Mecikalski M B, Cutillo A G, Renzetti A D
Bull Eur Physiopathol Respir. 1984 Nov-Dec;20(6):513-9.
Right-to-left shunting decreases the efficiency of carbon dioxide excretion and increases the alveolar dead space (physiological dead space minus anatomical dead space). The theoretical effects of shunting on alveolar dead space were studied, using a human blood nomogram, for different values of inspired oxygen fraction (FIO2), respiratory quotient (R), and arterial-venous oxygen content difference. An equation developed to define the relationship between alveolar dead space and shunt could be closely fitted to the nomogram data. With high levels of shunt, FIO2 and R, alveolar dead space can substantially increase above normal levels. The conditions needed for this increase are unusual but lie within the range observed in critically ill patients. A rise in dead space of this magnitude can be clinically important in the absence of effective compensatory mechanisms.
右向左分流会降低二氧化碳排出的效率，并增加肺泡死腔（生理死腔减去解剖死腔）。利用人体血液列线图，针对不同的吸入氧分数（FIO2）、呼吸商（R）和动静脉氧含量差的值，研究了分流对肺泡死腔的理论影响。所建立的用于定义肺泡死腔与分流之间关系的方程能够很好地拟合列线图数据。在高分流水平、FIO2和R的情况下，肺泡死腔可大幅增加至高于正常水平。这种增加所需的条件并不常见，但处于危重症患者所观察到的范围内。在缺乏有效代偿机制的情况下，如此大幅度的死腔增加在临床上可能具有重要意义。
