FR2544202A1 - Burns treatment equipment - Google Patents

Abstract

Equipment includes a blower, filters, a heater and a treatment chamber for the injured limb with a temp. sensor. The temp. controller is an OFF-ON unit with a setter for the initial temp. which is first cyclically varied and then lowered by the regulator of the dead zone of the controller, combined with a lengthening of the cycle time.

Description

 The present invention relates to medical technique and in particular relates to an installation for treating thermal lesions with abacterial air.

 The invention can be used most effectively to treat burns, frostbite and trophic ulcers due to burns.

 The device proposed to treat thermal lesions can also be used to improve the healing process for soft tissue injuries due to mechanical trauma, as well as trophic ulcers of different etiologies.

 There is an installation for treating thermal injuries, mentioned in the USSR author's certificate no. 939010 (Int. Cl. AGi L 9/00) "Installation for the supply of purified air.

 This known installation comprises, placed in the order of the air treatment operations, an air repressor, namely, a centrifugal fan for taking air from the room and bringing this air to the traumatized part of the body. of the patient, a filter system consisting of an air prepurification filter and a bacterial filter, an electric heater and an air piping device for bringing the abacterial air into the treatment enclosure, more precisely in a inflatable elastic bag. There is also an abacterial air temperature sensor, connected to a control block of the electric heater.

 The known installation blows the traumatized part of the patient's body, placed in the treatment enclosure, by a stream of air at constant temperature.

 The air temperature is determined using a setpoint device forming part of the temperature regulator, mounted in the control block of the electric heater. The optimum temperature for the air flow is between 30 and 320C. This value corresponds to the temperature of the patient's body surface and creates a feeling of thermal comfort.

 There is also a Sterishieîg installation from the company "CAPE ENGINEERING C ~ LTD, Great Britain.

This installation is intended for postoperative treatment of members of diabetics and can also be used to accelerate the treatment of burns and injuries of muscle tissue.

 The known installation comprises, arranged according to the technological sequence, an air prepurification filter, a multi-stage centrifugal fan which draws air from the room through said filter, # a bacterial filter where the air arrives from the fan to carry out the elimination of mineral and biological impurities, an electric heater of the purified abacterial air, and a device for bringing the air into the treatment enclosure, produced in the form of a flexible pipe. At the point of connection of the flexible hose to the treatment enclosure (inflatable elastic bag), an air temperature sensor is placed, electrically connected to a temperature regulator forming part of a control block.

 The known installation ensures the stabilization of the air temperature at a given level (within the limits of 30 to 360C), determined using a setpoint device forming part of the temperature regulator. The temperature controller has a non-adjustable insensitivity zone.

 Every specialist working in this field knows that "insensitive zone of the regulator" means the difference between two temperature values at the place of installation of the temperature sensor, namely, between the value of the temperature at which the temperature regulator activates the temperature heater, and the temperature value at which the temperature regulator stops the electric heater for an invariable position of the temperature setpoint device.

 In other words, the insensitivity zone can be considered as the difference between the temperature measured by the sensor and a predetermined temperature at which the temperature controller operates by reversing its output signal (yes-no).

 The peculiarity of the "Sterishield" installation resides in the following: it can create both a current of air at constant pressure in the treatment bag and produce a cyclically variable pressure. The cyclic variation of the pressure consists of the following: a determined pressure of the air is maintained in the treatment enclosure for a period of time, after which the pressure rises to a determined value and is maintained at this level during the next time interval.

 Said time periods form a phase of # low pressure and a phase of high pressure of a pressure variation cycle.

 The pressure variation ensures the soft tissue massage in the postoperative period of diabetics or patients suffering from vascular disturbances.

The use of cyclically variable pressure for the treatment of burns is not rational in the following cases #
- superficial burns when the epidermis of the skin is absent, there is excitation of the naked nerve endings, and as a consequence, intensification of the pain. In the case of deep burns, the soft tissues do not react to the change in pressure, the therapeutic effect is not obtained.

