A 19-year-old male with a gunshot wound to the abdomen had an exploratory laparotomy and a partial small intestinal resection. Postoperatively he had persistent tachycardia with blood pressure (BP) 85/50 mm Hg, heart rate (HR) 150, cardiac index (CI) 3.75 L/min/m2, pulmonary wedge pressure (PWP) 3 mm Hg, with a systemic vascular resistance (SVR) of 780 dyne·sec/cm5. Increased fluid resuscitation led to pulmonary edema and the need for intubation and ventilator support. BP was 140/85 mm Hg, CI 2.56 L/min/m2, SVR 820 dyne·sec/cm5, mixed venous oxygen saturation (SVO2) 75%, PWP 13 mm Hg, and HR 145. The arterial partial pressure of oxygen (PaO2) was 154 torr with fraction of inspired oxygen (FIO2) 0.6. Electrocardiogram indicated sinus tachycardia without ischemia. Esmolol 200 mg/kg infusion was started to control the heart rate. After 5 minutes, the HR decreased to 100 and the systolic BP decreased to 80 mm Hg. At this point the infusion was halted, but the BP and HR continued to decrease to HR 20 and systolic BP less than 40 mm Hg. The patient received numerous 1-mg dosages of epinephrine and 0.8 mg of atropine. He also received IV dopamine continuous infusions (400 mg/250 ml). In spite of this, cardiac arrest ensued and the patient died 30 minutes after the beginning of the esmolol infusion. Urine screens for cocaine, amphetamines, and barbiturates were negative. Crit Care Med. 1993; 21: 1975.
This patient had a persistent tachycardia with a low SVR and a depressed CI in spite of adequate filling pressures. This indicates myocardial depression; cardiac output is often rate dependent in this circumstance. Beta blockade in conjunction with myocardial depression, a low SVR, tachycardia, and recent refractory traumatic shock can be hazardous. The possibility of past cocaine usage was discussed. The percentage of positive toxicology screens among adolescents admitted with intentional injuries is high (21 of 42 in one series from Philadelphia Childrens Hospital) as compared with unintentional injuries (1 of 23) (P<.001). Ann Emerg Med. 1993; 22:1530.
Recent studies have demonstrated that beta adrenergic blockade is contraindicated in cocaine toxicity due to exacerbation of cocaine-induced alpha-adrenergic coronary artery vasoconstriction. Beta adrenergic blocking agents probably should be avoided in patients with cocaine-associated myocardial ischemia or infarction. Ann Intern Med. 1990; 112: 897. Cocaine-induced cardiomyopathy with blockage of the presynaptic uptake of norepinephrine may be sensitive to beta blockade. These patients may also be susceptible to hypovolemia-induced myocardial ischemia, as low diastolic blood pressures result in decreased coronary artery perfusion pressures. JAMA. 1990; 63: 1106.
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