Further analysis of this data revealed that paramedics infused up to 1000mL ambient temperature fluid during CPR prior to enrolment as part of standard paramedic treatment. In addition, the rapid infusion of cold fluid was commenced en-route to hospital. Thus, cooling commenced approximately 30 minutes after paramedic arrival and only just prior to hospital cooling. Although there was a decrease in the core temperatures of the patients allocated to pre-hospital cooling on arrival at the ED, this was a transient effect lasting only approximately 20 minutes. Subsequently, the cooling curves of the patients in both groups were identical. Thus, it was considered unlikely that this transient difference in core temperature could have a measurable effect on outcomes.