Introduction: Spinal anaesthesia is the technique of choice for, lower limb surgeries. Various adjuvants are used intrathecally with local anaesthetics to improve the duration of action and analgesic effect. Among various adjuvants, intrathecal opioids has provide an effective prolongation of postoperative analgesia after orthopedic surgical procedure.¹

Fentanyl and nalbuphine are opioid analgesics. Fentanyl is a opioid agonist and acts on µ opioid receptor.² Nalbuphine is a synthetic opioid analgesic with agonist-antagonist activity and acts as antagonist at µ receptor and agonist at k receptor. Nalbuphine, when used as adjuvant to hyperbaric bupivacaine has improved the quality of perioperative analgesia with fewer side effects.³

The availability of fentanyl and other µ opioids is difficult compared to nalbuphine which is easily available and has lesser side effects. Therefore a prospective controlled comparative clinical study of intrathecal nalbuphine 0.4mg versus intrathecal is being taken up.

Fentanyl l 25µg with 12.5mg of 0.5% bupivacaine in patients undergoing lowerlimb orthopedic surgeries

Aim: To compare the onset and duration of sensory and motor block as well as postoperative analgesia provided by intrathecal 0.4mg nalbuphine and intrathecal 25µg fentanyl when used as adjuvants to 2.5ml of 0.5% bupivacaine.

Methodology: 50 patients of [American Society of Anesthesiologists (ASA) physical status I and II], aged 18 to 60 years, posted for lower limb orthopedic surgeries under spinal anaesthesia will be included in the study after obtaining ethical committee clearance and written informed consent from the patients. Group BF will receive 2.5ml bupivacaine 0.5% and fentanyl 25 µg (0.5ml) and Group BN receives 2.5ml of bupivacaine 0.5% and nalbuphine 0.4mg (made in to 0.5ml with normal saline)

The total amount of the intrathecal mixture was constant (3ml) in both the groups

Intra and post operatively patients were assessed for hemodynamic parameters, sensory and motor blocked, analgesia, sedation and side effects.

Results: The demographic data (age, weight, sex, and ASA grading) were comparable and statistically non-significant. Mann Whitney U test is used for statistical analysis. The mean time for 2 segment regression of sensory blockade was more in Group BN (112.52 ± 6.15minutes) whereas it was 99.68 ± 5.66minutes in Group BF. Statistically highly significant and The p value was<0.0001*

The duration of motor block was highest for group BN with 153.12 minutes, Where as group BF    had shorter duration at 137.04 minutes. The p value <0.0001 (statistically highly significant)

The mean time of resue analgesia was 211.92 ± 6.73 min in group BN and 178.68 ± 2.65 min in grop BF. The p value is < 0.0001 which is highly significant. Hence the patients in group BN needed analgesia after much longer duration compared to group BF

Conclusion: Intrathecal nalbuphine is better compared to intrathecal fentanyl when used as adjuvant to 0.5% hyperbaric bupivacaine for lower limb orthopedic surgery under subarachanoid block.