Cold saline infusion and ice packs alone are effective in inducing and maintaining therapeutic hypothermia after cardiac arrest

Aim of the study

Hypothermia treatment with cold intravenous infusion and ice packs after cardiac arrest has been described and used in clinical practice. We hypothesised that with this method a target temperature of 32-34 °C could be achieved and maintained during treatment and that rewarming could be controlled.

Materials and methods

Thirty-eight patients treated with hypothermia after cardiac arrest were included in this prospective observational study. The patients were cooled with 4 °C intravenous saline infusion combined with ice packs applied in the groins, axillae, and along the neck. Hypothermia treatment was maintained for 26 h after cardiac arrest. It was estimated that passive rewarming would occur over a period of 8 h. Body temperature was monitored continuously and recorded every 15 min up to 44 h after cardiac arrest.

Results

All patients reached the target temperature interval of 32-34 °C within 279 ± 185 min from cardiac arrest and 216 ± 177 min from induction of cooling. In nine patients the temperature dropped to below 32 °C during a period of 15 min up to 2.5 h, with the lowest (nadir) temperature of 31.3 °C in one of the patients. The target temperature was maintained by periodically applying ice packs on the patients. Passive rewarming started 26 h after cardiac arrest and continued for 8 ± 3 h. Rebound hyperthermia (>38 °C) occurred in eight patients 44 h after cardiac arrest.

Conclusions

Intravenous cold saline infusion combined with ice packs is effective in inducing and maintaining therapeutic hypothermia, with good temperature control even during rewarming.