Hypoxic pulmonary vasoconstriction and the concept of hyperexis.

Professor Cournand has a special interest in hypoxic pulmonary vasoconstriction, and Professor Richards, his colleague, had a special interest in hyperexis, two seemingly unrelated phenomena in physiology. But at the end of a series of studies on cardiac output, when younger members of the Laboratory were assessing the effect of granulomatous lung disease on the calculation of output by the Fick principle, the pulmonary vessels in the diseased lung showed behaviour consistent with hyperexis, and the individual interests of the two men unexpectedly converged.