Tomimatsu Takuji, Pena Jorge Pereyra, Longo Lawrence D
Center for Perinatal Biology, Department of Physiology and Obstetrics, School of Medicine, Loma Linda University, Loma Linda, California 92350, USA.
Reprod Sci. 2007 Jan;14(1):51-8. doi: 10.1177/1933719106298211.
The authors tested the hypothesis that in the high-altitude acclimatized fetus, hypercapnia has a significantly less effect on cerebral blood flow (CBF) and cerebral oxygenation than that in normoxic sea level controls. In the high-altitude acclimatized fetus (3801 m; maintained from day 30 of gestation to near term; n = 6), by use of a laser Doppler flowmeter with a fluorescent O (2) probe, the authors measured relative CBF (laser Doppler CBF [LD-CBF]), cortical tissue PO(2) (tPO(2)), and sagittal sinus oxyhemoglobin saturation (HbO(2)) in response to 20-minute hypercapnia. They also calculated cerebral O(2)delivery and cerebral fractional O(2) extraction. The authors compared these results to those obtained in near-sea-level control animals (low-altitude group). In response to hypercapnia (arterial PCO(2) = 63+/- 2 torr vs 42+/- 1 torr baseline), high-altitude fetuses showed similar increases in LD-CBF, cortical tPO(2), and sagittal sinus (HbO(2)) as compared with those responses seen in the fetus at low altitude. Nonetheless, these fetuses showed a significantly smaller decrease in cerebral fractional O(2) extraction compared to low-altitude fetuses. In response to hypercapnia in high-altitude, acclimatized, long-term hypoxic fetal sheep, the response of CBF and cerebral oxygenation did not differ significantly from that of low-altitude controls.
在高原适应胎儿中，与常氧海平面对照组相比，高碳酸血症对脑血流量（CBF）和脑氧合的影响显著较小。在高原适应胎儿（海拔3801米；从妊娠第30天维持至接近足月；n = 6）中，作者使用带有荧光O₂探头的激光多普勒血流仪，测量了在20分钟高碳酸血症期间的相对CBF（激光多普勒CBF [LD-CBF]）、皮质组织PO₂（tPO₂）和矢状窦氧合血红蛋白饱和度（HbO₂）。他们还计算了脑O₂输送和脑O₂分数提取。作者将这些结果与在近海平面对照动物（低海拔组）中获得的结果进行了比较。在高碳酸血症（动脉PCO₂ = 63±2托vs基线42±1托）时，与低海拔胎儿的反应相比，高海拔胎儿的LD-CBF、皮质tPO₂和矢状窦（HbO₂）有类似的增加。尽管如此，与低海拔胎儿相比，这些胎儿的脑O₂分数提取的下降明显较小。在高海拔、适应、长期缺氧的胎儿绵羊中，对高碳酸血症的反应，CBF和脑氧合的反应与低海拔对照组没有显著差异。
