Anesthesia with flunitrazepam and fentanyl supplemented with droperidol or chlorpromazine (Largactil) in coronary...

Sixty coronary patients undergoing aortocoronary bypassgrafts, some with left ventricular resection and some with associated valvular surgery were anesthetised with flunitrazepam, pancuronium and fentanyl according to systolic blood pressure (SBP) and heart rate (HR). When 40 micrograms kg-1 fentanyl was amounted, a neuroleptic was added to the protocol either droperidol (D series, 30 cases), or chlorpromazine (L series, 30 cases), 0.005 mg kg-1 at random, if the SBP remained above 100 mm Hg or when the mean BP rose during the ECC at constant flow. Analgesia was maintained adding 0.05 mg fentanyl to each 2.5 mg neuroleptic dose. A stable cardiovascular state was achieved during the entire procedure in both series. Total doses were 53.25 +/- 10 mukg-1 (D) and 49.45 +/- 6.46 micrograms kg-1 (L) fentanyl, 0.5 +/- 0.25 microgram kg-1 droperidol and 0.38 +/0 0.032 mg kg-1 chlorpromazine. The large dispersion in the doses of neuroleptics was due to a few cases of resistance to their action during ECC. A low dose of neuroleptic (less than 0.4 mg kg-1) was sufficient in a statistically different number of patients in each series, 23 patients were given 0.25 +/- 0.1 mg kg-1 chlorpromazine and only 9 patients were given 0.23 +/- 0.11 mg kg-1 droperidol. This is thought to be due to the longer duration of action of chlorpromazine. All patients came off bypass easily. No low output state developed. During the postoperative period hypertension was not a problem when taking into account that hypertensive patients were not excluded. Thirteen patients in each series had a HR greater than or equal to 100 b.p. m. during more than 1 h, but longer after chlorpromazine (n.s.). There was no other difference in the course of the 2 series until discharge. These results prompt us to continue using droperidol because of its more satisfactory pharmacokinetic characteristics.