuable in the treatment of critical conditions and injuries. The research paper endeavours to investigate existing evidence in medical literature that therapeutic hypothermia has found use in the treatment of specific conditions.
Batra, R. B., & Paddle, J. J., 2009. Therapeutic hypothermia in drowning induced hypoxic brain injury: a case report. Cases Journal, Vol. 2, No. 9103.
Therapeutic hypothermia has found application in neuroprotection for over 50 years now but with proper guidelines lacking, its use has remained at best controversial. Nonetheless, the last 20 years have seen renewed interest by researchers and medical practitioners in the administration of mild therapeutic hypothermia in neuroprotection. The case study by Batra and Paddle (2009) was aimed at assessing the effect of therapeutic hypothermia in helping to alleviate hypoxic brain injury brought about by drowning. The case study involved a female tourist aged 17 years who had been rescued from sea. Cardio-pulmonary resuscitation was administered to her for 16 minutes. However, the patient had already sustained profound neurological insult owing to the hypoxic brain injury. While still in intensive care unit, she was exposed to a neuroprotection regime to which therapeutic hypothermia was included. Within 8 hours, the patient’s neurological status has improved markedly. By day 4, her coma score had been fully corrected. Therapeutic hypothermia in neuroprotection is yet to undergo formal controlled randomised trial and as such, there is no reasonable proof to show that the good outcome recorded by the case was mainly contributed by therapeutic hypothermia.
Bernard, S. A., Gray, T. W., Buist, M. D., Jones, B. M., Silvester, W., Gutteridge, G., & Smith, K., 2002. Treatment of Comatose Survivors of Out-of-Hospital Cardiac Arrest with Induced Hypothermia. N Engl J Med, Vol. 346, pp. 557-563
Incidences of patients having a cardiac arrest outside the hospital are becoming common, and the outcome is often poor. Research conducted on laboratory animals reveal that if induced hypothermia is administered shortly after spontaneous circulation has been restored, the neurologic outcome of the patient may improve. Nonetheless, conclusive studies are yet to be conducted on humans. In the current study, Bernard et al (2003) undertook a controlled, randomized trial whereby they assessed the impact of normothermia and moderate hypothermia on unconscious patients following a period of resuscitation for a cardiac arrest that had occurred outside the hospital. 77 patients were assigned to receive normothermia or hypothermia treatment randomly. Within 2 hours, the core body temperature of the patients had been lowered to 33 degrees C. This was after spontaneous circulation had resumed and held at this temperature for 12 hours. The outcome of the trial would dictate if the patients would be referred to rehabilitation, or discharged. The results of the study drew a link between a lower cardiac arrest, hyperglycaemia, elevated systemic vascular resistance and hypothermia. Preliminary observations made by the researchers suggested that the outcomes of coma patients appeared to improve once they had received moderate hypothermia treatment. This was following a period of out-of-hospital resuscitation against cardiac arrest.
Holzer, M., 2002. Mild Therapeutic Hypothermia to Improve the Neurologic Outcome after Cardiac Arrest. N Engl J Med, Vol. 346, pp. 549-556
In Europe alone, some 375,000 individuals are estimated to experience sudden cardiac arrest annually (Holzer, 2002). It is very rare for such patients to recover devoid of residual neurological damage. If there is no blood flow for over five minutes following cardiac arrest free radicals, along with other mediators can be generated during reperfusion, forming chemical cascades that can cause cerebral injury. For a long time, there lacked a therapy with accepted effectiveness in preventing damage following a cardiac arrest. A number of studies reveal that mild hypothermia (34°C) or moderate systemic hypothermia (30°C) significantly reduces brain damage in dogs after cardiac arrest, although the actual mechanism is far from clear. The study by Holzer (2002) was aimed at assessing the use of mild hypothermia to enhance neurological outcome following an episodes of cardiac arrest. The study was a controlled randomized trial in which the outcome assessment was blinded. Standard intensive care was administered to all patient based on detailed protocol. The Utstein style was used in recording individual patient’s data regarding their cardiac arrest. Within six months, a positive neurologic outcome had been realised. The study results revealed favourable neurological outcome among patients who had their spontaneous circulation restored once they had experienced cardiac arrest, in comparison with that receiving standard normothermic life care.
McIntryre, L. A., Ferguson, D. A., Hebert, P. C., Moher, D., & Hutchison, J. S., 2003. Prolonged Therapeutic Hypothermia After Traumatic Brain Injury in Adults. JAMA, Vol. 289, No. 22, pp. 2992-2999.