 If the "Sterishield" installation is used in a blowing mode of the surface traumatized by a stream of abacterial air at a constant pressure and temperature, the parts of the patient's body subjected to the action of air at a stable temperature get used to it, de-train. After the end of the treatment, said parts are subjected to the action of atmospheric air, the temperature of which varies within wide limits.

This causes inflammation of the areas of the skin which have undergone the treatment and causes a "withdrawal syndrome, known in medicine. This is a drawback reducing the therapeutic capacity of the" Sterishield "installation.

 The object of the present invention is to create an installation for treating thermal lesions with abacterial air, in which the control unit would be produced so as to provide treatment with a stream of abacterial air at a cyclically variable temperature from a maximum value given at the start of treatment up to values gradually decreased during treatment, the duration of the cycle being increased.

 This object is achieved by the fact that in an installation for treating thermal lesions by abacterial air, which comprises, arranged according to the technological sequence, an air repeller for the intake of air and for its blowing on the part traumatized body, a filter system including a bacterial filter, an electric heater and, connected to the latter, a control unit with a temperature regulator and a temperature sensor installed in a treatment enclosure, as well as a device for supplying abacterial air to the treatment chamber, according to the invention, the temperature regulator of the control block is in two positions and includes a regulator of the insensitivity zone, connected to a comparison block forming part of the two-position temperature regulator, in order to achieve a cyclic variation of the temperature from a predetermined maximum value, to which is preset a temperature setpoint device, connected hey on the comparison block, and which acts on the patient's body during the initial treatment period, up to gradually decreasing temperature values, determined by the insensitivity zone regulator according to the treatment stages, respectively, with simultaneous increase in cycle time.

The installation proposed for treating thermal lesions with abacterial air, comprising the control unit described above, ensures a cyclic variation of the temperature within predetermined limits, in particular
during the initial period of treatment, which lasts two days from the start of treatment for superficial burns, and the preparation time for self-dermoplasty, and during the first day after self-dermoplasty for deep burns, frostbite and trophic ulcers, the air temperature is maintained in the range of 30 to 320C, then the temperature range is regularly increased, while maintaining the maximum value at its initial level, while bringing the minimum temperature , on the sixth or eighth day, up to 20 to 220C, that is to say up to the ambient temperature level, and then the temperature of the supply air is maintained in the range reached. The cycle time increases regularly simultaneously with the widening of 1 temperature range.

 The use of the installation proposed in the regime described above ensures an effective treatment of thermal lesions and, from a certain moment of the treatment, the entrainment of the traumatized surface of the body by variation of the temperature of the supply air.

Said thermal entrainment of the traumatized surface accelerates its adaptation to fluctuations in atmospheric temperature and makes it possible to exclude the "withdrawal syndrome" that is observed when the treated surfaces are removed from the thermostatically controlled treatment enclosure during use. known installations.

 The installation for treating thermal lesions, carried out in accordance with the present invention, provides a very effective treatment of burns of various severities of frostbite and trophic ulcers, including at the end of treatment.

 The installation proposed for treating thermal injuries is distinguished by its simple organization and its easy and reliable use.

The invention will be better understood and other objects, details and advantages thereof will appear better in the light of the explanatory description which will follow of different embodiments given solely by way of nonlimiting example, with reference to the drawing not limiting annexed in which
- Figure 1 schematically shows an installation for treating thermal injuries, produced in accordance with the present invention;
- Figure 2 shows a graph of variation over time of the temperature of the blown abacterial air.

 The installation for treating thermal lesions by abacterial air, produced in accordance with the present invention, comprises an air repeller 1 (FIG. 1) in the form of a centrifugal fan of any known construction which can be used at this end. The air repressor 1 is intended for the intake of air, generally from the premises of the medical establishment, for its discharge then, through the elements arranged successively in the order of the treatment operations and the description of which is given below, and to the blowing of the traumatized part of the body by the abacterial air.

