title: Differences in blood pressure by body position (supine, Fowler's, and sitting) in hypertensive subjects.
abstract: BACKGROUND
  Although blood pressure (BP) differences from supine to sitting position have long been recognized, limited data are available on other commonly used body positions. We performed a cross-sectional study to compare BP values obtained in supine, sitting, and Fowler's positions in essential hypertensive subjects.
  
  
  METHODS
  Systolic BP (SBP) and diastolic BP (DBP) were recorded using an automatic oscillometric device. Nine measurements were taken: three measurements, in random order, in supine, Fowler's, and sitting position. Two generalized estimating equations models were used to evaluate potential predictors of SBP and DBP adjusting for heart rate and measurement order.
  
  
  RESULTS
  The sample consisted of 250 subjects (mean age 66.3 ± 13.4 years; 44.4% males). Measured in supine, Fowler's, and sitting position, mean SBPs were 139.3 ± 14.0; 138.1 ± 13.8; 137.2 ± 13.7 mm Hg, respectively, and mean DBPs 80.1 ± 9.1; 81.9 ± 9.4; 83.0 ± 9.6 mm Hg, respectively. At multivariate analysis, mean SBP significantly decreased if measured in Fowler's and sitting positions, as compared to supine. In contrast, DBP significantly increased. A relevant proportion of subjects showed large differences (≤ or ≥10 mm Hg) in mean SBP across positions: i.e., 30.0% comparing supine vs. sitting SBP. An even higher prevalence of large differences was observed according to the measurement order within the same positions, with no univocal direction (random variation).
  
  
  CONCLUSIONS
  Fowler's position may represent a valid alternative to sitting and supine positions for BP measurement in clinical practice. BP random variability was found to be large regardless of body position, reinforcing the need for operators to closely follow current guidelines that recommend ≥2 recordings at each measurement.
authors.affiliation: Department of Medicine and Science of Aging, University G. d'Annunzio of Chieti, Chieti, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Cicolini
authors.forename: Carmine
authors.initials: C
authors.lastname: Pizzi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Palma
authors.forename: Marco
authors.initials: M
authors.lastname: Bucci
authors.forename: Francesco
authors.initials: F
authors.lastname: Schioppa
authors.forename: Andrea
authors.initials: A
authors.lastname: Mezzetti
authors.forename: Lamberto
authors.initials: L
authors.lastname: Manzoli
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D001795:Blood Pressure Determination; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011187:Posture; D016683:Supine Position