COLD & HEAT
The human body maintains a constant temperature by balancing internal heat generation and heat loss from the environment.
Radiation, evaporation, conduction, and convection are the four common processes by which heat exchange between the body and the environment occurs.
The body’s thermoregulation system may fail in high temperatures. As a result, the core body temperature rises toward the temperature of the surrounding environment.
HEAT-RELATED DISORDERS
PREVENTABLE HEAT-RELATED ILLNESSES: HEAT CRAMPS, HEAT EXHAUSTION, HEAT SYNCOPE, AND HEATSTROKE.
One of the most common environmental emergencies seen in emergency rooms is a heat-related illness. The amount of heat retained in the body is affected by internal metabolic function as well as environmental conditions such as temperature and humidity.
CLINICAL STUDIES
The use of an internal rectal, Foley, or esophageal thermometer is required when diagnosing and treating heat-related illnesses because skin temperature may not accurately reflect core body temperature.
Heat cramps are acute muscle spasms and painful skeletal muscle contractions that occur during or shortly after activity. Tender, hard, lumpy, painful muscles that may be twitching are typical examination findings, as are stable vital signs, normal or elevated core body temperature, moist and cold skin, and tender, hard, lumpy, painful muscles that may be twitching.
TREATMENT
A. HEAT STROKE
The patient’s ABCs (airway, breathing, and circulation) must first be handled and stabilized, and then treatment is focused on rapidly lowering core body temperature within 1 hour while maintaining circulation and perfusion.
Pulse oximetry and cardiac monitors should be used to monitor patients, as well as core body temperature and fluid input and outflow.
Hypovolemic or cardiogenic shock, metabolic anomalies, cardiac arrhythmias, coagulopathy, acute respiratory distress syndrome (ARDS), hypoglycemia, rhabdomyolysis, seizures, organ failure, infection, and severe edema that might lead to compartment syndrome should all be monitored.
To provide sufficient urinary output, oral or intravenous fluid supplementation is required.
For non-exertional heat stroke, evaporative cooling is preferred, while conductive-based cooling is preferred for exertional heat stroke.
The undressed patient is placed in a lateral recumbent position or supported on hands and knees to expose the most skin surface to the air, while the entire undressed body is sprayed with lukewarm water (20°C) and cooled by huge fans circulating room air.
Inhaled cool air or oxygen can help with cooling, but it should not be utilized alone.
Cool fluid infusion, stomach or bladder lavage, ice packs, and immersion in ice water or cool water are all examples of conductive-based cooling.
Immersion in ice water or cold water is the favored way of cooling for exertional heat stroke when it is accessible in the field.
Ice packs are more effective when applied to the entire body rather than just the axilla and crotch
Core body temperature has been successfully reduced utilizing intravascular heat exchange catheter systems and hemodialysis with cold dialysate (30–35°C).
Shivering should be avoided since it reduces cooling efficiency by increasing internal heat output.
Magnesium, quick-acting opioid analgesics, benzodiazepines, and quick-acting anesthetic agents are some of the medications that can be used to stop shivering.
Skin massage is recommended to prevent cutaneous vasoconstriction.
Antipyretics (aspirin, acetaminophen) have no effect on environmentally
induced hyperthermia and are contraindicated.
The treatment must be continued until the core body temperature falls below 39 degrees Celsius.
B. HEAT CRAMPS
The patient must be moved to a cool, shaded area and given an oral rehydration solution to substitute both electrolytes and water. Oral salt tablets are not advised. Before returning to work or resuming exertion in the heat, the patient may have to rest for at least two days with continued dietary supplementation.
C. HEAT EXHAUSTION
Treatment involves moving patients to a shaded, cool environment, replacing fluids and electrolytes, and, if necessary, initiating active cooling measures.
When oral administration is not possible, physiologic saline or isotonic glucose solution may be administered intravenously. At least 48 hours of rest and rehydration are recommended.
D. HEAT SYNCOPE
Rest and recumbency in a shady, cool location are recommended, as is fluid and electrolyte supplementation orally or intravenously if necessary.
PREVENTION
Those who are physically engaged in a hot atmosphere should drink more water before, during, and after their workouts. Fluid and electrolyte drinks should be consumed in moderation.
It is not recommended to have salt tablets available for use because of the risk of hypertonic hypernatremia
PROGNOSIS
Heat stroke is a leading cause of death, with multiorgan dysfunction being the most common cause. Even when the temperature has returned to normal, the patient is in danger of rhabdomyolysis, ARDS, and inflammation. Immediate reexposure to ambient heat after a heat stroke must be avoided.
All persons who have been diagnosed with heat stroke should be admitted to a hospital that offers intensive care and is closely monitored.