Cardiopulmonary function of dogs with plutonium-induced chronic lung injury

Beagle dogs had signs of restrictive lung disease 1 to 5 years after exposure by inhalation to 239PuO2 aerosols. The 239PuO2 aerosols were monodisperse with activity median aerodynamic diameters of 0.75, 1.5, or 3.0 microns. The plutonium particles produced protracted alpha irradiation of the lungs. Ten dogs had specific initial pulmonary burdens (IPB) of 330 to 4,100 kBq of 239PuO2/kg of body mass. The average onset time of clinical signs of lung injury was 3 years after exposure; the average time from the onset of signs until cardiorespiratory function evaluation was 5.5 years. A second group of 10 dogs had IPB of 110 to 2000 kBq of 239Pu/kg of body mass but no signs of lung injury. A third group of 10 dogs, not exposed to 239Pu, were matched for age and sex. Cardiopulmonary function tests were performed. Only the dogs in group I with signs of lung injury had a mild respiratory function disorder consisting of smaller lung volumes, reduced compliance, increased respiratory frequency and minute volume, and reduced carbon monoxide diffusing capacity. Cardiac function of all three groups was similar. These findings indicate that alpha irradiation of the lungs of man could produce restrictive lung disease at long times after initial exposure.