Upstream, in the direction of flow of the air flow from the recirculation 1, a filter 2 of known construction is placed to pre-purify the air by removing large particles polluting the air, while downstream of the repeller 1 is placed a bacterial filter 3 which ensures the total purification of the air consisting in ridding it of all impurities in the form of an aerosol, including bacteria. The bacterial filter 3 can be of any suitable construction, for example, like "HEPA."
The bacterial filter 3 is followed, in the order of succession of the technological elements of the installation, by an electric heater 4 of any suitable construction. The purpose of the electric heater 4 is to heat the air stream to the temperature necessary for the treatment of thermal injuries. The heater 4 must satisfy only two requirements: reduced temperature of its useful surface (not exceeding 70 to 90 C), and
absence of dust production by said surface. These requirements are due to the need to preserve the properties of the initial air as much as possible. The operation of the electric heater 4 is controlled by a control block 5. The temperature control of the abacterial air is ensured by a temperature sensor 6 placed in the stream of blown air on the traumatized part of the body and having a construction appropriate.

 In order to bring the abacterial air heated by the air heater 4, there is provided in the installation described a device 7 for supplying air into a treatment enclosure 8 in which the temperature sensor is mounted. 6.

 Said elements may have any suitable construction. The most rational is to produce the device 7 for the supply of the abacterial air in the form of flexible piping, and the treatment enclosure 8, in the form of a transparent elastic bag inflated by the current -d abacterial air.

 This construction is the one that is most suitable for the treatment, because it ensures a convenient conduct of the treatment process for both the personnel (visual control of the traumatized surface, possibility of palpation, ease of sealing of the bag on the traumatized part of the body, easy access for sterilization) than for the patient (minimum mass of the bag, possibility of changing the position of the traumatized part of the body with the bag, possibility of connecting the treatment enclosure to the source of abacterial air).

 The control unit 5 controls the operation of the electric heater 4 in order to maintain the temperature of the abacterial air within given limits, determined in a differentiated manner according to the stages of treatment.

In addition to this, the control unit 5 comprises an element Sa electrically connected to the discharge valve 1 and used to control its operation. One can use as element Sa a suitable construction device, known per se.

 In said control unit 5 is installed a temperature regulator 9 with two positions, intended to start or stop the electric heater 4 as a function of the difference between the air temperature measured by the temperature sensor 6 and the preset preset value. If the temperature of the Abacterian air current is exceeded by a certain value compared to the value of the set temperature, the regulator 9 stops the electric heater 4 and, on the contrary, in the event of a lowering of the temperature of the air current of a certain value below the value of the set temperature, the regulator 9 starts the electric heater 4.

 The two-position temperature controller 9 can have any suitable construction, known per se, provided that it is in two positions, that is to say that its output signal varies in a discrete manner.

 To modify said value of deviation from the actual temperature measured by the temperature sensor 6, with respect to the set temperature not causing a response from the regulator and called the insensitivity zone, a regulator 10 of zone d has been provided. insensitivity, which is part of the temperature regulator 9 and which, more precisely, is connected SUE to the comparison block 11 of the latter.

 The comparison block 11 is intended for the comparison of two signals: the one corresponding to the actual value of the temperature of the air stream and the one corresponding to the set temperature value. The signal representative of the actual value of the temperature of the air stream is applied to the comparison block 11 by the temperature sensor 6 located in said air stream. The signal representing the temperature setpoint is formed in a temperature setpoint device 12, connected to the comparison block 11.

 Depending on the result of the comparison of said signals, the comparison block 11 forms a discrete output signal (yes-no) from the temperature regulator 9.

 The regulator 10 of the insensitivity zone, the comparison block 11 and the device 12 for setting the temperature of the temperature regulator 9 can be of any suitable mechanical or electronic design, known per se.

 To make use more convenient r the regulator 10 of the insensitivity zone must ensure an asymmetrical variation of the insensitivity zone, more precisely a variation of its lower limit alone.

Thanks to this design of the regulator 10, the value of the overshoot of the actual temperature, measured by the sensor 6, above the set point temperature determined by the set point device 12 and at which the regulator 9 stops the electric heater 4, is constant. The value of the decrease in the actual temperature, measured by the detector 6, relative to the setpoint determined by the setpoint device 12 and causing the electric heater 4 to start up by the regulator 9, varies as a function of the adjustment of the regulator 10 of the insensitivity zone.

