The Usefulness of Base Deficit (BD) as a Predictor of Severity in Organophosphorus (OP) Poisoning: A Retrospective Single-center Observational Study
Meghna Somaraj *
Department of Internal Medicine, Kasturba Medical College, Manipal, India.
Arundhati Negi
Department of Internal Medicine, Kasturba Medical College, Manipal, India.
Rupa Neelakantan
Department of Internal Medicine, Kasturba Medical College, Manipal, India.
Vivek Nayak
Department of Internal Medicine, Kasturba Medical College, Manipal, India.
Raghavendra Rao
Department of Internal Medicine, Kasturba Medical College, Manipal, India.
*Author to whom correspondence should be addressed.
Abstract
Objective: Organophosphates are chemical agents that originate from derivatives of phosphoric, phosphonic, or phosphinic acid compounds. They are one of the leading causes of death by intentional self-harm worldwide. The objective of the study is to evaluate the utility of Base Deficit as a prognostic indicator of OP poisoning and assess its predictive accuracy for in-hospital mortality.
Methodology: This retrospective single-center observational study analyzed data from adult patients who presented to the emergency department with the history of organophosphorus compound ingestion over a 2-year 6-month period. Relevant clinical history, physical examination details, and biochemical investigations were collected from electronic medical records and entered into appropriate sections on a pre-designed proforma. Patients with a history of co-ingestion of other compounds or carbamates, chronic kidney disease, pre-hospital cardiac arrest, or those discharged against medical advice were excluded.
Results: Data from 122 patients were analyzed. They were stratified into quartiles based on their base deficit values. The most common OP compound ingested was found to be Chlorpyrifos (n=41, 33.6%). The average duration of hospital stay documented in this study was 16 days, and the in-hospital case fatality rate was 15.38%.
In univariate logistic regression, both base deficit (BD) and APACHE II scores were significantly associated with in-hospital mortality. Receiver Operating Characteristic (ROC) analysis showed that when BD was more than 6.42, it predicted mortality with a 73.7% sensitivity and 70.9% specificity, and when APACHE II scores were above 14.5, sensitivity was 73.7% and specificity was 75.7%. Used in conjunction, these markers enhanced predictive accuracy.
Further, multivariate regression analysis confirmed base deficit as an independent predictor of in-hospital mortality (aOR 1.25, p = 0.031). A combined model of base deficit and APACHE II score showed improved predictive performance (AUC = 0.86), supporting their use in early clinical risk stratification.
Conclusion: Our study shows that base deficit is a valuable and accessible marker for early risk stratification in OP poisoning. Particularly when combined with APACHE II scoring, it can guide timely clinical decisions and resource allocation, especially in resource-limited settings.
Keywords: Organophosphate, base deficit, prognostication, toxicology