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Biomedical subjects

M Franetzki

Publications and source records attributed to M Franetzki.

At least 19 recordsLinked to original sources
PubMed1982

Total implantation of a remotely controlled insulin minipump in a human insulin-dependent diabetic.

This study reports our first total implantation of an insulin minipump in a severely unstable 23-year-old female insulin-dependent diabetic. The implantable unit includes a stepping motor, a percutaneously refillable insulin reservoir (10 ml, U 100 special insulin), a battery with a life span of one year, and a method for prevention of overdosage. Variable continuous basal and superimposed 1-hour high rates are programmed and checked via an external remote controller. The pump was inserted in the lateral muscles of the abdomen and the insulin delivery catheter terminated in the peritoneal cavity. Excellent glycemic control was reached rapidly and has continued seven months after implantation (mean blood glucose is 123 +/- 62 mg/dl; glycosylated hemoglobin is 7.0 +/- 1.2%), with the unit providing the only source of insulin. The only negative aspects were a chronic lymphorrhea in the first two months, and a need for frequent and laborious insulin refills (every 20 days). Only slight local discomfort was experienced. Thus, although further miniaturization and autonomy are expected, these preliminary results show that with careful instruction and followup, implanted pumps could represent a reliable and safe alternative to conventional insulin therapy for selected diabetics.

Adult↗
PubMed1981

Long-term continuous intraperitoneal insulin infusion with an implanted remote-controlled insulin infusion device.

This is a report of the implantation and first 100-day operation using a remote-controlled programmable insulin infusion device in an insulin-dependent diabetic. To prevent insulin aggregation, a special surface-active polymer developed by Hoechst AG, Frankfurt, was used as an additive. Implantation was completed on April 8, 1981, and good metabolic control was reached immediately and has continued to date (July 1981), with this unit providing the only source of insulin. There have been no hypoglycemic attacks. Patient acceptance is very good. The Siemens unit, PFA 01 (external) and DFA 01 (implanted) has proved reliable and precise.

Blood Glucose↗
PubMed1979

A direct-display oscillation method for measurement of respiratory impedance.

The basic principle of the method described here is derived from a variant of the oscillation method. A reference impedance is connected to the mouth; between these two an oscillating flow is imposed. As a reference impedance we use a flexible tube, which acts as a virtually pure inductance or inertance. Respiration is hardly impeded. The only measured parameter is the alternating pressure in front of the mouth and this is easily picked up by a simple microphone. In contrast to former direct-display methods, the inertia and elasticity of the respiratory gas and the respiratory tract, i.e., airways including lungs and thorax, are also taken into account for the evaluation. The respiratory resistance is studied as a complex parameters, i.e., as an impedance. With the aid of diagrams or via electronic computation circuitry, the direct and continuous display of all impedance components such as its magnitude and phase, resistance, and reactance is possible. They can be read out as a function of time, respiratory flow, or volume.

Airway Resistance↗
PubMed1979

Preprogrammed insulin infusion with a portable pump system.

A glucose-controlled insulin infusion system (Biostator) was used to determine patient insulin requirement for clinical evaluation of a portable pump system (technical development by Siemens AG). Results from 6 insulin-dependent diabetics with respect to quality of control, carbohydrate/insulin ratio, and insulin requirement are shown. Preprogrammed insulin infusion with the portable system was carried out for up to 117 days.

Adolescent↗
PubMed1979

Use of glucose-controlled insulin infusion system for improvement of subcutaneous insulin regimen.

The use of an artificial pancreas for blood glucose monitoring and feedback correction for evaluation and improvement of subcutaneous insulin therapy facilitates the process of finding an optimal therapy regime for the individual patient. The frequency of hypoglycemic episodes can be reduced while maintaining good control, and hospital stays can be considerably shortened. This procedure is particularly useful in achieving tight control in pregnant diabetics.

Adolescent↗
PubMed1979

Continuous intravenous insulin therapy with a miniaturized open-loop system.

