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Biomedical subjects

Shinpei Yoshii

Publications and source records attributed to Shinpei Yoshii.

9 recordsLinked to original sources
PubMed2006

Lower limits of hematocrit and mixed venous oxygen saturation ensuring sufficient cerebral oxygenation during hemodilution in rabbits.

OBJECTIVES: We have assessed clinically systemic tissue oxygenation by monitoring mixed venous oxygen saturation (SvO2) in addition to hematocrit (Hct) during cardiopulmonary bypass. Based on results of experimental studies together with clinical experience, we previously defined the lower limits of the critical range as an Hct of 12% and an SvO2 of 46%. However, these values do not provide direct information about cerebral oxygenation. This study was performed to identify critical values for these variables that would be able to ensure sufficient jugular venous oxygen saturation (SjO2), which reflects global cerebral oxygenation. METHODS: Normovolemic hemodilution was performed in ten rabbits. Hct, SvO2 and SjO2 were measured every 7 minutes. The safety limit for cerebral oxygenation was defined as an SjO2 of 50% based on studies of Croughwell et al. and Cook et al. The limit point was defined as 7 minutes before the time that the SjO2 decreased below 50% for the first time. RESULTS: Minimal values for Hct and SvO2 to maintain SjO2 at 50% or more during normovolemic normothermic hemodilution, expressed as the 95% confidence interval, were Hct of 7.4% to 10.0% and SvO2 of 41.8% to 51.4%. CONCLUSION: Adopting the higher values of these pairs, safety limits for cerebral oxygenation would be an Hct of 10.0% and an SvO2 of 51.4%. In conclusion, our experiments in rabbits suggest new safety limits during normovolemic normothermic hemodilution of Hct of 12% and SvO2 of 52%, taking both whole-body and cerebral oxygenation into consideration.

Animals↗
PubMed2006

Large saphenous vein graft aneurysm with a fistula to the right atrium.

We report on a case of a 65-year-old man who was admitted for anterior chest pain on effort. He had received coronary artery bypass grafting (CABG) surgery 20 years ago with saphenous vein grafts (SVGs) to the left anterior descending artery (LAD) and right coronary artery (RCA). An angiography demonstrated large aneurysmal dilatation of both grafts and a fistulous communication between the middle portion of the right SVG and the right atrium (RA). The aneurysm was excised surgically, and the fistula was closed with the right atrial wall with additional bypass grafts of the left internal thoracic artery (LITA) and gastroepiploic artery (GEA).

Aged↗
PubMed2004

Critical values of hematocrit and mixed venous oxygen saturation as parameters for a safe cardiopulmonary bypass.

OBJECTIVE: Mixed venous oxygen saturation (SvO2) is high despite a low hematocrit implies that the relationship between oxygen demand and supply is in a safe state. This study was sought to determine the critical values for hematocrit and SvO2 for safe cardiopulmonary bypass. METHODS: Study 1: To evaluate the limit of hemodilution without cardiopulmonary bypass, normovolemic hemodilution with Dextran 40 (10%) was performed in 14 rabbits. SvO2 was monitored from the right atrium, and the hemodynamic parameters were recorded continuously. Study 2: To determine the critical values for hematocrit and SvO2 during cardiopulmonary bypass, normothermic and hypothermic cardiopulmonary bypass were performed in 13 rabbits and hemodynamic parameters were corrected. RESULTS: Study 1: The heart rate decreased to unsafe levels abruptly, when the SvO2 was < or = 43% or the hematocrit was < or = 10%. The lactate concentration increased when the SvO2 was < or = 46% or the hematocrit was < or = 12%. Study 2: When the hematocrit was < or = 12%, the SvO2 decreased gradually. Even when weaning was possible, the animals with a hematocrit < or = 12% collapsed hemodynamically within 40 minutes after cardiopulmonary bypass. Most of the animals could not be weaned from cardiopulmonary bypass during either normothermic or hypothermic cardiopulmonary bypass when the SvO2 was < or = 46%. CONCLUSIONS: Continuous monitoring of hematocrit and SvO2 provides evidence-based guidelines for safe cardiopulmonary bypass. The lower limits of critical range for a safer cardiopulmonary bypass are hematocrit of 12% and SvO2 of 46%.

Animals↗
PubMed2004

Angiogenic strategy for human ischemic heart disease: brief overview.

In the Western World ischemic coronary disease is the leading cause of morbidity and mortality. Therapeutic approaches mostly aim to restore flow to a localized segment by angioplasty or bypass surgery. Therapeutic angiogenesis and or arteriogenesis describes a strategy where blood vessel formation is induced for the purposes of treating and/or preventing ischemic disease. At present, at least 17 clinical trials of myocardial angiogenesis have been presented involving over 900 patients. Therapeutic angiogenesis makes use of the administration of angiogenic growth factor protein or gene to promote the development of endogenous collateral vessels in ischemic myocardium. Most recently, interest has grown in the potential angiogenesis effects of cell therapy--such as autologous bone marrow cells or cultured stem cells--and there are now several groups initiating phase I/II trials in this area.

Animals↗
PubMed2003

Preliminary results of intermittent retrograde cerebral perfusion during proximal aortic arch surgery.

