Perioperative hypothermia: use and therapeutic implications

Area of Science:

• Neurology
• Cardiothoracic Surgery
• Critical Care Medicine

Background:

• Perioperative cerebral ischemic insults are a significant concern in various surgical procedures.
• Induced hypothermia has been considered for decades to improve outcomes in surgical patients, particularly in cardiothoracic and neurosurgery.
• The efficacy of mild and moderate hypothermia has been questioned due to confounding factors like rewarming and incomplete understanding of injury mechanisms.

Purpose of the Study:

• To review the historical and current applications of induced hypothermia in surgical settings.
• To evaluate the evidence for the efficacy of mild, moderate, and deep hypothermia in preventing perioperative cerebral ischemia.
• To explore the implications of recent findings on mild hypothermia in cardiac arrest for perioperative brain insults.

Main Methods:

• Review of existing literature on induced hypothermia in cardiothoracic and neurosurgery.
• Analysis of studies investigating mild (32-35°C), moderate (26-31°C), and deep (18-25°C) hypothermia.
• Consideration of preclinical models for ischemic/anoxic injury and cardiopulmonary bypass.

Main Results:

• Mild and moderate hypothermia have shown little to no benefit in numerous cardiac procedures.
• Evidence for mild hypothermia's efficacy is lacking in cerebral aneurysm clipping and carotid endarterectomy.
• Deep hypothermia during circulatory arrest demonstrates clear protective efficacy in complex cardiac and neurosurgical repairs.

Conclusions:

• While deep hypothermia is effective, refining its application is crucial.
• Recent evidence suggests mild hypothermia may benefit patients with anoxic or global ischemic brain insults.
• Further research using advanced preclinical models is needed to optimize cooling strategies and understand hypothermia's mechanisms for perioperative use.