Heat Temperature-related Emergencies

Definition/Etiology:

• A heat emergency is a serious medical condition resulting from the body’s inability to cope with a particular heat load, and includes heat cramps, heat exhaustion, heat syncope, and heat stroke.
• These are basically caused by an individual who is in a hot environment and the body, for whatever reason, cannot compensate for the elevated temperatures. Basically, they cannot cool down.

Pathophysiology:

• The primary pathogenic mechanism of heat stroke involves transition from a compensable thermoregulatory phase (in which heat loss exceeds heat gain) to a non-compensable phase (in which heat gain is greater than heat loss), when cardiac output is insufficient to cope with the high thermoregulatory needs. Consequently, core body temperature continues to rise, leading to a direct cytotoxic effect and an inflammatory response, creating a vicious cycle, and eventually causing multiorgan failure

Clinical Presentation:

Heat Cramps:

• Cramps, obviously. Especially in the shoulders, lower extremities, and abdominal wall.
• Weakness
• Thirst
• Nausea
• Tachycardia
• Extreme diaphoresis
• Pale, cool, moist skin

Heat Exhaustion:

• Symptoms of heat cramps, and:
• Anorexia, vomiting
• General malaise
• Core temp of 98.6-111.2
• Headache
• Dehydration – orthostatic hypotension
• Syncope

Heat Stroke:

• N/V/D
• Classic and textbook symptom! – Skin is hot and DRY!!! Sweating early, that eventually stops as the body can no longer compensate. We know sweating is a cooling mechanism. At some point the body gets too overheated and the cooling process ceases to function.
• Tachycardia
• Tachypnea
• Decreased LOC, seizures
• Unresponsive pupils – And why do we get these neuro complications??? – yea…basically we are boiling the brain.
• Hypotension

Collaborative Management:

• This one is pretty simple… Cool them down! Get them to a cool place, crank up the AC if you can.
• For heat cramps, you want to replace the electrolyte loss, IV NS is good and something as simple as Gatorade is acceptable.
• For Exhaustion – similar treatment. Basic and supportive care as well as indicated.

Heat stroke is an emergency, so we need to do a little more.

• Remove clothing
• Spray and fan the patient. Using a fine mist, weather with a spray bottle or some other means. This helps to minimize shivering and promotes evaporative cooling.
• Rehydrate with room temp fluids
• Draw labs to monitor electrolytes, coags, lactate.
• Urine for myoglobin – rhabdo!
• If they start shivering, control with meds like thorazine.

Evaluation | Patient Monitoring | Education:

Core temp is top eval.

• With cramps and exhaustion – basically are they feeling better? Are they hemodynamically stable? Is there core temp within normal ranges?
• With heat stroke, aside from the cooling measures, we need to make sure their bloodwork is back to baseline.
• Education is pretty much finding out why they overheated and letting them know how to avoid the same situation. If it was too hot, get out of the heat. And make sure to hydrate as the heat rises. This is especially true of athletes in warm climates. Even more so when the weather changes over days. If they are practicing every day for weeks and maintaining a specific hydration status and then the temp jumps 20 degrees in a day, they may not change their hydration habits and run into problems.

Linchpins: (Key Points)

• Hot Dry Skin – Heat stroke
• Rhabdo – muscle breakdown
• Brain Stew – Changes in LOC