大人 熱射病 up to dateとワシントンマニュアルより
SUMMARY AND RECOMMENDATIONS
●Body temperature is maintained within a narrow range by balancing heat load with heat dissipation. Evaporation is the principal mechanism of heat loss in a hot
●The differential diagnosis of hyperthermia is extensive and includes infectious, endocrine, central nervous
●The diagnosis of
●The management of
●We suggest that rapid cooling of patients with
●Nonexertional heat stroke can cause a number of complications, including respiratory and cardiac dysfunction, hypotension, seizures, rhabdomyolysis, acute renal and hepatic injury, and disseminated intravascular coagulation.
Evaporative and convective cooling is the method used most often to treat classic heat stroke because it is effective, noninvasive, easily performed, and does not interfere with other aspects of patient care. When used to treat elderly patients with classic heat stroke, evaporative and convective cooling is associated with decreased morbidity and mortality.
With evaporative and convective cooling, the naked patient is sprayed with a mist of lukewarm water while fans are used to blow air over the moist skin. Special beds called body cooling units have been made for this purpose . Agitation from an altered mental status or shivering induced by evaporative and convective cooling or other treatments may generate heat and can be suppressed with short-acting IV benzodiazepines, such as lorazepam (1 to 2 mg IV). Benzodiazepines may also improve core body cooling. If neuroleptic malignant syndrome (NMS) is not suspected and benzodiazepines are ineffective at controlling shivering, chlorpromazine (25 to 50 mg IV) may be used. However, chlorpromazine has anticholinergic properties and thus, may impair sweating and exacerbate hypotension.
Other effective cooling methods are less commonly used in patients with classic heat stroke. Immersing the patient in ice water (cold water immersion) is an efficient, noninvasive method of rapid cooling , but it complicates monitoring and intravenous
Cold thoracic and peritoneal lavage results in rapid cooling. However, it is invasive and peritoneal lavage is contraindicated in pregnant patients and those with previous abdominal surgery. Cooled oxygen, cooling blankets, and cold (ie, room temperature, or approximately 22°C [71.6°F]) intravenous fluids may be helpful adjuncts. Cold gastric lavage may cause water intoxication.
Recommendations for the treatment of heat stroke are based primarily upon small observational studies. A systematic review of clinical studies investigating the treatment of heat stroke noted the following]:
●There are no definitive studies supporting any particular approach to cooling in classic heat stroke.
●Evaporative and convective cooling methods for the treatment of classic heat stroke are better tolerated.
●Immersion in ice water is rapid and effective in young patients with exertional heat stroke. However, immersion therapy is associated with increased mortality when used to treat elderly patients with classic heat stroke.
●Pharmacologic therapy (eg, dantrolene) is ineffective and not indicated in the treatment of exertional or classic heat stroke.
Alcohol sponge baths should be avoided because large amounts of the drug may be absorbed through dilated cutaneous vessels and produce toxicity.
Pharmacologic therapy is not required in heat stroke. There is no role for antipyretic agents such as acetaminophen or aspirin in the management of heat
Salicylates can contribute to hyperthermia by uncoupling oxidative phosphorylation. Dantrolene is ineffective in patients with severe temperature elevation not caused by malignant hyperthermia. In cases where the
What is heat stroke?
Heat stroke is a condition that can happen when a person's body gets too hot. Most often, heat stroke happens when people exercise in very hot and humid weather without drinking enough fluids. But heat stroke can also happen in people who are not exercising. It is especially likely to affect older people and people who have health problems, so they need to be extra careful in hot conditions.
Heat stroke is a medical emergency that needs to be treated quickly. That's because heat stroke can lead to death if it is not treated quickly.
When people get too hot, they can also get "heat cramps" and "heat exhaustion." These conditions are not as serious as heat stroke, but they can lead to heat stroke if they aren't treated.
What are the symptoms of heat stroke?
People with heat stroke have:
●A body temperature of 104°F (40°C) or higher
●Brain symptoms – These can include:
•Confusion or trouble thinking clearly
•Seeing or hearing things that aren't real (called "hallucinating")
Heat stroke can also cause:
●Fast breathing or a fast heartbeat
●Skin redness and warmth
●Muscle cramps or weakness
Should I see a doctor or nurse?
Yes. If you or someone you are with has heat stroke, get medical help right away.
Is there a test for heat stroke?
Yes. The doctor will do an exam and take your temperature. He or she will probably do other tests to check if the heat stroke hurt other organs in your body. These tests can include:
●Electrocardiogram (ECG) – This test measures the electrical activity in your heart (figure 1).
How is heat stroke treated?
The main treatment involves cooling your body down. Your doctor can do this in the hospital in different ways.
Your doctor will also treat any other problems the heat stroke has caused.
Can heat stroke be prevented?
Yes. When it is hot or humid out, you can do the following things to prevent heat stroke:
●Try not to be too active, and take breaks when you exercise.
●Drink enough fluids, such as water or sports drinks, so you do not feel thirsty. But don't force yourself to drink very large amounts in a short time, and don't drink so much that you feel uncomfortable. This can be harmful.
●Do any exercise early in the day, before it gets too hot out.
●Wear loose, lightweight clothes. Don't wear too many layers.
●Avoid being in a hot car.
You should also watch for symptoms of heat cramps or heat exhaustion. Heat cramps cause painful muscle cramps. Heat exhaustion can cause headaches, dizziness, nausea, or vomiting. It can also make you thirsty or tired.
If you have symptoms of heat cramps or heat exhaustion, you should cool your body down right away to avoid getting heat stroke.
To cool your body down, you can:
●Spray yourself with cool water and then sit in front of a fan.
●Move into the shade, or go into an air-conditioned building or car.
●Take a cool shower or bath.
●Drink water or a sports drink. Do not have a drink with alcohol or caffeine.
●Take off any extra clothing you are wearing.
●Put a cold pack or cool cloth on your neck or armpit.