WO2016147115A1

WO2016147115A1 - Heating mattress for hospital use

Info

Publication number: WO2016147115A1
Application number: PCT/IB2016/051458
Authority: WO
Inventors: Davide PIZZI
Original assignee: Gvp Med S.A.S. Di Mian Antonella & C.
Priority date: 2015-03-19
Filing date: 2016-03-15
Publication date: 2016-09-22

Abstract

A heating mattress for hospital use comprises a main body adapted to accommodate a patient and means of thermoelectric power supply associated to the main body and adapted to transfer thermal energy to the patient; the mattress also comprises means of detection of a local surface temperature placed on the surface of the main body in contact with the patient, said detection means controlling signalling means which and adapted to emit an alarm signal as a function of a threshold temperature detection by the same detection means.

Description

DESCRIPTION

HEATING MATTRESS FOR HOSPITAL USE

The present invention relates to a heating mattress for hospital use, usable in a position interposed between a bed or operating table and a patient to keep him in constant thermal conditions.

As it is known, during the course of surgical operations where it is necessary to keep the temperature of a patient under control to prevent the onset of dangerous levels of hypothermia, it is possible nowadays to use forced-air, water circulation or electrical blankets and/or heating mattresses. The latter are typically constituted by a suitable arrangement of the electro-conductive elements which, due to the Joule effect, transmit heat to a patient that is placed on them (in the case of so-called "mattresses" or "below blankets", in industry-specific designation) or is covered by these objects (in the case of so-called "above-blankets").

In particular, when a patient undergoes particularly long surgical operations, or if he needs substantial help to his body thermal regulation during the same operation, the heating mattresses or below blankets can be conveniently used to transmit heat to the dorsal part of the same patient and then to keep him in clinical conditions sufficiently distant from hypothermia.

Nevertheless, during the execution of specific surgical techniques - particularly if "electrosurgical scalpels" or similar devices are used - it may be that the conditions in which the patient's body is found favour the channelling of electric currents (e.g. those dispersed by the electrosurgical scalpel and focusing on those areas of the body where sweat or highly saline body fluids accumulate), which in turn give rise to localized increases of the contact temperatures at the patient's dermis, causing different phenomena, also traumatizing ones, such as 2^nd and 3^rd-degree burns, potentially capable of causing patient's death.

Nevertheless, the use of heating mattresses, while being aimed at achieving and maintaining an ideal and controlled body temperature depending on the type of surgery, is not able to counteract these risk factors and indeed, in the absence of appropriate innovations, the constant influx of thermal energy "from below" together with a concentration of thermal energy resulting from localized pass/accumulation of electric currents could worsen the situation by accelerating burn phenomena or extending their surface and/or depth. Therefore, the above-mentioned known technique has some drawbacks. First, heating mattresses (and more generally, heating blankets) of known type thermally control the temperature they produce but are not able to detect any localized or widespread temperature increases in the body portion of the patient they are in contact with, and therefore are not able to detect and notify caregivers of the onset risk of traumatic phenomena determined by these localized increases in temperature during the use of high-risk electromedical equipment such as electrosurgical scalpels.

The present invention is therefore aimed at the design of a heating mattress for hospital use capable of overcoming the above-mentioned limitations.

Mainly, the present invention is aimed at the design of a heating mattress for surgical use, which may determine an effective safety condition for a patient that is lying on it, at least in terms of maximum perceptible actual temperature at the "local" level with respect to a part of the body of the same patient.

The present invention is also aimed at the design of a heating mattress for surgical use, which is equally efficient in ensuring a heat supply sufficient to maintain the patient in optimal conditions, and which can be optionally interrupted in order to equally counteract any increase of temperature beyond a certain threshold of concern or alarm.

Lastly, the present invention is also aimed at producing a heating mattress for surgical use, of high-quality construction, easy maintenance and/or inspection and lowest possible costs.

The mentioned technical task and the specified objects are substantially achieved by a heating mattress for surgical use, comprising the technical features set out in one or more of the appended claims.

Below is set forth the description of a preferred but not exclusive embodiment of a heating mattress for surgical use according to the invention, by way of example and not of limitation, shown in the enclosed drawings, wherein:

- figure 1 shows a schematic plan view of the mattress according to the invention (in which, moreover, a possible position of a patient relative to said mattress is equally visible in schematic form).

With reference to the enclosed figures, the heating mattress for hospital use according to the present invention has been indicated with reference numeral 1 and substantially comprises a main body 2 adapted to accommodate, typically in lying condition, a patient (indicated with the alphanumeric reference "P" in the figure) in correspondence to a surface 2a, as well as suitable means of thermoelectric power supply 3 associated to the main body 2 and adapted to transfer a given amount of thermal energy converted by the Joule effect to the patient P.