OBJECTIVE: Continuous retrograde cerebral perfusion during aortic arch surgery is associated with cerebral edema. In this report, we describe the clinical use of a new type of intermittent retrograde cerebral perfusion. SUBJECTS AND METHODS: Fourteen patients with a Stanford type A dissection were included in this study. With the usual method of retrograde cerebral perfusion, about 2,500 mL venous blood is drained from bicaval cannulae into a hard-shell reservoir, and oxygenated blood is perfused through the superior vena caval cannula. The flow rate is 300 mL/min. After about 15 min, retrograde perfusion is discontinued, and drainage from the bicaval cannulae is restarted. When a bloodless field is necessary, perfusion also is discontinued. RESULTS: Two to seven cycles of intermittent retrograde cerebral perfusion were administered (average, 3.1+/-0.4, mean+/-SD). The total retrograde perfusion time was 36.0+/-1.9 min which was equivalent to 74.8% of the circulatory arrest time. No patient developed edema of the upper body. The time to wake-up was 3 to 14 h (average, 6.5+/-1.0 h). No patient suffered any neurologic complications even though the time of circulatory arrest was greater than 60 min in four cases. Head magnetic resonance imaging or computed tomography was performed in 12 cases, and no evidence of hypoxic brain injury was detected. CONCLUSIONS: Our clinical experience using a moderate amount of intermittent retrograde cerebral perfusion is superior to continuous retrograde cerebral perfusion for protecting the brain during aortic arch surgery.

Adult↗
PubMed2002

Partial left ventriculectomy in pediatric end-stage dilated cardiomyopathy.

OBJECTIVE: Although a recent survey on pediatric cardiomyopathy in Japan showed that 48% of patients died despite the medical treatment, pediatric cardiac transplantation is not legal in Japan. We determined the feasibility of partial left ventriculectomy as an alternative to end-stage dilated cardiomyopathy. METHOD: We retrospective analyzed partial left ventriculectomy in 4 pediatric patients with end-stage dilated cardiomyopathy. RESULTS: In case 1, an 8-month-old girl underwent semiemergency partial left ventriculectomy. Her ejection fraction increased from 10% to 25%, and her condition improved initially, but she developed heart failure and underwent cardiac transplantation 6 months later in the US. In case 2, a 3-year-old boy developed severe heart failure 2 months after ventricular septal defect repair. Intensive medical therapy failed, so partial left ventriculectomy was done, which increased his ejection fraction from 15% to 35%. His condition is stable 35 months after surgery. In case 3, a 2-year-old girl with a chromosomal anomaly undergoing ventricular septal defect repair developed progressive heart failure 1 year later. Despite emergency partial left ventriculectomy, she died of hemoptysis 2 weeks postoperatively. In case 4, a 2-year-old girl developing progressive heart failure unresponsive to medical therapy after 10 months underwent elective partial left ventriculectomy and remains in stable condition 18 months postoperatively. CONCLUSION: Partial left ventriculectomy is appropriate for selected patients with end-stage dilated cardiomyopathy if medical therapy is not effective and heart transplantation is not possible.

Cardiac Surgical Procedures↗
PubMed2002

Indications for partial left ventriculectomy in pediatric dilated cardiomyopathy.

The purpose of this study was to define the role and indications of partial left ventriculectomy (PLV) in children with end-stage dilated cardiomyopathy (DCM). Clinical data were collected by retrospective chart review of children with DCM who were treated from 1997 to 2000. Four patients underwent PLV (PLV group) and 5 patients were managed without PLV (non-PLV group). In the PLV group, 2 patients are well 18 and 35 months postoperatively. One infant survived 6 months and then successfully underwent heart transplantation, and the other child died of hemoptysis 2 weeks postoperatively. Factors affecting outcome were preoperative status, in particular whether surgery was performed urgently or electively. In the non-PLV group, 4 patients were well controlled by medical treatment and 1 infant underwent mitral valve replacement for severe mitral regurgitation. The cardiothoracic ratio ranged from 72% to 76% in the PLV group and from 45% to 60% in the non-PLV group. The percentage of the expected left ventricular diastolic dimension ranged from 184% to 218% in the PLV group and from 109% to 163% in the non-PLV group. Ejection fractions in the PLV group were from 10% to 22% and from 36% to 56% in the non-PLV group. The serum brain natriuretic peptide concentration was above 1,200 pg/ml in the PLV group and below 168 pg/ml in the non-PLV group. In conclusion, PLV is indicated for selected children with end-stage DCM, and is most appropriate when medical therapy is not effective and heart transplantation is unavailable.

Adolescent↗
PubMed2002

Accessory hepatic vein complicating extra-cardiac total cavopulmonary connection.

We encountered unexpected, severe hypoxia after the right heart bypass operation in a patient with isomerism. A 2-year-old girl with polysplenia had a complex cardiac anomaly consisting of a single atrium, single ventricle, pulmonary stenosis, absence of the right superior vena cava, hemiazygos continuation of the left inferior vena cava, and d-malposition of the great arteries. After a total cavopulmonary shunt, we performed an extra-cardiac total cavo-pulmonary connection with a 14 mm tube graft. The postoperative course was complicated by severe hypoxia. Angiography performed 20 days after the operation showed that contrast medium in the conduit poured into the hepatic vein, and through the intrahepatic communications, it passed into a left-sided accessory hepatic vein, which was connected directly to the left side of the aspect of the atrium. As the intrahepatic communication was adequate, we ligated the accessory hepatic vein within the pericardial cavity. The SpO2 returned to normal and no hepatic dysfunction was detected. We conclude that surgeons performing extra-cardiac total cavopulmonary connection need to pay closer attention to the possibility that an accessory hepatic vein might exist.

Child, Preschool↗