ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Extracorporeal membrane oxygenation (ECMO) can provide univentricular or biventricular cardiac, as well as respiratory, support; it has extended the application of ECMO to infants and children who develop refractory cardiogenic shock before or after repair of congenital heart defects. The Pediatric Cardiac ECMO Registry, recently established by the Extracorporeal Life Support Organization, reports an overall survival rate of 47%. ⋯ Hemorrhage remains the most common complication of ECMO. The future of ECMO for cardiac support depends on development of methods to prevent cardiac failure, improved ECMO techniques, and increased pediatric cardiac transplantation.
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Hypoxemia during acetate dialysis is caused by hypoventilation due to bicarbonate loss across the dialyzer and its regeneration from acetate by a CO2 consuming process. Loss of bicarbonate is prevented by using a bicarbonate containing dialysate, but hypoxemia is still found by many authors. In the current study, ten patients were dialyzed twice against acetate dialysate, high concentration bicarbonate (36 mmol/L), and low concentration bicarbonate (29 mmol/L) dialysates. ⋯ Hypoxemia was prevented by low concentration bicarbonate dialysate. A possible explanation for the hypoxemia in high concentration bicarbonate dialysis may be hypoventilation induced by alkalosis. It was concluded that low concentration bicarbonate dialysate prevents hypoxemia during hemodialysis.
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The implantable pump field is now more than 20 years old. The original goal of developing a totally artificial beta-cell remains unrealized, but programmable insulin pumps that contain all of the elements of the artificial beta-cell except the glucose sensor are involved in clinical trials in the United States and are commercially available in Europe. ⋯ Only a few of the potential applications of implantable pumps have been developed to the stage of commercial availability. This is, in part, because drug companies have traditionally developed parenteral drug applications only as a last resort and, in part, because of the complexity of the regulatory process for implantable pumps, often requiring review by both the drug and device branches of the Food and Drug Administration.
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Most extracorporeal continuous renal replacement therapies (CRRT) require inflow pumping of either dialysate, filtrate replacement solution, or both. Outflow of spent dialysate and ultrafiltrate can be accomplished by gravity drainage or pump. Intravenous infusion pumps have been commonly used for these purposes, although little is known about the accuracy of these pumps. ⋯ The linear peristaltic pumps were most accurate under conditions of low pump inlet pressure, whereas piston pumps were most accurate under conditions of low pump pressure gradient (outlet minus inlet) of 0 or -100 mmHg. The magnitude of error outside these conditions was substantial, reaching 12.5% for the linear peristaltic pump when inlet pressure was -100 mmHg and outlet pressure was 100 mmHg. Error may be minimized in the clinical setting by choosing the pump type best suited for the pressure conditions expected for the renal replacement modality in use.
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Case Reports
Where should the hemofiltration circuit be placed in relation to the extracorporeal membrane oxygenation circuit?
Patients requiring extracorporeal membrane oxygenation (ECMO) frequently experience hypervolemia and metabolic abnormalities that can be effectively managed by hemofiltration. Although several options for hemofiltration circuit placement exist, some may have the disadvantage of recirculation or shunting of poorly oxygenated blood to the patient. ⋯ Despite the absence of pump generated pressure and a low blood flow rate, effective hemofiltration and diafiltration were achieved. This article examines whether placement of the hemofiltration circuit proximal to the ECMO pump has advantages over other hemofiltration circuit placements.