Concentration-response relationships for fentanyl and sufentanil in patients undergoing coronary artery bypass grafting.
BACKGROUND
Concentration-response relationships for sufentanil and fentanyl are undefined in patients undergoing coronary artery bypass grafting.


METHODS
Separate studies of sufentanil and fentanyl were performed in lorazepam-premedicated patients undergoing coronary artery bypass grafting. Patients were assigned randomly to groups with different prebypass effect-site opioid concentrations targeted by computer-assisted infusion. The target sufentanil concentrations were 0.4 ng/ml (group LS, n = 11), 0.8 ng/ml (group MS, n = 10), and 1.2 ng/ml (group HS, n = 11); the target fentanyl concentrations were 5 ng/ml (group LF, n = 7), 10 ng/ml (group MF, n = 7), and 15 ng/ml (group HF, n = 6). Propofol at a dose of 1 mg/kg was administered at induction of anesthesia and isoflurane was used for hemodynamic control Hemodynamics, end-tidal isoflurane concentration, and opioid concentration in arterial blood were measured at specific intervals.


RESULTS
Intraoperative opioid concentrations were constant, averaging 0.71 +/- 0.13, 1.25 +/- 0.21, and 2.03 +/- 0.46 ng/ml for groups LS, MS, and HS, respectively, and 7.3 +/- 1.1, 13.2 +/- 2.2, and 24.4 +/- 5.8 ng/ml for groups LF, MF, and HF, respectively (all mean +/- SD). Isoflurane requirements were significantly greater in group LS than in groups MS and HS and greater in group LF than in groups MF and HF. The serum opioid and end-tidal isoflurane concentrations were correlated significantly. There were no intergroup differences in hemodynamics.


CONCLUSIONS
Serum sufentanil and fentanyl concentrations of 0.71 +/- 0.13 ng/ml and 7.3 +/- 1.3 ng/ml, respectively, are on the steep parts of the concentration-response relationships and facilitate prebypass hemodynamic control in patients undergoing coronary artery bypass grafting with opioid-isoflurane anesthesia. Concentrations of sufentanil > or = 1.25 +/- 0.21 ng/ml and of fentanyl > or = 13.3 +/- 2.2 ng/ml minimize isoflurane requirements but do not improve hemodynamic control.
Department of Anesthesia, University of Manitoba, Winnipeg, Canada. ithomson@sbrc.umanitoba.ca
I R
IR
Thomson
B T
BT
Henderson
K
K
Singh
R J
RJ
Hudson
D000368:Aged; D000701:Analgesics, Opioid / Q000097:blood* / Q000627:therapeutic use*; D018685:Anesthetics, Inhalation / Q000097:blood / Q000627:therapeutic use; D018686:Anesthetics, Intravenous / Q000009:adverse effects* / Q000627:therapeutic use*; D001026:Coronary Artery Bypass; D004305:Dose-Response Relationship, Drug; D004360:Drug Therapy, Computer-Assisted; D005260:Female; D005283:Fentanyl / Q000097:blood* / Q000627:therapeutic use*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007260:Infusion Pumps; D007530:Isoflurane / Q000097:blood / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017409:Sufentanil / Q000097:blood* / Q000627:therapeutic use*
D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D017409:Sufentanil; D007530:Isoflurane; D005283:Fentanyl