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Biomedical subjects

U Wegelius

Publications and source records attributed to U Wegelius.

35 records · Page 2Linked to original sources
PubMed1992

Euglycemic hyperinsulinemic clamp and oral glucose load in stimulating myocardial glucose utilization during positron emission tomography.

To enable assessment of myocardial viability, myocardial glucose utilization has commonly been stimulated by oral glucose loading. To compare the effects of glucose loading and insulin and glucose infusion (insulin clamp) on PET fluorodeoxyglucose ([18F]FDG) myocardial scan image quality and regional myocardial glucose utilization rate (rMGU), eight patients with angiographically documented coronary artery disease and previous myocardial Q-wave infarction were studied twice, once during insulin clamp and once 1 hr after oral glucose loading. The rMGU rates were derived by graphic Patlak analysis in 33 normal, 10 scar and 6 "hot spot" myocardial segments. Infusion of insulin and glucose gave stable plasma-glucose and serum-insulin levels during imaging. In contrast, glucose loading caused marked changes in plasma-glucose and insulin concentrations. The image quality was clearly superior and the fractional utilization rates of [18F]FDG were twice as high during insulin clamp than after glucose loading (p less than 0.0001). Due to the higher plasma-glucose levels after glucose loading, the calculated rMGU in normal, scar and hot spot myocardial segments was comparable between the two protocols. The insulin clamp technique makes it possible to adjust and maintain a metabolic steady state during the PET study. It does not alter [18F]FDG uptake patterns in different myocardial areas when compared to the standard glucose loading protocol, but this technique results in superior image quality and permits the use of smaller [18F] FDG patient doses.

Administration, Oral↗
PubMed1985

Haemodynamic response to nitrous oxide during high-dose fentanyl pancuronium anaesthesia.

Ten patients subjected to coronary by-pass surgery were studied to determine the haemodynamic effects of replacing Fio2 1.0 normoventilation with nitrous oxide in oxygen (Fio2 0.3) after induction of anaesthesia with fentanyl (50 micrograms/kg), flunitrazepam and pancuronium. In all patients the application of N2O decreased systemic arterial pressures by an average of 10% (P less than 0.001), but left pulmonary arterial pressures and systemic vascular resistance unchanged. The slight bradycardia induced was associated with moderate depression of the cardiac index and the left ventricular stroke work index (P less than 0.001) at the time when the rate-pressure product was decreased by 20% (P less than 0.001). The cardiac depression produced by N2O was most prominent in patients with left ventricular wall hypokinesia and an ejection fraction below 55%, in whom the cardiac work index was diminished by 29%. The replacement of oxygen with nitrous oxide in oxygen during high-dose fentanyl-pancuronium anaesthesia seems not to be associated with sympathetic stimulation, and the myocardial depressant effect of N2O should be weighed against the possible reduction in myocardial oxygen consumption with special care in patients with compromised myocardial function.

Adult↗
PubMed1977

Surgical treatment of aneurysms of the ascending aorta. With special reference to cystic medial necrosis of the aorta.

The clinical series comprised 14 patients with aneurysms of the ascending aorta. In the autopsy series, there were additionally 19 patients, who had died suddenly as a results of free perforation or dissection of the ascending aorta. In the clinical series, the cause of the aneurysmal formation was cystic medial necrosis in 10 patients, 8 of whom had severe aortic valve insufficiency. Twelve patients were operated on using extracorporeal circulation, Both the ascending aorta and aortic valve were replaced with prosthesis in 6 cases. Three patients underwent emergency surgery due to pericardial tamponade. All three died, despite a technically successful operation. One patient out of 9 electively operated upon died. A follow-up examination was carried out on the 5 surviving cystic medial necrosis patients. Aneurysms of the sinuses of Valsalva developed after supracoronary resection in 2 patients. The results showed that elective operations in the event of aneurysms of the ascending aorta can be carried out with an acceptably low mortality rate. However, after supracoronary resection, in cases of cystic medial necrosis, the risk of developing aneurysms of the proximal aortic remnant seems obvious. Therefore, in patients in whom the whole aortic root is involved, total removal of the ascending aorta and re-implantation of the coronary ostia into the prosthetic tube is preferable.

Adolescent↗
PubMed1976

Experiences with the Björk-Shiley tilting disc valve in aortic and mitral valve surgery.

During a four-year period, aortic or mitral valve replacements with the Björk-Shiley tilting disc valve were performed in 114 cases. The series comprises 75 aortic, 34 mitral and 5 double valve replacements. In the aortic valve group (AVR) concomitant resection of the ascending aorta (cystic medial necrosis aneurysm)) was carried out in 5 cases, aortocoronary bypass in 2 cases and closure of a VSD in one case. Antibiotic prophylaxis and postoperative anticoagulant treatment were used routinely. The hospital mortality rates were6 8.0% in the AVR-group (single aortic valve mortality 7.1 %), 8.8% in the MVR-group and 60% in the double valve group. Late mortality in the AVR-group was 2.8%. There were no late thromboembolic complications in this group. Aortography showed grade II--III regurgitation (paravalvular leaks) in 15 % of the cases. In the MVR-group the late mortality was 9.7%. One patient died because of malfunction (thrombosis) of the prosthesis. The thrombotic complication was obviously caused by discontinuation of anticoagulant therapy. The clinically estimated functional capacity NYHA classification) improved considerably, especially in the MVR-group.

Adolescent↗