Clinical Validation of B-type Natriuretic Peptide as a Defining Characteristic of Excess Fluid Volume in Patients with Decompensated Heart Failure

Introduction: Systemic congestion is the main factor related to decompensation of patients with heart failure (HF). The main clinical manifestations resulting from congestion are dyspnea, orthopnea, tiredness, distension of jugular vein, and edema. These signs and symptoms, considered as defining characteristics in the Nursing Diagnoses classification of NANDA-I, are part of the diagnosis of Excess Fluid Volume often established in congested patients. In the context of clinical congestion in patients with HF, the B-type Natriuretic Peptide (BNP) is a reliable tool for the diagnosis of dyspnea, becoming also an important clinical indicator to Excess Fluid Volume Nursing Diagnoses, however, it is not included as a defining characteristics yet. Hypothesis: To clinically validate the blood marker BNP as defining characteristics to diagnose Excess Fluid Volume in patients congested with HF. Methods: Longitudinal study conducted in the emergence of a public university hospital, Porto Alegre, RS. We included patients with HF diagnosis, reduced or preserved systolic function, who were hospitalized by acute decompensation. The collection was systematized through a clinical evaluation at admission and discharge, containing the defining characteristics already clinically validated for this diagnosis in patients with HF. Blood samples were also collected for BNP measurements. Results: Forty-seven patients were included, with mean age of 66 ± 12 years, and fraction ejection of the left ventricular of 46 ± 17%. The frequencies of defining characteristics of the Excess Fluid Volume nursing diagnoses on admission and discharge were statistically significant: jugular vein distension (54% × 33%), edema (90% × 61%), weight gain (51% × 11%), orthopnea (91% × 78%), increased central venous pressure (50% × 26%), positive hepatojugular reflux (59% × 35%), adventitious respiratory noises (83% × 52%), and paroxysmal nocturnal dyspnea (96% × 28%). The median of the BNP values reduced between admission and discharge, although not significantly: 471(263–919) pg/ml in hospitalization, and 430(242.25–941) pg/ml in discharge, P = .093. There was no association between the frequency of the defining characteristics and BNP values both in admission and discharge. Conclusion: The results indicated a reduction in the congestive state observed by the decrease of defining characteristics in discharge as well as in BNP values. These findings indicate that this blood marker can be used as a clinical indicator in congested patients, thus improving diagnostic accuracy.