Efficiency of acidemia correction on intermittent versus continuous hemodialysis in acute methanol poisoning

Acidemia is a marker of prognosis in methanol poisoning, as well as compounding formate-induced cytotoxicity. Prompt correction of acidemia is a key treatment of methanol toxicity and methods to optimize this are poorly defined.

We studied the efficiency of acidemia correction by intermittent hemodialysis (IHD) and continuous renal replacement therapy (CRRT) in a mass outbreak of methanol poisoning.

The study was designed as observational cohort study. The mean time for an increase of 1 mmol/L HCO₃^-, 0.01 unit arterial blood pH, and the total time for correction of HCO₃^- were determined in IHD- and CRRT-treated patients.

Data were obtained from 18 patients treated with IHD and 13 patients treated with CRRT. At baseline, CRRT group was more acidemic than IHD group (mean arterial pH 6.79 ± 0.10 versus 7.05 ± 0.10; p = 0.001). No association was found between the rate of acidemia correction and age, weight, serum methanol, lactate, formate, and glucose on admission. The time to HCO₃^- correction correlated with arterial blood pH (r= -0.511; p = 0.003) and creatinine (r = 0.415; p = 0.020). There was association between the time to HCO₃^- correction and dialysate/effluent and blood flow rates (r= -0.738; p < 0.001 and r= -0.602; p < 0.001, correspondingly). The mean time for HCO₃^- to increase by 1 mmol/L was 12 ± 2 min for IHD versus 34 ± 8 min for CRRT (p < 0.001), and the mean time for arterial blood pH to increase 0.01 was 7 ± 1 mins for IHD versus 11 ± 4 min for CRRT (p = 0.024). The mean increase in HCO₃^- was 5.67 ± 0.90 mmol/L/h for IHD versus 2.17 ± 0.74 mmol/L/h for CRRT (p < 0.001).

Our study supports the superiority of IHD over CRRT in terms of the rate of acidemia correction.