| | | | | The use of hypothermia, a medical treatment which lowers the internal body temperature, has been applied therapeutically for centuries. The Greek physician Hippocrates, arguably the world’s first modern doctor, advocated the packing of wounded soldiers in snow and ice.(2) Napoleonic surgeon Baron Dominque Larrey recorded that wounded soldiers who were kept further from the fire had better survival rates than those who were kept closer.(2) In modern times, the first documented clinical use was in 1938 when Dr. Fay, a neurosurgeon at Temple University, used ice water baths and open windows in winter to treat patients with cancer. The first medical study concerning therapeutic hypothermia was published in 1945 and focused on the effects of hypothermia on patients suffering from severe head injury (2). And in the 1950’s, therapeutic hypothermia received its first medical application, as a means to create a bloodless field in intracerebal aneurysm surgery. (2) |
| Temperature Management Therapy Post-Cardiac Arrest |
| Two studies published in the New England Journal of Medicine in 2002 documented therapeutic hypothermia’s ability to minimize damage to organs following cardiac arrest. The first of these studies focused on people who were resuscitated 5-15 minutes after collapse. Patients participating in this study experienced spontaneous return of circulation (ROSC) after a median downtime of 22 minutes (normothermia group) and 21 minutes (hypothermia group). Hypothermia was initiated within 105 minutes after ROSC. Subjects were then cooled over a 24 hour period. 55% of the patients in the hypothermia group experienced favorable outcomes, compared with only 39% in the group that received standard care following resuscitation. Notably, complications between the two groups did not differ substantially. This data was supported by a similar study that took place simultaneously in Australia, which found that 49% of the patients treated with hypothermia following cardiac arrest experienced good outcomes, compared to only 26% of those who received standard care.(1,5) Responding to this research, in 2003 the American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR) endorsed the use of therapeutic hypothermia following cardiac arrest.(3) Currently, a growing percentage of hospitals around the world incorporate the AHA/ILCOR guidelines and include therapeutic hypothermia in their standard care for patients post-cardiac arrest. In addition to the studies published in the New England Journal of Medicine, (1,2) studies in Stroke, (3) Neurosurgery, (4) Journal of the American College of Cardiology, Circulation (5) and Critical Care Medicine (6) support the benefits of temperature management for patients who survive out-of-hospital cardiac arrest: Expected neurological outcome of induced hypothermia is a 40% net clinical benefit compared to normothermia (p>0.009). (1) Therapeutic hypothermia increased the rate of a favorable outcome and reduced mortality in patients who have been successfully resuscitated after cardiac arrest due to ventricular fibrillation. (1) Twice as many patients that were treated with hypothermia were able to survive and had good outcomes - that is they were discharged home or to a rehabilitation facility – as compared to with patients treated with normothermia.(2)
|
| Protecting the Brain with Temperature Management Therapy |
| Therapeutic hypothermia has been demonstrated to prevent reperfusion injuries that occur after circulation returns to the brain. An individual suffering from an ischemic event may continue to experience injuries well after circulation is restored. This delayed reaction derives from the various inflammatory immune responses that occur during reperfusion. Hypothermia has been shown to help minimize the harmful effect of a patient’s inflammatory immune responses during reperfusion. Some researchers go so far as to contend that hypothermia represents a better neuroprotectant following a blockage of blood to the brain than any known drug.(4) Neuroprotective strategies after ischemic stroke are a promising field for therapeutic interventions, and hypothermia is the strongest available neuroprotectant therapy in pre-clinical studies. Advances in hypothermia delivery using endovascular heat exchanges and novel anti-shivering protocols make routine clinical use of hypothermia after ischemic stroke possible. (12) Patients with subarachnoid hemorrhage (SAH) commonly experience difficult-to-control fever, which is associated with negative clinical outcomes. Researchers observed that fever can be safely and effectively controlled in SAH patients for at least 24 hours with endovascular cooling. Induced hypothermia decreases intracranial hypertension and improves neurological outcomes in patients with moderate to severe TBI (Therapeutic Hypothermia in TBI). (10, 11) Given the potential to prevent reperfusion injuries, endovascular cooling may have clinical benefits for patients undergoing cerebrovascular surgery, as well as acute stroke, head injury or ischemic patients. (4) |
| | Temperature management and hypothermia induction are gaining importance in critical care medicine. Intensive care unit physicians, critical care nurses, and others (emergency physicians, neurologists, and cardiologists) should be familiar with the physiologic effects, current indications, techniques, complications and practical issues of temperature management and induced hypothermia. In experienced hands the technique is safe and highly effective.(9) |
| | 1. Hypothermia After Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med. 2002;346:549-556.
2. Bernard SA, et al. Treatment of comatose survivors of out-of-hospitals cardiac arrest with induced hypothermia. N Eng J Med. 2002;346:557-563.
3. Holzer M, Müllner M, Sterz F, et al. Efficacy and safety of endovascular cooling after cardiac arrest: cohort study and Bayesian approach. Stroke. 2006;37:1792-1797.
4. Steinberg GK, Ogilvy CS, Shuer LM et al. Comparison of endovascular and surface cooling during unruptured cerebral aneurysm repair. Neurosurgery. 2004;55:307-315.
5. American Heart Association. Part 4: Advanced Life Support. Circulation. Nov. 2005; 112: III-25 - III-54.
6. Oddo M, Schaller MD, Feihl F, Ribordy V, Liaudet L. From evidence to clinical practice: effective implementation of therapeutic hypothermia to improve patient outcome after cardiac arrest. Crit Care Med. 2006;34:1865-1873.
7. Nolan JP, Morely PT, Hoek TL. Hickey RW. Therapeutic hypothermia after cardiac arrest: an advisory statement by the Advancement Life support Task Force of the International Liaison Committee on Resuscitation. Resuscitation. 2003:57:231-235.
8. Labiche LA, Grotta JC. Clinical trials for cytoprotection in stroke. NeuroRx 2004;1:46-70.
9. Polderman, KH, Ingeborg H, Critical Care Med 2009; 37: 1101-1120.
10. Badjatia N, O'Donnell J, Baker JR, Huang D, Ayata C, Greer DM, Carter BS, Olgilvy CS, McDonald CT. Achieving normothermia in patients with febrile subarachnoid hemorrhage. Feasibility and safety of a novel intravascular cooling catheter. Neurocritical Care. 2004;1:145-156.
11. Wright J. Therapeutic hypothermia in traumatic brain injury. Crit Care Nurs Q 2005;28:150-161.
12. Hemmen, TM, Lyden PD , Hypothermia after Acute Ischemic Stroke, Journal of Neurotraauma 2009; 26;387-391 |
| For further information, please contact: |
| | About Royal Philips Electronics |
| Royal Philips Electronics of the Netherlands (NYSE: PHG, AEX: PHI) is a diversified Health and Well-being company, focused on improving people’s lives through timely innovations. As a world leader in healthcare, lifestyle and lighting, Philips integrates technologies and design into people-centric solutions, based on fundamental customer insights and the brand promise of “sense and simplicity”. Headquartered in the Netherlands, Philips employs approximately 116,000 employees in more than 60 countries worldwide. With sales of EUR 26 billion in 2008, the company is a market leader in cardiac care, acute care and home healthcare, energy efficient lighting solutions and new lighting applications, as well as lifestyle products for personal well-being and pleasure with strong leadership positions in flat TV, male shaving and grooming, portable entertainment and oral healthcare. News from Philips is located at www.philips.com/newscenter. |
|
|
| | | | |
|