Comparative study of intrathecal low dose hyperbaric bupivacaine 7.5mg and 12.5mg hyperbaric bupivacaine using fentanyl as an adjuvant in elderly patients undergoing lower limb and abdominal surgeries

Abstract

Background: Spinal anaesthesia for lower limb surgeries is routinely used. It provides both analgesia and muscle relaxation, has rapid onset of action. However, many geriatric patients have coexisting cardiac or pulmonary diseases, it’s very important to limit the distribution of the block to prevent the possible hemodynamic and pulmonary adverse effects by using very small doses of local anesthetics. Many adjuvants have been used to prolong the duration of spinal anaesthesia. Aim: The aim of this study is to compare intrathecal low dose bupivacaine (7.5mg) + fentanyl (25μg) and 12.5mg bupivacaine + fentanyl in elderly patients undergoing lower limb and abdominal surgeries. Material and methods: Prospective, randomized, comparative study. After obtaining the Institutional ethics committee clearance and informed consent, a total of 80 elderly patients with ASA grade II-III scheduled for elective lower limb and abdominal surgeries were recruited in this study. Study was carried out at Dept, of Anaesthesiology, Krishna institute of medical sciences, Secunderabad. Results: Onset of sensory blockade, onset of motor blockade, time for two segment regression of sensory blockade, duration of motor blockade, duration of analgesia were studied. These parameters were tested every 2minutes until complete motor and sensory levels were achieved. Hemodynamic parameters like HR,SBP,DBP,MAP were studied in both the groups, and were recorded every 5 min for first 30 min, then every 15 min till the end of surgery . Demographic variables age, sex, ASA grade, weight, height were all comparable between the two groups. Basline HR, MAP, SPO2 were also comparable between the two groups. Time for onset of sensory blockade( group A- 4.17 ± 0.446 & group B – 3.5 ± 0.599 (p value 0. 001) Onset of motor blockade ( group A- 5.28±0.504 & group B - 4.36±0.476 ( p value 0.001 ).Duration of motor blockade (group A- 116.4±7.669 & group B-232.82±13.311 p value 0.001 ), In group B, there was significant delay in two segment regression of sensory blockade ( group A- 81.05± 5.905 & group B – 129.75± 15.890 p value 0.001) and also longer duration of analgesia was seen ( group A- 177.83± 13.7 & group B - 228.80± 14.576 p value 0.001 ). Conclusion: Based on the above observations, we conclude that low dose bupivacaine(7.5mg) with fentanyl is as good as 12.5mg bupivacaine with fentanyl in elderly patients undergoing lower limb and abdominal procedures as it provides profound analgesia, good muscle relaxation, good patient and surgeon satisfaction and better hemodynamic profile.