Prehospital cooling with hypothermia caps (PreCoCa): a feasibility study

Animal studies suggest that the induction of therapeutic hypothermia in patients after cardiac arrest should be initiated as soon as possible after ROSC to achieve optimal neuroprotective benefit. A “gold standard” for the method of inducing hypothermia quickly and safely has not yet been established. In order to evaluate the feasibility of a hypothermia cap we conducted a study for the prehospital setting.

The hypothermia cap was applied to 20 patients after out-of-hospital cardiac arrest with a median of 10 min after ROSC (25/75 IQR 8–15 min). The median time interval between initiation of cooling and hospital admission was 28 min (19–40 min). The median tympanic temperature before application of the hypothermia cap was 35.5°C (34.8–36.3). Until hospital admission we observed a drop of tympanic temperature to a median of 34.4°C (33.6–35.4). This difference was statistically significant (P < 0.001). We could not observe any side effects related to the hypothermia cap. 25 patients who had not received prehospital cooling procedures served as a control group. Temperature at hospital admission was 35.9°C (35.3–36.4). This was statistically significant different compared to patients treated with the hypothermia cap (P < 0.001).

In summary we demonstrated that the prehospital use of hypothermia caps is a safe and effective procedure to start therapeutic hypothermia after cardiac arrest. This approach is rapidly available, inexpensive, non-invasive, easy to learn and applicable in almost any situation.