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[Combined use of dihydralazine and nitroglycerin during and after cardiac surgery (author's transl)]
Insights
Combined dihydralazine and nitroglycerin effectively improved hemodynamic parameters in cardiac surgery patients. This combination therapy enhanced cardiac output and stroke index while reducing vascular resistance, proving beneficial during perioperative care.
Area of Science:
- Cardiovascular Surgery
- Pharmacology
- Anesthesiology
Background:
- Cardiac surgery patients often experience hemodynamic instability.
- Managing cardiac preload and afterload is crucial in perioperative care.
Purpose of the Study:
- To evaluate the hemodynamic effects of combined intravenous dihydralazine and nitroglycerin.
- To assess the efficacy of this combination in managing cardiac index and peripheral resistance during cardiac surgery.
Main Methods:
- Intravenous administration of dihydralazine (18 mg/h) and nitroglycerin (0.6 mg/h).
- Hemodynamic monitoring during intraoperative and postoperative phases in cardiac surgery patients.
- Comparison with nitroglycerin-only and untreated control groups.
Main Results:
- Significant increase in cardiac index (+36%) and stroke index (+19%) with combined therapy.
- Significant decrease in peripheral vascular resistance (-16%) and left atrial pressure (-20%).
- Nitroglycerin-only group showed decreased cardiac index (-8%) and increased resistance (+6%); control group showed minimal changes.
Conclusions:
- Combined dihydralazine and nitroglycerin therapy is recommendable for perioperative cardiac surgery.
- This combination allows for effective monitoring and management of cardiac preload and afterload.
- The selective pharmacological actions contribute to its therapeutic benefit.
Abstract:
The haemodynamic effect of combined intravenous administration of 18 mg/h dihydralazine and 0.6 mg/h nitroglycerine was examined in the intraoperative and postoperative phases of cardiac surgery (replacement of the aortic and mitral valve or of both valves, and aortocoronary bypass surgery(. Indication for therapy was supplied by a preoperative cardiac index below 2.8 l/min . m2 and an enhanced peripheral resistance above 1200 dyne . sec . cm-5. During a 19-hour observation period the haemodynamic parameters such as cardiac index (+36%) and stroke index (+19%) increased significantly within the investigated group, whereas the peripheral vascular resistance dropped by 16% and the left atrial pressure by 20%. Arterial mean pressure and heart rate did not change. In a patient group treated exclusively with nitroglycerin, the cardiac index decreased (-8%), while the peripheral vascular resistance increased (+6%); an untreated control group showed an increase of the cardiac index by 5%, whereas there was no appreciable change in peripheral vascular resistance and stroke index. The combined use of dihydralazine and nitroglycerin during the perioperative phase of cardiac surgery appears recommendable, since it is possible by such administration to monitor cardiac preload and afterload due to selectivity of the pharmacological sites of action.