Effect of β2-adrenergic receptor stimulation on lung fluid in stable heart failure patients

Introduction: The purpose of this study was to determine 1) if stable heart-failure patients with reduced ejection fraction (HFrEF) have elevated extravascular lung water (EVLW) versus healthy control subjects, and 2) the effect of acute β2AR agonist inhalation on lung fluid balance. Methods: Twenty-two stable HFrEF patients and 18 age- and sex-matched healthy subjects were studied. Lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary conductance (DmCO), pulmonary capillary blood volume (Vc) (via rebreathe) and lung tissue volume (Vtis) (via computed tomography) were assessed before and within 30 min of administration of nebulized albuterol. EVLW was derived as Vtis – Vc. Results: Pre-albuterol, Vtis and EVLW were greater in HFrEF vs. control (998 ± 200 vs. 884 ± 123 ml, P = 0.041; 943 ± 202 vs. 802 ± 133 ml, P = 0.015, respectively). Albuterol decreased Vtis and EVLW in HFrEF (−4.6 ± 7.8%, P = 0.010; −4.6 ± 8.8%, P = 0.018) and control (−2.8 ± 4.9%, P = 0.029; −3.0 ± 5.7%, P = 0.045). There was an inverse relationship between pre-albuterol values and the pre- to post-albuterol change for EVLW (r2 = −0.264, P = 0.015) and DmCO (r2 = −0.343, P = 0.004) in HFrEF only. Conclusion: Lung fluid is elevated in stable HFrEF patients relative to healthy subjects. Stimulation of the β2ARs may cause fluid removal in HFrEF, especially in patients who exhibit greater evidence for increased lung water at baseline.