| 1. |
- Koul, Bansi, et al.
(författare)
-
Twenty-four-hour heparin-free veno-right ventricular ECMO: an experimental study
- 1992
-
Ingår i: Annals of Thoracic Surgery. - 1552-6259. ; 53:6, s. 1046-1051
-
Tidskriftsartikel (refereegranskat)abstract
- Platelets and coagulation factors were studied during 24-hour heparin-free veno-right ventricular extracorporeal membrane oxygenation (ECMO) in 6 healthy pigs. An endpoint attached and covalently bonded heparin-coated ECMO system was used in these experiments. The veno-right ventricular ECMO supplied the total lung function of the animals, and after 24 hours, all the animals were successfully weaned from ECMO. Lung function and central hemodynamics were not affected by the procedure. Because all the animals showed a significant reduction in plasma volume, the concentration of measured coagulation variables was corrected both for plasma volume changes and for hemodilution. The platelet count and the plasma-free hemoglobin level were not significantly altered by ECMO. Similarly, the prothrombin complex, antithrombin, thrombin-antithrombin complex, factor XII, and the urinary excretion of 2,3-dinor-thromboxane B2 were not significantly altered. Fibrinogen and fibrin monomer increased significantly, whereas von Willebrand factor was significantly decreased after ECMO. In summary, 24-hour heparin-free veno-right ventricular total extracorporeal lung assistance does not affect the platelets and the coagulation system significantly in healthy juvenile pigs.
|
|
| 2. |
- Koul, Bansi, et al.
(författare)
-
Venoarterial extracorporeal membrane oxygenation--how safe is it? Evaluation with a new experimental model
- 1992
-
Ingår i: Journal of Thoracic and Cardiovascular Surgery. - 1097-685X. ; 104:3, s. 579-584
-
Tidskriftsartikel (refereegranskat)abstract
- This study was undertaken to find out if about 25% right cardiac output is sufficient for preservation of lung function during prolonged periods of venoarterial extracorporeal membrane oxygenation. Six healthy pigs weighing 57 kg were subjected to 18-hour venoarterial extracorporeal membrane oxygenation. During this period 1200 ml/min venous blood was delivered to the lungs through the pulmonary artery with the help of a separate roller pump and with use of the animal's own right ventricle to generate the pulse. Animals were observed for 6 hours after weaning from the venoarterial extracorporeal membrane oxygenation. At the sixth hour after extracorporeal membrane oxygenation, arterial oxygen tension, venous oxygen tension, lung compliance, and cardiac output had decreased significantly. Pulmonary vascular resistance and pulmonary clearance of technetium 99m-diethylenetriamine pentaacetic acid increased significantly also. The systemic arterial and venous carbon dioxide tensions, pH, and the base excess remained unchanged, as did the blood pressure and the systemic vascular resistance. Histopathology of the lung specimens revealed focal alveolar wall thickening and alveolar capillary congestion. The major portion of the pulmonary parenchyma looked normal. Alterations in pulmonary parameters cited were, to a major extent, explained on the basis of the experimental protocol followed and were believed to be reversible. This study suggests that about 25% of the systemic cardiac output should be diverted into the pulmonary artery for prevention of irreversible physiologic and histopathologic changes in the lungs during 18-hour normothermic venoarterial extracorporeal membrane oxygenation in healthy juvenile pigs.
|
|
| 3. |
- Sjöberg, Trygve, et al.
(författare)
-
Endothelium-mediated relaxation in transplanted aorta
- 1992
-
Ingår i: Annals of Thoracic Surgery. - 1552-6259. ; 53:6, s. 1068-1073
-
Tidskriftsartikel (refereegranskat)abstract
- This study compares the vasodilating effect of endothelium-derived relaxing factors (EDRFs) in free arterial grafts with that in their normal control vessels. The infrarenal aorta of Sprague-Dawley rats was transplanted into the same position in other inbred recipient rats. A Krebs buffer solution (4 degrees C) served as the preservation solution. The ischemic time for the grafts (n = 8) was 42 +/- 1 minutes. Two grafts were studied after 3 days and six grafts, after 60 days. Ring segments were cut from all vessels, and isometric contractions were recorded in organ baths. The vessel segments were constricted with noradrenaline, a thromboxane A2 mimic (U-46619), or prostaglandin F2 alpha. Concentration-response curves with acetylcholine, which was used as the endothelium-stimulating substance causing release of EDRFs, were obtained. The patency of the grafts was 100%. Acetylcholine induced relaxation in all vessel segments with intact intima, whereas no relaxation was seen when the endothelium was manually removed. No significant differences were found between the grafts and the normal control vessels. Histology of the 60-day grafts showed elastomuscular arteries without intimal thickening and a media consisting of eight to ten muscle layers interrupted by five to six elastic lamellae. Scanning electron microscopy showed no major differences between normal endothelium and the endothelium of 3-day or 60-day grafts. This study indicates that free elastomuscular arterial grafts, in which the morphology of the intima is preserved, will retain their full ability to release EDRFs.
|
|
| 4. |
- Wetterberg, T, et al.
(författare)
-
Combined use of hypothermia and buffering in the treatment of critical respiratory failure
- 1992
-
Ingår i: Acta Anaesthesiologica Scandinavica. - 0001-5172. ; 36:5, s. 490-492
-
Tidskriftsartikel (refereegranskat)abstract
- A 20-year-old male, recovering from post-traumatic ARDS, subsequently developed pneumonia with extreme hypercapnia (PaCO2 max 19.4 kPa) and hypoxemia (PaO2 min 5.1 kPa), in spite of maximal mechanical ventilation. Hypothermia was induced by surface cooling, reducing the body temperature from 40 degrees C to a mean of 33.3 degrees C. Buffer infusion (1375 mmol) during the first 2 days increased base excess from 3 to 22 mmol/l and pH from 7.16 to a median value of 7.30. Active cooling was discontinued on day 11. Weaning from the ventilator was possible 9 days later and the patient subsequently recovered fully. Combined use of hypothermia and buffering might offer an alternative to extracorporeal lung assist (ECLA) and facilitate a reduction of barotrauma and oxygen toxicity during mechanical ventilation.
|
|
