Mild hypothermia induction following cardiac arrest using a water-circulating cooling device

Introduction

The use of mild hypothermia for comatose survivors of cardiac arrest has been endorsed by the American Heart Association and the International Liaison Committee on Resuscitation [1, 2]. Unintentional overcooling is common with some techniques such as cool intravascular fluid or the use of ice packs. Nowadays, the maintenance of hypothermia can be facilitated with new technology to avoid unintentional overcooling.

Methods

A 77-year-old male with a history of hypertension, previous replacement of aortic valve and a right coronary artery bypass was admitted to our ICU after cardiac arrest. He suffered a collapse while walking. The emergency service arrived within 5 minutes. The initial cardiac rhythm was ventricular fibrillation. The estimated time to return to spontaneous circulation was 20 minutes. The patient arrived in the hospital 50 minutes after collapse and was immediately admitted to the ICU. Thirty minutes after ICU admission, he was unconscious with a Glasgow coma score of 5. Hypothermia was induced by the Artic Sun 2000 cooling system (Medivance, Louisville, CO, USA), and the goal temperature was obtained 105 minutes after induction. The body temperature was monitored continuously with a Foley catheter. Hypothermia was maintained for 24 hours at 33°C and rewarming to the target temperature of 37°C was achieved over 12 hours. No electrolyte imbalances or coagulopathies were observed. No overcooling was observed at any moment. The patient was extubated on day 6 after admission and discharged from the ICU on day 10 without neurological sequelae.

Conclusion

Careful monitoring of temperature is important during use of therapeutic hypothermia because unintentional overcooling below 32°C may place the patient at risk for serious complications such as arrhythmias, infection, and coagulopathy. Cooling with a water-circulating cooling device is fast and safe. Clinicians should work to institute protocols for mild hypothermia treatment for such patients as a part of their critical care treatment.