Efficacy of continuous femoral three-in-one nerve block using stimulating nerve catheter and non stimulating nerve catheter for postoperative analgesia in surgeries over thigh: a comparative study

Introduction: Continuous femoral analgesia provides extended pain relief for surgeries over thigh. Successful continuous peripheral nerve analgesia depends on catheter proximity to the target nerve and stimulating catheters may allow more accurate placement of catheters. Hence we conducted a study to compare the efficacy of stimulating nerve catheter and non stimulating nerve catheter in femoral 3-in-1 nerve block for postoperative analgesia. Materials and Methods: 60 ASA grade I & II patients of either sex between 18 to 65 years of age posted for total knee replacement surgery were randomly allocated into two groups: Group SC (stimulating catheter) and Group NSC(non stimulating catheter). All patients received subarachnoid block and after completion of surgery femoral catheter (stimulating/non stimulating depending on the group) was placed using peripheral nerve stimulator for postoperative analgesia. When spinal level regressed to T12 dermatomal level, Inj.Bupivacaine (0.25%) 20ml with Inj.Lignocaine (1%) 10ml was given. The patients were followed for next 24 hours from the time of first bolus. After the 1st bolus when the VRS score was ?3, intermittent boluses of Inj.Bupivacaine (0.25%) 15 ml with Inj.Fentanyl 0.5µg/kg were given. All patients received Inj. Paracetamol 20 mg/kg IV 6 hourly. In case patient still had VRS score ?3 then rescue analgesia in the form of Inj.Diclofenac sodium 1 mg/kg IV was given. Two groups were observed for total duration of sensory block (time from 1st bolus dose till the time VAS score was ?3); requirement of analgesic solution; requirement of rescue analgesia; and any complication or side effects. Results: Total duration of sensory block in group SC was 9.40±0.21 hours compared to 7.10±0.23 hours in group NSC (p=0.0001). Total requirement of analgesic solution was less in SC group in comparison to NSC group. No significant complication observed in either group. Conclusion: Stimulating nerve catheter provides longer duration of sensory blockade with decreased requirement of local anaesthetic solution and opioid when compared to non stimulating nerve catheter.