Question 277

Question:

At the onset of an acute myocardial infarction, a patient was placed on an intravenous vasodilator. Three days later, the patient had become short of breath, cyanotic, and occasionally drifted in and out of consciousness. Arterial blood gas results revealed an oxygen saturation of 87% on room air. The arterial blood was chocolate-brown in color. On what drug was the patient most likely placed?

Correct Answer: C.  Glyceryl trinitrate

Glyceryl trinitrate, an organic nitrate, is often given IV at the onset of acute MI. A side effect of all organic nitrates is the oxidation of hemoglobin to form methemoglobin, which decreases the oxygen carrying capacity of blood. This produces shortness of breath, cyanosis, and can occasionally cause unconsciousness. Blood color is characteristically chocolate-brown or dark red.