1987 Fiscal Year Final Research Report Summary
Respiratory assist system with extracorporcal CO_2 removal for severe respiratory failure
| Project/Area Number |
61570670
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thoracic surgery
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| Research Institution | Osaka University |
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Principal Investigator |
OHTANI Masakatsu First Department of Surgery, Osaka University Medical School, 医学部第一外科, 助手 (90168980)
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| Co-Investigator(Kenkyū-buntansha) |
大久保 修和 大阪大学, 医学部附属病院, 医員
MATSUDA Hikaru First Department of Surgery, Osaka University Medical School, 医学部第一外科, 講師 (00028614)
OHKUBO Nobukazu First Department of Surgery, Osaka University Hospital
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| Project Period (FY) |
1986 – 1987
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| Keywords | RESPIRATORY FAILURE / EXTRACORPOREAL MEMBRANE OXYGENEATION / PULMONARY LEUKOCYTE SEQUESTRATION / 肺leukocyte sequestration |
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| Research Abstract |
(1) Modification of an ECCO_2R to improve CO_2 removal: Diffusion oxygenation combined with the extracorporeal CO_2 removal(ECCO_2R) with a membrane lung is a new modality in ECMO for severe respiratory failure. It has been showed that the minimum bypass flow of 1.kL/min was required for sufficient CO_2 removal. The reduction of the bypass flow would offer several advantages such as percutaneous cannulation and less hemolysis. The refore, we attempted to modify ECCO_2R system by incorporating a recirculation loop in order to enhance CO_2 removal. The assessment with model circuits revealed that this modification enhanced the performance of CO_2 removal and the CO_2 removal rate of this new system was estimated to be within clinically acceptable range at 0.5-1.0L/min of blood flow rate. These results indicated that the modified ECCO_2R system is to be clinically applicable at very low blood flow rates.
(2) Clinical survey to ensure the indication of ECMO: The conventional mechanical vent
… More
ilation therapy was reviewed in 91 patients with severe respiratory failure, in which the alveolar-arterial O_2 difference(A-aDo2) exceeded 500mmHg. 21 patients(23.3%) died due to respiratory failure in spite of the mechanical ventilation, whose dead space ratio averaged 74.2%, higher than tha survivors. A high mortality(94%) was documented in the patients with A-aDo2 over 250mmHg for more than 4 days on the mechanical ventilation. ECMO would be indicated to the patients with a high dead space ratio, and furthermore, when the A-aDo2 showed no improvement in spite of the mechanical ventilation therapy.
(3) Leukocyte activation in ECCO_2R and its attenuation by cAMP phosphodiesterase inhibitor: The actvated leukocyte may have an important role in developing compliment-related lung injury during extracorporeal circulation. In these situations, the activated leukocyte may be entrapped in the pulmonary capillary and generate oxygen radicals, presumably resulting in tissue injury. We investigated leukocyte kinetics mainly in the pulmonary circulation during the experimental ECCO_2R in dogs and also evaluated the effect of a new phosphodiesterase inhibitor(DN-9693) on the pulmonary leukocyte sequestration. The ECCO_2R induced the pulmonary leukocyte sequestration in the early phase of bypass and about 50% reduction in the circulating leukocyte at 30 min of bypass. However, under the continuous infusion of DN-9693, the pulmonary leukocyte sequestration and leukocyte depletion were not observed during ECCO_2R. These results suggested that DN-9693 prevents the pulmonary leukocyte sequestration induced by ECCO_2R with attenuation of the systemic leukocyte depletion. Less
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Research Products
(4 results)
