RESUMEN
BACKGROUND: The acute effect of supplemental oxygen during exercise has been shown to differ largely among patients with COPD. It is unknown what factors influence oxygen response. METHODS: In a randomized, single-blind fashion, 124 patients with COPD underwent one 6-min walk test on supplemental oxygen (6MWTO2) and one 6-min walk test on room air after a practice 6-min walk test. Both gases were delivered via standard nasal prongs (2 L/min). For analyses, patients were stratified on the basis of PaO2 values and compared: (1) 34 patients with resting hypoxemia (HYX); (2) 43 patients with exercise-induced hypoxemia (EIH); and (3) 31 patients with normoxemia (NOX). RESULTS: Oxygen supplementation resulted in an increase in the 6-min walk distance in the total cohort (27 ± 42 meters; P < .001) and in the subgroups of HYX (37 ± 40 meters; P < .001) and EIH (28 ± 44 meters; P < .001) but not in the NOX subgroup (15 ± 43 meters; P = .065). Forty-two percent of patients with HYX and 47% of patients with EIH improved their 6-min walk distance to a clinically relevant extent (≥ 30 meters) by using oxygen. These oxygen responders were characterized by significantly lower 6-min walk distance using room air compared with patients without a relevant response (306 ± 106 meters vs 358 ± 113 meters; P < .05). Although oxygen saturation was significantly higher during 6MWTO2 compared with the 6-min walk test on room air in all 3 subgroups, it dropped to < 88% during 6MWTO2 in 73.5% of patients with HYX. CONCLUSIONS: In contrast to patients with NOX, patients with HYX and EIH generally benefit from supplemental oxygen by increasing exercise capacity. However, less than one-half of patients reached the threshold of clinically relevant improvements. These oxygen responders were characterized by significantly lower exercise capacity levels. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00886639; URL: www.clinicaltrials.gov.
Asunto(s)
Terapia por Inhalación de Oxígeno/métodos , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/terapia , Prueba de Paso , Anciano , Estudios Cruzados , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Método Simple Ciego , Resultado del TratamientoRESUMEN
INTRODUCTION: To date endurance and strength training are established and evidence-based exercise methods in patients with chronic obstructive pulmonary disease (COPD). There is an unmet need for further research in new and complementary exercise modalities. Additional whole body vibration training during pulmonary rehabilitation may be such a new approach that has not yet been investigated in patients with COPD. METHODS: Eighty-two patients (65 ± 9 yrs, FEV(1) pred. 38 ± 11%, female 51%) with COPD in GOLD stage III to IV assessed for a 3-week inpatient multidisciplinary rehabilitation program were on top randomly assigned to one of two intervention groups: (1) 3 × 3 min of bilateral dynamic squat exercises on a side-alternating vibration platform at 24-26 Hz three times per week (WBV) and (2) a control group (CON) with the same amount of exercise time without WBV. RESULTS: Thirty-six patients completed the study in each group. The improvement in 6-min walking distance was significantly higher in the WBV-group when compared to the CON-group (WBV: 64 ± 59 m, CON: 37 ± 52 m with a between-group difference of 27 m [95% CI, 1-53], p = 0.046). The time required for a sit-to-stand test also decreased more markedly in the WBV-group than in the CON-group (WBV: -4.0 ± 4.8 s, CON: -2.0 ± 3.1 s with a between-group difference of -1.9 s [95% CI, -4.0 to 0.1], p = 0.067). Improvements in health-related quality of life were similar in both groups. CONCLUSIONS: WBV training seems to be a promising new exercise modality for patients with COPD and may enhance the effects of a multidisciplinary rehabilitation program.