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Biomedical subjects

K Motohiro

Publications and source records attributed to K Motohiro.

48 records · Page 3Linked to original sources

Influence of surgery for ischemic heart disease on early postoperative left ventricular function.

The pre- and postoperative systolic time intervals, hemodynamics and serum catecholamines were studied in 30 patients with successful myocardial revascularization surgery or left ventricular aneurysmectomy and the influence of the surgery on the left ventricular function was evaluated. 1. Significant depression of left ventricular performance was recognized in the group of patients with left ventricular aneurysm as compared to the patients with angina pectoris with or without previous myocardial infarction before the operation. 2. At 2 hours after the operation, signigicant decrease of ET/PEP, cardiac index and stroke work index and marked elevation of systemic vascular resistance were seen in the group of patients with aortocoronary bypass surgery who had previous myocardial infarction and with left ventricular aneurysmectomy as compared to the group of patients without previous myocardial infarction. 3. At 2 hours after the operation, ET/PEP seemed to reflect the left ventricular stroke work and the depression of the left ventricular function was mainly affected by the elevation of systemic vascular resistance due to the hypersecrection of serum catecholamines. 4. Reduction of systemic vascular resistance by vasodilator brought an improvement of EG/PEP, cardiac index and stroke work index.

Cardiac Output↗

Relation of stroke and cardiac indices to serum catecholamines following open heart surgery.

Serum catecholamines (epinephrine, dopamine and norepinephrine) were measured two, four and six hours after open heart surgery. The ratios of stroke index (SI) and cardiac index (CI) to catecholamines (CA) were determined. Patients studied consisted of 27 with congenital and 14 with acquired heart disease. Extracorporeal circulation (ECC) time was longer than 90 minutes in 17 and shorter in 24 patients. SI and CI diminished in elder patients with congenital disease (Group Cg-ad), patients with acquired disease (Group Ac) and patients with a longer ECC time (Group L). Therefore, elder age and/or longer ECC time seems to be responsible to the lower indices. However, the ratios of the indices to CA showed that the lower indices indicated the poor response of the myocardium to CA in Group Ac and Group L. The response was larger in Group Cg-ad and the lower indices were related to lower serum CA level. It was concluded, therefore, that the indices of stroke volume and cardiac output had inverse correlation to ECC time, but not to age, namely, prolonged ECC compromised more severely the myocardium and resulted in the poor response of the myocardium to CA. Subsequently, to compensate for the poor response, serum CA levels were elevated probably to maintain due SI and CI in patients with prolonged ECC.

Adolescent↗

Myocardial protection during open-heart surgery: intermittent aortic crossclamping versus coronary perfusion.

Twenty-seven patients undergoing open-heart surgery were divided into three groups, i.e., control, intermittent aortic crossclamping and coronary perfusion groups. Myocardial oxygen extraction, lactate extraction, arterial-coronary sinus hydrogen ion difference, potassium difference and glucose difference were determined during the operation, as well as, postoperative stroke and cardiac indices and comparisons were made. When the ascending aorta was not crossclamped, myocardial metabolism was well preserved during and after the perfusion at a flow rate of 2.0 L./min/m2. Intermittent aortic crossclamping for 15 minutes alternating with a period of perfusion for five minutes at 30 degrees C was sufficient to protect the myocardium from ischemia. Perfusion of the left coronary artery alone at a flow rate of six per cent of total body perfusion (150 to 200 ml per minute) at 30 degrees C was sufficient to protect the myocardium when the aorta was opened. Since intermittent perfusion of the left coronary artery may produce myocardial derangement, coronary perfusion should be continuous. Otherwise topical cardiac cooling or other means of myocardial protection should be used.

Adolescent↗

Mechanodynamics at the interventricular sulcus--reciprocal effect of the ventricles on the ventricular function.

The forces acting on IVS were analyzed to delineate reciprocal effects of the two ventricles on the ventricular fucntion as a whole. The resultant force (FT) was dependent on the LV pressure but independent on the RV pressure. But the composite forces (F1 and F2) of FT were affected by the LV and RV pressures. In a normal heart F1 increased with increasing LV and/or RV pressures. But in F2 increase occurred only with increasing RV pressure. In the LV pressure increase occurred only when the RV pressure was 10 mmHg and decrease did when the RV pressure was 50 mmHg, while stable at 30 mmHg. Directions of both the forces (F1 and F2) diverged as the RV pressure increased and the LV pressure decreased. When FRV was hypertrophic, increases of the magnitudes of the forces were decreased when the pressures of the LV and RV were higher. The angle between the forces was also decreased so that the efficiency of the forces was risen. When a portion of the ventricles lost its contractility, FT increased, particularly, when FLV lost its contractility. But these increases seemed to well be within range of compensation.

Biomechanical Phenomena↗

Lung cancer associated with pulmonary bulla. case report and review of literature.

A few reports have suggested the possible association between lung cancer and bullous disease. We report a surgical case of lung adenocarcinoma located in close proximity to pulmonary bullae. A 48-year-old nonsmoker, asymptomatic male was found to have a pulmonary tumor mass and giant bulla in the right lung. Thoracotomy identified a tumor arising from a firm, scarred and contracted area close to the bulla wall. Based on this report and review of other cases in the literature, we emphasize the need for physicians to be aware of the potential development of lung cancer in patients with pulmonary bulla.

Adenocarcinoma↗