Cooling intravenous fluids by refrigeration: implications for therapeutic hypothermia

ILCOR recommend the use of therapeutic hypothermia (32-34 degrees C) for 12-24 h in unconscious adult patients with spontaneous circulation after cardiac arrest with a VF rhythm. Among various methods of inducing hypothermia, the rapid infusion of ice-cold intravenous fluid has been used.

To investigate the time required to cool intravenous fluids in a domestic refrigerator and freezer, bags of compound sodium lactate were placed on the upper shelf of a refrigerator. Continuous temperature measurement was performed for 2 h for 10 500 ml and 10 1000 ml bags. The procedure was then repeated in the freezer.

The mean time for 500 ml bags to cool to 4 degrees C or below was 90 minutes or more in a refrigerator and 60-90 minutes in the freezer. 1000 ml bags are cooled to 4 degrees C or below within 120 minutes in the freezer, but it takes longer in a refrigerator.

As induced hypothermia should be started as soon as possible in eligible patients, crystalloids should be stored in a refrigerator.