Effect of fentanyl and epinephrine, alone or together with and without lidocaine on the sensory and motor block duration and hemodynamic variations in spinal anesthesia

Spinal anesthesia due to its simplicity, rapid onset of its effect and low dose of drug administration, is a desirable procedure to anesthetics particularly for lower extremity and lower abdomen operations. Lidocaine is widely used in this method of anesthesia for prolongation of the sensory block. In the method, different drugs are used to prolong the duration of sensory block. Fentanyl and epinephrine are being used widely for this purpose and so far, the effects of these drugs were not compared. Therefore, in this study, the effect of the two drugs, alone or together, with and without lidocaine, on the duration and intensity of sensory and motor block has been investigated. In this double-blinded clinical trial, 60 candidates for elective surgery of lower abdomen were randomly divided into three equal groups. For spinal anesthesia, the first group was subjected to 50 mg lidocaine plus 0.2 mg epinephrine, the second one to 50 mg lidocaine plus 0.2 mg epinephrine and 20-µg fentanyl and the third group to 50 mg lidocaine plus 20-µg fentanyl. Subsequently, the patients in the 3 groups were evaluated and compared for the duration of sensory and motor block and their hemodynamic variations. The data was analyzed using ANOVA and Chi-square tests. Age and sex distribution among the three groups was not significantly different. The mean of sensory block duration in the first, second and third groups were 130.25±19.05, 133±32.7 and 116±14.58 min, respectively with no significant difference. The mean of motor block duration in the first, second and third groups were 120.95±14.63, 118.75±25.74 and 107±18.23 min, respectively. ANOVA test showed no significant difference among the three groups as well. Also, with respect to hemodynamic variation, there was no significant difference among the three groups. Our findings showed that addition of epinephrine and fentanyl and combination of them to the lidocaine had no effect on the duration of sensory and motor block and hemodynamic variations. Therefore, combined use of these drugs is not necessary