Nelin L D, Wearden M E, Welty S E, Hansen T N
Department of Pediatrics, Baylor College of Medicine, Houston, Texas.
Respir Physiol. 1992 Jun;88(3):333-42. doi: 10.1016/0034-5687(92)90007-j.
Previous studies suggest that pulmonary capillary distensibility and recruitment may differ in lambs and sheep. To study the effect of pulmonary blood flow (PBF) and vascular pressure on capillary hemodynamics in lambs and sheep we measured the diffusing capacity for carbon monoxide (DLCO) as an index of pulmonary capillary blood volume during a baseline period, after increasing PBF, and during left atrial hypertension. In the lamb, DLCO did not change significantly either with a 65% increase in PBF or with an increase in left atrial pressure (Pla) of 1.33 kPa at constant PBF. In the sheep on the other hand, doubling PBF led to a 28% increase in DLCO (P less than 0.02), and an increase in Pla of 1.87 kPa at constant PBF led to a 19% increase in DLCO (P less than 0.01). These results suggest that the neonatal lamb has a nearly fully recruited and relatively non-compliant pulmonary capillary bed at rest, unlike the adult sheep which can respond to hemodynamic changes with distension and recruitment of the pulmonary capillary bed.
先前的研究表明，羔羊和成年羊的肺毛细血管扩张性和募集情况可能有所不同。为了研究肺血流量（PBF）和血管压力对羔羊和成年羊毛细血管血流动力学的影响，我们在基线期、增加PBF后以及左心房高压期间测量了一氧化碳弥散能力（DLCO），以此作为肺毛细血管血容量的指标。在羔羊中，当PBF增加65%或在恒定PBF下左心房压力（Pla）增加1.33 kPa时，DLCO均无显著变化。另一方面，在成年羊中，PBF翻倍导致DLCO增加28%（P<0.02），在恒定PBF下Pla增加1.87 kPa导致DLCO增加19%（P<0.01）。这些结果表明，新生羔羊在静息时肺毛细血管床几乎已完全募集且顺应性相对较低，这与成年羊不同，成年羊可通过肺毛细血管床的扩张和募集来应对血流动力学变化。
