Intravenous membrane oxygenator (IVOX), an artificial lung usually located in vena caval system, can provide extra oxygen outside the lung for patients suffering from respiratory failure. However, gas exchange areas of IVOX are limited because of confined space in caval system. The increase of the diameter of IVOX may impede the return of venous blood to heart, and result in serious low blood pressure. Thus, it is important to increase the efficiency of IVOX by reducing the diffusive resistance of boundary layers. In the present study, the hollow member fiber of IVOX was weaved in braids; we tested the oxygen transfer efficiency and blood flow resistance of this IVOX in vitro. The results showed that the total transferred oxygen, the oxygen transfer rate and blood resistance increased with the increase of blood flow. The oxygen volume transferred by the IVOX and the oxygen transfer rate were (55.97 +/- 0.51) ml/min and (127.19 +/- 0.66) ml/(min x m)2 respectively at the blood flow of 5 L/min and hemoglobin of 120 g/L. They were significantly higher than those at 4 L/min and 3.5 L/min, respectively. The pressure drop also increased from (11.87 +/- 1.57) cmH2O at 3.5 L/min of blood flow to (18.53 +/- 0.99) cmH2O at 4 L/min and 19.77+/- 0.51 cmH2O at 5 L/min. However, they are safe to the patients (< 20 cmH2O). These results suggest that this braid type of IVOX can safely provide 20%-30% oxygen outside the lung for an adult patient.
Animals ; Carbon Dioxide ; blood ; Hemoglobin A ; analysis ; Oxygen ; blood ; Oxygenators, Membrane ; classification ; Regional Blood Flow ; Swine

Objective To investigate which cells persistantly express interleukin (IL)-1β during the transition of acute neuroinflammaiton to chronic neuroinflammaiton and therefore to provide the evidences of targeted therapy for blocking neuroinflammation.Methods A single does of lipopolysaccharide (LPS) (2 mg/kg,LPS group) or 0.9％ saline (Control group) was intraperitoneally injected in aged rats.Level and gene expression of IL-1β in hippocampual tissue were measured by enzyme-linked immunosorbent assay (ELISA) and real time polymerase chain reaction (RT-PCR),respectively.Cells secreted IL-1β in hippocampus was detected via double fluorescence.Results Glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule-1 (IBA-1) positive cells were significantly increased day 1 (P ＜ 0.05) and latee on,gradually return to base level 30 days after LPS exposure.These changes were consistent with mRNA expressions of IL-1β and astrocytes-derived IL-1β in hippocampus.Neither IL-1β expressed in microglia nor in neurons was observed at any time point following LPS-treated.Conclusions LPS induces prolonged activation of glial cells and sustained expression of astrocytes-derived IL-1β,which may play an important role in the transition of acute neuroinflammation to chronic neuroinflammation.