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Biomedical subjects

O Geiran

Publications and source records attributed to O Geiran.

At least 91 records · Page 5Linked to original sources
PubMed1986

Continuous monitoring of cardiac output postoperatively using an implantable Doppler probe.

The authors evolved a Doppler probe which can be attached to the ascending aorta intraoperatively. Using a pulsed echo Doppler flowmeter operating at 2 mHz, cardiac output was continuously measured during the first 2 days after open-heart surgery in 20 patients. The internal diameter of the aorta was assessed with ultrasound echo technique. The probe was fixed to the ascending aorta with a double suture through the adventitia. The suture was tightened by means of a long tourniquet which was passed through an infraxiphoid skin incision, between the two chest drains. A stable position providing adequate signals was achieved by use of probes with stabilizing "side flaps". In 8 cases the method was compared with the thermodilution technique using Swan-Ganz catheters. Analysis of 44 simultaneously performed measurements revealed a highly significant correlation between the two methods, and the results remained comparable throughout the 48-hour test period. There were no complications and all the probes could be easily removed.

Cardiac Output↗
PubMed1985

Heart transplantation in Norway. One-year experience.

Eight patients underwent orthotopic heart transplantation in Norway during 1984, with retransplantation in one case. The age range of the 5 men and 3 women was 19-53 years. The preoperative diagnosis was cardiomyopathy in 6 patients, ischaemic heart disease in one, and a combination of the two disorders in one patient. The immunosuppressive regimen, with cyclosporin A and low-dose prednisolone, and the treatment of graft rejection, followed the Stanford University protocol. There was no operative mortality. Three patients died shortly after the transplantation, 2 of them after about a week from acute rejection; in one of these 2 cases a second transplant was made, but was followed by pulmonary and renal complications. The third death occurred about 10 weeks postoperatively, from donor heart failure due to Toxoplasma myocarditis. The 5 survivors are clinically in good condition.

Adult↗
PubMed1985

High-dose corticosteroids in thoracic trauma.

Experimental data show that lung injury may be prevented or reduced when steroids are administered early. It seems, however, difficult to reverse a lung injury which is already established. Accordingly, we have since 1976 administered high doses of methylprednisolone already on admission in patients with multiple rib fractures and/or flail chest (30 mg/kg i.v. X 3 at 8 hr intervals). A retrospective analysis of 143 patients with severe blunt chest trauma, most of whom were multitraumatized (72%) and many in shock (19%) revealed a significantly lower mortality for 44 steroid treated patients compared to 99 nonsteroid patients with similar injuries (9.1 vs 29.3%, p = 0.02). The incidence of bronchial infection and septicemia was not increased in steroid treated patients. There was also a lower incidence of multiple organ failure in the steroid treated group (4.5%) as compared to the control group (9.1%, n.s.). Hemodynamic and blood gas changes were examined in a prospective controlled study including 40 patients with multiple rib fractures and lung contusion. Pulmonary vascular resistance (PVR), which is a good parameter of injury severity, was reduced significantly in the steroid treated group. This led to a reduction in right heart work. The corticosteroid induced reduction in PVR was seen whether the patient was on a ventilator or breathed spontaneously. There were no significant differences in the a-v oxygen difference or in intrapulmonary shunting. Both the number of complications and the duration of artificial respiration were reduced in the steroid group.

Female↗
PubMed1984

Should the lungs be ventilated during cardiopulmonary bypass? Clinical, hemodynamic, and metabolic changes in patients undergoing elective coronary artery surgery.

No beneficial effects were achieved by ventilating the lungs of a group of 10 patients during total extracorporeal circulation for coronary artery bypass operation. Ventilation of nonperfused lungs, which was suggested to prevent postoperative atelectasis, may even have negative effects. Intrapulmonary shunting increased significantly (p less than 0.05), while the shunt fraction in the nonventilated lungs of another group of 10 patients remained unchanged. There were only minor differences between the two groups with respect to systemic and pulmonary hemodynamic changes.

Cardiopulmonary Bypass↗
PubMed1984

Corticosteroids in the treatment of blunt injury of the chest.

In a prospective, controlled study, the effects of large doses of methylprednisolone sodium succinate (MP) were examined in patients subjected to severe blunt injury of the chest. Forty patients with multiple fractures of ribs were selected for the study. The majority of the patients had associated extrathoracic injuries. Chest X-ray films revealed changes characteristic of pulmonary contusion in all cases. Twenty patients were given MP 30 mg/kg body weight intravenously and were compared with 20 patients receiving no steroids, but who were otherwise treated identically. There were no differences between the two groups with respect to the A-VO2 difference and intrapulmonary shunting. However, the steroid treatment led to a significant reduction in pulmonary vascular resistance and to a reduction of the work of the right side of the heart. The number of complications and periods of artificial respiration were reduced in the steroid group. All patients survived.

Adult↗
PubMed1984

Compensatory cardiac mechanisms evoked by acute occlusion of the right coronary artery in dogs.

The cardiac response to intermittent occlusion of the right coronary artery was examined in anesthetized open-chest dogs at different levels of blood volume. The reduction in stroke volume averaged 15 +/- 2% and was related to the extent of the ischemic area (r = 0.72), which comprised 45-70% of the free wall of the right ventricle. Ultrasonic recordings of segment lengths showed end-diastolic distention and activation of the Frank-Starling mechanism in the uninjured parts of the free wall. The transseptal end-diastolic pressure difference was abolished, suggesting movement of the interventricular septum to the left. Nevertheless, the relationship between stroke volume and left ventricular end-diastolic pressure (left ventricular function curve) as well as the relationship between stroke volume and the end-diastolic segment length of the left ventricular free wall were unaltered. Comparisons of data obtained at similar stroke volume showed activation of the Frank-Starling mechanism in the interventricular septum which may compensate for the negative effect of a change in its position.

Animals↗
PubMed1983

Compensatory cardiac mechanisms evoked by septal ischemia in dogs.

To examine the cardiac responses to selective septal ischemia, the septal artery was occluded intermittently in anesthetized open-chest dogs. Myocardial segment length was recorded continuously by an ultrasonic technique in the interventricular septum and the right and left ventricular free walls. At left ventricular end-diastolic pressure of 3.0 +/- 0.6 mm Hg, occlusion of the septal artery increased left ventricular end-diastolic segment length by 3.9 +/- 0.9% and stroke volume was maintained. After blood volume expansion to a left ventricular end-diastolic pressure of 7.2 +/- 1.4 mm Hg, occlusion of the septal artery did not increase end-diastolic dimensions and stroke volume decreased significantly but by less than 10%. At all levels of blood volume expansion, occlusion of the septal artery did not alter significantly the end-systolic segment length of the free wall of the left ventricle and the dimensions of the free wall of the right ventricle. The distance between the septum and the right ventricular free wall was unchanged in end-diastole and reduced in end-systole after occlusion of the septal artery. These observations indicate paradoxical movement of the ischemic septum. The ischemic septum seems to act as a passive diaphragm pump on the right ventricle without activation of the Frank-Starling mechanism in uninjured areas. In the left ventricle, the Frank-Starling mechanism is fully exploited with unaltered end-systolic dimensions of the uninjured myocardium because of the systolic bulging of the ischemia septum.

Animals↗