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Biomedical subjects

F D Dorman

Publications and source records attributed to F D Dorman.

At least 19 recordsLinked to original sources
PubMed1986

A new peritoneovenous shunt.

For today's most common peritoneovenous shunt catheters, the high incidence of complications (disseminated intravascular coagulation [DIC], pulmonary problems, clotting of the intravascular end, and shunt kinking) results in limited use. We have designed a new peritoneovenous shunt catheter in which we improved mechanical biocompatibility with respect to both the peritoneum and the vasculature. The device consists of: a multimicroorifice ascites filter in a double-chambered collecting device, a tubular compression pump with an intratubular check-valve, and a check-valve catheter at the intravascular end for positive exclusion of blood by reflux or back diffusion. This configuration filters the proteinaceous material from the ascites fluid, transports the filtrate into the blood stream, maintains patency, act to prevent DIC by inhibiting the creation and transport of microthrombi into the cardiovascular system, and eliminates clot formation at the intravascular end.

Aged↗
PubMed1979

Control of blood glucose in experimental diabetes by means of a totally implantable insulin infusion device.

Near-normal glucose tolerance tests in diabetic dogs were obtained during basal rate insulin infusions in restrained animals by use of extracorporeal infusion pumps and in conscious, unrestrained animals by means of implanted infusion pumps. Even better regulation of blood glucose in diabetic animals was obtained by the addition of predetermined pulses of insulin at higher flow rates than the basal flow rate, accomplished by use of a transcutaneously activated valve mechanism attached to the implanted infusion pump. We conclude that near-normal blood glucose concentrations can be maintained throughout the day in the dog by these means and that similar approaches, using implantable infusion pumps, in man may lead to better long-term control of diabetes than is currently available.

Animals↗
PubMed1973

Study leave in UK.

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Bedding and Linens↗
PubMedDate not supplied

The Minnesota shunt.

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Ascites↗
PubMedDate not supplied

The spring-driven implantable pump. A low-cost alternative.

In the current era of cost containment in medicine, manufacturing economics have become increasingly important. The authors devised an implantable pump powered by spring force from an elastomeric Belleville washer, which is also the outer flexible wall of the drug reservoir. Use of formed and injection molded parts provides for low-cost manufacturing, in contrast to the precision welded alternative designs. Additional advantages include insensitivity to changes in ambient temperature and pressure. Finite element modeling of the elastomer spring allows prediction of the effects of parameter changes on performance, so that expansions and reductions of scale can be made without compromising the uniform spring rate of the device. A concern that subcutaneous fibrous encapsulation might markedly alter reservoir pressure was not supported by experimental data. In a unit implanted subcutaneously in a dog, reservoir pressures measured over a 4 year period were stable. This new, simple, implantable infusion pump can serve as an economical vehicle for prolonged parenteral drug treatment of ambulatory subjects in circumstances where continuous single-rate infusion is appropriate.

Animals↗
PubMedDate not supplied

Catheter with an anchoring tip for chronic joint capsule perfusion.

An orthopedic catheter for long-term access to the synovial joint is anchored by a hollow threaded tap that penetrates the capsule through a hole drilled in the surrounding bone. The proximal end of the catheter is connected to either an implantable drug infusion pump or an implantable access port for continuous or intermittent perfusion or sampling. Four catheters were evaluated in dogs. Three were attached to ports, the fourth to a pump. Water (one trial, 22 weeks) and hyaluronic acid (HA) (5 mg/ml; two trials of 8 weeks each) were administered through ports twice weekly in 1.5 ml boluses; 5 mg/ml HA was delivered by pump (1 trial of 33 weeks) at 0.31 ml/day.

Animals↗