Transactions - American Society for Artificial Internal Organs最新文献

Continuous arteriovenous hemofiltration (CAVH) is increasingly used in treatment of acute renal failure. There are no clinical comparisons to acute hemodialysis (HD). We studied control of uremia, electrolyte and fluid balance, and incidence of bleeding, hypotension, and tachyarrhythmia in 4 patients randomly alternated between CAVH and HD. The side effects both during and 4.3 hrs after each HD (total 88 + 97 = 187 hrs) were analyzed to allow time comparison. Five CAVH treatments (total 187 hrs) where 147 L BUN clearance and 10.9 kg net ultrafiltration (UF) occurred; and 23 HD (88 hrs) where 790 L BUN clearance and an UF of 34 kg were compared. Uremia and fluid and electrolyte control were achieved by all treatments except one CAVH session. Two patients had bleeding episodes on CAVH, and none on HD, despite careful minimal heparinization. There were 2 episodes of sudden hypotension on CAVH versus 6 on or after HD. Per unit time, there were 3 times as many episodes of hypotension with HD. Four episodes of sustained tachyarrhythmia occurred on CAVH, and 5 occurred on or after HD. When these side effects were more meaningfully normalized to BUN clearance, there were twice as many hypotensive events and 4 times as many tachyarrhythmic episodes on CAVH as on HD, although UF rate was 7 times faster on HD. CAVH is simple to do, but has more clinical ill effects than HD when normalized to treatment efficiency. The continuous heparinization necessary for CAVH is potentially dangerous, despite careful monitoring. The clinical safety of CAVH has probably been over-rated, and it best may be suited to patients with acute renal failure who do poorly on HD.

The LVAS utilizing an intrathoracic blood pump and a parathoracic, electrohydraulic energy converter has a number of promising features. These include: transcutaneous energy transmission and an implanted variable volume device which eliminate the need for percutaneous access; utilization of an intrathoracic blood pump and variable volume device which allow the diaphragm and abdominal cavity to remain intact; parathoracic or subcutaneous location of the transformer secondary, energy converter, internal battery and interconnecting elements allowing replacement with a minor surgical procedure; employment of the "biolized" continuous blood contacting surface which has the potential of long-term use without anticoagulants and utilization of an electrohydraulic energy converter which provides synchronization without requiring transducers and associated electronics and which provides lubrication of mechanical components. The development effort, which began separately in 1977 and has been conducted jointly by Nimbus and the Cleveland Clinic since 1980, has demonstrated that the above features can be incorporated in a reliable LVAS. In particular, the system in vivo test series have demonstrated the soundness of the basic concepts and led to refinements which were demonstrated in the 6-1/2 mo test. All elements of the system have been utilized during the in vivo test program. Component tests of significance include: LVAS and total heart blood pump in vivo experiments of up to 7 mos duration which demonstrate the blood compatibility of the biolized surface without the use of long-term anticoagulation.(ABSTRACT TRUNCATED AT 250 WORDS)

A review of animals receiving a TAH with 4 mechanical valves suggests that the least damage to the blood cell components is associated with the BS valve when compared with the MH valve at similar heart rates. Clinical anemia in varying stages was observed in most animals in this study. However, most calves compensated for the increased rate of hemolysis and none required blood transfusions. The BS valve would appear to combine minimal turbulence and mechanical crushing in a physiological setting.

We have introduced novel synthetic anticoagulant and complement inhibitors for controlled release systems with high biocompatibility. These drugs were molecularly designed for extremely high biospecific inhibition, are readily soluble in polar organic solvents, such that they have versatile applications in commonly used hydrophilic polymeric systems via an easily attainable one-step co-casting technique at a given amount of loading. Another characteristic feature of the controlled release system is that both release rate and duration are controlled by the material, formulation and fabrication variables. These are easily manipulated by the hydrophilicity of polymers, amount of loading and film thickness. The drug-impregnated system may generate a new dimension in the formulation of controlled release biocompatibility.