Evaluation of plasma fentanyl concentrations in infants during cardiopulmonary bypass with low-volume circuits.
OBJECTIVE
The purpose of the study was to measure changes in plasma fentanyl concentrations during infant cardiac surgery using a bypass circuit with low priming volume and to examine the relation of plasma fentanyl concentration and temperature to Bispectral Index (BIS) as an index of conscious level during infant cardiac surgery.


METHODS
Prospective cohort study.


METHODS
Tertiary care, academic children's hospital.


METHODS
Fifteen neonates and infants undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB).


METHODS
Patients were anesthetized with fentanyl, receiving a 30 microg/kg bolus for induction immediately followed by continuous infusion of 0.3 microg/kg/min until skin closure.


RESULTS
Intraoperative data and total plasma fentanyl concentration were measured at preinduction; 30 minutes postinduction; sternotomy; aortic cannulation; at 4, 30, and 60 minutes on CPB; and at 1 and 30 minutes off CPB. At the onset of CPB, fentanyl declined from 15 +/- 6 to 11 +/- 5 ng/mL (p < 0.01), increasing to 16 +/- 5 ng/mL (p < 0.01) at 30 minutes on CPB and maintaining a similar level until 30 minutes off CPB. BIS decreased from 88 +/- 20 to 42 +/- 11 (p = 0.02) with induction, declined further during cooling to 9 +/- 11 at the nadir temperature ( p < 0.001), and increased during rewarming to 29 +/- 9 at 1 minute (p < 0.001) and 35 +/- 10 at 30 minutes off CPB ( p < 0.01). Because of wide individual variation in BIS, there was no significant correlation between fentanyl and BIS and temperature.


CONCLUSIONS
There was minimal variability in the plasma fentanyl concentration using a low-volume bypass circuit and constant infusion of fentanyl during surgery. There appears to be minimal utility for using BIS during infant cardiac surgery with no relationship between fentanyl concentration, temperature, and BIS established.
Kussman
Barry D
BD
Department of Anesthesiology, Perioperative, and Pain Medicine, Children's Hospital, Boston, MA 02115, USA. barry.kussman@childrens.harvard.edu
Zurakowski
David
D
Sullivan
Lorna
L
McGowan
Francis X
FX
Davis
Peter J
PJ
Laussen
Peter C
PC
D000701:Analgesics, Opioid / Q000097:blood*; D001831:Body Temperature / Q000502:physiology; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass / Q000379:methods*; D015331:Cohort Studies; D003243:Consciousness / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000379:methods; D005260:Female; D005283:Fentanyl / Q000097:blood*; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods; D011446:Prospective Studies; D013997:Time Factors
D000701:Analgesics, Opioid; D005283:Fentanyl