Exertional Heat Stroke on the Perimeter
It is 15:20 in August, 36 degrees Celsius and 60 percent humidity. A tactical team has held a perimeter for three hours in full kit, including plates and helmet, at a barricaded-subject incident. An officer collapses behind a cruiser. He is confused, combative, and sweating; his skin is hot. HR 150, RR 26, BP 100/60, SpO2 97 percent. You have no rectal thermometer on scene and no ambulance attached; the nearest hospital is 12 minutes away. Two other officers report cramps, dizziness, and nausea but are alert and oriented. The incident is ongoing and the commander cannot pull the whole perimeter. You have a tarp, ice, cold water, IV fluids, and oral rehydration supplies.
1. How do you distinguish heat stroke from heat exhaustion here, and what is your first priority? Address the thermometer problem and the cooling method.
Read the worked answer
Altered mental status plus collapse in full kit in 36-degree heat is exertional heat stroke until proven otherwise; heat exhaustion does not cause confusion or combativeness. My first priority is immediate cooling, not transport and not a rectal temperature. I move him out of the sun, strip his kit and uniform, and start cold-water immersion in a tarp if I can make one; if not, I use ice towels to the neck, axillae, and groin, fan him, and mist him. I check a glucose and monitor the airway. A rectal thermometer is ideal to guide cooling, but its absence must not delay cooling. I target a core temperature below 39 degrees Celsius within 30 minutes and stop active cooling around 38.5 degrees Celsius to avoid overshoot. Antipyretics do not work for environmental heat stroke. I start IV fluids for hypotension and monitor for seizures. Cool first, transport second, unless the airway or arrest requires otherwise.
2. The commander asks whether the other two officers can stay on the line. Give your disposition and return-to-duty criteria.
Read the worked answer
The two officers with cramps, dizziness, and nausea but normal mentation have heat exhaustion, not heat stroke. I remove them from the perimeter, get them out of kit, into shade, and start oral rehydration with a balanced electrolyte solution. I monitor mental status and temperature. They can return to duty only if symptoms fully resolve, they tolerate fluids, and their mental status is normal; they should not return to full kit on the same perimeter without rest and rehydration. If either becomes confused, vomits, or collapses, I treat as heat stroke and cool. The commander cannot keep them on the line; replacing them is a tactical decision, but medically I will not clear them to stay in full kit. I recommend work-rest cycles and hydration for the rest of the team.
3. What complications and monitoring concerns affect transport and the first hour of care?
Read the worked answer
I transport him even if he improves, because heat stroke causes rhabdomyolysis, acute kidney injury, hyperkalemia, hepatic injury, coagulopathy, and seizures after the initial cooling. I monitor ECG, mental status, urine output and color, and temperature; I avoid NSAIDs and continue IV fluids. If he seizes, I treat the seizure and check glucose and sodium. Hyponatremia is a risk if he has been drinking free water or if I over-resuscitate with hypotonic fluids, so I use isotonic fluids. In the first hour I keep cooling if his temperature rebounds, watch for recurrent hyperthermia, and reassess his airway. I give a complete handoff with the maximum temperature, cooling method and duration, fluids, and any drugs. I do not discharge him back to the team from the scene.