How Does A Doctor Treat Severe Heat Illness in Hospital?

How Does A Doctor Treat Severe Heat Illness in Hospital?

Written by Dr Andrew Stein, Consultant Nephrologist (UHCW Coventry). Last updated: June 2026

When a patient arrives at the hospital with severe heat illness or heatstroke, it is treated as a critical, life-threatening medical emergency. The overriding clinical goal is to drop the core body temperature to a safe level as fast as possible to halt multi-organ damage.

Here is how medical teams manage severe heatstroke in an emergency and intensive care setting.

1. Rapid Resuscitation and Airway Management

Before cooling even begins, doctors stabilize the patient’s vital signs using standard emergency protocols:

• Airway Protection: Severe heatstroke often causes altered consciousness, confusion, or seizures. If the patient cannot protect their own airway, clinicians will intubate them (place a breathing tube) to ensure adequate oxygenation and prevent aspiration.

• Continuous Monitoring: The team inserts a rectal or esophageal probe for continuous core temperature monitoring. Standard thermometers (oral or tympanic) are highly inaccurate in these scenarios.

2. Aggressive External Cooling Techniques

The gold standard for treating heatstroke is to lower the core temperature below 39°C ($102.2^\circ\text{F}$) within 30 to 60 minutes of arrival.

• Evaporative and Convective Cooling: The patient is stripped, sprayed or draped with lukewarm water, and placed directly under high-velocity fans. This mimics and accelerates the body’s natural sweat mechanism.

• Conductive Cooling: Ice packs are placed strategically at the groin, armpits, and neck to cool the major blood vessels.

• Ice-Water Immersion: If the patient is young and fit (such as an athlete or military recruit with exertional heatstroke), they may be submerged in a tub of ice water, which is the fastest method to dump heat.

3. Advanced Internal Cooling (Invasive Methods)

If external methods are not dropping the temperature fast enough, or if the patient is experiencing a severe non-exertional heatstroke, more invasive techniques are deployed:

• Cold Intravenous Fluids: Large volumes of chilled normal saline ($4^\circ\text{C}$) are infused intravenously.

• Body Cavity Lavage: Instilling iced saline into the stomach (gastric lavage), urinary bladder, or even the peritoneal/pleural cavities via tubes, then draining it out to cool internal organs directly.

• Extracorporeal Cooling: In the most extreme, refractory cases, teams use continuous renal replacement therapy (CRRT) or ECMO machines to circulate the patient’s blood outside the body, cool it through a heat exchanger, and return it to the body.

4. Controlled Shivering Management

As the body is rapidly cooled, its natural defense mechanism is to shiver to generate heat. Shivering is highly counterproductive because it creates internal metabolic heat and increases oxygen consumption.

To prevent this, clinicians administer medications to suppress the shivering reflex:

• Intravenous Sedatives: Continuous infusions of medications like propofol or midazolam.

• Neuromuscular Blockers: In intubated patients, muscle relaxants (paralytics) can be used to completely halt physical muscle twitching and heat production.

5. Managing Secondary Organ Complications

Once the temperature begins to stabilize, the focus shifts to treating the systemic fallout of extreme thermal stress in the Intensive Care Unit (ICU):

The Cooling Target: The clinical team will typically stop aggressive cooling measures once the core temperature hits 38.5°C (101.3F). This prevents “overshooting,” which can cause dangerous therapeutic hypothermia and cardiac arrhythmias.