Prolonged oxygen kinetics during early recovery from maximal exercise in adult patients with cystic fibrosis.
OBJECTIVE
To explore the significance of oxygen kinetics during early recovery after maximal cardiopulmonary exercise testing (CPET) in the assessment of functional capacity and severity of the disease in cystic fibrosis (CF) patients.


METHODS
Eighteen patients with CF (9 male/9 female; mean +/- SD age, 23 +/- 13 years) and 11 healthy subjects (3 male/8 female; mean age, 29 +/- 4 years) underwent maximum CPET on a treadmill. Breath-by-breath analysis was used for measuring oxygen consumption (VO(2)), carbon dioxide production, and ventilation. Maximum VO(2) (VO(2)peak) and the first-degree slope of VO(2) decline during early recovery (VO(2)/t-slope) were calculated. To assess the severity of the disease, we used standard indexes like FEV(1) (% predicted), VO(2)peak, and a widely accepted system of clinical evaluation, the Schwachman score (SS).


RESULTS
VO(2)/t-slope was significantly lower in CF patients compared to healthy subjects (0.61 +/- 0.31 L/min/min vs 1.1 +/- 0.13 L/min/min; p < 0.01) and was closely correlated to FEV(1)(r = 0.90, p < 0.001), VO(2)peak (r = 0.81, p < 0.001), and the SS (r = 0.81, p < 0.001). The multivariate analysis showed that the only independent predictor of the SS is the VO(2)/t-slope.


CONCLUSIONS
We conclude that in CF patients, the prolonged oxygen kinetics during early recovery from maximal exercise is related to the disease severity.
Pouliou
E
E
Adult Cystic Fibrosis Outpatient Clinic, Athens Chest Hospital, Greece. snanas@cc.uoa.gr
Nanas
S
S
Papamichalopoulos
A
A
Kyprianou
T
T
Perpati
G
G
Mavrou
I
I
Roussos
C
C
D000293:Adolescent; D000328:Adult; D002245:Carbon Dioxide / Q000502:physiology; D003550:Cystic Fibrosis / Q000378:metabolism / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D015656:Respiratory Mechanics; D012720:Severity of Illness Index; D014797:Vital Capacity
D002245:Carbon Dioxide