For the continuous intravenous application of insulin, a portable open-loop system was developed consisting of a delivery unit with a miniaturized pump and an insulin reservoir which is connected with an electronic control unit. The infusion rates were either preprogrammed or patient-controlled. Blood glucose control with both systems was tested in eight juvenile-type diabetics, among them two of the brittle type. Diabetic control during a 1-2-day pre-infusion period was compared with 2-3 days of continuous insulin infusion; as judged by the mean blood glucose value (MBG), the mean amplitude of glycemic excursions (MAGE), and glucosuria, all patients were significantly better controlled by the open-loop systems than by conventional therapy with subcutaneous insulin. The use of portable open-loop systems offers a promising approach to an improvement of metabolic control in insulin-requiring diabetics.

Adult↗
PubMed1979

Technological problems of miniaturized insulin dosing devices and some approaches to clinical trials.

With the long-term goal of developing implantable insulin dosing devices, we have since 1971 developed various types of programme-controlled units for clinical research. In the initial stage, a 24-hour, fixed-programme bed-side device has been in clinical use since 1973. The good results with even labile diabetics has supplied the basis for the further development of sensorless units. Via intermediate stages, two types of miniaturized portable devices were constructed: fixed-programme and demand-programme devices. The essential equipment components have been optimized with a view to later implantability: hermetically sealed capsule for the dosing device, refilling membrane for the insulin reservoir, bubble-free drawing off of the insulin via a wick from a collapsible silicone reservoir, the stepping motor-driven roller pump of approx. 9 cm3 volume, an energy consumption of about 50 mu W, and electronic safety and alarm circuits. Because of stability problems of the insulin, the neutral insulin U-1000 used initially was changed to acid insulin U-100 (both from Hoechst).

Animals↗
PubMed1979

[Oscillatory determination of functional residual capacity (FRC)].

The washing-in of a low density gas (80% He, 20% O2) into the lung is being eased by greater diffusibility and diminished work of breathing. Helium analysis was performed by means of the oscillation method with an equipment suitable for the assessment of resistance to breathing. The density of helium gas mixture is being compared to the density of ambient air.

Functional Residual Capacity↗
PubMed1978

[Diabetic control with a portable insulin infusion pump for 7 weeks (author's transl)].

A portable insulin infusion pump was used to achieve diabetic control over a period of 7 weeks in a juvenile onset-type diabetic. Insulin was infused at a basal rate and further doses could be triggered externally by the patient. Insulin requirement had been previously determined by means of an artifical beta-cell (Glucose Controlled Insulin Infusion System). This method of insulin administration resulted in a clear improvement in diabetic control. Some problems did arise in connection with materials from which the instrument and catheter were constructed. However, it was shown that a portable insulin pump can be used with out-clinic patients for a number of weeks and is also justified for at least certain cases.

Adult↗
PubMed1976

[Viscosity and density fluctuations of natural respiratory gases and of mixtures of helium, oxygen and nitrogen due to temperature and composition of the gas mixture (author's transl)].

For the estimation and correction of errors in the measurement of the respiratory flow with viscosity-affected respiratory flow receptors the viscosity of natural respiratory gases (N2, O2, CO2, H2O) and of the ternary system helium-oxygen-nitrogen, which is of importance in pulmonary function diagnosis, was determined. Corresponding density values were calculated. Allowance was made for such special features of spirometry as exchange of O2 for CO2 and water vapour saturation at 37 degrees C. The viscosity of the ternary system is shown in a graph. The formulae indicated have been simplified as far as this was compatible with the demands of accuracy. The fluctuations in density and viscosity of natural respiratory gases can be read directly from a table.

Carbon Dioxide↗
PubMedDate not supplied

Development of program-controlled portable insulin delivery devices.

Various alternatives for program-controlled insulin delivery systems, on which we have been working since 1972, are described. Fixed-programmable and demand-programmable devices, both in two parts comprising separate control and delivery units, have been miniaturized and technically improved to the extent that they can now be used for the ambulant, long-term treatment of diabetic patients. The electronic drive systems, including control and safety circuits, that are discussed using the demand-type system as an example have been conventionally designed, using CMOS technology. The mechanical components of the insulin-delivery devices, in particular the roller pump driven by a stepping motor, have been developed in such a way that they can also be employed in implantable devices, without any essential modifications. Particular attention was thus paid to the features of miniaturization, high insulin concentration, low energy consumption, and a high degree of safety and reliability. The experience obtained from broad-based clinical trials of the devices is summarized briefly.

Animals↗