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Hemodynamic effects of nitroprusside infusion during coronary artery operation in man
Insights
Sodium nitroprusside effectively manages hemodynamics in severe coronary artery disease (CAD) patients during surgery. This vasodilator improves left ventricular function and controls hypertension in patients with elevated left ventricular filling pressure (LVFP).
Area of Science:
- Cardiology
- Anesthesiology
- Pharmacology
Background:
- Severe coronary artery disease (CAD) poses significant hemodynamic challenges during cardiac surgery.
- Left ventricular dysfunction (LVD) and elevated left ventricular filling pressure (LVFP) are common complications.
- Managing intraoperative hypertension is critical in patients with CAD and LVD.
Purpose of the Study:
- To assess the hemodynamic response to sodium nitroprusside in patients with severe CAD undergoing surgery.
- To evaluate the efficacy of sodium nitroprusside in improving left ventricular function and controlling hypertension.
- To compare the effects of sodium nitroprusside across different groups based on LVFP and LV function.
Main Methods:
- 33 patients with severe CAD were divided into three groups based on LVFP and LV function.
- Sodium nitroprusside was administered intraoperatively, with infusion rates adjusted for effective therapy.
- Hemodynamic parameters including arterial pressures, ventricular filling pressures, vascular resistance, and cardiac indices were monitored.
Main Results:
- Nitroprusside significantly decreased pulmonary and systemic arterial pressures, ventricular filling pressures, and vascular resistance in all groups.
- Stroke index increased in patients with elevated LVFP (Groups 2 and 3), while left ventricular stroke work index improved in Group 2.
- Right ventricular stroke work index decreased significantly across all groups; heart rate increased in Group 1 but remained stable in Groups 2 and 3.
Conclusions:
- Judicious intraoperative use of sodium nitroprusside improves left ventricular function in CAD patients with elevated LVFP and LVD.
- Sodium nitroprusside is effective for controlling intraoperative hypertensive episodes in this patient population.
- The findings support the use of sodium nitroprusside for hemodynamic management during complex cardiac surgeries.
Abstract:
The hemodynamic response to vasodilator therapy with sodium nitroprusside has been assessed in 33 patients with severe coronary artery disease (CAD) during coronary artery operation. The patients were divided into three groups; Group 1 included seven patients with CAD and normal left ventricular filling pressure (LVFP less than 12 mm Hg); Group 2 included 18 patients with CAD and chronic left ventricular (LV) dysfunction (LVFP greater than 12 mm Hg) and Group 3 included eight patients with CAD and acute LV dysfunction (LVFP greater than 12 mm Hg) associated with an intraoperative hypertensive episode. Nitroprusside was administered intraoperatively at an initial infusion rate of 10-15 mcg/min and the rate was gradually increased thereafter until the criteria for effective therapy were satisfied. The effective dose ranged from 10-120 mcg/min with an average of 52 +/- 4 (SEM) mcg/min. In all three groups, pulmonary and systemic arterial pressure, right and left ventricular filling pressure, and pulmonary and systemic vascular resistance decreased significantly with nitroprusside infusion. Heart rate increased significantly in Group 1 and remained unchanged in Group 2 and 3. Heart rate X systolic arterial pressure decreased significantly in Group 1 and 3 and did not change in Group 2. Stroke index increased significantly in both groups of patients with elevated control LVFP (Group 2 and 3) and remained unchanged in patients with normal left ventricular function (Group 1). Left ventricular stroke work index decreased in Group 1, increased in Group 2, and remained unchanged in Group 3. Right ventricular stroke work index decreased significantly in all groups. These findings suggest that judicious intraoperative administration of sodium nitroprusside improves left ventricular function in patients with acute or chronic elevation of LVFP and LV dysfunction associated with severe CAD. Furthermore, nitroprusside is an effective drug for control of intraoperative hypertensive episodes in such patients.