1. FIRST AID and EMERGENCY NURSING
University of Tabuk Faculty of Applied Medical Sciences Department of Nursing
FIRST AID and EMERGENCY NURSING

2. HEAT STROKE
Heat stroke is defined typically as hyperthermia exceeding 41°C, it is a medical emergency. Even with immediate treatment, it can be life-threatening or result in serious, long-term complications. After calling 997 or other emergency medical services.

3. Heatstroke occurs when the body fails to regulate its own temperature and body temperature continues to rise, often to 105° (40.6°) or higher.

4. Signs of rapidly progressing heatstroke include: • Unconsciousness for longer than a few seconds. • Convulsion (seizure). • Signs of moderate to severe difficulty breathing. • A rectal temperature over 104° (40°) after exposure to a hot environment. • Confusion, severe restlessness, or anxiety. • Fast heart rate. • Severe vomiting and diarrhea.

5. Types of Heat Stroke Exertional Heat Stroke (EHS)
- Occurs in young individuals who engage in strenuous physical activity for a prolonged period of time in a hot environment.
EHS is characterized by hyperthermia, diaphoresis, and an altered sensorium, which may manifest suddenly during extreme physical exertion in a hot environment.
A number of symptoms (eg, abdominal and muscular cramping, nausea, vomiting, diarrhea, headache, dizziness, dyspnea, weakness) commonly precede the heat stroke and may remain unrecognized. Syncope and loss of consciousness also are observed commonly before the development of EHS.

6. EHS commonly is observed in young, healthy individuals (eg, athletes, firefighters, military personnel) who, while engaging in strenuous physical activity, overwhelm their thermoregulatory system and become hyperthermic. Because their ability to sweat remains intact, patients with EHS are able to cool down after cessation of physical activity and may present for medical attention with temperatures well below 41°C.
Risk factors that increase the likelihood of heat-related illnesses include a preceding viral infection, dehydration, fatigue, obesity, lack of sleep, and poor physical fitness.
EHS also may occur because of increased motor activity due to drug use, such as cocaine and amphetamines, and as a complication of status epilepticus.

7. Classic Non Exertional Heat Stroke (NEHS)
Commonly affects sedentary elderly individuals, persons who are chronically ill and very young persons. Classic NEHS occurs during environmental heat waves and is more common in areas that have not experienced a heat wave in many years.

8. • Classic NEHS is characterized by hyperthermia, anhidrosis and an altered sensorium, which develop suddenly after a period of prolonged elevations in ambient temperatures (ie, heat waves). Core body temperatures greater than 41°C are diagnostic, although heat stroke may occur with lower core body temperatures. • Numerous CNS symptoms, ranging from minor irritability to delusions, irrational behavior, hallucinations, and coma have been described. • Anhidrosis due to cessation of sweating is a late occurrence in heat stroke and may not be present when patients are examined.

10. • Other CNS symptoms include hallucinations, seizures, cranial nerve abnormalities, cerebellar dysfunction, and opisthotonos. • Classic heat stroke most commonly occurs during episodes of prolonged elevations in ambient temperatures. It affects people who are unable to control their environment and water intake (eg, infants, elderly persons, individuals who are chronically ill), people with reduced cardiovascular reserve (eg, elderly persons, patients with chronic cardiovascular illnesses), and people with impaired sweating (eg, patients with skin disease, patients ingesting anticholinergic and psychiatric drugs). In addition, infants have an immature thermoregulatory system, and elderly persons have impaired perception of changes in body and ambient temperatures and a decreased capacity to sweat.

12. Both types of heat stroke are associated with a high morbidity and mortality, especially when therapy is delayed. Prevention of heat stroke 1. A variety of human factors should be taken into account, such as acclimatization, general health and salt intake, peculiarities of religious devotion and liability to neglect, regulations intended to promote public health. 2. Athletes or pilgrims should be informed of the work load and the level of heat stress they may encounter, and of the risks of heat stroke. 3. A period of acclimatization is recommended before vigorous physical activity and/or severe exposure is risked.

13. 4. The level of activity should be matched to the ambient temperature, and physical exertion should be avoided or at least minimized during the hottest hours of the day. 5. The opportunity for voluntary ingestion of water may be limited, thus delaying restitution from thermal dehydration, electrolytes should also be replaced in case of profuse sweating. 6. Proper clothing is also an important measure. Clothes made of fabrics which are both water-absorbent and permeable to air and water vapor facilitates heat dissipation.

14. Management
a. Emergency Care 1. Immersion in cool or iced water with skin massage is a classic technique for cooling heat stroke patients. Both have demonstrated effectiveness in lowering body temperature. Ice water probably produces the most rapid rate of cooling. However, ice water is an uncomfortable environment in which to work and, in the field, is very difficult to obtain. Circulating cooling blankets (unlikely to be available in the field situation) will also lower body temperature. Although cooling blankets have the advantage of maintaining a dry working environment, their limited contact surface provides slower cooling than immersion or surface wetting techniques. Their best use is probably maintaining normal body temperature in the period after resusitation and rapid cooling where temperature instability is characteristic.

15. 2. Invasive cooling techniques have been tried including ice water lavage or enemas and peritoneal lavage with cool fluids. These techniques do not provide faster cooling and have the additional disadvantages of potential complications and substantial inappropriate fluid loads. These techniques are not recommended. 3. Heat stroke patients usually do not require aggressive fluid resuscitation. Fluid requirements of 1 to 1.5 liters in the first few hours are typical. Over-replacement carries the risk of congestive heart failure, cerebral edema and pulmonary edema. Since heat stroke patients are frequently hypoglycemic, the initial fluid should include dextrose.

16. 4. Airway control is essential
4. Airway control is essential. Vomiting is common and endotracheal intubation should be used in any patient with a reduced level of consciousness. Supplemental oxygen should be provided when available.
Patients are frequently agitated, combative or seizing. Valium is effective for control and can be administered iv, endotracheally or rectally. The sedated heat stroke patient should be intubated. Nasogastric intubation to control vomiting should be done as soon as practicable.
6. Hyperkalemia is the most life threatening early clinical problem. Measurement of plasma [K] is an early priority.

17. 7. Acute renal injury is common in exertional heat stroke
7. Acute renal injury is common in exertional heat stroke. Urinary catheterization to monitor urine output and obtain urine for [Na] should be done early. The oliguric patient with a casts, pigmenturia or red cells and urine [Na] greater than 30 meq/l (before diuretics) has a high likelihood of acute renal failure. Early management of suspected acute renal failure should include assuring adequate renal perfusion and mannitol ( grams iv).

18. Continuing Care
After cooling and hemodynamic stabilization, continuing care is supportive and is directed at the complications of heat stroke as they appear.
Patients with heat stroke frequently have impaired temperature regulation for several days with alternate periods of hyperthermia and hypothermia. Constant monitoring is essential and clinically significant deviations in temperature may require either cooling or warming measures. It is important to remember that changes in temperature may be due to reasons OTHER than hypothalamic instability, such as infection.