A number of research studies have investigated therapeutic hypothermia as a possible neuro-protective strategy to reduce or prevent traumatic brain injury among adults. Nonetheless, benefits accruing from treating traumatic brain injury (TBI) using therapeutic hypothermia techniques remain unclear. In this study, McIntryre and colleagues aimed at examining the effects of duration, rate, and depth of rewarming following a period of hypothermia discontinuation on neurologic outcome and mortality in adults who were the victims of traumatic brain injury. The its data sources, the researchers undertook an electronic search of the Cochrane Library, EMBASE, MEDLINE, Current Contents, as well as a hand search to locate key journals. In addition, the study identified corresponding authors of studies identified who they then contacted to provide additional information on ongoing or unpublished clinical trials. The study selected all the randomized control trials in which therapeutic hypothermia had been administered for a minimum of 24 hours in TBI adults. This was compared with nonthermal treatment for adults with TBI. 2 independent reviewers were located to abstract clinical and demographic data, neurological outcomes and mortality, methodological quality, and hypothermia interventions and cointerventions. Data analysis was performed on those trials that had fulfilled the eligibility criteria. The study found out that administering therapeutic hypothermia on TBI adults can lower the risk of poor neurologic outcome and mortality. Nonetheless, the duration and depth of hypothermia, along with the rewarming rate once hypothermia had been discontinued, influenced the outcomes. However, the researcher cautions us that the evidence of their study is still far from sufficient and as such, we cannot entirely rely on it in recommending the administering of therapeutic hypothermia routinely for TBI subjects beyond the scope of research settings.
Scholefield, B. R., Duncan, H. P., & Morris, K. P., 2010. Survey of the use of therapeutic hypothermia post cardiac arrest. Arch Dis Child, Vol. 95, No. 10, pp. 796-9
Therapeutic hypothermia results in profound improvement of neurological outcome in comatose adult patients following instances of ventricular fibrillation cardiac arrest. At the moment however, there is no clinical research evidence that the same has been replicated in children. In their survey, Scholefield and colleagues (2010) intended to ascertain opinions, attitudes and current practices in the UK regarding the administration of therapeutic hypothermia among children who have been resuscitated from cardiac arrest. The study methodology involves the use of anonymous surveys in which paediatric intensive care consultants in the UK (n=149) were interviewed. 76% of the respondents completed and returned their surveys (a total of 113). More than two thirds of the respondents (65%) answered that they were not aware whether therapeutic hypothermia has the potential to improve chances of survival to patients with cardiac arrest. Nonetheless almost half of the respondents (48%) answered that they ‘often’ or ‘always” administer therapeutic hypothermia once spontaneous circulation had resumed in children who have had cardiac arrest. On the other hand, 33% of the respondents answered that the reason did not use therapeutic hypothermia, with a majority of them citing lack of ‘enough research evidence’ (91%) as the most common reason. The study concluded that UK practices with regard to the application of therapeutic hypothermia vary widely. The study further shows a wide variation in the state of clinical equipoise. This is a demonstration of valuable support for collaboration efforts by UK multicenter in developing future therapeutic hypothermia trials following the occurrence of cardiac arrest.
Reference List
Batra, R. B., & Paddle, J. J., 2009. Therapeutic hypothermia in drowning induced hypoxic brain injury: a case report. Cases Journal, Vol. 2, No. 9103.
Bernard, S. A., Gray, T. W., Buist, M. D., Jones, B. M., Silvester, W., Gutteridge, G., & Smith, K., 2002. Treatment of Comatose Survivors of Out-of-Hospital Cardiac Arrest with Induced Hypothermia. N Engl J Med, Vol. 346, pp. 557-563.
Holzer, M., 2002. Mild Therapeutic Hypothermia to Improve the Neurologic Outcome after Cardiac Arrest. N Engl J Med, Vol. 346, pp. 549-556.
McIntryre, L. A., Ferguson, D. A., Hebert, P. C., Moher, D., & Hutchison, J. S., 2003.
Prolonged Therapeutic Hypothermia After Traumatic Brain Injury in Adults. JAMA, Vol. 289, No. 22, pp. 2992-2999.
Scholefield, B. R., Duncan, H. P., & Morris, K. P., 2010. Survey of the use of therapeutic hypothermia post cardiac arrest. Arch Dis Child, Vol. 95, No. 10, pp. 796-9.