Mechanisms of action, physiological effects, and complications of hypothermia
Top Cited Papers
- 1 July 2009
- journal article
- review article
- Published by Wolters Kluwer Health in Critical Care Medicine
- Vol. 37 (Supplement), S186-S202
- https://doi.org/10.1097/ccm.0b013e3181aa5241
Abstract
Mild to moderate hypothermia (32-35 degrees C) is the first treatment with proven efficacy for postischemic neurological injury. In recent years important insights have been gained into the mechanisms underlying hypothermia's protective effects; in addition, physiological and pathophysiological changes associated with cooling have become better understood. To discuss hypothermia's mechanisms of action, to review (patho)physiological changes associated with cooling, and to discuss potential side effects. Review article. None. A myriad of destructive processes unfold in injured tissue following ischemia-reperfusion. These include excitotoxicty, neuroinflammation, apoptosis, free radical production, seizure activity, blood-brain barrier disruption, blood vessel leakage, cerebral thermopooling, and numerous others. The severity of this destructive cascade determines whether injured cells will survive or die. Hypothermia can inhibit or mitigate all of these mechanisms, while stimulating protective systems such as early gene activation. Hypothermia is also effective in mitigating intracranial hypertension and reducing brain edema. Side effects include immunosuppression with increased infection risk, cold diuresis and hypovolemia, electrolyte disorders, insulin resistance, impaired drug clearance, and mild coagulopathy. Targeted interventions are required to effectively manage these side effects. Hypothermia does not decrease myocardial contractility or induce hypotension if hypovolemia is corrected, and preliminary evidence suggests that it can be safely used in patients with cardiac shock. Cardiac output will decrease due to hypothermia-induced bradycardia, but given that metabolic rate also decreases the balance between supply and demand, is usually maintained or improved. In contrast to deep hypothermia (<or=30 degrees C), moderate hypothermia does not induce arrhythmias; indeed, the evidence suggests that arrhythmias can be prevented and/or more easily treated under hypothermic conditions. Therapeutic hypothermia is a highly promising treatment, but the potential side effects need to be properly managed particularly if prolonged treatment periods are required. Understanding the underlying mechanisms, awareness of physiological changes associated with cooling, and prevention of potential side effects are all key factors for its effective clinical usage.Keywords
This publication has 226 references indexed in Scilit:
- Induced hypothermia and fever control for prevention and treatment of neurological injuriesThe Lancet, 2008
- Hypothermia Treatment for Traumatic Brain Injury: A Systematic Review and Meta-AnalysisJournal of Neurotrauma, 2008
- Increased Matrix Metalloproteinase-9 in Blood in Association with Activation of Interleukin-6 after Traumatic Brain Injury: Influence of Hypothermic TherapyJournal of Neurotrauma, 2004
- Mild hypothermia protects the spinal cord from ischemic injury in a chronic porcine model☆European Journal of Cardio-Thoracic Surgery, 2004
- Thrombolysis using plasminogen activator and heparin reduces cerebral no-reflow after resuscitation from cardiac arrest: An experimental study in the catIntensive Care Medicine, 1996
- Neurochemical Mechanisms in Brain Injury and Treatment: A ReviewJournal of Clinical and Experimental Neuropsychology, 1996
- Cytokines in inflammatory brain lesions: helpful and harmfulTrends in Neurosciences, 1996
- Body temperature in acute stroke: relation to stroke severity, infarct size, mortality, and outcomeThe Lancet, 1996
- Hyperthermia following cardiopulmonary resuscitationIntensive Care Medicine, 1991
- Randomized Clinical Study of Thiopental Loading in Comatose Survivors of Cardiac ArrestNew England Journal of Medicine, 1986