title: Effects of side lying on lung function in older individuals.
abstract: OBJECTIVE
  Body positioning exerts a strong effect on pulmonary function, but its effect on other components of the oxygen transport pathway are less well understood, especially the effects of side-lying positions. This study investigated the interrelationships between side-lying positions and indexes of lung function such as spirometry, alveolar diffusing capacity, and inhomogeneity of ventilation in older individuals.
  
  
  METHODS
  Nineteen nonsmoking subjects (mean age=62.8 years, SD=6.8, range=50-74) with no history of cardiac or pulmonary disease were tested over 2 sessions. The test positions were sitting and left side lying in one session and sitting and right side lying in the other session. In each of the positions, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), single-breath pulmonary diffusing capacity (DLCO/VA), and the slope of phase III (DN2%/L) of the single-breath nitrogen washout test to determine inhomogeneity of ventilation were measured.
  
  
  RESULTS
  Compared with measurements obtained in the sitting position, FVC and FEV1 were decreased equally in the side-lying positions, but no change was observed in DLCO/VA or DN2%/L.
  
  
  CONCLUSIONS
  Side-lying positions resulted in decreases in FVC and FEV1, which is consistent with the well-documented effects of the supine position. These findings further support the need for prescriptive rather than routine body positioning of patients with risks of cardiopulmonary compromise and the need to use upright positions in which lung volumes and capacities are maximized.
authors.affiliation: Family Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Manning
authors.forename: E
authors.initials: E
authors.lastname: Dean
authors.forename: J
authors.initials: J
authors.lastname: Ross
authors.forename: R T
authors.initials: RT
authors.lastname: Abboud
mesh_terms: D000368:Aged / Q000502:physiology*; D001944:Breath Tests; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006331:Heart Diseases / Q000517:prevention & control; D006801:Humans; D008171:Lung Diseases / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011237:Predictive Value of Tests; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D013147:Spirometry; D014797:Vital Capacity / Q000502:physiology*