Usefulness of N-terminal pro-B-type natriuretic peptide (NT-ProBNP) as a marker for cardiotoxicity and comparison with echocardiography in paediatric carbon monoxide poisoning

Objectives: To demonstrate the usefulness of N-Terminal Pro-B-Type natriuretic peptide (NT-proBNP) as an early biomarker of carbon monoxide-induced myocardial injury in children. It also aimed to identify the correlation between NT-proBNP and left ventricular systolic dysfunction findings shown by echocardiography. Methods: Prospective, observational study conducted at a paediatric emergency department between October 2017 and April 2019 which involved children aged 0-17 years. The patients were divided into three groups based on severity; mild, moderate and severe groups. The patient characteristics, carboxyhaemoglobin, CK-MB Mass (CKMB-M), troponin-T, and NT-proBNP levels were measured, and echocardiography was performed and left ventricular ejection fraction was measured. Results: Sixty-nine patients and 60 healthy controls were included. Male gender, younger age, higher carboxyhaemoglobin levels, and altered mental status were found as independent predictors of carbon monoxide-induced myocardial injury. If the cut-off value for NT-proBNP level is >480 pg/ml, the sensitivity-specificity for decreased left ventricular ejection fraction, which is the strongest carbon monoxide-induced myocardial injury sign, were 100-96%, respectively. A high negative correlation was found between NT-proBNP levels and left ventricular ejection fraction (r = -0.769, p < 0.01) in the carbon monoxide poisoning group, and there was a positive correlation between the carboxyhaemoglobin and NT-proBNP levels (r = 0.583, p < 0.01). Conclusion: Echocardiography is an ideal tool and very sensitive, but its routine use is limited due to its non-availability. An increased level of NT-proBNP (>480pg/ml) may be useful as an ideal biomarker for early detection of carbon monoxide-induced myocardial injury sign and reduced left ventricular ejection fraction which is the most crucial point in making a decision on hyperbaric oxygen therapy.