We evaluated the clinical efficacy and safety of spinal anesthesia with 0.5
% hyperbaric ropivacaine compared with 0.5% hyperbaric bupivacaine for elec
tive cesarean delivery. Sixty healthy, full-term parturients were randomly
assigned to receive either 12 mg of 0.5% hyperbaric bupivacaine or 18 mg of
0.5% hyperbaric ropivacaine intrathecally. There were no significant diffe
rences in demographic or surgical variables or neonatal outcomes between gr
oups. Onset time of sensory block to T10 or to peak level was later in the
Ropivacaine group (P < 0.05). The median (range) peak level of analgesia wa
s T3 (T1-5) in the Bupivacaine group and T3 (T1-4) in the Ropivacaine group
. Time for sensory block to recede to T10 did not differ between groups. Du
ration of sensory block was shorter in the Ropivacaine group (188.5 +/- 28.
2 min vs 162.5 +/- 20.2 min; P < 0.05). Complete motor block of the lower e
xtremities was obtained in all patients. Ropivacaine also produced a shorte
r duration of motor blockade than bupivacaine (113.7 +/- 18.6 min vs 158.7
+/- 31.2 min; P < 0.000). The intraoperative quality of anesthesia was exce
llent and similar in both groups. Side effects did not differ between group
s. Eighteen milligrams of 0.5% hyperbaric ropivacaine provided effective sp
inal anesthesia with shorter duration of sensory and motor block, com pared
with 12 mg of 0.5% hyperbaric bupivacaine when administered for cesarean d
elivery.