Variations in hemodynamic and stress hormonal responses in open heart surgery with buprenorphine/diazepam anesthesia

The use of buprenorphine-diazepam-N2O (60%)-O2 anesthesia in open heart surgery was investigated. The authors examined the hemodynamic changes produced and the response of stress hormones. Twenty adult patients with atrial septal defects undergoing surgical correction were studied in two groups of 10, receiving either 6 micrograms/kg of buprenorphine (B6) or 12 micrograms/kg of buprenorphine (B12) for the induction of anesthesia. Both groups received a subsequent dose of 6 micrograms/kg of buprenorphine with the commencement of extracorporeal circulation (ECC). With surgery, mean arterial pressure showed a transient increase in both groups and thereafter was stable. Heart rate in the B6 group was increased from the onset of surgery to the day after, while the B12 group showed no significant change. Filling pressures showed no change in either group. Plasma catecholamine concentrations in the B6 group, in contrast to the B12 group, increased significantly from midoperation to after completion of the operation (ECC 10 minutes, B6 group v B12 group: plasma norepinephrine 616 +/- 231 v 195 +/- 38 pg/mL, plasma epinephrine 1385 +/- 392 v 572 +/- 132 pg/mL, P less than 0.05). Plasma ADH levels in both groups rose with the commencement of surgery, reaching a peak at ECC 10 minutes (B6 group 88.1 +/- 8.4 v B12 group 124.4 +/- 27.2 pg/mL). However, in contrast to plasma catecholamines, the antidiuretic hormone (ADH) levels in the B12 group remained higher until the first postoperative day. Therefore, patients who received the larger dose of buprenorphine had better control of hemodynamics and catecholamines, but a greater elevation of plasma ADH levels.