[Sodium nitroprusside and coronary surgery].

The anti-hypertensive properties of sodium nitroprusside have been tested in 20 patients undergoing coronary arterial surgery. Were measured the arterial pressure, heart rate, mean right atrial pressure and mean left atrial pressure. The cardiac output, systemic vascular resistance and left ventricular stroke work index were deduced. A dose of 0.8 to 3 micrograms . kg-1 . min-1 sodium nitroprusside was given at the start of surgery, and immediately afterwards. The results showed a decrease of the systemic vascular resistance, a significant drop of arterial pressure, and a significant increase of heart rate as well as a tendency for the cardiac output to fall, probably because of insufficient vascular filing. When the mean left atrial pressure was kept at 14.8 +/- 3 mmHg (1.97 +/- 0.40 kPa), and left ventricular stroke work index fell, whilst cardiac output increased. Sodium nitroprusside seemed to be useful in coronary arterial surgery if used with care.