Alveolar-arterial partial pressure difference as an early predictor for patients with acute paraquat poisoning

Paraquat (PQ) is associated with high mortality rates in acute poisoning. This study aimed to determine the importance of the alveolar-arterial partial pressure difference (A-aDo₂) in the expected consequences of acute PQ poisoning.

Patients who were hospitalized for PQ poisoning in 2018 were enrolled in this retrospective study. A-aDo₂ data were collected. Multivariate analysis was performed using binary logistic regression to determine whether A-aDo₂ is an independent risk factor for mortality from PQ.

A total of 352 cases were analyzed. The mean PQ dose was 36.84 ± 50.30 mL (0.3-500 mL). There were 185 survivors and 167 non-survivors. The mean A-aDo₂ was not significantly correlated between survivors and non-survivors on day 1. However, there were significant differences in A-aDo₂ between survivors and non-survivors on days 3, 7, 14, and 21. Increased A-aDo₂ values were correlated with an increased mortality rate. The mean A-aDo₂ on day 14 showed the most significant difference between survivors and non-survivors.

Our study suggests that A-aDo₂ plays an important role as a reference index, which could be a useful predictor in assessing acute PQ poisoning, especially on the 14th day after onset of poisoning.