Ventilation Ratio

The ventilation/perfusion ratio is a simple, but powerful, determinant of the primary source of dyspnea, whether it be heart or lung. If the ratio is less than 0.6, the limitation is predominantly lung. If greater than 0.6, is it heart or circulatory. Although simple, this test is based on the physiology of carbon dioxide transport and transfer, and is highly sensitive and specific. Shape-HF computes this ratio automatically.




Ventilation ratio helps

define predominant limitation—

heart or lung—and is

based on the physiology of

CO2 transport and transfer.

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