ITMI20121006A1 - PORTABLE HANDHELD DEVICE TO ASSESS THE CUTANEOUS THERMAL SENSITIVITY OF A PATIENT - Google Patents

Description

PORTABLE HANDHELD DEVICE TO ASSESS A PATIENT'S THERMAL SKIN SENSITIVITY

FIELD OF THE INVENTION

The present invention relates to medical devices and more precisely to a portable handheld device for evaluating lesions to nerve fibers and receptors responsible for skin thermal sensitivity in a patient.

BACKGROUND

Painful symptomatology is by far the main reason for medical consultation and is one of the most expensive items of expenditure for investigations and therapies. A correct and early diagnosis, with relative appropriate therapy, can lead to a net reduction in healthcare costs, medical services, tests and drugs, as well as obvious benefits for the patient.

In the light of international literature (Prof. Bonezzi, Doti. Buonocore, "BEDSIDE EVALUATION", Institute for Scientific Hospitalization and Care of the Maugeri Pavia Foundation) and the new guidelines of the Ministry of Health (law no. 38 of March 2010) , thermal sensitivity turns out to be one of the fundamental components on which the doctor must always investigate in the presence of painful symptoms, in order to identify a possible neuropathy and consequently set the most correct therapy.

In the presence of painful symptoms or suspected damage to the somatosensory system, the evaluation of lesions to nerve fibers and receptors responsible for transmitting thermal sensitivity is now entrusted to empirical methods, such as the use of a test tube filled with hot water, currently recommended. by the SIMG (Italian Society of General Medicine).

Alternatively, very complex and expensive machines are available, such as the one disclosed at the web address http://www.medoc-web.com, which is almost exclusively used for a limited number of hospitals, consisting of several units, including such as a probe that can be used to generate a thermal stimulus on the patient's skin by obtaining a report via a computer.

This instrument is very complex, expensive, difficult to transport and unusable if not directly connected to the electrical network. Other less known instruments have similar characteristics.

It is therefore desirable to have an instrument for assessing skin thermal sensitivity that is inexpensive, easily transportable and usable, with adequate autonomy, even away from electrical mains sockets.

SUMMARY

All the aforementioned points find an innovative and effective solution in the portable handheld device according to the present description.

The new handheld device includes an elongated hollow shell, possibly ergonomically shaped, which can be used and handled with one hand. One end of the device ends with a plate made of heat-conducting material, preferably metal, intended to be placed in contact with the patient's skin. This chip is heated by an electrical component, thermally coupled to it, through which a current supplied by an internal electrical energy accumulator, regulated by a control circuit, is circulated.

The control circuit, connected to a temperature sensor in contact with the plate, thermostates the temperature of the plate to a value selected by the doctor from a discrete set of values.

By placing the plate heated to the desired temperature in contact with different points of the patient's skin for a period of time defined by the medical literature, the doctor can easily draw up a diagnosis by evaluating the patient's response.

The claims as filed form an integral part of this specification and are incorporated herein by express reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 and 2 show front and side views of the new portable handheld device according to the preferred embodiment, with the aid of a support base for recharging an electrical energy accumulator contained in the device itself.

Figure 3 is a perspective view of the handheld device and the support base of Figures 1 and 2.

Figure 4 is a sectional view of the handheld device and the support base of Figures 1 and 2.

Figure 5 is a side view of a handheld device according to the present disclosure, shown in another drawing and powered by batteries.

Figure 6 is a block diagram illustrating the operation of an embodiment of the handheld device according to the present disclosure.

Figure 7 is an exemplary wiring diagram of a control circuit, suitable for heating the chip to certain temperatures.

DESCRIPTION OF EXAMPLE EMBODIMENTS

A preferred embodiment of the new apparatus for testing the patient's skin thermal sensitivity is shown in Figures 1 to 4. The apparatus is substantially a portable handheld device having a hollow rigid shell (11) which can be gripped with a single but no. The device, at one of its ends, ends with a plate (9), which can be for example of passivated aluminum, thermally coupled with one or more heating elements (not shown in the drawings).

An electric energy accumulator (5), contained inside the rigid shell, supplies the electric current necessary to heat the plate (9) by means of the heating element. The electronic thermostat, which is part of the control circuit (6) and the temperature sensor (10), thermally coupled to the plate and the heating element, stabilize the temperature of the plate itself. The doctor can choose the desired temperature from the temperatures that can be selected using the button

(7).

