Benoit A, Ducas J, Girling L, Schick U, Prewitt R M
Anesthesiology. 1985 Jun;62(6):754-8. doi: 10.1097/00000542-198506000-00009.
In a canine model of acute respiratory failure, the authors investigated acute cardiopulmonary effects of nitroglycerin (TNG) and compared the results with those obtained after phlebotomy. Oleic acid increased intrapulmonary shunt (Qs/Qt) from 7.4 to 31% (P less than 0.001) and decreased (P less than 0.01) cardiac output (CO). In the presence of assumed low-pressure pulmonary edema, TNG was infused to decrease mean blood pressure (BP) by 40%; this was associated with a 26% decrease (P less than 0.05) in CO. Qs/Qt increased from 31 to 42% (P less than 0.01). There was a slight increase (P less than 0.01) in pulmonary vascular resistance (PVR) with TNG, and mean pulmonary artery pressure (PAP) decreased (P less than 0.05). In contrast, when CO was decreased by a similar amount with phlebotomy, mean Qs/Qt did not significantly change. There were similar changes in PVR and PAP and mixed venous O2 tension with TNG and phlebotomy. Accordingly, current results rule out increased flow, increased PVO2, and mechanical alterations in pulmonary vascular pressures as contributory to the increase in Qs/Qt with TNG. Alternatively, the increase in Qs/Qt with TNG may be explained by a direct pharmacologic decrease in pulmonary hypoxic vasoconstriction and/or by nonspecific pharmacologic effects.
在急性呼吸衰竭的犬模型中，作者研究了硝酸甘油（TNG）的急性心肺效应，并将结果与放血后的结果进行了比较。油酸使肺内分流（Qs/Qt）从7.4%增加到31%（P<0.001），并使心输出量（CO）降低（P<0.01）。在假定存在低压性肺水肿的情况下，输注TNG使平均血压（BP）降低40%；这与CO降低26%（P<0.05）相关。Qs/Qt从31%增加到42%（P<0.01）。TNG使肺血管阻力（PVR）略有增加（P<0.01），平均肺动脉压（PAP）降低（P<0.05）。相比之下，当放血使CO以相似幅度降低时，平均Qs/Qt没有显著变化。TNG和放血时，PVR、PAP以及混合静脉血氧张力有相似的变化。因此，目前的结果排除了流量增加、PVO2增加以及肺血管压力的机械改变是TNG导致Qs/Qt增加的原因。另外，TNG导致Qs/Qt增加可能是由于肺缺氧性血管收缩的直接药理学降低和/或非特异性药理学效应。
