Arterial blood gases and serum cortisol level as predictors for mortality in acute aluminum phosphide poisoned patients: A prospective cohort study

Abstract

Aluminum phosphide (ALP) is an extremely toxic substance that causes significant morbidity and mortality. Early identification of patients at risk could improve their outcomes. Therefore, this study evaluated the role of serial arterial blood gases and serum cortisol levels in predicting outcomes in patients with acute ALP poisoning. This prospective cohort study included sixty ALP-poisoned patients. Arterial blood gases and serum cortisol levels were assessed at the time of hospital admission, at 6 hours, and at 12 hours after hospital admission. The mortality rate was 55 %. At the time of hospital admission, non-survivors had significantly lower blood pH (7.36 ± 0.08 vs. 7.31 ± 0.09, p = 0.025), reduced bicarbonate values (15.67 ± 4.72 vs. 11.44 ± 3.05 mEq/L, p = 0.001) and higher serum cortisol levels (41.83 ± 15.93 vs. 58.41 ± 19.61 μg/dL, p = 0.002) compared to the survivors. A receiver-operating characteristic (ROC) analysis for the prediction of mortality indicates that the area under the curve (AUC) of blood pH is 0.712 at a cut-off value of ≤ 7.34, with a sensitivity of 75.76 % and a specificity of 66.67 %. At a cut-off value of ≤ 13.5 mEq/L, the AUC of bicarbonate was 0.777, with a sensitivity of 75.76 % and a specificity of 66.67 %. The serum cortisol level exhibited an AUC of 0.737 at a cut-off level of > 45.5 μg/dL, with a sensitivity of 69.70 % and a specificity of 67 %. Therefore, it can be posited that low arterial pH, bicarbonate values, and elevated cortisol levels can predict mortality in acutely poisoned patients with ALP.