Nowicki P T, Hansen N B, Hayes J R, Menke J A, Miller R R
Am J Physiol. 1986 Jul;251(1 Pt 1):G19-24. doi: 10.1152/ajpgi.1986.251.1.G19.
Previous work has indicated that the neonatal intestinal circulation responds to hypoxemia with vasoconstriction and subsequent intestinal ischemia. This work was carried out in newborn lambs, a ruminant species, and may not be representative of all newborns. Therefore, we measured intestinal blood flow, vascular resistance, tissue O2 uptake, and cardiac output during normoxemia and varying degrees of hypoxemia in newborn piglets, a nonruminant species. Hypoxemia was induced by adding N2 gas to the inspired gas mixture, and measurements were obtained over a wide range of arterial O2 contents (2.2-15.6 ml O2 X dl-1). Intestinal blood flow increased in response to moderate hypoxemia and decreased in response to severe hypoxemia. The changes in intestinal blood flow were primarily due to change in intestinal vascular resistance, not cardiac output. Intestinal O2 was independent of arterial O2 content until the latter decreased below approximately 6.5 ml O2 X dl-1. These data indicate that the response of the neonatal intestinal circulation to hypoxemia is species specific and that the nonruminant neonatal intestine is capable of vasodilation in response to moderate hypoxemia.
先前的研究表明，新生儿肠道循环对低氧血症的反应是血管收缩及随后的肠道缺血。这项研究是在新生羔羊（一种反刍动物）身上进行的，可能并不代表所有新生儿。因此，我们在新生仔猪（一种非反刍动物）身上测量了常氧血症和不同程度低氧血症期间的肠道血流量、血管阻力、组织氧摄取和心输出量。通过向吸入气体混合物中添加氮气来诱导低氧血症，并在广泛的动脉氧含量范围（2.2 - 15.6 ml O2×dl-1）内进行测量。肠道血流量在中度低氧血症时增加，在重度低氧血症时减少。肠道血流量的变化主要是由于肠道血管阻力的变化，而非心输出量的变化。在动脉氧含量降至约6.5 ml O2×dl-1以下之前，肠道氧摄取与动脉氧含量无关。这些数据表明，新生儿肠道循环对低氧血症的反应具有物种特异性，并且非反刍动物新生儿肠道能够对中度低氧血症做出血管舒张反应。
