DA1-receptor stimulation by fenoldopam in the treatment of postcardiac surgical hypertension.
BACKGROUND
Besides adequate analgesia, sedation and ventilation, postcardiac surgical hypertension has to be treated frequently with vasoactive drugs to avoid possible complications. In this study the hemodynamic effects of the DA1-receptor agonist fenoldopam (F) are compared to those of the Ca-channel antagonist nifedipine (N).


METHODS
Postoperatively, 64 CABG-patients with a mean arterial pressure (MAP) of more than 105 mmHg over 10 min were investigated. Patients with compromised ventricular function, insufficient surgical repair, arrhythmia or an ECG unable to detect myocardial ischemia were excluded. The study drugs (initial dosage: F: 0.8; N: 0.3 micrograms.kg-1.min-1) were given continuously via a central venous catheter to reduce and to maintain the MAP between 80 and 95 mmHg. Hemodynamic parameters were determined using thermodilution technique.


RESULTS
A significant reduction of the MAP (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 970 +/- 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 increase of heart rate, cardiac index and stroke volume index could be observed, which was more pronounced due to the initially stronger decrease of SVR with F. There was also a stronger decrease of pulmonary vascular resistance in the F group, but the indices of right ventricular function did not differ between the groups.


CONCLUSIONS
Fenoldopam seems to be an efficient alternative to nifedipine, especially because of its more rapid onset of action.
Gombotz
H
H
Department of Anaesthesiology and Intensive Care Medicine, University of Graz, Austria.
Plaza
J
J
Mahla
E
E
Berger
J
J
Metzler
H
H
D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use; D002302:Cardiac Output / Q000187:drug effects; D002405:Catheterization, Central Venous; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D018818:Fenoldopam / Q000008:administration & dosage / Q000627:therapeutic use*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000008:administration & dosage / Q000627:therapeutic use; D011651:Pulmonary Artery / Q000187:drug effects; D011954:Receptors, Dopamine / Q000187:drug effects*; D013318:Stroke Volume / Q000187:drug effects; D013815:Thermodilution; D014655:Vascular Resistance / Q000187:drug effects; D016278:Ventricular Function, Right / Q000187:drug effects
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D018491:Dopamine Agonists; D011954:Receptors, Dopamine; D009543:Nifedipine; D018818:Fenoldopam