title: Effects of hemoglobin on pulmonary arterial pressure and pulmonary vascular resistance in patients with chronic emphysema.
abstract: BACKGROUND
  The increase in viscosity caused by secondary polycythemia is thought to be one of the major causes of pulmonary hypertension secondary to chronic emphysema. However, very few clinical studies considered the relation between pulmonary hypertension and polycythemia in the case of chronic obstructive pulmonary disease.
  
  
  OBJECTIVE
  The purpose of this study is to elucidate the relative contribution of an increase in hemoglobin level (Hb) to mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR).
  
  
  METHODS
  We retrospectively investigated 41 patients with chronic emphysema who had undergone a right heart catheterization. Multiple-regression analysis and F test were performed to investigate both direct effects of Hb and PaO(2) as independent variables on mPAP and PVR as dependent variables.
  
  
  RESULTS
  Significant correlations were found between PaO(2) and mPAP (or PVR), or Hb and mPAP (or PVR), indicating that both Hb and PaO(2) are contributory to mPAP and PVR. The F test demonstrated that Hb and PaO(2) could directly affect the level of either mPAP or PVR.
  
  
  CONCLUSIONS
  It was concluded that Hb had a direct effect on mPAP and PVR, independently of hypoxia in patients with chronic emphysema.
authors.affiliation: Department of Respiratory Medicine, Hamamatsu Medical Center, Hamamatsu, Japan. nakamura@physiol12.m.chiba-u.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.forename: N
authors.initials: N
authors.lastname: Kasamatsu
authors.forename: I
authors.initials: I
authors.lastname: Hashizume
authors.forename: T
authors.initials: T
authors.lastname: Shirai
authors.forename: S
authors.initials: S
authors.lastname: Hanzawa
authors.forename: S
authors.initials: S
authors.lastname: Momiki
authors.forename: K
authors.initials: K
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Kinoshita
authors.forename: O
authors.initials: O
authors.lastname: Okada
authors.forename: K
authors.initials: K
authors.lastname: Tatsumi
authors.forename: T
authors.initials: T
authors.lastname: Kuriyama
mesh_terms: D000368:Aged; D001794:Blood Pressure; D005260:Female; D006454:Hemoglobins / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology*; D008297:Male; D011086:Polycythemia / Q000150:complications*; D011651:Pulmonary Artery / Q000502:physiology*; D011656:Pulmonary Emphysema / Q000150:complications / Q000503:physiopathology*; D012044:Regression Analysis; D012189:Retrospective Studies; D014655:Vascular Resistance
chemical_list: D006454:Hemoglobins