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.