Lovering Andrew T, Elliott Jonathan E, Davis James T
University of Oregon, Department of Human Physiology, Eugene, Oregon;
Oregon Health & Science University, Department of Neurology and VA Portland Health Care System, Portland, Oregon; and.
J Appl Physiol (1985). 2016 Aug 1;121(2):512-7. doi: 10.1152/japplphysiol.00192.2015. Epub 2016 Jul 14.
The foramen ovale, which is part of the normal fetal cardiopulmonary circulation, fails to close after birth in ∼35% of the population and represents a potential source of right-to-left shunt. Despite the prevalence of patent foramen ovale (PFO) in the general population, cardiopulmonary, exercise, thermoregulatory, and altitude physiologists may have underestimated the potential effect of this shunted blood flow on normal physiological processes in otherwise healthy humans. Because this shunted blood bypasses the respiratory system, it would not participate in either gas exchange or respiratory system cooling and may have impacts on other physiological processes that remain undetermined. The consequences of this shunted blood flow in PFO-positive (PFO+) subjects can potentially have a significant, and negative, impact on the alveolar-to-arterial oxygen difference (AaDO2), ventilatory acclimatization to high altitude and respiratory system cooling with PFO+ subjects having a wider AaDO2 at rest, during exercise after acclimatization, blunted ventilatory acclimatization, and a higher core body temperature (∼0.4(°)C) at rest and during exercise. There is also an association of PFO with high-altitude pulmonary edema and acute mountain sickness. These effects on physiological processes are likely dependent on both the presence and size of the PFO, with small PFOs not likely to have significant/measureable effects. The PFO can be an important determinant of normal physiological processes and should be considered a potential confounder to the interpretation of former and future data, particularly in small data sets where a significant number of PFO+ subjects could be present and significantly impact the measured outcomes.
卵圆孔是正常胎儿心肺循环的一部分，在出生后约35%的人群中未能闭合，是潜在的右向左分流来源。尽管普通人群中卵圆孔未闭（PFO）很常见，但心肺、运动、体温调节和高原生理学家可能低估了这种分流血液对健康人群正常生理过程的潜在影响。由于这种分流血液绕过呼吸系统，它既不参与气体交换也不参与呼吸系统散热，可能会对其他尚未确定的生理过程产生影响。PFO阳性（PFO+）受试者中这种分流血液的后果可能对肺泡-动脉氧分压差（AaDO2）、对高原的通气适应以及呼吸系统散热产生重大负面影响，PFO+受试者在静息时、适应后运动期间的AaDO2更大，通气适应减弱，静息和运动时的核心体温更高（约0.4℃）。PFO还与高原肺水肿和急性高山病有关。这些对生理过程的影响可能取决于PFO的存在和大小，小的PFO不太可能产生显著/可测量的影响。PFO可能是正常生理过程的重要决定因素，应被视为解释既往和未来数据的潜在混杂因素，尤其是在可能存在大量PFO+受试者并显著影响测量结果的小数据集中。
