rnal paCO2 in awake pregnant women. However, there is no evidence that this target, compared to other targets, would enable optimal conditions for the fetus during general anesthesia. Maternal paCO2 can affect uterine blood flow, affinity of hemoglobin for oxygen, and fetal CO2 elimination. In this study, a range of potential targets of maternal paCO2 was investigated in the ovine model, aiming to determine which target is most conducive to physiological fetal blood gas values during laparotomy with general anesthesia. METHODS: Ten time-mated pregnant Swifter ewes with a gestational age of 93 to 104 days were used. During the first phase of the experiment, anesthesia was induced, all ewes were ventilated to target a physiological maternal paCO2 of 30 mm Hg, a maternal laparotomy was performed, and a fetal microcatheter was inserted surgically to enable blood sampling from the fetal aorta. Thereafter, in the second phase of the experiment, the 10 pregnant ewes were randomized to 10 different targets of maternal paCO2 between 27 and 50 mm Hg (1 target for each ewe), and maternal ventilation was adjusted accordingly. Forty-five minutes later, maternal and fetal arterial blood gas samples were analyzed. Linear regression models were used to estimate maternal paCO2 enabling physiologic fetal parameters, including fetal paCO2 (primary outcome). RESULTS: A maternal paCO2 of 27.4 mm Hg (95% confidence interval, 23.1–30.3) enabled physiological fetal paCO2. Each increase in maternal paCO2 by 1 mm Hg, on average, increased fetal paCO2 by 0.94 mm Hg (0.69–1.19). This relationship had a strong correlation (r² = 0.906). No fetuses died during the experiment. CONCLUSIONS: This study provides experimental support for the clinical recommendation to maintain maternal paCO2 close to the physiologic value of 30 mm Hg during general anesthesia for maternal laparotomy in pregnancy as it is conducive to physiological fetal blood gas values. Given the lower bound of the 95% confidence interval, the possibility that a lower maternal paCO2 would improve fetal gas exchange cannot be excluded....

中文翻译：

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绵羊模型妊娠期全身麻醉剖腹手术期间的最佳产妇通气


清醒孕妇的 rnal paCO2。然而，没有证据表明与其他靶点相比，该靶点会在全身麻醉期间为胎儿提供最佳条件。母体 paCO2 可影响子宫血流、血红蛋白对氧的亲和力以及胎儿 CO2 的消除。在这项研究中，在绵羊模型中调查了母体 paCO2 的一系列潜在靶点，旨在确定在全身麻醉下剖腹手术期间哪个靶点最有利于生理胎儿血气值。方法： 使用 10 只胎龄为 93 至 104 天的定时交配怀孕 Swifter 母羊。在实验的第一阶段，诱导麻醉，所有母羊通气以达到 30 mm Hg 的生理母体 paCO2，进行母体剖腹手术，并通过手术插入胎儿微导管，以便从胎儿主动脉进行血液采样。此后，在实验的第二阶段，将 10 只怀孕母羊随机分配到 27 至 50 毫米汞柱之间的 10 个不同目标母体 paCO2（每只母羊 1 个目标），并相应地调整母体通气。45 分钟后，分析母体和胎儿动脉血气样本。线性回归模型用于估计母体 paCO2 启用胎儿生理参数，包括胎儿 paCO2 （主要结局）。结果： 母体 paCO2 为 27.4 mm Hg （95% 置信区间，23.1-30.3） 使生理性胎儿 paCO2 成为可能。平均而言，母体 paCO2 每增加 1 mmHg，胎儿 paCO2 就会增加 0.94 mm Hg （0.69-1.19）。这种关系具有很强的相关性 （r² = 0.906）。实验期间没有胎儿死亡。 结论： 本研究为临床建议妊娠期母体剖腹手术全身麻醉时将母体 paCO2 维持在 30 mm Hg 的生理值附近，因为它有利于胎儿生理血气值。鉴于 95% 置信区间的下限，不能排除较低的母体 paCO2 会改善胎儿气体交换的可能性。