DA(1)-RECEPTOR STIMULATION BY FENOLDOPAM IN THE TREATMENT OF POSTCARDIAC SURGICAL HYPERTENSION

Background: Besides adequate analgesia, sedation and ventilation, post cardiac surgical hypertension has to be treated frequently with vasoac tive drugs to avoid possible complications. In this study the hemodyna mic effects of the DA(1)-receptor agonist fenoldopam (F) are compared to those of the Ca-channel antagonist nifedipine (N). Methods: Postope ratively, 64 CABG-patients with a mean arterial pressure (MAP) of more than 105 mmHg over 10 min were investigated. Patients with compromise d ventricular function, insufficient surgical repair, arrhythmia or an ECG unable to detect myocardial ischemia were excluded. The study dru gs (initial dosage: F: 0.8; N: 0.3 mu g.kg(-1).min(-1)) were given con tinuously via a central venous catheter to reduce and to maintain the MAP between 80 and 95 mmHg. Hemodynamic parameters were determined usi ng thermodilution technique. Results: A significant reduction of the M AP (F: from 121+/-11 to 83+/-4, N: from 119+/-8 to 82+/-9 mmHg) and of the calculated systemic vascular resistance (SVR) (F: 2110+/-500 to 9 70+/-200, N: 1980+/-660 to 1020+/-300 dyn.s.cm(-5)) were noted in both groups, whereby in the F group the therapeutic goal could be achieved more quickly with the dosage regimen chosen. As a result, a marked in crease of heart rate, cardiac index and stroke volume index could be o bserved, which was more pronounced due to the initially stronger decre ase of SVR with F. There was also a stronger decrease of pulmonary vas cular resistance in the F group, but the indices of right ventricular function did not differ between the groups. Conclusion: Fenoldopam see ms to be an efficient alternative to nifedipine, especially because of its more rapid onset of action.