Liang C, Huckabee W E
J Clin Invest. 1973 Dec;52(12):3129-34. doi: 10.1172/JCI107512.
Acute hypoxemia produced by the inhalation of 8% and 5% oxygen increased cardiac output in intact anesthetized dogs by 38% and 62%, respectively. Although practolol, a cardioselective beta-adrenergic blocking agent, reduced the increase in cardiac output in dogs subjected to severe hypoxemia (5% O(2) breathing) from 62% to 43%, it only slightly reduced the cardiac output rise in dogs subjected to moderate hypoxemia (8% O(2) breathing). Splenectomy, on the other hand, abolished the increase in cardiac output produced by moderate hypoxemia except for a small initial rise, but it reduced the increase in cardiac output during severe hypoxemia only to 37%. The entire increase, except for a small initial rise, disappeared only when splenectomized dogs were pretreated with practolol. Sham operation did not affect the cardiac output response to hypoxemia. It is concluded that an intact spleen is required for a significant portion of the increased cardiac output that occurs during both moderate and severe hypoxemia and that catecholamines do not participate in the regulation of cardiac output unless severe hypoxemia occurs.
吸入8%和5%的氧气所导致的急性低氧血症，分别使完整麻醉犬的心输出量增加了38%和62%。虽然心得宁（一种心脏选择性β-肾上腺素能阻滞剂）使严重低氧血症（呼吸5% O₂）犬的心输出量增加幅度从62%降至43%，但仅轻微降低了中度低氧血症（呼吸8% O₂）犬的心输出量升高幅度。另一方面，脾切除术消除了中度低氧血症所引起的心输出量增加，仅保留了最初的小幅升高，但它仅将严重低氧血症期间的心输出量增加幅度降至37%。除了最初的小幅升高外，只有当脾切除犬预先用心得宁处理时，整个增加幅度才消失。假手术不影响心输出量对低氧血症的反应。结论是，完整的脾脏对于中度和重度低氧血症期间发生的心输出量显著增加的很大一部分是必需的，并且除非发生严重低氧血症，儿茶酚胺不参与心输出量的调节。
