Paranjothy Shantini, Griffiths James D, Broughton Hannah K, Gyte Gillian M L, Brown Heather C, Thomas Jane
Cochrane Institute of Primary Care and Public Health, School of Medicine, Cardiff University, Cardiff, UK.
Cochrane Database Syst Rev. 2014 Feb 5;2014(2):CD004943. doi: 10.1002/14651858.CD004943.pub4.
Aspiration pneumonitis is a syndrome resulting from the inhalation of gastric contents. The incidence in obstetric anaesthesia has fallen, largely due to improved anaesthetic techniques and the increased use of regional anaesthesia at caesarean section. However, aspiration pneumonitis is still a cause of maternal morbidity and mortality, and it is important to use effective prophylaxis.
To determine whether interventions given prior to caesarean section reduce the risk of aspiration pneumonitis in women with an uncomplicated pregnancy.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2013).
Randomised controlled trials were included. Quasi-randomised trials were excluded.
Review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked. Fixed-effect meta-analysis was used to combine data where it was reasonable to assume that studies were estimating the same underlying treatment effect. If substantial clinical or statistical heterogeneity was detected, we used random-effects analysis to produce an overall summary.
Thirty-two studies were included in this review. However, only 22 studies, involving 2658 women, provided data for analysis. All the women in the included studies had a caesarean section under general anaesthesia. The studies covered a number of comparisons, but were mostly small and of unclear or poor quality.When compared with no treatment or placebo, there was a significant reduction in the risk of intragastric pH < 2.5 with antacids (risk ratio (RR) 0.17, 95% confidence interval (CI) 0.09 to 0.32, two studies, 108 women), H2 antagonists (RR 0.09, 95% CI 0.05 to 0.18, two studies, 170 women) and proton pump antagonists (RR 0.26, 95% CI 0.14 to 0.46, one study 80 women). H2 antagonists were associated with a reduced the risk of intragastric pH < 2.5 at intubation when compared with proton pump antagonists (RR 0.39, 95% CI 0.16 to 0.97, one study, 120 women), but compared with antacids the findings were unclear. The combined use of 'antacids plus H2 antagonists' was associated with a significant reduction in the risk of intragastric pH < 2.5 at intubation when compared with placebo (RR 0.02, 95% CI 0.00 to 0.15, one study, 89 women) or compared with antacids alone (RR 0.12, 95% CI 0.02 to 0.92, one study, 119 women).
AUTHORS' CONCLUSIONS: The quality of the evidence was poor, but the findings suggest that the combination of antacids plus H2 antagonists was more effective than no intervention, and superior to antacids alone in preventing low gastric pH. However, none of the studies assessed potential adverse effects or substantive clinical outcomes. These findings are relevant for all women undergoing caesarean section under general anaesthesia.
误吸性肺炎是一种因吸入胃内容物而导致的综合征。产科麻醉中其发病率已有所下降，这主要归功于麻醉技术的改进以及剖宫产术中区域麻醉使用的增加。然而，误吸性肺炎仍是孕产妇发病和死亡的一个原因，因此采用有效的预防措施很重要。
确定剖宫产术前采取的干预措施是否能降低无并发症妊娠女性发生误吸性肺炎的风险。
我们检索了Cochrane妊娠与分娩组试验注册库（2013年4月30日）。
纳入随机对照试验。排除半随机试验。
综述作者独立评估纳入研究，评估偏倚风险并进行数据提取。检查数据录入情况。当合理假设各研究估计的是相同的潜在治疗效果时，采用固定效应荟萃分析合并数据。如果检测到显著的临床或统计异质性，我们则使用随机效应分析得出总体总结。
本综述纳入了32项研究。然而，只有22项研究（涉及2658名女性）提供了分析数据。纳入研究中的所有女性均在全身麻醉下进行剖宫产。这些研究涵盖了多种比较，但大多规模较小且质量不明或较差。与未治疗或安慰剂相比，使用抗酸剂（风险比（RR）0.17，95%置信区间（CI）0.09至0.32，两项研究，108名女性）、H2拮抗剂（RR 0.09，95%CI 0.05至0.18，两项研究，170名女性）和质子泵拮抗剂（RR 0.26，95%CI 0.14至0.46，一项研究，80名女性）可使胃内pH值<2.5的风险显著降低。与质子泵拮抗剂相比，H2拮抗剂在插管时可降低胃内pH值<2.5的风险（RR 0.39，95%CI 0.16至0.97，一项研究，120名女性），但与抗酸剂相比，结果尚不清楚。与安慰剂（RR 0.02，95%CI 0.00至0.15，一项研究，89名女性）或单独使用抗酸剂相比（RR 0.12，95%CI 0.02至0.92，一项研究，119名女性），“抗酸剂加H2拮抗剂”联合使用在插管时可使胃内pH值<2.5的风险显著降低。
证据质量较差，但研究结果表明，抗酸剂加H2拮抗剂联合使用比不干预更有效，且在预防低胃pH值方面优于单独使用抗酸剂。然而，没有一项研究评估潜在的不良反应或实质性临床结局。这些研究结果适用于所有在全身麻醉下进行剖宫产的女性。
