Validating facemask use for gas exchange analysis in patients with congestive heart failure.
OBJECTIVE
Functional limitation, often associated with congestive heart failure (CHF), is most accurately assessed with measurement of peak VO2 (VO2peak) during exercise testing. VO2peak strongly predicts survival in CHF patients and is used to triage patients for cardiac transplantation. However, the traditional mouthpiece/noseclip equipment used for gas exchange analysis is often cumbersome and uncomfortable. Several alternative facemask designs tested previously in healthy cohorts were inferior to the mouthpiece for measuring VO2peak. In this study, a series of facemasks designed specifically for VO2peak testing (Hans-Rudolph) was employed. Although previously validated in healthy young adults, this apparatus has not been validated in patients with severe CHF.


METHODS
The Hans-Rudolph facemasks were compared with the mouthpiece apparatus in 30 patients with severe CHF. Each subject completed a cardiopulmonary exercise test with each device. Twelve subjects were randomized to evaluate a possible training effect. To enhance recruitment, 18 additional subjects were recruited after they had completed a test with the mouthpiece.


RESULTS
There was no evidence of a training effect and no differences in gas exchange measurements were found between the two devices. The weight-adjusted VO2peak measurements were 17.1 +/- 5.3 ml O2/kg/min for the mouthpiece group and 17.3 +/- 5.6 ml O2/kg/min for the mask group (P = 0.54).


CONCLUSIONS
The facemask was shown to be equivalent to the mouthpiece for measuring VO2peak in CHF patients. Concerns of hypoventilation and decreased VO2peak associated with previous facemask designs were not substantiated. Since successful exercise testing depends on maximal exertion, providing a choice of equipment may facilitate cooperation without sacrificing accuracy.
Baran
D A
DA
Mt. Sinai Medical Center, Department of Medicine, Division of Cardiology, 1 Gustave L. Levy Place, Box 1030, New York, NY 10029, USA.
Rosenwinkel
E
E
Spierer
D K
DK
Lisker
J
J
Whelan
J
J
Rosa
M
M
Goldsmith
R L
RL
D000328:Adult; D018849:Controlled Clinical Trials as Topic; D018592:Cross-Over Studies; D004867:Equipment Design; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008397:Masks; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis; D011659:Pulmonary Gas Exchange