the frequency of the causes of acid base disturbances in patients hospitalized in the toxicology ward of baharloo hospital in 2009

background: the aim of this study was to evaluate the efficacy of arterial blood gases (abgs) in determining the type of intoxication. methods: medical charts of all patients who had referred to the toxicology ward of baharloo hospital between january 2009 and december 2009 were evaluated. after excluding the patients with multi-drug toxicity, data, including age, sex, type of intoxication (the medication ingested), abg options, including ph, pco2, hco3, and the type of acid-base disturbance were collected and recorded in a self-made questionnaire. data were analyzed using spss version 11. results: of the 1570 cases evaluated, 807(51.4%) were male and 763(48.6%) were female. most of the patients were 20 to 29 years old (554 patients 35.3%). arterial blood gases were normal in 578 (36.8%) patients. metabolic acidosis, respiratory acidosis, respiratory alkalosis, mixed acidosis, and mixed alkalosis were detected in 434(27.6%), 292(18.6%), 177(11.3%), 60 (3.8%), and 29(1.8%) patients, respectively. pure metabolic alkalosis was not detected in any of the patients. the toxins were classified into 18 groups with opium/opioids, acetaminophen/nsaids, and antidepressants and anticonvulsants being the most common toxicities. conclusion: although metabolic acidosis may not be helpful in diagnosis of the type of intoxication, respiratory and mixed acidosis as well as mixed alkalosis may indicate special types of intoxication. this may help faster diagnosis and reduce the mortality and morbidity of the patients.