The hand-held device shown can therefore be conveniently used to test the skin sensitivity in the patient at different temperatures. By simply placing the platelet in contact with the skin at certain temperatures and evaluating the patient's response, the doctor can detect a pathological state and formulate a consequent diagnosis.

The device shown is light, preferably ergonomically shaped so that it can be comfortably held like a pencil or a flashlight, easy to carry, as well as usable independently thanks to the presence of an autonomous power supply (5), which can be a rechargeable battery or not, or a supercapacitor, or more generally an accumulator of any type, which supplies the necessary energy even where a mains electricity source is not available.

According to the preferred embodiment shown in Figure 4, the handheld device has electrical terminals (4) installed in correspondence with the shell (11) at the opposite end to the plate (9). The terminals (4) and the contacts (2) allow an electrical connection between the device (5) and the desktop charging base (1), which has a housing for the portable handheld device. The same support can contain inside (3) the battery recharging circuit (not shown in the figure) and can have an electric cable for connection to the network. In this way, when the device is inserted in the housing, the internal accumulator is charged and will allow, once recharging, to use the device without connection to the mains.

According to another embodiment (not shown in the figures), the device does not have the terminals (4) but includes an inductive or magnetic wireless charging circuit block, equipped with an antenna or a resonant circuit configured to generate a voltage battery charging when immersed in a variable electromagnetic field. Correspondingly, the desktop charging base (1) will have no electrical connectors (2) but will contain a remote wireless power system configured to generate and radiate a variable electromagnetic field within the housing. In this way, when the device is inserted into the desktop charging base (1), the wireless charging circuit block will be hit by the electromagnetic field radiated by the wireless power system and will recharge the battery.

According to another embodiment schematically illustrated in Figure 5, the portable handheld device of this disclosure is devoid of the electrical connection terminals (4) since the electrical energy accumulator consists of batteries inserted in a compartment defined in the shell of the device.

According to the preferred embodiment, the shell of the portable handheld device has an ergonomic shape which allows it to be comfortably gripped in different ways, for example as a pencil or as a flashlight.

A block diagram illustrating the operation of an embodiment of the handheld device of the present invention is shown in Figure 6. It comprises:

- an electrical energy accumulator, which in the example shown is a battery, which supplies the energy necessary for the operation of the device;

- a general control and management circuit, consisting of a microcontroller that sets the temperature chosen by the doctor at which to heat the plate, signals the state of charge of the battery and through LEDs indicates that the desired temperature has been reached, as well as switching off the device if due to a fault, the temperature of the plate should exceed a maximum value;

- a voltage reference, which provides a stable and precisely determined voltage, corresponding to the selected temperature;

- a temperature sensor in thermal contact with the plate, followed by a signal amplification stage;

- a PID type regulator receives the reference voltage and the signal generated by the sensor, controlling the current flowing through the heating element;

- a heating element, which can be for example a power transistor or a resistance, thermally coupled to the chip so as to heat it.

Indicatively, for the type of diagnosis for which the device is mainly intended, three temperatures considered optimal will be set: 39 ° C, 42 ° C, 45 ° C. The plate can then be heated to one of the three predetermined values. To reduce costs, but above all to make temperature identification more immediate even at a distance, it was preferred to use a multicolor LED (8) as an alternative to a display. Each time the button (7) is pressed briefly, the desired temperature is varied and simultaneously, by checking the color of the LED, it is identified. For example: when switched on, the instrument is preset to a temperature of 39 ° C. To bring the temperature to 45 ° C, briefly press the button (7) twice and the red color, corresponding to 45 ° C, will indicate that the desired temperature has been selected.

By briefly pressing the button (7) once more, it will switch to the preset temperature of 39 ° C, corresponding to the green color of the LED. Repeating this last operation, the temperature will be 42 ° C, indicated by the blue color.

The LED, emitting steady light, indicates when the plate has reached and maintains the set temperature. By selecting a different temperature, for the fraction of time necessary for its stabilization, the LED will emit a flashing light of the color corresponding to the selected temperature to indicate that the plate has not yet reached the desired temperature.

The electronic circuit (6) will preferably comprise a microcontroller which, through the use of the button (7), will allow to set the temperature at which to heat the chip. The same button (7) has the function of switching the instrument on and off. With the appliance switched off, by holding the button down for at least two seconds, it switches on. Vice versa when the appliance is switched on, by acting in the same way it turns off.

