Lin C J, Huang C L, Hsu H W, Chen T L
Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan, R.O.C.
Acta Anaesthesiol Sin. 1996 Dec;34(4):179-84.
Acid aspiration syndrome is still an important cause which contributes to maternal mortality in obstetric anesthesia. In this study, we compared famotidine, ranitidine, omeprazole with placebo for prophylaxis against aspiration pneumonitis in elective Cesarean section under regional anesthesia.
One hundred and sixty patients undergoing elective Cesarean section under spinal anesthesia were allocated randomly into four groups: Group P (n = 40) received placebo only; Group F (n = 40) received famotidine 40 mg Group R (n = 40) received ranitidine 300 mg; and Group O (n = 40) received omeprazole 40 mg. All drugs were given orally at least three hours before the patients entering the operating room. Gastric content was directly aspirated and measured respectively with a flexible fiberoscope under visualization and by a pH meter after delivery.
Although these three drugs (F, R, and O) were all effective in controlling the secretion of gastric acid, from gastric analysis it was demonstrated that famotidine and ranitidine could be more defective to neutralize acidity than omeprazole (p < 0.05). Percentages of patients with pH < or = 2.5 in Groups P, F, R, and O were respectively 88%, 10%, 8%, and 21%, showing that the innate pH of gastric juice was far lower than expected. Patients receiving omeprazole in single oral dose regimen retained a greater gastric volume (> or = 0.4 ml/kg) than those who received famotidine or ranitidine (p < 0.005). From the criteria defining the patients "at risk" (pH < or = 2.5 and gastric volume > or = 0.4 ml/kg), it is speculated that all these three regimens could potentially reduce the incidence of patients with calculated risk.
Our data demonstrated that parturients under regional anesthesia were at a higher risk of aspiration pneumonitis than generally thought. Single dose of ranitidine or famotidine administered orally three hours before surgery provided a more effective means to control and neutralize gastric secretion than omeprazole in parturients.
误吸综合征仍是产科麻醉中导致孕产妇死亡的重要原因。在本研究中，我们比较了法莫替丁、雷尼替丁、奥美拉唑与安慰剂在区域麻醉下择期剖宫产术中预防误吸性肺炎的效果。
160例行脊髓麻醉下择期剖宫产的患者被随机分为四组：P组（n = 40）仅接受安慰剂；F组（n = 40）接受40 mg法莫替丁；R组（n = 40）接受300 mg雷尼替丁；O组（n = 40）接受40 mg奥美拉唑。所有药物均在患者进入手术室前至少3小时口服。分娩后，通过可视的柔性纤维镜直接抽吸胃内容物并测量，并用pH计测量。
虽然这三种药物（F、R和O）均能有效控制胃酸分泌，但胃分析表明，法莫替丁和雷尼替丁中和酸度的效果不如奥美拉唑（p < 0.05）。P组、F组、R组和O组中pH≤2.5的患者百分比分别为88%、10%、8%和21%，表明胃液的固有pH值远低于预期。单剂量口服奥美拉唑的患者胃容量（≥0.4 ml/kg）大于接受法莫替丁或雷尼替丁的患者（p < 0.005）。根据定义“有风险”患者的标准（pH≤2.5且胃容量≥0.4 ml/kg）推测，这三种方案都有可能降低计算出的有风险患者的发生率。
我们的数据表明，区域麻醉下的产妇发生误吸性肺炎的风险高于一般认为的风险。术前3小时口服单剂量雷尼替丁或法莫替丁比奥美拉唑能更有效地控制和中和产妇的胃分泌。
