Propofol requirement titrated to bispectral index: a comparison between hypothermic and normothermic cardiopulmonary bypass.

Though propofol requirement is expected to decrease during cardiopulmonary bypass (CPB), a few studies have failed to demonstrate this. The factors affecting pharmacokinetics of propofol and, therefore, the requirement, are different during hypothermic and normothermic CPB. We evaluated and compared the requirement of propofol during hypothermic and normothermic CPB. Fifty adult patients scheduled for elective cardiac surgery on CPB were recruited and randomly allocated into hypothermic CPB (28–300 C) (Group H) and normothermic CPB (35–370 C) (Group N) groups. Patients were induced and maintained with propofol titrated to maintain a target bispectral index (BIS) of 50 ± 10. Propofol requirement (mean ± SD) was similar in normothermic and hypothermic groups, both before CPB (4.9 ± 1.5 mg.kg−1hr−1 in Group N, 4.6 ± 1.5 mg.kg−1hr−1 in Group H) and after cessation of bypass (p > 0.05) (4.6 ± 1.8 mg.kg−1hr−1 in Group N and 4.3 ± 1.7 mg.kg−1hr−1 in Group H). CPB significantly reduced (p < 0.001) propofol requir...