Question 3 of 10

A 25-year-old man was drinking an excessive amount of alcohol and apparently fell asleep in the park on a February night. On arrival at the ED, he is unresponsive with a core temperature of 27.8°C (82°F) and a pulse of 40/min. You know that:

Continuous CPR must be performed until the patient is rewarmed.

A large positive deflection at the end of the QRS complex indicates a poor prognosis.

Bradycardia should be treated with intravenous pacemaker placement.

Cardiopulmonary bypass therapy is useless in the hypothermic patient without a pulse.

Hypothermic patients are usually volume depleted.

Hypothermic patients are volume-depleted for a variety of reasons, including alcohol, cold-induced diuresis, and third spacing of intravascular volume. The hypothermic kidney loses its ability to concentrate urine, rendering urine output and specific gravity inaccurate as a sole guide to intravascular volume. Controversy exists about the indications for CPR in hypothermic patients. It may be difficult to monitor cardiac activity in these patients. If no pulse is detected after a minute in the hypothermic patient, or if obvious ventricular fibrillation or asystole is present, CPR is clearly indicated. A variety of EKG changes are often seen in hypothermia, including the Osborn (J) wave, a positive deflection at the end of the QRS complex. The Osborn wave has no bearing on prognosis and resolves with rewarming. Dysrhythmias are common, especially with a core temperature below 30°C (86°F), and are generally best treated with rewarming rather than pharmacologic therapy. The cold myocardium is both susceptible to ventricular fibrillation (which may be precipitated by rough handing of the patient or intracardiac devices) and refractory to defibrillation. If one or two attempts to defibrillate the hypothermic patient are unsuccessful, CPR is carried out simultaneously with rewarming efforts and defibrillation attempted after each few degrees increase in core temperature. Cardiopulmonary bypass therapy is extremely beneficial in the pulseless, hypothermic patient.

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