PHENTOLAMINE-INDUCED PROTECTION FROM NEUROGENIC PULMONARY-EDEMA

Haemorrhagic pulmonary oedema may develop from mechanical head injury or increased intracranial pressure. This neurogenic pulmonary oedema h as been attributed to a neurohaemodynamic or Gushing response or to a more direct increase in pulmonary capillary permeability from neural o r circulating factors. The purpose of the present study was to determi ne whether pulmonary vascular permeability changes resulting from a pu lse of high intracranial pressure, demonstrated subsequently in an exc ised perfused rabbit lung preparation, could be prevented or ameliorat ed by infusion of the alpha sympathetic blocking agent phentolamine. T he capillary filtration coefficient, measured in excised lungs from no rmal controls rabbits, increased from 0.30+/-0.04 to 0.60+/-0.10 mL mi n(-1) mmHg(-1) 100 g(-1) in rabbits exposed to high intracranial press ure. The administration of phentolamine prevented the increase in the capillary filtration coefficient, resulting in a capillary filtration coefficient of 0.20+/-0.04. The results from the present study suggest that the mechanism of inducing oedema involved alpha sympathetic rece ptors.