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

Abstract

Context: Acidemia is a marker of prognosis in methanol poisoning, as well as compounding formateinduced cytotoxicity. Prompt correction of acidemia is a key treatment of methanol toxicity and methods to optimize this are poorly defined. Objective: We studied the efficiency of acidemia correction by intermittent hemodialysis (IHD) and continuous renal replacement therapy (CRRT) in a mass outbreak of methanol poisoning. Methods: The study was designed as observational cohort study. The mean time for an increase of 1 mmol/L HCO 3 -, 0.01 unit arterial blood pH, and the total time for correction of HCO 3 -were determined in IHD-and CRRT-treated patients. Results: 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 ¼ 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 HCO 3 -correction correlated with arterial blood pH (r¼ À0.511; p ¼ 0.003) and creatinine (r ¼ 0.415; p ¼ 0.020). There was association between the time to HCO 3 -correction and dialysate/effluent and blood flow rates (r¼ À0.738; p < 0.001 and r¼ À0.602; p < 0.001, correspondingly). The mean time for HCO 3 -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 ¼ 0.024). The mean increase in HCO 3 -was 5.67 ± 0.90 mmol/L/h for IHD versus 2.17 ± 0.74 mmol/L/h for CRRT (p < 0.001). Conclusions: Our study supports the superiority of IHD over CRRT in terms of the rate of acidemia correction. ARTICLE HISTORY

Severe methanol poisoning with neurological sequelae: implications for diagnosis and management

“…As both fomepizole and ethanol are dialysable, the rate of antidote administration must be increased during ECTR to avoid subtherapeutic concentrations . Hence, IHD is more effective than CRRT at enhancing elimination of methanol and formic acid and for acidaemia correction, and is the consensus guideline recommended modality of choice for severe methanol poisoning . This is relevant because CRRT is the modality routinely preferred in most Australian and New Zealand ICU; however, IHD is typically also available.…”

“…9 Hence, IHD is more effective than CRRT at enhancing elimination of methanol and formic acid and for acidaemia correction, and is the consensus guideline recommended modality of choice for severe methanol poisoning. 9,20,21 This is relevant because CRRT is the modality routinely preferred in most Australian and New Zealand ICU; however, IHD is typically also available. A duration of 8 h of ECTR has been empirically suggested.…”

Leukotriene-mediated neuroinflammation, toxic brain damage, and neurodegeneration in acute methanol poisoning

“…Formic acid, the main toxic metabolite of methanol, induces cellular toxicity through inhibition of cytochrome c oxidase, which impairs oxygen utilization, causing a shift from aerobic to anaerobic metabolism [14,15]. If ADH is blocked by antidote (ethanol or fomepizole), formic acid is effectively eliminated by hemodialysis with a half-life of 1.6-3.6 h and acidemia is corrected during the first hours after hospital treatment initiation [33,34]. In addition to its primary cytotoxic effect, formic acid induces secondary effects including ischemia, edema, BBB disruption, hemorrhages, reactive oxidative damage, axonal demyelination, neuronal degeneration, and cell death.…”

“…Finally, the patients treated with IHD had higher concentration of cys-LTs than those treated with CRRT. This fact can be explained by more rapid elimination of formic acid and correction of acidemia in patients treated with IHD [33,34].…”

“…Intermittent hemodialysis (IHD) or continuous veno-venous hemodialysis/hemodiafiltration (CRRT) was performed to eliminate formic acid and methanol and to correct academia [33,34]. Folates were administered to substitute the internal pool (folinic or folic acid) [35].…”