The aim of this study is to evaluate the prognostic value of initial arterial lactate level and 12-hour lactate metabolic clearance rate (MCR) in patients with acute paraquat poisoning.

A total of 204 patients with acute paraquat poisoning were admitted to the Emergency Intensive Care Unit at The First Affiliated Hospital of China Medical University from January 2009 to December 2011.

The overall mortality rate was 72.5% (148/204) during a 28-day follow-up period; only 56 of 204 patients with acute paraquat poisoning survived. The initial arterial lactate level was higher in nonsurvivors than in survivors (P = .026). The 12-hour lactate MCR was lower in nonsurvivors than in survivors (P = .040). The initial arterial lactate level (P = .004) and 12-hour lactate MCR (P < .001) were associated with increased risk in 28-day mortality. In the receiver operating characteristic curve analysis, the initial arterial lactate level had an area of 0.749 (95% confidence interval, 0.714-0.856) and a cutoff concentration at 2.5 mmol/L (sensitivity = 84.6%, specificity = 79.2%, Youden index = 0.64). The 12-hour lactate MCR had an area of 0.871 (95% confidence interval, 0.807-0.935), and the cutoff was at 13.5% (sensitivity = 87.1%, specificity = 84.3%, Youden index = 0.71).

The initial arterial lactate level and 12-hour lactate MCR had good predictive powers in evaluating the prognosis of patients with acute paraquat poisoning, which may prove to be simpler and more practical tools in assessing the severity of paraquat poisoning.