Ventilation-perfusion relationships with high cardiac output in lobar atelectasis.
Ventilation-perfusion relationships with high cardiac output in lobar atelectasis.
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肺叶不张中通气-灌注与高心输出量的关系。
DOI：
10.1152/jappl.1981.50.2.341
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Powers,SR
中科院分区：
文献类型：
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作者：
Schumacker,PT;Newell,JC;Saba,TM;Powers,SR
在10只麻醉机械通气的狗中评价肺气体交换。通过开放外周动静脉内瘘，心输出量（QT）增加约50%。随着双肺通气，增加QT增加混合静脉O2的压力（PO 2）和肺动脉压，但无论是分流分数，也没有通气-灌注的分布始终改变。在左肺不张期间，增加QT再次增加混合静脉PO 2和肺动脉压，但在分流样灌注中测量到两种不同的反应。在4只犬中，左肺肺不张导致46 +/- 6%的分流分数，高QT未改变（P> 0.05）。在6只犬中，肺不张导致正常QT间期的分流分数为24 +/- 3%，在高QT间期增加至42 +/- 2%（P <0.001）。肺不张期间分流分数高且QT未改变的犬的动脉pH值（7.24 +/- 0.03）低于分流分数最初较低且随QT增加的犬（7.36 +/- 0.02）（P <0.01）。我们的结论是，增加QT可以恶化分流在肺叶肺不张时，缺氧性血管收缩已有效地限制灌注的塌陷区在正常水平的QT。
Pulmonary gas exchange was evaluated in 10 anesthetized mechanically ventilated dogs. Cardiac output (QT) was increased approximately 50% by opening peripheral arteriovenous fistulas. With both lungs ventilated, increasing QT increased mixed venous O2 both pressure (PO2) and pulmonary arterial pressure, but neither shunt fraction nor the distribution of ventilation-perfusion was consistently altered. During left lung atelectasis, increasing QT again increased mixed venous PO2 and pulmonary arterial pressure, but two different responses in shunt-like perfusion were measured. In four dogs, left lung atelectasis caused a shunt fraction of 46 +/- 6% that was not changed by high QT (P greater than 0.05). In six dogs, atelectasis caused a shunt fraction of 24 +/- 3% during normal QT that increased to 42 +/- 2% during high QT (P less than 0.001). Dogs whose shunt fraction during atelectasis was high and unchanged by QT had lower arterial pH (7.24 +/- 0.03) than dogs whose shunt fraction was initially lower and was increased with QT (7.36 +/- 0.02) (P less than 0.01). We conclude that increased QT can worsen shunt flow during lobar atelectasis when hypoxic vasoconstriction has been effective in limiting perfusion to the collapsed region at normal levels of QT.