RU2672354C2 - Method for continuous monitoring of analyte content in blood - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: method for the continuous monitoring of analyte concentrations in blood with a molecule mass of 400 Daltons or less is that a monitoring device is implanted into the patient's body and the analyte concentration in the blood is continually measured by means of a proximity sensor and signals on the analyte concentration in blood are transmitted to the monitor. The monitoring device comprises a polymeric body connected on one side along the perimeter with the inlet end of the polymer tube and, on the other side along the perimeter with the outlet end of the polymer tube, a tubular shaped membrane placed coaxially in the body in its end openings and seamlessly connected to the inner surface of the inlet and outlet ends of the tube to form a blood flow path, the cavity between the body wall and the membrane being an analytical reservoir. At that, during the implantation of the monitoring device, the inlet end of the tube is connected to the wall of the arterial vessel to divert a portion of the arterial blood from the vessel to the analytical reservoir, and the outlet end of the tube is connected to the venous vessel wall to drain blood from the analytical reservoir, the connection to the blood vessels being carried out by the shunt principle. Under the influence of the difference in the concentrations of the analyte dissolved in blood and the analyte in the filtrate in the analytical reservoir, the analyte is filtered through the membrane into the analytical reservoir.EFFECT: method provides blood analyte monitoring in real time.2 dwg

Description

Technical field

The present invention relates to medicine and medical equipment, and in particular to a method for continuous monitoring of the content of analyte in the blood.

State of the art

A portable device for measuring and monitoring analytes in biological fluids is known from the state of the art, which comprises: one disposable measuring cell for application to the patient’s skin, a measuring unit connected to the measuring cell, a remote control unit connected to the measuring cell and the measuring unit. The measuring cell and the measuring unit are made in the form of separate modules and are connected to each other through electrical connections and capillary tubes. The measuring cell contains: a subcutaneous probe, an enzymatic cell connected to the subcutaneous probe by means of a hydraulic connection, a heat sensor connected to the first capillary tube at the outlet of the enzymatic cell, an element containing a glucose sample for functional testing of the system before the subcutaneous probe is introduced, and an air bubble separator.

As follows from the description, the measuring cell is disposable, it follows that each time to control the analyte in the blood, a mini-operation should be performed to insert a subcutaneous probe of the measuring cell under the skin, which provides inconvenience to the patient associated with the installation of the measuring cell. In addition, the measuring cell has a limited service life and it is impossible to apply this technique in non-stationary conditions (patent RU 2470300, published on December 20, 2012).

Closest to the claimed technical solution is an electrochemical system for determining the concentration of analyte in a sample, an electrochemical sensor strip and a method for quantitative determination of analyte (patent RU 2415410, published 03/27/2011). An electrochemical system for determining the analyte concentration in a sample contains: a sensor strip, which includes a substrate, a first electrode on this substrate, which is a working electrode and has a first layer on the first conductor located on the substrate. The first layer has an average initial thickness of less than 30 μm and contains a binder forming a diffusion barrier layer of DBL, which has an internal volume. The second electrode on the substrate is the counter electrode. The measuring device is electrically connected to the first electrode through the first conductor and to the second electrode through the second conductor, while the measuring device applies a read pulse with a duration of less than 5 seconds to the first and second electrodes.

The diffusion barrier layer of the DBL provides a porous space with a certain internal volume where the measured substance can be located. The pores of the DBL are selected so that the measured substance can diffuse in the DBL, and physically larger sample components, such as red blood cells, are essentially excluded.

When controlling the duration of the measurement reaction on the surface of the conductor, the sensor strip can measure the measured substance inside the DBL, while simultaneously excluding the measured substance from the outside of the DBL from the measurement. With respect to the surface of the conductor, the internal volume of the DBL changes the physical parameter of the diffusion rate of the measured substance contained inside it compared to the diffusion rate of the measured substance outside the DBL.

The disadvantages of this technical solution are the impossibility of continuous monitoring, since there is a need for frequent replacement of sensor strips, as well as patient discomfort when replacing sensor strips.

SUMMARY OF THE INVENTION

The problem to which the claimed invention is directed, is to create a method for continuous monitoring of the analyte content in the patient’s blood in real time with minimal discomfort for the patient during monitoring. This problem is solved by creating a method for continuous monitoring of the analyte content in the blood, which is based on the property of diffusion of the analyte dissolved in the blood with a molecular size of 2 nm or less, or a mass of 400 daltons or less, through the membrane under the influence of the analyte concentration difference between the filtrate in the analytical reservoir and in blood.

According to the invention, a method for continuously monitoring the concentration of an analyte in a blood with a molecular weight of 400 Daltons or less includes operations in which

a monitoring device is implanted into the patient’s body, which contains a polymer case - a polymer tube connected on one side along the perimeter with the inlet end of the polymer tube, and on the other hand along the perimeter with the outlet end of the polymer tube, a tubular membrane placed coaxially in the case in the end openings of the case and connected by seamless connections to the inner surface of the inlet and outlet ends of the tube with the formation of a duct for blood, and the cavity between the wall of the body and the membrane is analytically m reservoir

connecting the lead end of the tube to the wall of the arterial vessel to divert part of the arterial blood from the vessel to the analytical reservoir, and

connecting the output end of the tube to the wall of the venous vessel to drain blood from the analytical reservoir, and the connection with the blood vessels is carried out according to the principle of a shunt,

under the influence of the difference in the concentrations of the analyte dissolved in the blood and the analyte in the filtrate in the analytical tank, the analyte is filtered through the membrane into the analytical tank,

Through a non-contact sensor, signals of analyte concentration in the blood are continuously transmitted to the monitor.

