Elevation of B-type natriuretic peptide levels in acute respiratory distress syndrome

B-type natriuretic peptide (BNP) has been proven to be a biochemical marker of severity of congestive heart failure. We are aware of only few papers reporting the association of BNP elevation and pulmonary hypertension (primary, thromboembolic, or as a consequence of chronic obstructive pulmonary disease). Less is known about BNP in patients with acute respiratory distress syndrome (ARDS).

We present the case of a previously healthy 27-year-old man with parapneumonic ARDS and an extraordinarily increased BNP level. The ventricular systolic ejection fraction assessed echocardiographically was normal with no evidence of left ventricular diastolic dysfunction. However, a peak BNP level of >1300 pg/mL (normal <100 pg/mL) was recorded. Repeated BNP values were obtained on nine separate days over a period of 3 weeks of mechanical ventilation. With the respiratory improvement following the inhalation of nitric oxide BNP levels decreased to 113 pg/mL. The possible pathophysiological mechanisms of BNP release are discussed.

There is evidence for BNP elevation in the absence left ventricular dysfunction. This case is an example of impressively high BNP levels associated with ARDS, probably attributable to right ventricular overload due to increased pulmonary vascular resistance.