Acid-base disturbances in acute poisoning and their association with survival

Purpose The purpose was to investigate the association between acid-base disturbances and mortality in acute poisoning. Materials and methods We performed a retrospective cross-sectional exploratory study on all acutely poisoned patients older than 12 years who had been admitted to the main tertiary toxicology hospital in Tehran between March and August 2010. Results Of a total of 1167 patients (median age=25 years, 50.9% male), 98 died (74.5% male). Psychotropic medications were the most common cause of poisoning (36.5%), whereas narcotics and psychodysleptics were the most common cause of death (23.5%). Mixed respiratory alkalosis and metabolic acidosis with normal pH were the most common acid-base status (333, 28.5%). However, patients with primary metabolic acidosis and respiratory compensation had significantly higher mortality (31 cases, 18.8%). Logistic regression analysis identified age (odds ratio [OR], 1.051; 95% confidence interval [CI], 1.031-1.070; P<.001), intensive care unit admission (OR, 12.405; 95% CI, 7.178-21.440; P<.001), consciousness level (OR, 1.752; 95% CI, 1.301-2.359; P<.001), hospitalization period (OR, 1.1361; 95% CI, 1.079-1.195; P<.001), severe metabolic acidosis (OR, 6.016; 95% CI, 1.647-21.968; P=.007), and primary respiratory alkalosis (OR, 5.579; 95% CI, 1.353-23.001; P=.017) as death predictors during hospitalization (P<.001). Conclusion On-arrival acid-base status predicts survival and can be used in prognostication of the poisoned patients.