Is hypothermia used post-stroke suffered intraoperatively after open heart surgery?

Therapeutic Hypothermia for Post-Stroke After Open Heart Surgery

Therapeutic hypothermia is NOT recommended for treatment of stroke occurring intraoperatively or postoperatively after open heart surgery, as there is no evidence demonstrating improved neurological outcomes in this specific clinical scenario, and the risks of complications including pneumonia, cardiac arrhythmias, and coagulopathy outweigh any theoretical benefits. 1

Evidence Against Hypothermia for Post-Stroke Treatment

The American Heart Association/American Stroke Association guidelines explicitly state that no data demonstrate that induced hypothermia improves neurological outcomes after stroke, despite strong experimental evidence of neuroprotection in other settings like cardiac arrest. 1

Key findings from stroke guidelines:

• A systematic review by Correia et al found no evidence that physical cooling would improve outcomes after stroke. 1
• While hypothermia shows neuroprotective properties in experimental models and cardiac arrest scenarios, data about the utility of induced hypothermia for treatment of patients with stroke are not yet available. 1
• Two small studies evaluating hypothermia in patients with malignant cerebral infarctions showed mixed results. 1

Significant Complications of Therapeutic Hypothermia

The risks are substantial and well-documented:

• Pneumonia occurs significantly more frequently with hypothermia (14 patients vs 3 in normothermia groups, P=0.001 in one trial). 2
• Cardiac arrhythmias are a recognized complication. 1
• Hypotension commonly occurs. 1
• Coagulopathy and increased bleeding risk are documented concerns. 1, 3

Intraoperative Hypothermia Context

During cardiac surgery itself, mild hypothermia (34°C) is preferred over moderate hypothermia (28°C) for cardiopulmonary bypass, as it provides adequate cerebral and myocardial protection with fewer complications. 1 However, this intraoperative use is distinct from therapeutic hypothermia applied after a stroke has occurred.

The American College of Chest Physicians guidelines note that systemic hypothermia during cardiac surgery provides myocardial, cerebral, and somatic protection, but this is a preventive measure during the procedure, not a treatment for established stroke. 1

Clinical Recommendation Algorithm

For stroke occurring during or after open heart surgery:

1. Do NOT initiate therapeutic hypothermia for stroke treatment. 1
2. Maintain normothermia (avoid both hyperthermia and hypothermia). 1
3. Treat fever aggressively if present, as hyperthermia worsens outcomes. 1
4. Focus on standard stroke management: blood pressure control, cardiac monitoring, and prevention of complications. 1

Important Caveats

• The 2014 ACC/AHA perioperative guidelines suggest that maintenance of normothermia may be reasonable to reduce perioperative cardiac events, but this is about avoiding inadvertent hypothermia, not inducing therapeutic hypothermia. 1
• While therapeutic hypothermia was historically introduced in the 1950s for neuroprotection during open-heart surgery to protect against global ischemia during the procedure itself, this is fundamentally different from treating a focal ischemic stroke that occurs as a complication. 4
• The established role of therapeutic hypothermia in post-cardiac arrest care does not translate to post-stroke care, as these represent different pathophysiological processes. 4, 5

The current evidence does not support therapeutic hypothermia for stroke treatment in any setting, including the perioperative cardiac surgery population, and the intervention carries significant risks that are not justified by any demonstrated benefit. 1