Depending on the needs of the moment, the means of thermoelectric power supply 3 may extend in length and/or width in any respect to the main body 2, so as to heat different body parts of the patient P: for example, in an exemplary embodiment of the invention, these means 3 extend from the neck to the buttocks of the patient P, but they can also be placed below the upper and/or lower limbs of the patient P itself.

Advantageously, the present invention also comprises detection means 4 of a local surface temperature, placed on the surface 2a (and more precisely, placed on the surface in contact with the patient P, as also will be described later); and signalling means, functionally controlled by detection means 4: the latter can be advantageously integrated in the power source that provides a given supply voltage to the thermoelectric power supply means 3 and receive a signal from the detection means, on the basis of which the device 1 shall globally signal the presence of an issue by visual and/or audible alarms.

In other words, the signalling means are adapted to emit an alarm signal as a function of a threshold temperature detection by the detection means 4 themselves.

At this point in the description, it should be noted that the present invention is directed to measuring the present "local" contact temperature of specific parts of a patient's back, such as the sacral and scapular areas.

What has been just noted is of fundamental importance, having to take into account the "heat flow" situation toward the patient P which is generated and stays in time by virtue of the basic functionality of the mattress 1 : in fact, if the purpose is to measure the temperature of the patient's epidermis when the thermoelectric power supply means are in operation (that is, are transferring current), the resulting thermal balance would be systematically influenced by the thermal conductivity conditions of the patient's body (for example, as a function of the layer of under-skin fatty tissue, surface vascularization and conditions of capillary blood circulation, body size and age of the patient, and so on) and therefore would not give rise to a sufficiently accurate measurement.

Nevertheless, in particular conditions of use, which will be described later on, the present invention can also be reconfigured to measure the patient's surface temperature.

Returning to the structural details of the invention, it should be noted that the detection means 4 in turn comprise one or more sensors locatable in correspondence of a scapular and/or sacral region of a patient P in the conditions of use of the mattress 1 : these regions are those of prevailing importance in the resting conditions of the patient P, as they are those with the highest concentration of pressure from the bony prominences of the shoulder blades, the weight of the same patient and the presence of liquid caused, for example, by sweating in the sacral area and therefore are those where contact (and thus the potential conduction/accumulation of parasitic and/or dispersed electric currents) occurs with greater intensity. With regard to the level of "predictive safety" offered by the present invention, it should be noted that the above-mentioned threshold temperature can be less than or equal to 40°C: thus ensuring compliance to the existing technical regulations, taking into account a reasonable variation range of physical parameters within which the risk of burns or comparable traumas is almost absent.

As regards the chosen implementation techniques of the sensors, it possible to conveniently adopt thermistors of the "PTC" or "NTC" types: in an exemplary embodiment (shown in figure 1 ), these sensors are present in a number equal to four in correspondence of a scapular region of a patient in conditions of use of the mattress (1 ), and can also be present in a number equal to four (more) at a sacral area of a patient in conditions of use of the mattress (1 ) .

Now, focusing attention on the main body 2, it should first be noted that the latter must have a proper size and flexibility to adapt to any shape of surgical bed or support, and must also have the ergonomics parameters suitable to support the body of a patient P by distributing loads and heat exchanges as evenly as possible.

Structurally, the main body 2 comprises a first layer (in contact with the surgical bed) in which the means of thermoelectric power supply 3 are embedded (this first layer may for example comprise a woven fabric or a non-woven fabric or a plastic substrate) and it is made in such a way that the means of thermoelectric power supply 3 include one or more threadlike or ribbon-like carbon fibre elements embedded in such woven or non- woven fabric. Alternatively, metal conductors, also embedded in the woven or non-woven fabric, or resistors printed on plastic substrates can be used instead of carbon-fibre conductors.

To provide the correct degree of comfort to the patient P, the main body 2 also comprises a second layer superimposed on the first layer: this second layer is thermally conductive and is adapted to come into contact with the patient P in the usage conditions of the mattress and is then adapted to reduce as much as possible the risk of pressure sores during long surgeries.

Given the structure of the main body 2 as described above, the detection means 4 are adapted to detect a local temperature on the surface of the patient to contact the second layer of the main body 2, while the signalling means present in the power source are arranged to compare this local temperature of the second layer of the main body 2 with the previously mentioned threshold temperature.

As for the choice of materials, it should be noted that at least the second layer of the main body 2 can be made of a biocompatible material (for example PVC or polyurethane containing, for example, cohesive medical gel) so as to be non-toxic and comfortable for the patient P lying above the same.

Returning to the thermoelectric power supply means 3, it is to be remarked that the latter are subjected to a nominal voltage lower than 50V, and preferably comprised between 24V and 12V, so as to comply with the safety regulations in force.

