Comparison of isobaric levobupivacaine versus hyperbaric bupivacaine in spinal anesthesia for cesarean section: A prospective unmatched case control study

Bothgroups were comparable regarding age, ASA grade, duration of surgery andpreoperative vital parameters

Sensory Motor Block characteristics:Sensory onset was significantly faster with hyperbaric bupivacaine as comparedto isobaric levobupivacaine, as shown by difference in time to T8 (3.12±0.86min in group L, 2.8 ±0.74 min in group B, p = 0.048) and time to T6(4.28±1.04 min in group L, 3.8±0.81 min in group B, p = 0.011) though thisdifference of less than 1 min was clinically not significant.     All patients of both groups achieved targetsensory level of T6 which was necessary to start caesarean sectionin spinal anaesthesia. Peak sensory level at 10 min ranged from T3-T6in both groups however  median value wasT6 in group L as compared to T4 in group B. Mean value ofpeak sensory level was comparable in two groups (T4.74±1.03 in groupB and T5.12±0.97in group L, p =0.060). The time to reach peaksensory level was also statistically comparable in two groups (4.68±0.81 min ingroup L, 4.44±0.63 min in group B, p = 0.095).

Allpatients of both groups achieved maximum Bromage score of 3, signifyingcomplete motor block. Motor onset in terms of time to achieve maximum Bromageof 3 was significantly faster with hyperbaric bupivacaine (3.04±0.69 min ingroup B) as compared to isobaric levobupivacaine (3.56±0.63 min in group L),p=0.0002, however this difference of less than 1 min was clinically notsignificant.

Durationof analgesia (time to first rescue analgesia)was significantly longer in group B (155.7±14.35 min) as compared to group L(140.3±12.74 min), p=0.0001. Sensory block duration was significantlylonger in group B (210.7±22.18 min) as compared to group L (186.0±21.26 min), p= 0.0001. Motor block duration was significantly longer in group B(250.9±24.20 min) as compared to group L (223.9±23.11 min), p = 0.0001

 **Haemodynamic Parameters:**There was no significant difference in mean value of systolic BP, diastolic BP,pulse rate and SpO2 in both groups throughout the study period(p>0.05).

**Adverse effects:**Occurrence of hypotension was comparatively more in group B, [36% (n=18)] ascompared to group L [28% (n=14)], p > 0.05. Perioperative nausea andvomiting was also more in group B (8%, n =4) than in group L (4%, n =2), p >0.05. No neonatal and maternal complications or any other adverse effects wereobserved.

Success rate (clinical efficacy) of spinal block**:**Incidence of “completely successful†spinal block (no supplementation) was 100%(n=50) in both the groups. None of the patient in both groups requiredanaesthetic supplementation or general anaesthesia. Both 12.5 mg isobaric levobupivacaine and 10 mg hyperbaricbupivacaine in spinal anaesthesia were graded as “perfect agent†for CS, owingto 100% complete success rate in both groups.