Document Detail

Early occurrence of respiratory muscle deoxygenation assessed by near-infrared spectroscopy during leg exercise in patients with chronic heart failure.
MedLine Citation:
PMID:  10084371     Owner:  NLM     Status:  MEDLINE    
The mechanisms of respiratory muscle deoxygenation during incremental leg exercise with expired gas analysis were investigated in 29 patients with chronic heart failure and 21 normal subjects. The deoxygenation and blood volume of the respiratory muscle and exercising leg muscle were assessed by near-infrared spectroscopy (NIRS). To evaluate the influence of the leg exercise on the blood volume of the respiratory muscle, 10 normal subjects also underwent a hyperventilation test with NIRS. The respiratory muscle deoxygenation point (RDP), at which oxygenated hemoglobin starts to decrease, was observed in both groups during exercise. The oxygen consumption (VO2) and the minute ventilation at the RDP in the patients was lower (p<0.01). At the same VO2, the respiratory rate was higher in patients (p<0.01). During exercise, the blood volume of the leg muscle increased, while that of the respiratory muscle decreased. During a hyperventilation test, the minute ventilation was higher than that of the RDP during exercise, the blood volume of the respiratory muscle did not decrease, and the RDP was not detectable. In conclusion, a limited ability to increase perfusion of respiratory muscles during exercise combined with the greater work of breathing results in early respiratory muscle deoxygenation in patients with chronic heart failure.
S Terakado; T Takeuchi; T Miura; H Sato; N Nishioka; Y Fujieda; R Kobayashi; C Ibukiyama
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Japanese circulation journal     Volume:  63     ISSN:  0047-1828     ISO Abbreviation:  Jpn. Circ. J.     Publication Date:  1999 Feb 
Date Detail:
Created Date:  1999-05-24     Completed Date:  1999-05-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7806868     Medline TA:  Jpn Circ J     Country:  AUSTRALIA    
Other Details:
Languages:  eng     Pagination:  97-103     Citation Subset:  IM    
The Second Department of Internal Medicine, Tokyo Medical University, Japan.
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MeSH Terms
Blood Volume
Cardiomyopathy, Dilated / complications,  physiopathology
Cell Hypoxia*
Coronary Disease / complications,  physiopathology
Dyspnea / etiology,  physiopathology
Heart Failure / metabolism,  physiopathology*
Hemoglobins / analysis*
Hyperventilation / physiopathology
Leg / physiopathology*
Middle Aged
Muscle Fatigue / physiology
Oxygen Consumption
Oxyhemoglobins / analysis*
Physical Exertion*
Regional Blood Flow
Respiratory Muscles / blood supply,  metabolism*
Spectrophotometry, Infrared
Reg. No./Substance:
0/Hemoglobins; 0/Oxyhemoglobins; 9008-02-0/deoxyhemoglobin

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