Predictors of oxygen desaturation during the six-minute walk test in patients with cystic fibrosis.
OBJECTIVE
To identify the predictive factors of oxygen desaturation during the six-minute walk test (6MWT) in patients with cystic fibrosis (CF).


METHODS
Prospective cross-sectional study involving clinically stable patients with CF aged > or = 10 years. The patients were submitted to nutritional evaluations, oral glucose tolerance tests, pulmonary function tests, chest X-rays and 6MWTs.


RESULTS
The study included 88 patients (43 females and 45 males; mean age, 19.9 + or - 7.2 years; mean FEV(1), 65.4 + or - 28.4%). We observed oxygen desaturation in 13 patients (OD+ group) and no oxygen desaturation in 75 (ODmicro group). In comparison with ODmicro group patients, OD+ group patients presented higher mean age (p = 0.004), worse clinical score (p < 0.001), worse radiological score (p < 0.001), higher incidence of glucose intolerance (p = 0.004), lower incidence of methicillin-sensitive Staphylococcus aureus infection (p < 0.001), higher incidence of methicillin-resistant S. aureus infection (p = 0.016), higher incidence of Pseudomonas aeruginosa infection (p = 0.008), lower mean resting SpO(2) (p < 0.001) and lower mean FEV(1) (p < 0.001). In the logistic regression analysis, oxygen desaturation during the 6MWT correlated with resting SpO(2) (OR = 0.305, p < 0.001) and FEV(1) (OR = 0.882, p = 0.025). The parameters maximizing the predictive value for oxygen desaturation were resting SpO(2) < 96% and FEV(1) < 40%. In this sample, 15% of the patients with CF aged > or = 10 years presented oxygen desaturation during the 6MWT.


CONCLUSIONS
Resting SpO(2) < 96% and FEV(1) < 40% can predict oxygen desaturation during the 6MWT.
Ziegler
Bruna
B
Department of Pulmonology, Porto Alegre Hospital de Clínicas, Universidade Federal do Rio Grande do Sul - UFRGS, Federal University of Grande do Sul - School of Medicine, Porto Alegre, Brazil. brunaziegler@yahoo.com.br
Rovedder
Paula Maria Eidt
PM
Oliveira
Claudine Lacerda
CL
Schuh
Sandra Jungblut
SJ
Silva
Fernando Abreu E
FA
Dalcin
Paulo de Tarso Roth
Pde T
D001424:Bacterial Infections / Q000382:microbiology; D003550:Cystic Fibrosis / Q000473:pathology / Q000503:physiopathology*; D004812:Epidemiologic Methods; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D018149:Glucose Intolerance / Q000473:pathology; D006801:Humans; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D012146:Rest; D013147:Spirometry; D016138:Walking / Q000502:physiology*; D055815:Young Adult
D010100:Oxygen