CPG I02: Hyperthermia describes several strategies to promote heat loss in clinical situations where patients are experiencing heat stress: “Sheltering and removal from the heat source, removing all clothing except for underwear, and ensuring airflow over the patient comprise the initial actions. Spray bottles of water, or wet towels, can also be used to help cool patients.”
These measures are appropriate for patients with mild heat stress (including heat exhaustion) but are insufficient for patients with more severe heat exposures. Heat stroke is a life-threatening emergency that requires immediate and aggressive measures to control body temperature: the single greatest contributor to patient morbidity and mortality is the duration of the elevated core temperature.
The clinical signs and symptoms of heat stress, including heat stroke, are more important than specific temperature measures. A careful review of patient history and presentation should be used to guide decision-making and care planning.
Certain populations are more vulnerable to heat stress. Both children and the elderly are uniquely at risk, as they are less able to manage exogenous heat. The clinical manifestations of heat stress in these groups may be atypical: paramedics, EMRs, and first responders should be suspicious of heat stress in patients whose levels of consciousness are depressed or who are hypotensive where those symptoms cannot be reasonably explained through other mechanisms.
Paramedics, emergency medical responders, and first responders caring for patients with severe heat stress, including heat stroke, are constrained in the types of interventions available in the out-of-hospital environment, which limits the degree of cooling that can be achieved. It is therefore important that all feasible avenues to promote heat loss be explored prior to and during conveyance to hospital. Patients should be completely disrobed and not covered with blankets, and paramedics, EMRs, and first responders should ensure they are using sufficient volumes of water to promote evaporative cooling. Cool water should be used wherever possible, but even tepid water can be useful given enough volume. In exceptional circumstances, the use of ice packs or ice baths may be appropriate if sufficient quantities of ice are available.
If volume replacement is necessary, paramedics should be aware of the temperature of fluid being administered: intravenous fluid in the ambulance can become very warm during these conditions, and will exacerbate heat exhaustion or heat stroke. Fluid should not be routinely administered to patients suffering from heat stress unless signs of dehydration, hypotension, or shock are present, in which case it should be given judiciously and with the goal of correcting hypoperfusion.
For BCEHS paramedics and EMRs, consultation with CliniCall may help to guide care planning in all cases of hyperthermia, and pre-arrival notification to receiving facilities can assist with a smoother transition of care which includes temperature management.
Paramedics, emergency medical responders, and first responders are reminded to maximize heat loss capacity in patients whose clinical condition is due to hyperthermia. Do not delay implementation of cooling measures where heat stroke is suspected. Use all appropriate resources to cool patients when required.
Clinical and Medical Programs is monitoring this issue closely. Further updates may be issued as warranted and may include an update to the hyperthermia practice guideline.
BCEHS paramedics and emergency medical responders should contact their Paramedic Practice Leader at firstname.lastname@example.org or their Paramedic Practice Educator for more information.