The utility of serial serum cholinesterase as a prognostic marker in organophosphorus compound poisoning

Background: Acute organophosphorus (OP) poisoning is one of the most common poisonings in India contributing to significant morbidity and mortality. Irreversible inhibition of cholinesterase enzymes is attributed to the serious clinical outcomes in these patients, which is assessed by the estimation of serum cholinesterase (SChE) levels. The present study was undertaken to evaluate the utility of serial estimation of SChE levels in patients of OP poisoning in predicting the clinical outcome. Methods: Medical records of 31 patients from January 2013 to December 2013 admitted in our institute with acute OP poisoning were analyzed for SChE at admission, 48 hrs, 72 hrs and 120 hrs after admission. Data regarding clinical findings at admission and outcomes were recorded. Results: Monocrotophos (55%) was the most commonly used OP compound. Mean serial SChE levels (in KU/L) at admission, 48, 72, and 120 hrs in patients who survived are 0.18±0.10, 0.28±0.14, 0.41±0.21, 0.46±0.16 and in patients who expired are 0.02±0.01, 0.05±0.02, 0.03±0.02, 0.03±0.02, respectively. SChE levels at admission in survived group, compared to those in expired group were statistically significant (p < 0.001). About 92% patients in moderate to severe grade of poisoning (SChE levels < 0.2 KU/L) were mechanically ventilated. The relationship between serial SChE levels in survival group and was found to be statistically significant (p < 0.01). Conclusion: In the present study, significant increase in serial SChE levels were correlating with better clinical outcome as evidenced by an improvement with mechanical ventilation and survival rates in acute OP poisoning.