Predicting the Need for Continuation of N-acetylcysteine Treatment among Acute Paracetamol Overdose Patients with Psi Parameter

Objective: AcetaCalc was used to evaluate Psi’s accuracy in predicting cases that required prolonged NAC therapy, as well as Psi’s optimal cut-off. Materials and Methods: This is a retrospective study of patients with acute paracetamol overdose who were treated with NAC at Siriraj Hospital between 2007 and 2016. The Psi parameter was calculated using the Acetacalc after entering paracetamol concentrations, blood sampling times, and NAC onset times. Indications for NAC continuation is in accordance with the guidelines, which recommended that NAC treatment be continued if the follow-up aminotransferase reached 50 U/L or higher. Results: We enrolled 403 patients, the proportion of NAC prolongation was 50.4 %. Psi was shown to be a significant predictor of NAC prolongation (p < 0.001) with area under the receiver operational characteristics curve 0.766 (95% confidence interval (CI) 0.719-0.813). The Psi cutoff with highest Youden index was 1.757 mM-hour. The sensitivities and specificities of the cutoff were 0.517 (95% CI 0.449-0.585) and 0.940 (95% CI 0.898-0.965), respectively. Conclusion: Psi parameter calculated through AcetaCalc is a useful tool for the prediction of cases where extension of NAC therapy beyond the standard regimen is indicated