Prediction and validation of hemodialysis duration in acute methanol poisoning

The duration of hemodialysis (HD) in methanol poisoning (MP) is dependent on the methanol concentration, the operational parameters used during HD, and the presence and severity of metabolic acidosis. However, methanol assays are not easily available, potentially leading to undue extension or premature termination of treatment. Here we provide a prediction model for the duration of high-efficiency HD in MP. In a retrospective cohort study, we identified 71 episodes of MP in 55 individuals who were treated with alcohol dehydrogenase inhibition and HD. Four patients had residual visual abnormality at discharge and only one patient died. In 46 unique episodes of MP with high-efficiency HD the mean methanol elimination half-life (T 1/2 ) during HD was 108min in women, significantly different from the 129min in men. In a training set of 28 patients with MP, using the 90th percentile of gender-specific elimination T 1/2 (147min in men and 141min in women) and a target methanol concentration of 4mmol/l allowed all cases to reach a safe methanol of under 6mmol/l. The prediction model was confirmed in a validation set of 18 patients with MP. High-efficiency HD time in hours can be estimated using 3.390 x(Ln (MCi/4)) for women and 3.534 x (Ln (MCi/4)) for men, where MCi is the initial methanol concentration in mmol/l, provided that metabolic acidosis is corrected.