Effect of transdermal nitroglycerin patch on intrathecal neostigmine with bupivacaine for post operative analgesia

Background: The international association for the study of pain has defined pain as unpleasant and emotional experience associated with actual or potential tissue damage or described in terms of such damage. Spinal anesthesia was first produced by Corning in 1885 and first used deliberately by Bier in 1898. Glucose containing solution for spinal anesthesia was introduced by Barker in 1907. Since then hyperbaric solutions are in use for spinal anesthesia. All these advantages of spinal anesthesia are offset by complain of postoperative pain when effect of local anesthesia wears off due to relatively shorter duration of action of local anesthetic drug. Aim: The present study was designed to evaluate the effect of intrathecal bupivacaine 0.5% heavy 3.0 ml (15 mg) with neostigmine 5 mcg and bupivacaine 0.5% heavy 3.0 ml (15 mg) with neostigmine 5 mcg and nitroglycerin patch (5 mg/24 hour) in various surgeries divided 2 groups, 25 patients in each group. The objectives of study were to observe onset and duration of sensory and motor blockade, to observe duration of post operative analgesia, to observe perioperative hemodynamic stability, to observe perioperative complications. Materials and methods: The study was conducted by taking 50 randomly selected patients for various surgeries. Patients belonged to ASA Grade I/II aged 18 to 60 years were included. Patients were divided into 2 groups. Group - A: 0.5% heavy bupivacaine 3 ml (15 mg) + preservative free neostigmine 5 mcg. Group - B: 0.5% heavy bupivacaine 3 ml (15 mg) + preservative free neostigmine 5 mcg + transdermal nitroglycerin patch (5 mg/24 hours), applied on a non anaesthetised area after 20 minutes. All the patients were evaluated preoperatively and those having history of allergy to any drug, having any contraindications to spinal anesthesia, any neurological disorder and psychiatric illness were excluded from the study. Detailed preoperative history of past and present illness was taken. Systemic and general examination was done and back of patients were examined to rule out any spinal deformity and infection at local site. Patients were investigated for laboratory investigations like complete blood count, blood Sugar, renal function test, serum electrolytes, serum bilirubin and chest X-Ray, ECG were reviewed. Results: In our study of 50 patients we observed that intrathecal neostigmine 5 mcg with bupivacaine 15 mg with transdermal nitroglycerin patch (5 mg/day) markedly prolong duration of post operative analgesia than intrathecal neostigmine with bupivacaine alone. Intra-operative complication like bradycardia do occur but it was not significant, and other complication like hypotension occur with both groups but more in group B which requires monitoring . Conclusion: Transdermal nitroglycerin patch increases post-operative analgesia of low dose intrathecal neostigmine with bupivacaine in spinal anesthesia with less side effects.