A prospective evaluation of the electrocardiographic manifestations of hypothermia.

OBJECTIVE: To determine the effects of body temperature, ethanol use, electrolyte status, and acid-base status on the electrocardiograms (ECGs) of hypothermic patients. METHODS: Prospective, two-year, observational study of patients presenting to an urban ED with temperature < or =95 degrees F (< or =35 degrees C). All patients had at least one ECG obtained. Electrocardiograms were interpreted by a cardiologist blinded to the patient's temperature. J-point elevations known as Osborn waves were defined as present if they were at least 1 mm in height in two consecutive complexes. RESULTS: 100 ECGs were obtained in 43 patients. Presenting temperatures ranged between 74 degrees F and 95 degrees F (23.3 degrees C-35 degrees C). Initial rhythms included normal sinus (n = 34), atrial fibrillation (n = 8), and junctional (n = 1). Osborn waves were present in 37 of 43 initial ECGs. Of the six initial ECGs that did not have Osborn waves present, all were obtained in patients whose temperatures were > or =90 degrees F > or =32.2 degrees C). For the entire group, the Osborn wave was significantly larger as temperature decreased (p = 0.0001, r = -0.441). The correlation between temperature and size of the Osborn wave was strongest in six patients with four or more ECGs (range r = -0.644 to r = -0.956, p = 0.001). No correlation could be demonstrated between the height of the Osborn waves and the serum electrolytes, including sodium, chloride, potassium, bicarbonate, BUN, creatinine, glucose, anion gap, and blood ethanol levels. CONCLUSIONS: The presence and size of the Osborn waves in hypothermic patients appear to be a function of temperature. The magnitude of the Osborn waves is inversely correlated with the temperature.

Bretylium tosylate and electrically induced cardiac arrhythmias during hypothermia in dogs.

The effect of bretylium tosylate on plasma catecholamines and on electrically induced arrhythmias was evaluated in anesthetized hypothermic dogs. Bretylium at a dose of 7.5 mg/kg was administered prior to cooling from 37 degrees C to 27 degrees C. During cooling, the ventricular arrhythmia threshold (VAT) in control animals decreased from 10.1 +/- 1.9 to 4.4 +/- 1.3 impulses, while the VAT in bretylium-treated animals increased from 9.8 +/- 2.9 to 23.2 +/- 2.7 impulses. Catecholamine levels increased during cooling in all animals. In control animals, the epinephrine/norepinephrine ratio was unchanged, but in animals treated with bretylium tosylate, the ratio increased more than 10-fold (from 0.48 +/- 0.1 to 5.49 +/- 0.32 at 29.9 degrees C). The demonstrated increase in catecholamine levels during hypothermia suggests that the protection offered by bretylium tosylate against cardiac arrhythmias is not explained by modification of catecholamine levels, and is more likely due to an alteration of the electrophysiologic properties of cardiac tissues.

Heatstroke. Underlying processes and lifesaving management.

Heatstroke occurs during intense physical exertion or environmental exposure to heat without exertion. The ability to eliminate heat is limited by volume depletion, cardiac and vascular insufficiency, and skin disorders or protective coverings that prevent sweating and evaporative heat loss. Also, many drugs predispose patients to heatstroke by impairing normal thermoregulatory function. Critical management strategies include (1) recognition of hyperthermia, (2) rapid cooling, and (3) supportive care and observation for heat-related complications of tissue injury (eg, hepatic failure, renal failure, disseminated intravascular coagulation).

Endocarditis in the emergency department.

Clinical presentations and pathogeneses of endocarditis and aspects of its diagnosis and management relevant to emergency department practice are reviewed. Guidelines for admission, laboratory evaluation, and decisions regarding the initiation of therapy in the ED are offered. Also discussed are the role of the emergency physician in the prevention of iatrogenic infection and current recommendations regarding administration of prophylactic antibiotics for ED procedures.

Pharmacologic effects on thermoregulation: mechanisms of drug-related heatstroke.

In summary, a number of pharmacologic agents interfere with the body's ability to maintain normal body temperature during exercise or under conditions of environmental heat stress. Life threatening elevation of body temperature may occur. Regardless of the predisposing cause of heatstroke, the final common pathway is heat injury to tissues causing cell death. Rapid cooling of the patient must take precedence and elucidation of the pathophysiologic disturbance is secondary to the accomplishment of this goal.

Emergency flexible fiberoptic nasotracheal intubation: a report of 60 cases.

We describe our experience with 60 consecutive intubations using flexible fiberoptic nasotracheal technique in the emergency setting. Fifty-seven of the procedures were carried out by two emergency physicians initially trained on intubation manikins. A learning curve is constructed demonstrating that time to intubation is decreased after nine or ten intubations. Complications are reviewed. Bleeding occurred in 22% of patients; the technique failed in 13%. Failure to intubate with fiberoptic technique was associated with specific problems such as bleeding, tumor, or agitation. Our results demonstrate both the limitations and special use of flexible fiberoptic technique.