Niblett D J, Cannon D, Sykes M K
Nuffield Department of Anaesthetics, Radcliffe Infirmary, Oxford.
Br J Anaesth. 1988 Feb;60(2):198-206. doi: 10.1093/bja/60.2.198.
Right-to-left shunt (Qs/Qt) was measured by the SF6 and oxygen methods in 13 anaesthetized closed-chest dogs intubated with a double-lumen endobronchial tube. Collapse of the left lung increased Qs/Qt from 10% to 23%, suggesting that blood flow to the left lung had been reduced by about 60%. Increasing right lung mean airway pressure by the alteration of the inspiratory:expiratory time ratio or the application of PEEP produced a small but non-significant increase in Qs/Qt with significant increases in arterial and mixed venous carbon dioxide tensions, and arterial to right lung end-tidal carbon dioxide tension difference. Fluid loading during collapse increased cardiac output and pulmonary vascular pressures, but Qs/Qt did not differ significantly from the normovolaemic collapsed state. Increasing the right mean airway pressure in this condition had no effect on Qs/Qt or carbon dioxide tensions.
采用六氟化硫（SF6）和氧法，对13只经双腔支气管内插管麻醉的闭胸犬测量了右向左分流（Qs/Qt）。左肺萎陷使Qs/Qt从10%增加到23%，提示流向左肺的血流减少了约60%。通过改变吸气:呼气时间比或应用呼气末正压（PEEP）增加右肺平均气道压，可使Qs/Qt有小幅度但不显著的增加，同时动脉血和混合静脉血二氧化碳张力以及动脉血与右肺潮气末二氧化碳张力差显著增加。左肺萎陷时输液增加了心输出量和肺血管压力，但Qs/Qt与血容量正常的萎陷状态相比无显著差异。在此情况下增加右肺平均气道压对Qs/Qt或二氧化碳张力无影响。
