Comportamento da hiperinsuflação dinâmica em teste em esteira rolante em pacientes com DPOC moderada a grave

Abstract

Objective: To characterize the presence, extent, and patterns of dynamic hyperinflation (DH) during treadmill exercise testing in patients with moderate to severe COPD. Methods: This was a cross-sectional study involving 30 non-hypoxemic patients (FEV 1 = 43 ± 14% of predicted) who were submitted to a cardiopulmonary exercise test on a treadmill at a constant speed (70-80% of maximum speed) to the tolerance limit (Tlim). Serial inspiratory capacity (IC) maneuvers were used in order to assess DH. Results: Of the 30 patients studied, 19 (63.3%) presented with DH (DH+ group), having greater pulmonary function impairment at rest than did those without DH (DH− group). None of the variables studied correlated with exercise tolerance in the DH− group, whereas Tlim, IC, and perception of dyspnea during exercise did so correlate in the DH+ group (p < 0.05). In the DH+ group, 7 and 12 patients, respectively, presented with a progressive and a stable pattern of DH (ΔIC Tlim,2min = −0.28 ± 0.11 L vs. 0.04 ± 0.10 L; p < 0.01). Patients with a progressive pattern of DH presented with higher perception of dyspnea/Tlim rate and lower exercise tolerance than did those with a stable pattern (354 ± 118 s and 465 ± 178 s, respectively; p < 0.05). Conclusions: The presence of DH is not a universal phenomenon during walking in COPD patients, even in those with moderate to severe airflow limitation. In the patients who presented DH, a progressive pattern of DH had a greater impact on exercise tolerance than did a stable pattern of DH.Keywords: Pulmonary disease, chronic obstructive; Exercise; Exercise test; Inspiratory capacity. ResumoObjetivo: Caracterizar a presença, extensão e padrões de hiperinsuflação dinâmica (HD) durante teste em esteira rolante em pacientes com DPOC moderada a grave. Métodos: Estudo transversal com 30 pacientes não hipoxêmicos (VEF 1 = 43 ± 14% do previsto) submetidos a teste cardiopulmonar de exercício em esteira rolante em velocidade constante (70-80% da velocidade máxima) até o limite da tolerância (Tlim). Manobras seriadas de capacidade inspiratória (CI) foram utilizadas para avaliação da HD. Resultados: Dos 30 pacientes estudados, 19 (63,3%) apresentaram HD (grupo HD+), que apresentaram maior comprometimento funcional em repouso do que os pacientes sem HD (grupo HD−). Nenhuma das variáveis obtidas relacionou-se com a tolerância ao exercício no grupo HD−, enquanto Tlim, CI e percepção de dispneia ao esforço foram significativamente correlacionados no grupo HD+ (p< 0,05). No grupo HD+, 7 e 12 pacientes, respectivamente, apresentaram padrão progressivo e estável de HD (ΔCI Tlim,2min = −0,28 ± 0,11 L e 0,04 ± 0,10 L; p < 0,01). Pacientes com padrão progressivo de HD apresentaram maior relação percepção de dispneia/Tlim e menor tolerância ao exercício do que aqueles com padrão estável (354 ± 118 s e 465 ± 178 s, respectivamente; p < 0,05). Conclusões: A HD não é um fenômeno universal durante a caminhada em pacientes com DPOC, mesmo que apresentem obstrução ao fluxo aéreo de graus moderado a acentuado. ...

Can bronchodilators improve exercise tolerance in COPD patients without dynamic hyperinflation?

“…( 22 - 25 ) In contrast, Guenette et al ( 26 ) recently analyzed a total of 130 COPD patients (whose FEV1 values were similar to those observed in previous studies, i.e., ~ 40-50% of predicted) and reported that the presence or absence of DH during exercise had no influence on the intensity of dyspnea or on exercise tolerance during high-intensity exercise. On the contrary, critical restriction of tidal volume expansion was shown to be the primary mechanism associated with those outcomes, independently of the presence of DH.…”

“…( 22 - 25 ) Por outro lado, mais recentemente, Guenette et al, ( 26 ) analisando um total de 130 pacientes com DPOC (na mesma faixa aproximada de gravidade do VEF 1 dos estudos anteriores, ou seja, ~ 40-50% do previsto), descreveram que a presença ou a ausência de HD no exercício não influenciou a intensidade da dispneia ou a tolerância durante exercício de alta intensidade. Pelo contrário, foi demonstrado que a limitação crítica na expansão do volume corrente foi o principal mecanismo associado com esses desfechos, independentemente da presença de HD.…”

Brazilian studies on pulmonary function in COPD patients: what are the gaps?

“…The authors also observed greater impairment of resting lung function in patients with DH than in those without DH. 32 In another Brazilian study, a randomized work including 30 COPD volunteers without severe hypoxemia, Scuarcialupi et al found that improvement in resting IC after bronchodilator use was associated with increased tolerance to effort, even in patients with COPD without DH. However, patients who showed no increase in resting IC were still able to obtain a functional benefit from bronchodilator use, provided they presented with DH during exercise.…”

Effects of an incremental walking test in the gait of individuals with Chronic Obstructive Pulmonary Disease

“…Cordoni et al 19 also found increased dyspnea score after stress test and attributed this condition to the movement of the arms, which causes the intercostal inspiratory muscles contribute less to respiratory mechanics, because they are actively participating in the support of the arms and trunk. The abdominal muscles also aid in stabilizing the trunk, being less efficient in expiratory lung emptying and, as a result, less efficient gas exchange and a worsening of ventilation/perfusion mismatching.…”