Spinal anesthesia with two different dosages of 0.75% glucose-free ropivacaine: a comparison of efficacy and safety in Chinese parturients undergoing cesarean section.

Background: We compared the clinical efficacy and safety between 2 doses of 2.5 ml (18.75 mg) and 3 ml (22.5 mg) of 0.75% glucose free spinal ropivacaine in Chinese parturients undergoing Cesarean section.

Methods: In this randomized, open-label study, 40 parturients enrolled were divided into two groups: Group A received a 2.5 ml 0.75% ropivacaine as opposed to 3 ml in Group B. Sensory and motor blocks were assessed during and after surgery until complete recovery. Eight standard measurements were taken: time at onset of sensory block; maximum cephalic sensory spread; maximum number of blocked segments; time to maximum sensory block; duration of sensory block at L3; time at onset of complete motor block and duration until complete recovery. Vital signs and any adverse effects related to spinal anesthesia were also recorded.

Results: Five of the 6 variables showed no significant difference between groups A and B: onset time of sensory block at L3 was 1.8 +/- 6.7 min vs. 2.3 +/- 9.8 min; maximum cephalic spread was T3-4 (C3-T7) vs. T3 (C2-T8); maximum number of blocked segments was 20.7 +/- 3.5 vs. 20.2 +/- 3.4; time to maximum sensory block 15.4 +/- 5.5 min vs. 20.3 +/- 15.1 min; time for regression to L3 was 200.8 +/- 59.5 min vs. 215.0 +/- 37.6 min and time for complete recovery of motor block 208.5 +/- 55.5 min vs. 226.5 +/- 461. min. Group B had a significantly faster onset time for complete motor block (P < 0.05) 15.4 +/- 5.6 min vs. 10.4 +/- 4.7 min. Moreover, there were no significant differences in global hemodynamic changes during and after the operation. Transient hypotension attacks were more frequent in group A at the beginning of anesthesia, perhaps due to inadequate prehydration. Otherwise, there were no differences in adverse effects during or after surgery.

Conclusions: We conclude that for Cesarean section in Chinese parturients either 18.75 mg (2.5 ml) or 22.5 mg (3 ml) 0.75% glucose-free ropivacaine can provide a spinal anesthesia of the same efficacy and safety.