Category: Medical Surgical Nursing
During hypothermic cardiac arrest, cardiac output and cerebral and myocardial blood flows are much less than those during normothermic closed chest compressions. Metabolic demands, however, are also less during hypothermia.
Category: Medical Surgical Nursing
Paradoxical undressing has been widely reported in hypothermic patients. This last preterminal effort may be related to the peripheral vasoconstrictive changes of hypothermia. Patients have been mistaken for having psychiatric disorders.
Category: Medical Surgical Nursing
Exposure to cold induces a diuresis, regardless of the state of hydration. The kidneys excrete a large amount of dilute urine that is essentially glomerular filtrate and does not clear nitrogenous waste products.
Category: Medical Surgical Nursing
Hypothermia progressively depresses the CNS. Significant alteration of the brain’s electrical activity begins below 33.5° C (92.3° F). The electroencephalogram silences at 19° C to 20° C (66.2° F–68° F).
Category: Medical Surgical Nursing
As hypothermia worsens, the PR interval, then the QRS interval, and finally the QTc interval become prolonged. Even in the absence of shivering, increased muscle tone may obscure P waves or produce artifacts.
Category: Medical Surgical Nursing
Atrial fibrillation is common when the core temperature is below 32° C (89.6° F). Sinus atrial or junctional rhythms also occur. Atrial fibrillation usually converts spontaneously during rewarming, but mesenteric embolization is a hazard.
Category: Medical Surgical Nursing
Atrial and ventricular dysrhythmias are common in moderate or severe hypothermia. Because the conduction system is more sensitive to the cold than the myocardium, cardiac cycle prolongation occurs
Category: Medical Surgical Nursing
Maximal heat production, primarily due to shivering, lasts only a few hours because of fatigue and glycogen depletion.
Shivering thermogenesis increases the basal metabolic rate up to five times, markedly increasing oxygen consumption.
Category: Medical Surgical Nursing
Human basal heat production increases with food ingestion, muscle activity, fever and acute cold exposure. Cold stress increases preshivering muscle tone, potentially doubling heat production.
Category: Medical Surgical Nursing
Most patients with severe immersion injury are military personnel who have worn boots continuously for days or weeks. Prevention of immersion injury may require frequent drying of feet and socks.
Category: Medical Surgical Nursing
Immersion injury can also occur from sweat, especially with the use of neoprene socks, vapor barrier boots or constrictive gaiters. People who soak their feet for hours in cool water for pain relief are also at risk.
Category: Medical Surgical Nursing
Trench foot is produced by prolonged exposure to wet cold at temperatures above freezing. It usually results in neurovascular damage. Immersion injury commonly develops while a person is wearing socks that are wet from immersion in water.
Category: Medical Surgical Nursing
Historically, frostbite, like burns, was classified into degrees of injury. Anesthesia and erythema were considered to be first-degree frostbite. Superficial vesiculation surrounded by edema and erythema indicated second-degree frostbite.
Category: Medical Surgical Nursing
The term frostnip refers to a superficial freezing injury manifested by transient numbness and tingling that resolves after rewarming. No tissue destruction occurs. The most common presenting symptom of frostbite is numbness.
Category: Medical Surgical Nursing
Cold injuries are often due to impairment or intoxication, primarily ethanol intoxication. Ethanol also produces peripheral vasodilation, which increases heat loss. Blunting of instincts can cause people to put themselves at increased risk.
Category: Medical Surgical Nursing
Frostbite occurs only when the tissue supercools well below 0° C (32° F). The required temperature is at least -4°C (24.8° F) and may be as low as -10° C (14° F) under some conditions.
Category: Medical Surgical Nursing
The human body attempts to maintain a core temperature of about 37° C (98.6° F). Skin cooling activates the anterior hypothalamus, causing catecholamine release, thyroid stimulation, shivering thermogenesis and peripheral vasoconstriction.
Category: Medical Surgical Nursing
Frostbite involves tissue freezing with formation of ice crystals in the tissues. Immersion injury (trench foot) is a nonfreezing injury that results from exposure to wet cold. Pernio (chilblains) is a nonfreezing injury after exposure to dry cold.
Category: Medical Surgical Nursing
In type 1 diabetes mellitus, increased urination and thirst are consequences of osmotic diuresis secondary to sustained hyperglycemia. The diuresis results in a loss of glucose as well as free water and electrolytes in the urine.
Category: Medical Surgical Nursing
Cyclosporine and tacrolimus impair insulin secretion. Sirolimus principally increases insulin resistance. These agents contribute to the development of new-onset diabetes after transplantation.
