A Comparative Perspective Study between Intrathecal Midazolam & Nalbuphine as an adjuvant with Hyperbaric Bupivacaine for Post-Operative Analgesia in Total Abdominal Hysterectomy

Background: Subarachnoid block is the preferred form of regional anesthesia for obstetric surgeries. Local anesthetic agents alone are insufficient in providing adequate postoperative analgesia, which is an essential factor for the patients & is the sole essence of anesthesia. Adding adjuvant will result in better quality, the efficacy of SAB & will prolong analgesia postoperatively. Due to minimal hemodynamic & respiratory complications, Nalbuphine, an opioid, can be favored as an adjuvant to subarachnoid block. The addition of Nalbuphine in limiting doses to Hyperbaric Bupivacaine offers improved block quality & adequate pre & post-operative analgesia. Midazolam, an imidazobenzodiazepine given intrathecally, raises the threshold of pain; it also has hypnotic, anticonvulsant, muscle relaxant & amnesic effects of other benzodiazepines.

Objectives: Primarily to compare the duration of pain relief in the postoperative period between administration of Intrathecal Nalbuphine (1mg) & Midazolam(2.5mg) ( Timing of 1st rescue analgesia). Secondarily to compare the onset of action & duration of motor & sensory block (Modified Bromage Scale), Effect on Hemodynamic Parameters, 24 hours requirement of analgesic (No. of Injection Paracetamol 15-20mg/kg ), Degree of sedation(Modified Ramsay Sedation Scale) & After-effects(PONV, Pruritis, Shivering & Retention of urine).

Methodology: The study type will be a Comparative Prospective Study on 60 ASA 1 & 2 females in the age group 35-75 years, planned for total abdominal hysterectomy will be separated in two equivalent Group M (n=30) & Group N (n=30). Group M will receive combination Midazolam preservative-free 0.5 ml (2.5 mg) with 0.5% Hyperbaric Bupivacaine 2.5 ml(12.5 mg), & Group N will receive combination Nalbuphine 1 ml (1 mg) with Hyperbaric Bupivacaine (0.5%) 2.5 ml (12.5mg) by Intrathecal Route. Analgesia duration in the postoperative period, the onset of action & duration of motor & sensory block, effect on hemodynamic parameters, 24 hours analgesics requirement, degree of sedation, after-effects, if any, will be studied & compared.

Conclusion: Expected to prove the hypothesis that adding which of the following adjuvant 1mg Nalbuphine or 2.5mg Midazolam with 0.5% Hyperbaric Bupivacaine intrathecally given in SAB prolongs the postoperative analgesia duration more as compared to other.