Finally, it is to be remembered that the signalling means (possibly integrated in the power source that will be used) are adapted to generate an audible and/or visual signal in correspondence with a measurement of the local temperature of the main body 2 (and/or the dermis of the patient P) higher than the threshold temperature: in particular, the operation of the present invention in the configuration for measuring the local temperature of the epidermis of the patient P can take place in a non-powered condition of the thermoelectric power supply means 3 (and, even more precisely, when the temperature of the mattress 1 has reached a sufficient degree of stabilization after the "switching off" of the thermoelectric power supply means themselves).

The invention achieves many advantages.

In fact, thanks to the particular construction architecture of this device, it is possible to set a threshold temperature through the power source that will be used, no higher than the limit of 40°C, after which it is possible to reasonably assume the rising risk of localized or widespread burns on the patient's back, and as a function of this temperature setting is possible to integrate an alert (and possible safety shutdown) feature in the mattress itself, presently not replicable in the other known state-of-the-art devices. In other words, the present invention controls each temperature in contact with the patient produced by any situation (by the heating mattress itself or by current produced by an electrosurgical scalpel) so as to prevent the risk of burns.

It is therefore to be noted that the implementation of this mattress allows to considerably increase the operating safety of the surgical environment, thanks to the fact that the generation of the alarm signal may take place in due time before the possible formation of traumatic injuries (burns or the like), thus providing enough scope for the surgical team to address them by adopting a preventive remedy.

Furthermore, the structural and functional integration achieved by the present invention may also allow different ways of use of this mattress (which in fact may also be used as "below blanket" or even as "above blanket" with a minimal set of changes in terms of weight, flexibility and intended use such as, for example, the thermal control of the epidermis of the chest and abdomen), as well as allowing different temperature detection modes (let us think, for instance, about the possibility of using the present invention as a "passive" body temperature detector, when thermoelectric power supply means are disabled).

Finally, it should be noted that the present invention allows to maintain low manufacture costs, to the whole advantage of the global economy of the product as well as of the optimal physiological outcome on the patient.

Claims

1 . heating mattress for hospital use, comprising:

- a main body (2) adapted to accommodate, preferably in resting condition, a patient (P) in correspondence of a surface (2a); and

- means for thermoelectric power supply (3) associated to said main body (2) and adapted to transfer to said patient (P) a given quantity of thermal energy converted by the Joule effect,

characterized in that it further comprises:

- detection means (4) of a local surface temperature placed on the surface (2a); and

- signalling means controlled by said detection means (4) and adapted to emit an alarm signal as a function of a threshold temperature detection by the detection means (4) themselves.

2. mattress according to claim 1 , wherein detection means (4) comprise one or more sensors locatable in correspondence of a scapular and/or sacral region of a patient (P) in conditions of use of the mattress (1 ), said threshold temperature being less than or equal to 40°C.

3. mattress according to claims 1 or 2, wherein said one or more sensors known as thermistors comprise thermistors of the "PTC" or "NTC" types, said sensors being present in a number preferably equal to four in correspondence of a scapular region of a patient in conditions of use of the mattress (1 ) and even more preferably being present in a number equal to four at a sacral area of a patient in conditions of use of the mattress (1 ).

4. mattress according to any one of the preceding claims, wherein said main body (2) comprises a first layer in which said thermoelectric power supply means (3) are embedded, said first layer comprising a woven or a non-woven fabric or a plastic substrate.

5. mattress according to claim 4, wherein the means of thermoelectric power supply (3) comprise one or more carbon fibre thread-like or ribbonlike elements embedded in said woven fabric or in said non-woven fabric, defining the first layer of the main body (2), the thermoelectric power supply means preferably also comprising metallic conductive elements embedded in the woven fabric or in the non-woven fabric or even more preferably resistors printed on plastic substrates.

6. mattress according to claims 4 or 5, wherein the main body (2) further comprises a second layer superimposed on the first layer, said second layer being thermally conductive and being adapted to come into contact with the patient (P) in conditions of use of the mattress (1 ).

7. mattress according to claim 6, wherein the detection means (4) are adapted to detect a local temperature of the second layer of the main body (2), the signalling means being adapted to compare said local temperature of the second layer of the main body (2) and comparing it with said threshold temperature.

8. mattress according to claim 6, wherein at least said second layer of the main body (2) is made of a biocompatible material, said material being preferably PVC or polyurethane.

9. mattress according to any one of the preceding claims, wherein the thermoelectric power supply means (3) are subjected to an electrical nominal voltage below 50V and preferably comprised between 24V and 12V.

10. mattress according to any one of the preceding claims, wherein the signalling means, said signalling means being preferably integrated in a power source connected to the thermoelectric power supply means (3), are adapted to generate an audible and/or visual signal in correspondence of a local temperature measurement of the main body (2) and/or of the patient (P) higher than the threshold temperature, a local temperature of the patient (P) being preferably measured in a non-powered condition of thermoelectric power supply means (3).