['It is believed that the stretch of cardiomyocytes is the most important stimulus of brain natriuretic peptide (BNP) release; however, its correlation with volume status represented by global end diastolic volume index (GEDVI) is less well established. The study aimed to investigate the correlation between the changes in BNP and the changes in GEDVI measured with transpulmonary thermodilution technique.', 'Critically ill patients requiring hemodynamic monitoring (PiCCO system) in a tertiary 18-bed intensive care unit were prospectively enrolled. Hemodynamic variables were measured simultaneously with blood sampling for BNP concentration. Correlations between changes in BNP and changes in GEDVI were tested using pairwise correlation analysis.', 'A total of 46 patients were included in the study. BNP level (median 4,602 pg/mL; IQR 1,988 to 12,439 pg/mL) was markedly elevated in the study population, but was not correlated with GEDVI (rho=-0.09, P=0.56). The changes in BNP (ΔBNP) showed significant correlation with changes in GEDVI (ΔGEDVI) (Figure 2; rho=0.52, P<0.01). Variables including Age (r=0.43, P=0.002), serum creatinine (r=0.36, P=0.012) and cardiac index (CI) (r=-0.35, P=0.016) were also significantly correlated with logBNP. Other variables such as APACHE II score, central venous pressure (CVP), heart rate (HR), intrathoracic blood volume (ITBVI), extravascular lung water (EVLWI) and systemic vascular resistance index (SVRI) were not significantly correlated with logBNP.'] Are changes in brain natriuretic peptide correlated with changes in global end-diastolic volume index?