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Respiratory muscle weakness increases dead-space ventilation ratio aggravating ventilation-perfusion mismatch during exercise in patients with chronic heart failure.
Hamazaki, Nobuaki; Masuda, Takashi; Kamiya, Kentaro; Matsuzawa, Ryota; Nozaki, Kohei; Maekawa, Emi; Noda, Chiharu; Yamaoka-Tojo, Minako; Ako, Junya.
Afiliação
  • Hamazaki N; Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan.
  • Masuda T; Department of Cardiovascular Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan.
  • Kamiya K; Department of Rehabilitation, Kitasato University School of Allied Health Sciences, Sagamihara, Japan.
  • Matsuzawa R; Department of Rehabilitation, Kitasato University School of Allied Health Sciences, Sagamihara, Japan.
  • Nozaki K; Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan.
  • Maekawa E; Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan.
  • Noda C; Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan.
  • Yamaoka-Tojo M; Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan.
  • Ako J; Department of Rehabilitation, Kitasato University School of Allied Health Sciences, Sagamihara, Japan.
Respirology ; 24(2): 154-161, 2019 02.
Article em En | MEDLINE | ID: mdl-30426601
BACKGROUND AND OBJECTIVE: Respiratory muscle weakness causes fatigue in these muscles during exercise and thereby increases dead-space ventilation ratio with decreased tidal volume. However, it remains unclear whether respiratory muscle weakness aggravates ventilation-perfusion mismatch through the increased dead-space ventilation ratio. In ventilation-perfusion mismatch during exercise, minute ventilation versus carbon dioxide production (VE/VCO2 ) slope > 34 is an indicator of poor prognosis in patients with chronic heart failure (CHF). We examined the relationship of respiratory muscle weakness with dead-space ventilation ratio and ventilation-perfusion mismatch during exercise and clarified whether respiratory muscle weakness was a clinical predictor of VE/VCO2 slope > 34 in patients with CHF. METHODS: Maximal inspiratory pressure (PImax ) was measured as respiratory muscle strength 2 months after hospital discharge in 256 compensated patients with CHF. During cardiopulmonary exercise test, we assessed minute dead-space ventilation versus VE (VD/VE ratio) as dead-space ventilation ratio and VE/VCO2 slope as ventilation-perfusion mismatch. Patients were divided into low, moderate and high PImax groups based on the PImax tertile. We investigated determinants of VE/VCO2 slope > 34 among these groups. RESULTS: The low PImax group showed significantly higher VD/VE ratios at 50% of peak workload and at peak workload and higher VE/VCO2 slope than the other two groups (P < 0.001, respectively). PImax was a significant independent determinant of VE/VCO2 slope > 34 (odds ratio (OR): 0.67, 95% CI: 0.54-0.82) with area under the receiver operating characteristic curve of 0.812 (95% CI: 0.750-0.874). CONCLUSION: Respiratory muscle weakness was associated with an increased dead-space ventilation ratio aggravating ventilation-perfusion mismatch during exercise in patients with CHF.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Músculos Respiratórios / Relação Ventilação-Perfusão / Tolerância ao Exercício / Debilidade Muscular / Insuficiência Cardíaca Tipo de estudo: Diagnostic_studies / Prognostic_studies Limite: Female / Humans / Male / Middle aged Idioma: En Revista: Respirology Ano de publicação: 2019 Tipo de documento: Article País de afiliação: Japão

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Músculos Respiratórios / Relação Ventilação-Perfusão / Tolerância ao Exercício / Debilidade Muscular / Insuficiência Cardíaca Tipo de estudo: Diagnostic_studies / Prognostic_studies Limite: Female / Humans / Male / Middle aged Idioma: En Revista: Respirology Ano de publicação: 2019 Tipo de documento: Article País de afiliação: Japão