title: Lateral decubitus position generates discomfort and worsens lung function in chronic heart failure.
abstract: BACKGROUND
  Lateral decubitus position is poorly tolerated by heart failure patients.
  
  
  OBJECTIVE
  To evaluated pulmonary function and lung diffusion in heart failure patients in the following five body positions: sitting, prone, supine, and left and right decubitus.
  
  
  METHODS
  Heart failure unit of a university hospital.
  
  
  METHODS
  We studied 14 chronic heart failure patients in New York Heart Association class III and 14 healthy volunteers.
  
  
  RESULTS
  After 15 min of a selected position, subjects were evaluated by a discomfort scale, ear oximetry, and pulmonary function, which included FEV1, FVC, vital capacity (VC), alveolar volume, and diffusing capacity of the lung for carbon monoxide (D(LCO)) with subcomponent membrane resistance (DM) and capillary volume. In healthy subjects, we observed a reduction of D(LCO) and capillary volume in both lateral decubiti. Some discomfort was documented in both lateral decubiti when selected positions were compared with the sitting position. In the sitting position, pulmonary function suggested slight restriction ([mean +/- SD] FVC, 89.8 +/- 22.3% predicted; FEV1, 84.7 +/- 16.9% predicted, VC, 88.6 +/- 21.5% predicted; and FEV1/VC, 74 +/- 7) with low D(LCO) (73 +/- 19% predicted). Compared with sitting, lung mechanics were unchanged in prone and supine positions; FEV1, FVC, and FEV1/VC were lower when patients were lying on their side, with unchanged alveolar volume and VC. D(LCO) was similar when comparing sitting, prone, and supine positions, and it was lower in lateral decubitus because of the lower capillary volume (vs sitting) and DM (vs prone and supine). Body position-related FVC and D(LCO) reduction were greatest in the largest hearts (deltaFVC and deltaD(LCO) vs left ventricle diastolic volume R = 0.524, p < 0.05 and R = 0.630, p < 0.02, respectively; deltaFVC and deltaD(LCO) vs cardiothoracic index R = 0.539, p < 0.05 and R = 0.685, p < 0.01, respectively).
  
  
  CONCLUSIONS
  In heart failure, lateral decubitus airway obstruction and lung diffusion impairment become greater as heart dimensions increase.
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico, Institute of Cardiology, University of Milan, 20138 Milan, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Palermo
authors.forename: Gaia
authors.initials: G
authors.lastname: Cattadori
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bussotti
authors.forename: Anna
authors.initials: A
authors.lastname: Apostolo
authors.forename: Mauro
authors.initials: M
authors.lastname: Contini
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Agostoni
mesh_terms: D000368:Aged; D000402:Airway Obstruction / Q000209:etiology / Q000503:physiopathology; D002908:Chronic Disease; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008171:Lung Diseases / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012129:Respiratory Function Tests