Acute paraquat intoxication - Using nuclear pulmonary studies to predict patient outcome

Study objectives: Paraquat, a widely used herbicide, has been shown to caus e severe and often fatal pulmonary fibrosis in humans and laboratory animal s, Although pal aquat is known to be directly cytotoxic to lung parenchyma, changes in routine lung scintigraphy results after acute paraquat intoxica tion have not been reported, The objective of this project was to investiga te changes in lung ventilation (LV) and alveolar permeability (AP) in patie nts with paraquat intoxication, using Tc-99m diethylenetriamine pentaacetat e (DTPA) radioaerosol lung scintigraphy. Design: Prospective, blinded study. Setting: Nuclear medicine and toxicology departments in two university-affi liated teaching hospitals. Patients or participants: Thirteen patients with acute paraquat intoxicatio n were included in this study, Ten volunteers without acute paraquat intoxi cation were studied for comparison. Measurements and results: Tc-99m DTPA aerosol inhalation and Tc-99m macroag gregated albumin (MAA) perfusion lung scintigraphies were performed to dete rmine LV, AP, and lung perfusion (LP), Five of the 13 patients (38%) had si gnificant LV abnormalities; 3 of these 5 patients also showed abnormal LP. Of the 13 patients, 4 patients (31%) showed normal AP and survived, The rem aining 9 patients (69%) showed abnormal AP and died, The mean values for AP were statistically different (p < 0.01) between survivor (0.72 +/- 0.16%) and nonsurvivor (1.52 +/- 0.40%) groups. Data from the normal volunteers an d survival patients showed a Tc-99m clearance slope < 1.00%. Data from pati ents who died showed a clearance slope > 1.00%. Conclusion: These results indicate that AP, measured by Tc-99m DTPA aerosol inhalation lung scintigraphy, may help predict outcome in patients with pa raquat intoxication.