Eisenach J C, Schlairet T J, Dobson C E, Hood D H
Department of Anesthesia, Wake Forest University Medical Center, Winston-Salem, North Carolina.
Anesth Analg. 1991 Aug;73(2):119-23. doi: 10.1213/00000539-199108000-00003.
The quality and duration of analgesia and incidence of side effects following epidurally administered morphine after cesarean section are highly variable. Two suggested sources of this variability are prior use of epinephrine-containing solutions, which may enhance both analgesia and side effects of morphine, and prior use of 2-chloroprocaine, which may inhibit epidural morphine analgesia. To examine these proposed sources of this variability we performed two studies. In the first, designed to test epinephrine's effect, 30 women underwent testing for epidural catheter tip location with injection of 2-chloroprocaine, followed by either 0.5% bupivacaine alone or 0.5% bupivacaine with 5 micrograms/mL epinephrine for epidural anesthesia. Inclusion of epinephrine with bupivacaine decreased the bupivacaine dose needed to achieve a T-4 sensory block by 24% (P less than 0.05), but did not alter analgesic duration or the incidence of side effects of epidural morphine (5 mg). In the second study, designed to test the effect of 2-chloroprocaine, 30 women received 7 mL of either 2% 2-chloroprocaine or lidocaine for epidural catheter testing, followed by 0.5% bupivacaine for epidural anesthesia. Compared to lidocaine testing, 2-chloroprocaine decreased the duration of epidural morphine analgesia (median 16 h with 2-chloroprocaine vs 24 h with lidocaine; P less than 0.05) without altering the incidence of side effects. The authors conclude that addition of epinephrine to local anesthetic does not increase the incidence of side effects or the analgesic effect from epidurally administered morphine. 2-Chloroprocaine, even when administered in small doses remote to the time of morphine injection, interferes with the duration of epidural morphine analgesia.
剖宫产术后硬膜外注射吗啡后的镇痛质量、持续时间以及副作用发生率差异很大。造成这种差异的两个可能原因是：先前使用过含肾上腺素的溶液，这可能会增强吗啡的镇痛效果和副作用；先前使用过2-氯普鲁卡因，这可能会抑制硬膜外吗啡的镇痛作用。为了探究这些可能导致差异的原因，我们进行了两项研究。在第一项旨在测试肾上腺素作用的研究中，30名女性先注射2-氯普鲁卡因以测试硬膜外导管尖端位置，随后分别接受仅0.5%布比卡因或含5微克/毫升肾上腺素的0.5%布比卡因进行硬膜外麻醉。布比卡因中加入肾上腺素可使达到T4感觉阻滞所需的布比卡因剂量减少24%（P<0.05），但并未改变硬膜外吗啡（5毫克）的镇痛持续时间或副作用发生率。在第二项旨在测试2-氯普鲁卡因作用的研究中，30名女性接受7毫升2% 2-氯普鲁卡因或利多卡因进行硬膜外导管测试，随后接受0.5%布比卡因进行硬膜外麻醉。与利多卡因测试相比，2-氯普鲁卡因缩短了硬膜外吗啡的镇痛持续时间（2-氯普鲁卡因组中位数为16小时，利多卡因组为24小时；P<0.05），但未改变副作用发生率。作者得出结论，在局部麻醉药中添加肾上腺素不会增加硬膜外注射吗啡的副作用发生率或镇痛效果。即使在距注射吗啡时间较远时小剂量使用2-氯普鲁卡因，也会干扰硬膜外吗啡的镇痛持续时间。
