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Abstract

In this study we compared the effects of four different admixtures of propofol and thiopental sodium on hypnotic dose, pain on injection and hemodynamic responses during induction of anesthesia in 124 ASA class I and II aged 25-55 years patients. In group P100: propofol 1% 20 mL, in group P75: propofol 1% 15 mL thiopental sodium 2.5% 5 mL, in group P50: propofol 1% 10 mL thiopental sodium 2.5% 10 mL and in group T100 : thiopental sodium 2.5% 20 mL were used. After premedication with fentanyl 1.5 μg kg-1, induction agent was injected at a rate of 20 mL min-1. Pain on injection after 10 sec and hemodynamic responses at zero, first, third and fifth minutes after induction were recorded and analyzed. Results showed that the required induction dose of admixtures had an additive interaction. Thiopental sodium resulted in more rapid induction of anesthesia than P100 and P75 (p = 0.016 and p = 0.046). Pain on injection in P50 and P75 were less than P100 (p = 0.0001) and in P50 was less than P75 (p = 0.009). Between subject differences were significant for Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) in P100 compared with other groups (p<0.05). There were no significant differences in Heart Rate (HR) at T0, T3 between four groups but HR was lower in P100 compared with P50 and P75 at T1 and T5 (p<0.05). Admixture of thiopental sodium with propofol results an additive hypnotic effect, reduces pain of injection and hemodynamic responses compared with propofol injection alone.