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Biomedical subjects

S Takamoto

Publications and source records attributed to S Takamoto.

At least 289 records · Page 16Linked to original sources
PubMed1978

Intra-aortic oxygen distribution during veno-arterial bypass (VAB) without oxygenation in circulatory assist.

Right atrium-femoral artery VAB without oxygenation was performed in 7 dogs at 3 different bypass ratios, 15% 30%, and 45%. Respiration and cardiac output were controlled. Precise intra-aortic distributions of PO2 and O2 saturation were determined by means of a PO2 catheter probe and an oxygen analyzer. The following was concluded: 1) The blood pumped from dog heart produced a narrow "mixing zone" in the mid-aorta with the blood pumped from VAB. The area of the "mixing zone" was in the distal half between renal artery and bifurcation at 15% bypass ratio, in the proximal half between renal artery and bifurcation at 30% bypass ratio, and from celiac artery to below renal artery at 45% bypass ratio. It shifted proximally as the bypass ratio increased. 2) In order to supply necessary oxygen to abdominal viscera, it is recommended that the bypass flow should not exceed 30% of the baseline cardiac output.

Animals↗
PubMed1978

Hemodynamic effects of the concomitant use of intra-aortic balloon pumping and venoarterial bypass without oxygenation in cardiogenic shock.

The concomitant use of INTRA-AORTIC BALLOON PUMPING (IABP) and venoarterial bypass (VAB) without oxygenation (VABsO) was performed in 10 experiments using 6 dogs in cardiogenic shock. VABsO was accomplished with the cricuit from the right atrium to the femoral artery and bypass flow rates were set at approximately one third of the baseline cardiac output. Displacement volume of the IABP balloon was 10 or 20 ml. Evaluation of hemodynamic effects of the concomitant use was carried out, as compared with the single use of IABP or VABsO. The following findings were obtained: (1) In the concomitant use, left ventricular afterload decreased, while mean aortic root pressure increased. Increase in total perfusion flow, decrease in mean left atrial pressure and decrease in left ventricular stroke work were shown more effective than each of the single uses. (2) These results suggest that the concomitant use of IABP and VABsO can be used as a second step assisted circulation when IABP is shown uneffective in the case of severe cardiogenic shock.

Animals↗
PubMedDate not supplied

Video-assisted cardioscopy for infectious endocarditis.

We successfully resected vegetation of infectious endocarditis in right ventricular outflow tract using a video-assisted cardioscopy without ventriculotomy. Video-assisted cardioscopy provided clear and precise visualization of vegetation on the anterior wall of right ventricular outflow. This technique is effective to visualize remote intra-cardiac structures, and to facilitate repairs, while avoiding the need for extended cardiac incisions.

Endocarditis, Bacterial↗
PubMedDate not supplied

Usefulness of intraoperative color doppler ultrasonography in decision making regarding conversion of an accessory hepatic vein after a Fontan-type operation.

An accessory hepatic vein (AHV) after a Fontan-type operation will result in progressive desaturation if left intact. We report a case in which intraoperative color Doppler ultrasonography revealed the absence of AHV flow and reversed portal vein flow when the AHV was clamped, suggesting that simple ligation of the AHV would lead to liver dysfunction in the area affected. Based on the results of the ultrasonography evaluations, diversion of the AHV into the pulmonary circulation was performed without cardiopulmonary bypass, and the clinical outcome has been favorable.

Adolescent↗
PubMedDate not supplied

Automated diagnosis of heart disease in patients with heart murmurs: application of a neural network technique.

This study was conducted to test a three-layered artificial neural network analysis of phonocardiogram recordings to diagnose, automatically and objectively, the condition of the heart in patients with heart murmurs. The data were recorded simultaneously in each of 49 patients with a heart murmur through eight microphones attached to the skin surface with adhesive tape, and were analysed by computer. The diagnosis was automated using a three-layered neural network technique. The neural network generated correct answers in over 70% of cases. Furthermore, about 80% of cases of two concurrent diseases were identified correctly. However, ventricular septal defects were incorrectly classified as aortic stenosis or aortic regurgitation, and patent ductus arteriosus was not diagnosed correctly. Accurate diagnoses can frequently be obtained using a neural network, but accuracy can be improved with further data accumulation.

Artificial Intelligence↗
PubMedDate not supplied

Transesophageal color Doppler echocardiography during mechanical assist circulation.

Information available to determine the optimal timing for separation of patients (pts) from mechanical assist circulation (MAC) is usually limited, due to the difficulty of transfer of patients with heavy MAC systems. To evaluate the clinical efficacy of transesophageal color Doppler echocardiography (TEE) in management of patients during MAC, we examined 37 pts (32, intra-aortic balloon pumping = IABP; 4, left ventricular assist device = LVAD; 1, right VAD = RVAD) by TEE. In the other 3 pts, thoracic aneurysms (AN) (2, dissecting An; 1, true AN) were detected by TEE, which were contraindications to safe introduction of IABPs. In 29 pts on IABPs, 2 pts with LVADs, and in 1 pt with a RVAD, patients were safely weaned from MACs with confirmation of full recovery of cardiac function by TEE. However, repeat introduction of IABP support was needed in 2 pts due to severe residual mitral regurgitation, even after initial success; these became the cause of late multiple organ failure. In one pt with a LVAD, a detrimental right to left shunt through the patent foramen ovale, which resulted in severe desaturation of the arterial blood oxygenation, was detected by TEE. Left main coronary flow was measured by TEE and found to increase by 55% on IABP and by 67% on a LVAD. In conclusion, TEE is the only currently available diagnostic tool for total evaluation of cardiac function in an intensive care unit, which can provide very important information for management of patients on MACs.

Adult↗
PubMedDate not supplied

Simple hypothermic retrograde cerebral perfusion during aortic arch surgery.

We have found that retrograde cerebral perfusion can be performed by simply elevating central venous pressure during aortic arch surgery. During hypothermia (15 degrees C) venous blood rich in oxygen perfuses the brain, while the lower half of the body is perfused with the descending aorta occluded. Fourteen cases of aortic arch aneurysm (11 males, 3 females) were treated by this method and evaluated. Median and lateral thoracotomies were performed in 6 and 8 cases, respectively. Cerebral circulatory arrest time was 65 +/- 14 min (32-93 min), and significant oxygen and lactate extraction were noted in the brain. Eleven cases showed no neurologic deficit, but loss of consciousness due to other causes occurred in 3. In conclusion, this method maintained the aerobic metabolism of the brain and protected it during prolonged cerebral circulatory arrest, simplifying the procedure and permitting both median and lateral approaches.

Age Factors↗