title: Effect of hyperoxia on left ventricular function and filling pressures in patients with and without congestive heart failure.
abstract: OBJECTIVE
  To determine the effects of hyperoxia on left ventricular (LV) function in humans with and without congestive heart failure (CHF).
  
  
  METHODS
  An acute physiologic study of the effect of hyperoxia on right-heart hemodynamics, LV contractility (peak positive rate of rise of LV pressure [+dP/dt]), time constant of isovolumic left ventricular relaxation (tau), and LV filling pressures.
  
  
  METHODS
  Bayer Cardiovascular Clinical Research Laboratory at the Mount Sinai Hospital, Toronto, Ontario.
  
  
  METHODS
  Sixteen patients with stable CHF and 12 subjects with normal LV function received the hyperoxia intervention.
  
  
  METHODS
  Patients received 21% O(2) by a nonrebreather mask, followed by 100% O(2) for 20 min, and 21% O(2) for a 10-min recovery period.
  
  
  RESULTS
  In response to hyperoxia, there was a 22 +/- 6% increase in LV end-diastolic pressure (LVEDP) in the CHF group and a similar 29 +/- 14% increase in LVEDP in the normal LV function group (p < 0.05 for both; mean +/- SEM). Hyperoxia was also associated with a prolongation in tau of 10 +/- 2% in the CHF group (p < 0.05) and 8 +/- 2% in the normal LV function group (p < 0.05). No changes in +dP/dt were observed in either group.
  
  
  CONCLUSIONS
  Hyperoxia was associated with impairment of cardiac relaxation and increased LV filling pressures in patients with and without CHF. These observations indicate that caution should be used in the administration of high inspired O(2) fractions to normoxic patients, especially in the setting of CHF.
authors.affiliation: Bayer Cardiovascular Clinical Research Laboratory, Department of Medicine, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Mak
authors.forename: E R
authors.initials: ER
authors.lastname: Azevedo
authors.forename: P P
authors.initials: PP
authors.lastname: Liu
authors.forename: G E
authors.initials: GE
authors.lastname: Newton
mesh_terms: D006328:Cardiac Catheterization; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D007773:Lactates / Q000097:blood; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D007773:Lactates; D010100:Oxygen