Respiratory and pulmonary haemodynamic changes during experimental organophosphate poisoning in goats

Five French Alpine goats received 2 mg kg-1 of dichlorvos (DDVP) by intravenous injection and 0.15 mg kg-1 of atropine sulphate 5-10 min later. Ventilatory mechanics, gas exchanges, pulmonary haemodynamics and pulmonary vascular resistance (PVR) were measured before treatment, 5 min after DDVP injection and 5 min after atropine injection. Within 2 min of DDVP administration, all the goats showed acute respiratory distress, excitation and slight muscle fasciculations. A post-inspiratory pause was recorded in 3 goats. Hypersecretion of saliva or nasal discharge was not observed. Dynamic compliance and heart rate decreased significantly and total pulmonary resistance, pulmonary artery and wedge pressures increased significantly. On the other hand, minute ventilation, arterial oxygen and carbon dioxide tensions were not significantly altered by DDVP. Atropine treatment reversed all the clinical and functional parameters, with the exception of the central nervous and muscular signs, which disappeared within 12 h. It was concluded that experimental DDVP toxicosis induced changes in the mechanics of breathing and pulmonary haemodynamics associated with diffuse bronchoconstriction and cardiac insufficiency respectively.