The International journal of artificial organs
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Comparative Study
Complete extracorporeal removal of metabolic carbon dioxide by alkali administration and dialysis in apnea.
The high mortality rate of patients afflicted with adult respiratory distress syndrome (ARDS) may be due, in part, to the hemodynamic changes and the barotrauma accompanying mechanical ventilation, especially when high positive pressure and oxygen tension are used. Recent experimental evidence suggests that prognosis may be improved by suspending ventilation: in the apneic condition, oxygenation can be maintained by transalveolar oxygen diffusion, while extracorporeal carbon dioxide removal (ECCO2R), achieved with membrane lungs, assures CO2 homeostasis. This technology, however, requires high blood flow rates, and is available only to very few specially equipped centers. ⋯ Sodium and fluid balance were maintained by ultrafiltration. Observations in five dogs confirm that systemic pCO2, TCO2, and pH can be maintained well within physiologic ranges, and that prolonged apnea followed by full recovery can be achieved with this methodology. Because of the wide availability of dialysis equipment and expertise, and of lower extracorporeal blood flow requirements, ECCO2R by alkali administration and hemodialysis offers a potentially attractive alternative approach to the use of membrane lungs in the apneic therapy of ARDS.
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Spinal opiate receptor tolerance is the major limitation of continuous intraspinal narcotic analgesia delivered by implanted reservoir pump. Six intractable pain patients receiving continuous epidural morphine were given trials of low dose bupivicaine HCL in order to assess the effects on implanted reservoir function, analgesia, and safety. Daily infusion of 2.6-18.8 mg bupivicaine HCL had no consistent effect on flow rates. ⋯ No sympathectomy was appreciated at these doses. The future of continuous intraspinal analgesia might require further advances in implantable infusion pump technology to allow manipulation of both daily infusion doses and multiple intraspinal analgesics. Further study is needed to assess the safety and effectiveness of higher continuous intraspinal bupivicaine doses for chronic pain relief.
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Exact control of ultrafiltration (UF) is a prerequisite for high flux dialysis and hemodiafiltration. Volumetric dialysate balancing is the best current method for the use of dialyzers with high water permeabilities. ⋯ A positive influence of volumetric UF control on patients undergoing chronic hemodialysis can be shown by the frequencies of dialysis side effects. Volumetric UF control is only a first step towards an intelligent UF module to correlate water removal, solute removal and sodium balance.