The circuit will also be able to switch off the device autonomously when: - the voltage supplied by the electrical energy accumulator falls below a pre-established minimum threshold;

- a predetermined time has elapsed since the button (7) was pressed for the last time;

- the plate temperature has exceeded a predetermined maximum value, due to possible incorrect operation.

The control circuit (6) indicated in Figure 4, a detailed exemplary diagram of which is shown in Figure 7, regulates the temperature by controlling a power transistor as a heating element.

Depending on whether the temperature of the plate is lower or higher than the desired temperature, the control circuit appropriately varies the conduction of the heating element, increasing or decreasing its dissipation.

With the component values indicated in the diagram, a PID-type control guarantees a temperature stability within ± 0.15 ° C of the set value, while the close thermal coupling between the heating element, the plate and the temperature sensor allows at the same time a considerable speed. response to external temperature variations and extremely stable regulation.

To avoid excessively high temperatures of the plate (9) in the event of malfunctions, the appliance can have five safety levels. A first level is given by the temperature control system which has been made as simple as possible and which has the sole purpose of stabilizing the temperature at the desired value. A second level concerns the maximum dissipation of the heating element which is limited via hardware. A third level is managed by the microcontroller which automatically turns off the device if it detects a temperature above 48 ° C. A fourth level, by means of a bimetallic switch with adequate tolerance, will cut off the power supply if the temperature of the plate (9) exceeds 50 ° C. The fifth level is assigned to a fuse placed electrically in series with the power source, should the previous systems fail.

The instrument, also in consideration of the limited cost, can be used on a large scale, in all general medicine clinics and in all specialist environments that deal with pain: diabetology, oncology, neurology, orthopedics and physiatry. It can also be used as a first-level instrumentation for doctors operating in pain therapy centers, in order to select patients to be referred to second-level assessments.

Claims (13)

CLAIMS 1. Portable handheld device for assessing the thermal sensitivity of a patient's skin, comprising a hollow rigid shell with an elongated shape, that can be gripped with a single hand, having a plate made of heat-conducting material at an elongated end of the shell and at least one component electric heater thermally coupled to the plate, said hollow shell containing: an electrical energy accumulator configured to circulate an adjustable electrical current through the heating electrical component; a temperature sensor in thermal contact with the plate; an electronic control circuit functionally connected to the accumulator and to the temperature sensor, suitable for regulating the current circulating through the electric heating component to thermostat the chip at a selected temperature in a discrete set of predetermined values and to generate a signal when said temperature is selected has been achieved. 2. Device according to claim 1, comprising male / female electrical terminals protruding from the shell, configured to connect said accumulator to the electrical network. 3. Device according to claim 2, wherein said electrical terminals are installed at one end of the rigid shell opposite to said elongated end. 4. A device according to claim 1, further comprising an inductive or magnetic wireless charging circuit block, having an antenna or a resonant circuit configured to generate a charging voltage of said accumulator when immersed in a variable electromagnetic field. 5. Device according to claim 1, wherein said electrical energy accumulator is a non-rechargeable battery. 6. Device according to claim 2, wherein said electrical energy accumulator is a rechargeable battery functionally connected to the male / female electrical terminals; Device according to one of the preceding claims, in which the heating electrical component is a power transistor or a Peltier cell. 8. Device according to one of the preceding claims, wherein said electronic control circuit further comprises: - a button or command to allow a user to switch the device on / off and select a temperature value of the plate, - a multicolored LED switched on / off by the control circuit, suitable for indicating the temperature value chosen by the user and to signal that the temperature of the plate is changing or has reached the selected value. 9. Device according to one of the preceding claims, in which said rigid shell is shaped so that it can be gripped like a pencil or like a torch. 10. Device according to one of the preceding claims, in which said plate is of passivated aluminum. Device according to one of the preceding claims, wherein said control circuit is configured to limit the power dissipated by the heating electrical component and to turn off the device when the chip exceeds a predetermined maximum temperature. 12. Apparatus for testing the skin sensitivity of a patient to heat, comprising a portable handheld device according to claim 2 or 3 and a support and recharging base connectable to an electrical socket, having a housing suitable for accommodating said device, provided with female / male electrical connectors suitable for mating with said male / female terminals when the device is inserted in the housing. 13. Apparatus for testing the skin sensitivity of a patient to heat, comprising a portable handheld device according to claim 4 and a support and recharging base connectable to an electrical socket, having a housing suitable for accommodating said device and a power supply system remote wireless configured to generate and radiate a variable electromagnetic field within said housing.