Hypothermia
Hypothermia refers to a core body temperature below 95° F (35° C) and affects chemical changes in the body. It may be classified as mild (89.6° to 95° F [32° to 35° C]), moderate (86° to 89.6° F [30° to 32° C]), or severe, which may be fatal (77° to 86° F [25° to 30° C]). Risk factors that contribute to serious cold injury, especially hypothermia, include lack of insulating body fat, wet or inadequate clothing, drug abuse, cardiac disease, smoking, fatigue, malnutrition and depletion of caloric reserves, and excessive alcohol intake. The incidence of hypothermia is highest in children and elderly people.
Hypothermia commonly results from cold-water near drowning and prolonged exposure to cold temperatures. It can also occur in normal temperatures, if disease or debility alters the patient’s homeostasis. The administration of large amounts of cold blood or blood products can also cause hypothermia. A process such as hemodialysis, which circulates the blood outside of the body and then returns it to the body, will result in hypothermia.
Act Now: Initiate cardiopulmonary resuscitation (CPR), if necessary. Hypothermia helps protect the brain from anoxia, which normally accompanies prolonged cardiopulmonary arrest. Therefore, even if the patient has been unresponsive for a long time, CPR may resuscitate him, especially after a cold-water near drowning.
Institute continuous cardiac monitoring and administer supplemental oxygen. Prepare the patient for intubation and mechanical ventilation, if necessary. Institute rewarding measures. Prepare the patient for placement of a pulmonary artery catheter insertion to monitor core body temperatures. Monitor the patient’s vital signs closely. Continue warming the patient until the core body temperature is within 1° to 2° F (0.6° to 1.1° C) of the desired body temperature. If the patient has been hypothermic for longer than 45 minutes, administer additional fluids, as ordered, to compensate for the expansion of the vascular space that occurs during vasodilation in warming.
Act Now: If oxygen therapy is needed, be sure to use warm, humidified oxygen to prevent additional cooling.
Assessment
History
Obtain the patient’s history for clues to the causative factor. Was he exposed to cold and if so, what temperature and for what length of time? Ask whether he has recently undergone hemodialysis therapy. Has he had major surgery, especially a type of surgery that requires cooling of the patient’s body? Has he recently received a blood transfusion that may have been administered while the blood was still cold? Does he have a history of thyroid, adrenal, liver, or cerebrovascular disease? Has the patient ingested any substances that result in a lowered body temperature, such as alcohol or barbiturates? If the exposure occurred indoors, determine whether the patient has adequate heat in his home. If the exposure occurred outdoors, determine whether he’s homeless and sleeping outside.
Physical examination
Assess level of consciousness; a patient with mild hypothermia will have amnesia, a patient with moderate hypothermia is unresponsive, and the patient with severe hypothermia will be comatose. A patient with a body temperature below 86° F (30° C) is at risk for cardiopulmonary arrest. Assess for shivering, slurred speech, and peripheral cyanosis. Assess the patient’s neurologic status and presence or absence of deep tendon reflexes. Assess for muscle rigidity that can produce a rigor-mortis-like state.
Medical causes
Prolonged exposure to extremely low temperatures
The patient will have severe hypothermia, accompanied by lethargy or coma, depressed respiratory rate and depth, bradycardia, and muscle stiffness. The patient may have been exposed to an extremely low temperature with an excessive wind chill factor. If the patient is elderly or debilitated, he may have been exposed to a low room temperature. The patient may also have recently received a blood transfusion with cold blood or underwent a hemodialysis treatment.
Other causes
Disorders
Hypothermia may be a result of a certain disorder, but may not require immediate intervention. Endocrine disorders, such as hypothyroidism, hypoadrenalism, hypopituitarism, diabetes mellitus, cirrhosis, stroke, and renal failure, also affect the body’s ability to regular temperature.
Drugs
Alcohol ingestion and an overdose of barbiturates can induce mild to moderate hypothermia as a result of vasodilation, lowered metabolism, and central nervous system effects.
Nursing considerations
Specific rewarming techniques include passive rewarming (the patient rewarms on his own); active rewarming (using heating blankets, warm-water immersion, heated objects such as water bottles, and radiant heat) and active core warming (using heated I.V. fluids, genitourinary tract irrigation, extracorporeal warming, and lavage). Arrhythmias that develop usually convert to a normal sinus rhythm with rewarming. Administration of oxygen, endotracheal intubation, controlled ventilation, I.V. fluids, and treatment of metabolic acidosis depends upon test results and careful patient monitoring.
ALERT: Stay alert for signs and symptoms of hyperkalemia. If hyperkalemia occurs, administer calcium chloride, sodium bicarbonate, glucose, and insulin as ordered. Anticipate the need for sodium polystyrene sulfonate enemas.
Patient teaching
Advise the patient, especially if he’s elderly, to maintain proper insulation in the home and keep the indoor temperature 70° F (21.1° C) or higher. Caution the patient to wear warm clothing and use warm bedding. Advise the patient of the importance of adequate nutrition, rest, and exercise. When the patient is expected to be out in the cold, especially for prolonged periods, advise him to wear loose-fitting clothing in layers and cover his hands, feet, and head; advise him to wear dry clothing and footwear and wind- and water-resistant outer garments and to avoid the intake of alcohol.
Book Source Details
- Book Title: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series
- Author(s): Springhouse
- Year of Publication: 2007
- Copyright Details: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, Copyright © 2007 Lippincott Williams & Wilkins.
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Copyright Details: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, Copyright © 2008 Williams & Wilkins.
More About Causes of Temperature symptoms
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