Surgery – Truss – Pad
Patent
1995-07-06
1997-10-28
Hindenburg, Max
Surgery
Truss
Pad
A61B 505
Patent
active
056808585
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority from PCT/DK93/00414 filed Dec. 10, 1993, which is incorporated herein be reference.
FIELD OF THE INVENTION
The invention relates to a method and a meter for in vivo determination of the concentration in a body fluid of metabolically significant substances.
BACKGROUND OF THE INVENTION
Knowledge of deviations from the accepted normal values in the concentration of metabolically significant substances in the body fluids is of great clinical importance. Especially excursions in the blood glucose concentration must be counteracted without delay by proper adjustments of the diet or the insulin injection regime. Diabetics must therefore have easy access to means for determining the concentration of glucose in their blood or other body fluids. A number of devices for in vitro determination of the concentration of glucose in blood are known.
The devices can be based on optical, chemical or electrochemical properties of glucose, but they all depend on the withdrawal of a small blood sample (about 25 .mu.l). The blood sample can be obtained e.g. by a finger prick or by a cut in the ear lobe. Taking a blood sample is unpleasant and can be painful for many people, because the fingers and the ear lobes are rather sensitive areas. Further, the device used for the analysis will be contaminated with blood which must be wiped off, or the sample receiving part of the device can be disposable, in which case it must be disposed of with care because of the possible contamination with infectious agents.
Consequently, it is the object of the invention to provide a method of analysis and a meter by which a determination of the concentration of metabolically significant substances in the blood is performed using known principles but without the need for taking a blood sample.
SUMMARY OF THE INVENTION
It is known to implant a glucose sensor subcutaneously and to monitor the glucose concentration during a period. Such sensor devices may determine the glucose concentration in the blood or in the interstitial fluid, the latter being only slightly lower than that in blood. No blood sample is taken when using this technique, but it is a disadvantage that the sensor must be implanted for some time before the signal representing the glucose concentration is sufficiently stable. A long (hours) insertion time of the needle is, however, not compatible with the requirements to a personal blood analysing device. A technique with a very short implantation time of the needle can, however, be practised by a method in accordance to the invention and characterized by the steps who's body fluid shall be analysed. the recorded signals.
With this technique the measurement takes place in the subcutaneous tissue of the patient, preferably in the interstitial fluid, making it unnecessary to take a blood sample. The insertion of the needle may cut a few small blood vessels, but especially if the needle is blunt, bleeding and pain associated with the insertion of the needle are usually insignificant. Body areas with low sensitivity, i.e the abdomen or the thigh, can be chosen for the insertion of the needle thus minimizing the pain.
When the needle with the sensor is used more than once it must be disinfected after each use. This is accomplished by storing the needle in an aqueous solution which contains a disinfecting agent e.g. merthiolate. Electrochemical sensors usually require some conditioning time in a suitable buffer before their output signal is stable. It is convenient to let the sterilizing solution serve this purpose. Further, the solution may be used for calibrating the sensor when the solution contains a suitable and constant quantity of the substance which should be determined.
For practical reasons, the time the needle is inserted in the patient should be as short as possible e.g. 1-100 seconds, preferably less than 5 seconds. Some types of sensors may need a longer time for reaching equilibrium, but even when such sensors are used, an insertion time of less t
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Ege Henrik
Hansen Henrik-Egesborg
Plum Thomas Munk
Hindenburg Max
Lambiris, Esq. Elias J.
Novo Nordisk A S
Zelson Esq. Steve T.
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