Detection of bronchial blood flow from earpiece dye-dilution curve.

In an attempt to detect an increased bronchial blood flow in man from the earpiece dye-dilution curve, the reliability of three indexes was investigated by comparing them with the values of bronchial blood flow measured from the left atrial dye-dilution curve following dye injection into the aortic root. The first index is obtained from the Cp method, in which the ratio of the peak concentration of early appearing dye-curve due to bronchial circulation to that of the dye-curve of the first circulation. The second is time index for appearance time of the early dye-curve, and the third is CL/Cr as a representation of elevation of the least dye concentration. Cp method showed a good agreement with the bronchial blood flow irrespective of dye injection sites. The last two indexes were both correlated to the bronchial blood flow at a borderline level of significance. It was noteworthy that there was a sharp separation in the second index without any overlapping between cases with and without increased bronchial blood flow. These suggest usefulness of these indexes for clinical assessment of augmented bronchial circulation.