Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.
CIBER de Enfermedades Respiratorias, Madrid, Spain.
J Appl Physiol (1985). 2019 Sep 1;127(3):745-752. doi: 10.1152/japplphysiol.00303.2019. Epub 2019 Aug 1.
Obstructive sleep apnea (OSA), characterized by events of hypoxia-reoxygenation, is highly prevalent in pregnancy, negatively affecting the gestation process and particularly the fetus. Whether the consequences of OSA for the fetus and offspring are mainly caused by systemic alterations in the mother or by a direct effect of intermittent hypoxia in the fetus is unknown. In fact, how apnea-induced hypoxemic swings in OSA are transmitted across the placenta remains to be investigated. The aim of this study was to test the hypothesis, based on a theoretical background on the damping effect of oxygen transfer in the placenta, that oxygen partial pressure (Po) swings resulting from obstructive apneas mimicking OSA are mitigated in the fetal circulation. To this end, four anesthetized ewes close to term pregnancy were subjected to obstructive apneas consisting of 25-s airway obstructions. Real-time Po was measured in the maternal carotid artery and in the umbilical vein with fast-response fiber-optic oxygen sensors. The amplitudes of Po swings in the umbilical vein were considerably smaller [3.1 ± 1.0 vs. 21.0 ± 6.1 mmHg (mean ± SE); < 0.05]. Corresponding estimated swings in fetal and maternal oxyhemoglobin saturation tracked Po swings. This study provides novel insights into fetal oxygenation in a model of gestational OSA and highlights the importance of further understanding the impact of sleep-disordered breathing on fetal and offspring development. This study in an airway obstruction sheep model of gestational sleep apnea provides novel data on how swings in oxygen partial pressure (Po) translate from maternal to fetal blood. Real-time simultaneous measurement of Po in maternal artery and in umbilical vein shows that placenta transfer attenuates the magnitude of oxygenation swings. These data prompt further investigation of the extent to which maternal apneas could induce similar direct oxidative stress in fetal and maternal tissues.
阻塞性睡眠呼吸暂停（OSA）以缺氧-再氧合事件为特征，在妊娠中非常普遍，对妊娠过程产生负面影响，特别是对胎儿。OSA 对胎儿和后代的影响主要是由母亲的全身改变引起，还是由胎儿间歇性缺氧的直接影响引起，目前尚不清楚。事实上，OSA 中呼吸暂停引起的低氧血症波动如何穿过胎盘传递仍有待研究。本研究旨在基于胎盘氧传递的阻尼效应的理论背景，检验以下假设：模拟 OSA 的阻塞性呼吸暂停引起的氧分压（Po）波动在胎儿循环中得到缓解。为此，对接近足月妊娠的四只麻醉母羊进行了 25 秒的气道阻塞性呼吸暂停。使用快速响应光纤氧传感器实时测量母颈动脉和脐静脉中的 Po。脐静脉中的 Po 波动幅度明显较小[3.1±1.0 与 21.0±6.1mmHg（平均值±SE）；<0.05]。相应的胎儿和母体血氧饱和度估计波动与 Po 波动相吻合。本研究为妊娠期 OSA 模型中的胎儿氧合提供了新的见解，并强调了进一步了解睡眠呼吸障碍对胎儿和后代发育的影响的重要性。本研究在妊娠期睡眠呼吸暂停的气道阻塞绵羊模型中提供了关于氧分压（Po）波动如何从母体血液传递到胎儿血液的新数据。实时同步测量母动脉和脐静脉中的 Po 表明，胎盘转移可降低氧合波动的幅度。这些数据促使进一步研究母体呼吸暂停在多大程度上可能在胎儿和母体组织中引起类似的直接氧化应激。
