The Quarterly journal of medicine
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Plasma lactate concentrations and acid-base status were determined in 53 patients poisoned with paracetamol. Eleven patients (Group 1) had plasma paracetamol concentrations below the standard treatment decision line; 19 cases (Group 2) presenting within 15 h of overdose had plasma paracetamol concentrations above the treatment line and received N-acetylcysteine. The remaining 23 patients (Group 3) arrived at hospital too late (more than 15 h after overdose) for treatment with N-acetylcysteine to be completely effective. ⋯ As uncompensated metabolic acidosis is found in 20 per cent of patients who present early and require protective therapy, it should be sought and corrected if it does not remit spontaneously. Second, half the patients presenting too late for effective treatment are acidotic and those with an uncompensated metabolic acidosis resistant to correction have a poor prognosis. Paracetamol poisoning should be considered in the differential diagnosis of metabolic acidosis of unknown aetiology.