A Prospective Study to Evaluate the Effect and Adverse reactions associated with Fentanyl or Clonidine in TURP Surgery

Abstract

Aim: Present study was designed to compare the effect of intrathecal clonidine and fentanyl in combination with low doses of bupivacaine in TURP surgery on the hemodynamics, quality of sensory and motor block as well as the duration of analgesia and motor block. Subjects and Methods: 120 patients scheduled to undergo TURP surgery were randomized into four groups. Group I and II received hyperbaric bupivacaine 5 mg and 7.5 mg respectively with fentanyl 25 μg whereas Group III and IV received Bupivacaine 5 mg and 7.5 mg respectively with clonidine 30 μg in subarachnoid space. Hemodynamic parameters (heart rate, systolic blood pressure, diastolic blood pressure) were recorded at regular intervals. Intensity of motor block was recorded at L2 to S1 myotomes and a myotome score was calculated for each limb. Measurement of level of pinprick analgesia and intensity of motor block were recorded at 0,2,4,8 and 10 minutes. Time to return of pain sensation and complete motor recovery was also noted. Results: There was statistically significant difference in occurance of bradycardia from baseline in group I at 10 and 20 minutes (p<0.05,p<0.001). In group IV there was significant fall in heart rate at 10, 20 and 30 minutes (p<0.05,p<0.05,p<0.001). In group II and III there was no significant fall in heart rate. In group I there is significant fall in SBP at 10, 20 and 30 minutes (p<0.05). In group II there is significant fall in SBP at 10 and 20 minute (p<0.05). In group III and IV, there is significant fall in SBP at 10, 20 and 30 minutes (p<0.05,p<0.05,p<0.001). The maximum level of sensory block was comparable in all the groups (T10.21±0.99, T10.30±0.75, T10.33±1.12, T10.13±1.11 in groups I,II,III and IV respectively). There is no statistical significant difference in achieving level of motor block on comparing group I/II and group III/IV but there is highly significant (p<0.001) difference in group I/III, group I/IV, group II/III, group II/IV at 10 minutes after onset of block. There was no statistical significant difference in return of pain sensation in all groups (91.60±18.95, 86.07±10.84, 85.37±17.39, 85.50±22.22 in groups I,II,III and IV respectively). Complete return of motor power (modified Bromage score =0) was seen at 158.17±18.17 min, 154 ± 18.50 min, 146.53 ± 16.54 min and 154.83 ± 21.27 min in group I,II,III and IV respectively. There is significant difference (p<0.05) in return of motor power on comparing group I with III, otherwise all groups are comparable. Conclusion: The addition of fentanyl or clonidine to intrathecal bupivacaine for TURP does not result in any significant difference in the quality and intensity of sensory block. Clonidine causes a greater degree of motor block when compared to fentanyl. Both clonidine and fentanyl causes bradycardia and hypotension although the degree and duration of hypotension is greater with clonidine.