ACETAMINOPHEN AND SALICYLATE SERUM LEVELS IN PATIENTS WITH SUICIDAL INGESTION OR ALTERED MENTAL STATUS

Is universal screening of acetaminophen (APAP) and salicylate (SAL) ne cessary in patients with a suicidal ingestion or an altered mental sta tus and suspected ingestion? This descriptive, retrospective chart rev iew in an emergency department in a large urban county hospital examin ed all patients who presented with a history of suicidal ingestion or an altered mental status with a strong suspicion of ingestion from Jan uary 1992 through October 1993, APAP and SAL serum levels were measure d in 1,820 patients, and charts of patients with APAP serum levels of >1 mu g/mL or SAL serum levels of >1 mg/dL were reviewed, The patient' s history of ingesting APAP or SAL was recorded, as well as the clinic ian's interpretation of that level. Sixteen charts were not available, APAP levels of >1 mu g/mL were found in 175 (9.6%) patients, 120 (6.5 %) of whom were APAP history-positive and 55 (3%) APAP history-negativ e. None of the APAP history negative group required therapy with N-ace tylcysteine. Eight (0.3%) of the APAP history-negative group had poten tially toxic levels of >50 mu g/mL. SAL levels of >1 mg/dL were found in 155 (8.5%) patients, 44 (2.5%) of whom were SAL history positive an d 111 (6%) SAL history-negative. Three patients were SAL history-negat ive but had a significant chronic SAL intoxication, All these patients presented with an altered mental status and had an anion gap of >20 m Eq/L. Universal screening found that 0.3% of suicidal ingestions had a potentially toxic APAP intoxication not suggested by history, This in cidence of infrequent but potentially life:threatening overdose should prompt clinicians to screen all of their patients with a suspected in gestion, Salicylate screening found that 0.16% of suicidal ingestions had a toxic SAL intoxication not suggested by history, although such i ntoxication should be suggested by an elevated anion gap and an altere d mental status, Since this less severe intoxication is less frequent and usually suggested by commonly obtained laboratory data, universal screening is not indicated, but a more selective approach to screening could be taken. Copyright (C) 1996 by W.B. Saunders Company