Potentially detrimental cardiovascular effects of oxygen in patients with chronic left ventricular systolic dysfunction.
BACKGROUND
Although the haemodynamic effects of oxygen in healthy subjects are well documented, there have been no well-controlled studies of the effects of oxygen in patients with heart failure (HF).


OBJECTIVE
To non-invasively evaluate haemodynamic and neurohumoral effects of oxygen in patients with HF at rest.


RESULTS
13 men with heart failure and left ventricular systolic dysfunction (LVSD) were randomised in a double-blind, placebo-controlled, crossover trial to receive medical air or oxygen (40% and high concentration via Hudson non-rebreathing mask). Haemodynamic measurements were made with applanation tonometry, impedance cardiography and venous occlusion plethysmography. Plasma C-terminal B-type natriuretic peptide and A-type natriuretic peptide were measured. Data were analysed with paired t tests. Cardiac output fell by -0.58 (0.62) l/min on high-flow oxygen compared with -0.02 (0.58) l/min on air, p=0.031. Oxygen caused a reduction in heart rate (-4.02 (4.21) vs 0.41 (5.35) beats/min, respectively, p=0.021) and a trend towards increased systemic vascular resistance (875 (1174) vs 235 (321) dyne/s/m(5), p=0.050). Oxygen led to a paradoxical increase in forearm blood flow (0.513 (0.391) vs 0.024 (0.246) ml/min/100 ml forearm volume on air, p=0.01). Natriuretic peptides were unchanged with oxygen.


CONCLUSIONS
High-concentration inhaled oxygen has significant haemodynamic effects in patients with LVSD and mild HF. Such effects may be detrimental in patients with decompensated HF.
Park
James H
JH
British Heart Foundation Cardiovascular Research Centre, University of Glasgow, 126 University Place, Glasgow, UK.
Balmain
Sean
S
Berry
Colin
C
Morton
John J
JJ
McMurray
John J V
JJ
D000368:Aged; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005542:Forearm / Q000098:blood supply; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D045265:Natriuretic Peptides / Q000378:metabolism; D010100:Oxygen / Q000009:adverse effects*; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology* / Q000628:therapy
D045265:Natriuretic Peptides; D010100:Oxygen