Effect of pregnancy on potency of bupivacaine for spinal anesthesia in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of pregnancy on the potency of bupivacaine for spinal anesthesia in rats. Methods Female non-pregnant SD rats weighing 180-220 g and 17 day pregnant SD rats weighing 350-400 g were used in this study. The rats ( 18 non-pregnant, 18 pregnant) in which PE-10 catheter were successfully placed without complications were selected. The 18 non-pregnant rats were randomly divided into 3 groups (n =6 each) control group (group C), 2% bupivacaine group (group B2 ) and 4% bupivacaine group (group B4). The 18 pregnant rats were also randomly divided into 3 groups (n = 6 each) control group (group PC),2% bupivacaine group (group PB2 ) and 4% bupivacaine group (group PB4 ). Group C and PC received intrathecal (IT) normal saline 30 μl, and the other 4 groups received 2% or 4% bupivacaine 30 μl intrathecally. Analgesia was determined using the taifllick latency (TFL) before IT administration (baseline), and at 10 min, 20 min,30 min, 1 h, 2 h, 4 h, 1 d, 2 d, 3 d and 4 d after IT administtation. The percentage of the maximal possible effect (MPE) was calculated. Hind-limb motor function (MF) was also assessed. Results Compared with the baseline value, MPE at 10 min-2 h after administration and MF scores at 10 min-1 h after administration were significantly increased in group B2, MPE at 10 min-4 h after administration and MF scores at 10 min-1 h after administration were significantly increased in group B4;MPE at 10 min-1 d after administration and MF scores at 10 min2 h were significantly increased in group PB2 and MPE at 10 min-1 d after administration and MF scores at 10 min4 h were significantly increased in group PB4 ( P ＜ 0.05 ). Conclusion Pregnancy can enhance the potency of bupivacaine for spinal anesthesia in rats.