Acute pulmonary hypertension, leucopenia and hypoxia in early haemodialysis.

A sheep model is described which produces acute pulmonary hypertension, leucopenia and hypoxia after blood, previously placed in contact with a Cuprophan hollow fibre artificial kidney, re-enters the circulation. Relationships between these manifestations (acute pulmonary hypertension, leucopenia and hypoxia) were examined in normal leucopenic and Indomethacin pre-treated sheep. The degree of pulmonary vascular response, and severity of leucopenia and hypoxia were all directly interrelated and were dependent upon the volume of blood injected. The induction of leucopenia did not affect the pulmonary hypertension or hypoxia. Pre-treating the animals with the cyclo-oxygenase inhibitor, Indomethacin, abolished both the pulmonary hypertension and the hypoxia without any effect on the development of neutropenia. These results suggest that leucocytes do not play a role in the haemodynamic response nor in the hypoxia; activation of the cyclo-oxygenase system is necessary for the development of acute pulmonary hypertension which causes hypoxia subsequent to alterations in ventilation perfusion relationships.