the premedications were given in a double-blind random order and were either a placebo , morphine ( 0.04 mg/kg ) , meperidine ( 0.35 mg/kg ) , fentanyl ( 0.75 microgram/kg ) or sufentanil ( 0.15 microgram/kg ) .
C0015846
fentanyl
C0143993
sufentanil