Risk factors related to poor outcome after methanol poisoning and the relation between outcome and antidotes - a multicenter study

Introduction. Thorough prognostic and metabolic studies of methanol poisonings are scarce. Our aims were to evaluate the factors associated with sequelae and death from methanol poisoning, to develop a simple risk-assessment chart to evaluate factors associated with sequelae and death from methanol poisoning, and to compare the antidotes ethanol and fomepizole. Patients and methods. We present a retrospective observational case series of methanol-poisoned patients from Norway (1979 and 2002-2005), Estonia (2001) and Tunisia (2003/2004), and patients from two different centers in Iran (Teheran 2004-2009 and Mashhad 2009-2010) who were identified by a positive serum methanol and had a blood acid-base status drawn on admission. The patients were divided into different groups according to their outcome: Survived, survived with sequelae, and died. Results. A total of 320 patients were identified and 117 were excluded. Of the remaining 203 patients, 48 died, and 34 were discharged with neurological sequelae. A pH < 7.00 was found to be the strongest risk factor for poor outcome, along with coma (Glasgow Coma Scale (GCS) < 8) and a pCO(2) > 3.1 kPa in spite of a pH < 7.00. More patients died despite hyperventilation (low pCO(2)) in the ethanol group. Conclusions. Low pH (pH < 7.00), coma (GCS < 8), and inadequate hyperventilation (pCO(2) >= 3.1 kPa in spite of a pH < 7.00) on admission were the strongest predictors of poor outcome after methanol poisoning. A simple flow-chart may help identify the patients associated with a poor outcome.