The Effect of Pulmonary Rehabilitation on Carotid Chemoreceptor Activity and Sensitivity in COPD
Notice bibliographique
Résumé
Chronic Obstructive Pulmonary Disease (COPD) is a respiratory disease characterized by progressive, partially reversible airway obstruction. While considered a disease of the lungs, COPD is associated with increased cardiovascular (CV) mortality; this increased CV risk may result from heightened sympathetic nervous activity secondary to elevated carotid chemoreceptor (CC) activity/sensitivity. Our recent work suggests that COPD patients have an exaggerated resting CC activity/sensitivity which appears to contribute to increased tonic vasoconstriction. Experimental chronic heart failure is characterized by heightened CC activity/sensitivity, and exercise training has been shown to normalize CC activity/sensitivity in this population. COPD patients are commonly referred to pulmonary rehabilitation (PR), an exercise‐based intervention shown to be effective in improving dyspnea, exercise tolerance, and quality of life. However, the physiological mechanisms underlying these improvements are unclear. The purpose of this study was to examine the effects of PR on CC activity/sensitivity in COPD. A case control study design was used; COPD patients either attended PR (experimental) or no PR (control) for 6–8 weeks. CC activity and sensitivity, exercise tolerance, and resting dyspnea were assessed before and after the respective 6–8 week period. Resting CC activity was determined by the reduction in minute ventilation (V̇ E ) while breathing transient hyperoxia (F I O 2 =1.0). CC sensitivity was evaluated by the increase in V̇ E relative to the drop in arterial saturation while breathing hypoxic gas (ΔV̇ E /ΔSpO 2 ). Exercise tolerance was assessed by six minute walk distance (6MWD), and the 0–4 modified Medical Research Council questionnaire (MMRC) was used to determine resting dyspnea. To date, data (mean±SD) have been collected on 45 patients completing PR (FEV 1 57±21% predicted; age 67±7 years) and 6 controls (FEV 1 68±19% predicted; age 71±6 years). Patients completing PR improved exercise tolerance (pre 6MWD: 441±80 m, post: 478±110 m, p<0.001) and reduced resting dyspnea (pre MMRC: 2.41±0.82, post: 2.15±0.84, p=0.04). Resting CC activity was unchanged following PR (pre: −1.07±1.55 L/min, post: −0.93±1.46 L/min, p=0.60), and similarly no change was observed in the control group (pre: −0.73±0.65 L/min, post: −0.96±1.36 L/min, p=0.53). CC sensitivity also remained unchanged in both the experimental (pre: 0.08±0.07 L/min/%SpO 2 , post: 0.11±0.15 L/min/%SpO 2 , p=0.561) and control (pre: 0.26±0.17 L/min/%SpO 2 , post: 0.31±0.11 L/min/%SpO 2 , p=0.363) groups. Current data suggest that PR does not influence CC activity/sensitivity in COPD. While previous studies have shown that exercise training normalizes CC activity/sensitivity in other diseases, it is possible that the intensity or length of PR is insufficient to elicit reductions in CC activity/sensitivity. Alternately, despite improving exercise tolerance and resting dyspnea, exercise training may not affect CC activity/sensitivity in COPD. Support or Funding Information Funding for this work is provided by Alberta Innovates Health Solutions, Canadian Institutes of Health Research, and Heart & Stroke Foundation of Alberta, NWT & Nunavut. (PI: M. Stickland).
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».