[The six minute walking test elicits lung hyperinflation in patients with severe chronic obstructive lung disease].
BACKGROUND
Exercise tolerance in patients with COPD is highly variable and poorly related to airways obstruction assessed by FEV1. These patients develop dynamic hyperinflation (DH) during an incremental exercise test which can be evaluated through a reduction in inspiratory capacity (IC).


OBJECTIVE
To evaluate: a) if the six minute walking test (6 MWD) induce DH reducing IC, b) if the reduction in IC is related to tidal expiratory flow limitation at rest (FL).


METHODS
Thirty eight stable COPD patients (28 FL and ten non FL during resting breathing, determined by the negative pressure technique). Inspiratory capacity was measured before and immediately after the 6 MWD test. Dyspnea, SpO2 and heart rate were measured before and after the test.


RESULTS
Inspiratory capacity was lower in FL patients as compared to patients without FL (p < 0.005). Although no differences were found between groups in 6 MWD, dyspnea and HR, a significant reduction in IC after the walking test was observed only in FL patients (p < 0.0001). In addition, SpO2 fell significantly (p < 0.0001) after walking in the same group.


CONCLUSIONS
Our results demonstrate that a moderate exercise such as the walking test induces DH and hypoxemia in patients with COPD and FL and stresses the importance of assessing DH by measuring IC in these patients.
Reid
R
R
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile.
Díaz
O
O
Jorquera
J
J
Lisboa
C
C
D000368:Aged; D016022:Case-Control Studies; D004417:Dyspnea / Q000209:etiology; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D012123:Pulmonary Ventilation; D012146:Rest; D013147:Spirometry; D018709:Statistics, Nonparametric; D014109:Total Lung Capacity; D016138:Walking
Efecto de la prueba de la caminata de seis minutos sobre la hiperinflación pulmonar en pacientes con enfermedad pulmonar obstructiva crónica avanzada.