The method is characterized by high accuracy, since the concentration of the analyte in the filtrate is directly proportional to the concentration of the analyte in the blood.

The technical result provided by the given set of features is the measurement in real time of the relative change in the concentration of analyte in the blood, and its speed depends only on the throughput of the membrane and the selected method of measuring the concentration of analyte in the filtrate. Depending on the requirements for the analyte, it is possible to increase the selectivity of the membrane for certain substances.

Brief Description of the Drawings

The invention is further illustrated by the description of a preferred embodiment with reference to the accompanying drawings, in which:

FIG. 1 shows a diagram of a device according to the invention;

figure 2 depicts a General view of the device (principle of operation) according to the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

The monitoring device according to the invention contains the lead-in end of the polymer tube 1 (Fig. 1), intended for blood sampling from the arterial bloodstream 7 (Fig. 2).

The monitoring device also contains a polymer case - a device tube 2, connected on one side along the perimeter with the inlet end of the polymer tube 1, and on the other side along the perimeter with the outlet end of the polymer tube 5, designed to drain blood into the venous bloodstream 8. The ends of the tube 1 and 5 are intended for filing according to the principle of a shunt to the vascular beds 7 and 8, respectively, of the “end to side” type, which is the standard in vascular surgery.

Inside the housing 2 is placed a membrane 3 of a tubular shape, i.e. a tube of membrane material, which is installed coaxially in the housing in the end openings of the housing 2. The cavity inside the membrane 3 forms a duct 6 of the device. A cavity is formed between the wall of the housing 2 and the membrane 3, which serves as an analytical reservoir 4, which, in some cases, is filled with physiological saline before installation.

The outer walls of the ends of the polymer tube 1, 5 are integral with the polymer body 2 of the device.

The method of continuous monitoring of the analyte in the blood is as follows.

A monitoring device is implanted into the patient’s body, which is connected to the blood vessels by the principle of a shunt, that is, the end of the polymer tube 1 of the device is connected by the method of vascular surgery to the wall of the arterial vessel 7, to divert an insignificant, but sufficient for work, part of the arterial blood to the implanted device.

The inner surface of the wall of the end of the polymer tube 1 smoothly, without creating obstacles to the laminarity of the blood flow, is connected to the inner or outer surface of the membrane 3.

Blood flows from the arterial vessel 7 and moves through the tube from the membrane, filtering the analyte into the analytical reservoir 4, before it enters the venous bloodstream. In the initial period of time, an analyte dissolved in blood with a molecular weight of 400 Daltons or less begins to be filtered into the analytical tank 4 through the membrane 3. Under the influence of the difference in the concentrations of the analyte dissolved in blood with a molecular mass of 400 Daltons or less into the analytical tank 4, that is, the cavity formed between the membrane and the housing of the device 2, analyte is filtered through the membrane 3, i.e. for some time, about 5 minutes, the analyte concentration in the analytical tank 4 is aligned with the blood.

The system is balanced. As soon as the concentration of the analyte in the blood becomes lower than the concentration of the analyte in the analytical reservoir, the analyte begins to move from the reservoir 4 through the membrane back into the blood.

From the duct 6 of the membrane 3, blood is withdrawn by means of a discharge end of the polymer tube 5, likewise connected to the membrane 3, into the venous bloodstream 8.

To take readings, a non-contact sensor, for example, an optical type, is placed on the patient’s skin, which transmits signals to a controller or personal computer.

Claims (6)

A method for continuously monitoring the concentration of an analyte in a blood with a molecular weight of 400 Daltons or less, comprising the steps of a monitoring device is implanted into the patient’s body, containing a polymer case connected on one side along the perimeter to the inlet end of the polymer tube, and on the other hand along the perimeter to the outlet end of the polymer tube, a tubular membrane placed coaxially in the case in the housing end openings and connected seamlessly compounds with the inner surface of the inlet and outlet ends of the tube with the formation of a duct for blood, and the cavity between the wall of the body and the membrane is an analytical reservoir, connecting the lead end of the tube to the wall of the arterial vessel to divert part of the arterial blood from the vessel to the analytical reservoir and connecting the output end of the tube to the wall of the venous vessel to drain blood from the analytical reservoir, and the connection with the blood vessels is carried out according to the principle of a shunt, under the influence of the difference in the concentrations of the analyte dissolved in the blood and the analyte in the filtrate in the analytical tank, the analyte is filtered through the membrane into the analytical tank, Using a non-contact sensor, the analyte concentration in the blood is continuously measured and signals about the analyte concentration in the blood are transmitted to the monitor.

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