Induced Hypothermia in Post Cardiac Arrest Essay

Induced Hypothermia in Post Cardiac Arrest - Essay Example Lowering the patient's core temperature to 32-34 C is typical and appropriate for post cardiac arrest according to Bernard & Buist (2003). The use of hypothermia as a means of cerebral protection became established in the early days of cardiac surgery, the time when it was shown that hypothermia could prolong the safe period of circulatory arrest. From then on, hypothermic-perfusion-actively cooling body temperature down to 28 to 32 degrees Celsius during post cardiac arrest has been favored by the majority of surgeons for both valve surgery and CABG (Coronary Artery Bypass Graft). However, many surgeons argue that hypothermia is an unnecessary convention if systemic circulation is uninterrupted with the use of CPB (Cardiopulmonary Bypass and cerebral perfusion is assumed to be adequate. On one hand, the use of normothermicperfusion (maintaining body temperature at around 37 degrees or allowing to drift down without active cooling) has not produced any solid evidence from neither clinical practice nor prospective randomized trials. Hypothermia may also be induced for several medical purposes. ... A few trials have indicated that hypothermic perfusion may be beneficial and that normothermic perfusion is potentially harmful. Martin et al. (1994) were the first to report an increased rate of postoperative stroke, both early and late, in CABG patients randomized to normothermic perfusion (actively warmed to 35 degrees Celsius or higher). These findings have been questioned, because the use of retrograde cardioplegia in these patients could have increased the risk of cerebral embolism. More patients with neurologic deficits were also found in the group randomized to normothermia by Mora et al. (1996), although NP testing did not support a difference in outcome between the two groups. Only one study so far has suggested an effect of temperature on NP performance. Regragui et al. (1996) studied 70 patients randomized to three temperature groups: 28 C, 32 C, and 37 C. Normothermia was found to result in worse NP performance than the other two groups. However, both the small numbers of patients and the method of analysis of NP deterioration in the study caution against accepting this finding. The application of hypothermia in a post cardiac arrest may also protect the brain and spinal cord (Schepens et al. 1994). However, Colon R. et al. (1987) had found that it can also cause its own complications especially when the hypothermia is profound (Svensson et al. 1993). As an alternative, some surgeons like Gott (1972) have provided adjunctive intraoperative perfusion with temporary arterial shunts and partial extracorporeal bypass (Bloodwell et al. 1968) or retrograde cerebral perfusion during hypothermic circulatory arrest. Furthermore, there are other techniques that have been tried like the preoperative radiographic