不同剂量甲氧明与麻黄碱联合预注对剖宫产母婴的影响

Effect of varying proportion of methoxamine and ephedrine combinations in parturients and fetus during the cesarean section

目的比较不同比例甲氧明和麻黄碱联合用于预防腰麻-硬膜外联合麻醉（combined spinal and epidural anesthesia, CSEA）剖宫产术中低血压的作用效果及对母婴的影响，评价联合用药不同药物比例的作用效果。方法采用随机数字表法将150例拟在CSEA下行剖宫产手术的产妇分成5组（1组～5组，每组30例），分别接受5种不同剂量浓度的甲氧明和麻黄碱混合静脉给药。假设2mg甲氧明约等效于8mg麻黄碱，各组比例分别相当于100％、75％、50％、25％、0的甲氧明和0、25％、50％、75％、100％的麻黄碱，调节输注速率以恒速泵注。测定产妇血流动力学变化和脐带血血气，记录新生儿Apgar评分，产妇恶心、呕吐及低血压情况。结果随1组-5组甲氧明的比例下降和麻黄碱比例的上升，低血压发生率有升高的趋势（1组3％、2组10％、3组7％、4组13％、5组30％）（P〈0．05）。2组、3组恶心呕吐发生率低于其他3组（1组7％、2组3％、3组0、4组10、5组23％）（P〈0．05）。1组-5组脐动脉胎儿血红蛋白值含量有下降的趋势[1组93（91～98）％、2组89（86～91）％、3组88（85～91）％、4组85（83～89）％、5组81（78～84）％]（P〈0．05），二氧化碳分压有逐渐升高的趋势[1组49（46～54）mmHg、2组51（45-56）mmHg、3组53（47-57）mmHg、4组55（50—59）mmHg、5组56（51-59）mmHg（1mmHg=133kPa）]（P〈0．05）。结论CSEA下剖宫产术不同剂量甲氧明和麻黄碱复合输注以维持血压时，随着甲氧明比例增大和麻黄碱比例减小，产妇血流动力学能得到更好的控制。0．375g／L甲氧明：0．5g/L麻黄碱至0．25g／L甲氧明：1g／L麻黄碱效果较好，能产生更为有利于胎儿的效应。

Objective Comparing the effects of combinations of methoxamine and ephedrine in varying proportions on preventing hypotension and maternal fetal to evaluate the curative effects of drug combinations in different proportions during combined spinal and epidural anesthesia （CSEA） for cesarean section. Methods One hundred and fifty parturients undergoing CSEA for elective cesarean delivery were randomly divided into five groups with 30 each parturients to receive intravenous administration of combinations of methoxamine and ephedrine in different proportions, respectively. Assuming that 2 mg methoxamine to be approximately equipotent to 8 mg ephedrine, five combinations drugs were infused in differents proportions which were potency equivalent of 100%, 75%, 50%, 25% or 0 of methoxamine and 0, 25%, 50%, 75% or 100% of ephedrine, respectively. Changes of maternal homodynamic and umbilical arterial blood gas analysis were measured. Infant Apgar score and incidence of maternal nausea and vomiting were also recorded. Results With the decreased proportion of methoxamine and increased ephedrine in these groups,the incidences of hypotension[group 1 （3%）, group 2（10%）, group 3（7%）, group 4 （13%）, group 5（30%）] showed a rising trend （P〈0.05）. The increased of nausea/vomiting of group 2 and 3 was lower than other three groups [（group 1 7%）, group 2 （3%）, group 3 （0%）, group 4 （10%）, group 5 （23%）]（P〈0.05）. The study showed a downtrend of the incidence of umbilical arterial fetal hemoglobin from group 1 to group 5[group 1 93（91-98）%, group 2 89（86-91 ）%,group 3 88（85-91 ）%,group 4 85（83-89）%,group 5 81 （ 78 -84 ） % ] （P〈0.05） and and a uptrend of partial pressure of carbon dioxide [ group 1 49 （46 -54 ） mmHg, group 2 51 （ 45-56 ） mmHg, group 3 53（47-57） mmHg, group 4 55（50-59） mmHg, group 5 56（51-59） mmHg（1 mmHg=0.133 kPa）]（P〈0.05）. Conclusions Combinations of methoxamine and ephedrine infused to maintain arterial blood pressure during CSEA for cesarean delivery in the proportion decreased of ephedrine and the increased proportion of methoxamine exhibits a strengthened control of maternal hemodynamic. The study shows that the range of combinations drugs from 0.375 g/L methoxamine： 0.5 g/L ephedrine to 0.25 g/L methoxamine： 1 g/L ephedrine can produce more beneficial effect on the fetus.