JaLCDOI 10.18926/AMO/32662
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Author Ishino, Kozo| Murakami, Taiji| Irie, Hiroyuki| Nakayama, Hironobu| Izumoto, Hiroshi| Yamada, Makoto| Teraoka, Hiromichi| Sanoo, Yoshimasa| Teramoto, Shigeru|
Abstract <p>The present study was undertaken to determine whether a biventricular bypass system operated in an independent variable rate (VR) mode can maintain the entire circulation. Two pusher-plate pumps which incorporated the Hall effect position sensors were used to bypass the right and left ventricles in 10 sheep under fibrillation. The flow distributions of the pump output to the carotid and renal arteries were investigated every 6 h using ultrasonic blood flow meters for 24 h in 5 animals, and the controllability of the VR mode was evaluated in 5 long-term experiments. The carotid artery flow ratio to the pump output decreased significantly from 4.7 +/- 0.8% before the bypass to 2.7 +/- 0.9% after 24 h. However, the renal artery flow ratio did not change throughout the experiments. In the long-term experiments, the animals were kept alive from 3 to 48 days (mean 15.6 days). The mean pump output had been maintained at more than 90 ml/min/kg for the first 7 days. After the surgery, the pump driving conditions were not readjusted in any experiment. The results indicate that the biventricular bypass system operated in the independent VR mode automatically maintains the entire circulation at a satisfactory level.</p>
Keywords biventricular bypass pusher-plate pump variable rate mode flow distribution
Amo Type Article
Published Date 1992-10
Publication Title Acta Medica Okayama
Volume volume46
Issue issue5
Publisher Okayama University Medical School
Start Page 317
End Page 321
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 1442154
Web of Science KeyUT A1992JX49500001
JaLCDOI 10.18926/AMO/32169
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Author Ishino, Kozo| Murakami, Taiji| Nakayama, Hironobu| Yamada, Makoto| Morimoto, Tooru| Hisamochi, Kunikazu| Tanaka, Takashi| Senoo, Yoshimasa| Teramoto, Shigeru|
Abstract <p>A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation.</p>
Keywords biventricular bypass total artificial heart pusher-plate pump Hall effect sensor variable rate mode
Amo Type Article
Published Date 1991-08
Publication Title Acta Medica Okayama
Volume volume45
Issue issue4
Publisher Okayama University Medical School
Start Page 223
End Page 231
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 1962530
Web of Science KeyUT A1991GD78000004
JaLCDOI 10.18926/AMO/30898
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Author Nawa, Sugato| Yamada, Makoto| Sugawara, Eiji| Kino, Kohichi| Teramoto, Shigeru|
Abstract <p>Geometrical measurements of angiocardiograms of the common outflow tract (COT) of 13 patients were made to determine in which cases internal conduit repair was feasible, and under which conditions a patch enlargement of the COT was indicated. In the pulmonary stenosis (PS) group, the area of the narrowest cross-section of the COT was significantly smaller than that in the pulmonary hypertension (PH) group (p less than 0.025). In the PS group, the area was rarely sufficient to be shared by systemic and pulmonary circulation. Therefore, stenosis in the outflow tract to the pulmonary artery will occur if the intraventricular tunnel technique is applied, without patch enlargement of this portion, to patients with PS. On the contrary, the cross-sectional areas of the COT and pulmonary arteries were significantly larger in the PH group than in the PS group. Accordingly, the intracardiac conduit operation may be possible in such patients without a patch enlargement, even in young patients if other intracardiac conditions allow. Preoperative angiocardiographic evaluation of the COT is helpful in preoperatively selecting the proper operative procedure for this anomaly.</p>
Keywords double-outlet right ventricle angiocardiography common outflow tract intraventricular tunnel technique patch enlargement
Amo Type Article
Published Date 1989-02
Publication Title Acta Medica Okayama
Volume volume43
Issue issue1
Publisher Okayama University Medical School
Start Page 65
End Page 72
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 2718771
Web of Science KeyUT A1989T938500008
JaLCDOI 10.18926/AMO/30859
FullText URL fulltext.pdf
Author Nawa, Sugato| Yamada, Makoto| Kino, Koichi| Teramoto, Shigeru| Morita, Kiyoshi|
Abstract <p>Changes in the hemodynamics of six patients having received Fontan-like operations were closely observed during the first 48 h after the operation. Catheterization studies and simultaneous angiocardiography were also performed before and after the operation. Hemodynamic derangement was particularly severe during the first 24 h postoperatively as indicated by a low cardiac output of less than 2.01/min/m2, which persisted in spite of very high central venous pressure. Furthermore, the central venous pressure needed to re-establish the circulation soon after the Fontan procedure significantly correlated with the angiocardiographically assessed preoperative size of distal pulmonary arteries. Accordingly, the preoperative evaluation of the distal pulmonary arterial size is very important, that provides a good guide-line for the degree of circulatory volume expansion necessary to elevate the central venous pressure and to sustain the circulation in the early postoperative period.</p>
Keywords Fontan's operation central venous pressure pulmonary arterial size hemodynamic characteristics post-Fontan care
Amo Type Article
Published Date 1989-08
Publication Title Acta Medica Okayama
Volume volume43
Issue issue4
Publisher Okayama University Medical School
Start Page 233
End Page 240
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 2801187
Web of Science KeyUT A1989AP79100005