1999 Fiscal Year Final Research Report Summary
Improvement of dyspnea sensation after lung volume reduction surgery and perceived site of dyspnea in severe pulmonary emphysema
| Project/Area Number |
10470146
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Respiratory organ internal medicine
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
HIDA Wataru Graduate of School of Medicine, Tohoku University, Associate Professor, 大学院・医学系研究科, 助教授 (10142944)
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| Co-Investigator(Kenkyū-buntansha) |
KUROKAWA Yoshimochi University Hospital, Lecturer, 医学部・附属病院, 講師 (80215087)
KIKUCHI Yoshihiro Graduate of School of Medicine, Tohoku University, Lecturer, 大学院・医学系研究科, 講師 (20195217)
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| Project Period (FY) |
1998 – 1999
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| Keywords | pulmonary emphysema / lung volume reduction surgery / dyspnea / ventilatory response / survival prognosis |
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| Research Abstract |
We studied the mechanisms of the improvement of dyspnea after lung volume reduction surgery (LVRS) in severe pulmonary emphysema with regard to the following aspects :
1) Estimation of dyspnea during exercise : Pulmonary functions after LVRS improved significantly as follows : FEV1 increased, vital capacity increased, residual volume decreased, PaO2 increased, PaCO2 decreased and FRC decreased. Maximal exercise capacity estimated by incremental loading and dyspnea sensation during exercise estimated by Borg scale also improved after LVRS. There was a significant correlation between decrease in FRC (ΔFRC) and improvement of dyspnea (ΔBorg).
2) Measurement of respiratory muscle oxygen consumption : Respiratory muscle oxygen consumption assessed by continuous dead space loading as developed previously by us decreased after LVRS in comparison with the corresponding ventilation before LVRS. This result may indicate an improvement of ventilatory efficiency.
3) Survival prognosis : Survival rates of LVRS patients' group were 91 and 78% at 1 and 3 years after surgery, respectively. Survival rates of non-surgical and severity-matched patients' group were 93 and 64% at 1 and 3 years after determination of the diagnosis. The difference between these two survival rates was significant.
4) Factors affecting the survival prognosis : The prognosis was affected by such factors as the degree of hypoxemia, diffusing capacity and nutrition before LVRS. Hypercapnia is not a limiting factor for surgery. Patients with a decreased ventilatory response to hypercapnia had worse prognoses.
5) Perceived site of dyspnea in pulmonary emphysema : We found that normal subjects had an enhancement of glucose metabolism assessed by positoron emission tomography in a part of the motor area and/or cingulate cortex during inspiratory resistive loading. These sites may be responsible for the dyspnea sensation. However, this study has not been extended to patients with pulmonary emphysema.
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Research Products
(8 results)