 The described organization of the control block 5 of the installation proposed for treating thermal lesions by abacterial air ensures a cyclic variation of the temperature of the current of said air.

 The temperature setpoint (nominal) and the minimum value of the insensitivity zone being preset, respectively, on the setpoint device 12 and on the regulator 101 the actual temperature of the air flow varies cyclically. The range of variation of the temperature compared to the set value will, in this case, be minimum and will be determined by the value of the insensitivity zone of the temperature regulator 9. The maximum air temperature will exceed the predetermined temperature by the setpoint device 12 by a value corresponding to a certain part of the entire insensitive zone, called "upper interval. The minimum air temperature will differ from the predetermined (setpoint) temperature by a value equal to the lower interval of the insensitivity zone, defined as the difference between the entire insensitivity zone and the value of the upper interval.

 The thermal regime described for the operation of the installation proposed for treating thermal lesions can be defined as a regime for stabilizing the temperature of the air flow from the air, with minimum deviations from the nominal temperature.

 In FIG. 2, the described regime of variation of the temperature of the abacterial air is represented in the form of a diagram (coordinates: temperature t, OC; cycle time r days) for the first two days of the treatment. The value of the duration of the cycle t at the indicated speed is determined by the treatment needs and is ensured by the dynamic characteristic of the proposed installation, and more particularly, by the thermal inertia of the electric heater 4, of the flexible piping 7, of the detector-6.

 In the installation proposed for treating thermal lesions, the transition to a new thermal cycle is done by increasing the insensitivity zone by an adequate adjustment of the regulator 10, the preset of the reference device 12 remaining the same.

où r 1 est la durée du cycle dans la période initiale
du traitement;
est la durée du cycle dans les. périodes suivantes
du traitement.In this case, the maximum admissible value of the actual temperature of the abacterial air flow remains the same. The minimum actual value of the air flow decreases in proportion to said increase in the insensitivity zone. Consequently, the range of the cyclic variation of the temperature of the air stream increases in the direction of the lower values of the temperature. Simultaneously with the increase in said range, the duration of the cycle takes place, provided that the powers of the electric heater 4 and of the air stream coming from the discharge valve 1. remain constant. According to Figure 2, this relationship is expressed by the formula:

where r 1 is the duration of the cycle in the initial period
treatment;
is the cycle time in. following periods
of treatment.

 For the proposed installation, the initial treatment period for thermal injuries is characterized by an optimal temperature level of the air flow in. limits from 30 to 320C. During this period, it is desirable to obtain minimum temperature deviations from the nominal value and, consequently, a minimum value of the insensitivity zone: of the order of 0.50C. The final treatment period involves training the traumatized surfaces at a normal temperature of 20 to 220C.

 The value of the insensitivity zone which ensures this lowering of the lower temperature of the air stream is approximately equal to 10oC.

 It should be noted that the variation of the absolute value of the duration of the cycle of variation of the temperature of the abacterial air stream in the proposed installation can be obtained by varying the flow of abacterial air by any known process, for example at using a throttle valve installed on the air piping, or by changing the power of the electric heater 4, also carried out by any known method, for example by cutting off the electric heater.

 The reduction in the power of the electric heater 4 and the reduction in the flow of air from the air causes an increase in the absolute duration of the cycle. In this case, the relative increase, described above, in the duration of the cycle is preserved as the value of the cyclic variation of the temperature of the air stream is increased.

 The specifics of the operation of the installation proposed for treating thermal lesions by abacterial air are as follows. In the initial treatment period, the temperature of the air stream is preset within the limits of 30 to 320C on the setpoint device 12, the value of the insensitivity zone preset on the regulator 10 being 0.50C. Consequently, in the initial period, the temperature of the bacterial air meets the requirement of thermal comfort and is maintained with the greatest possible precision for the concrete installation considered.

The initial period of treatment is equal to
- two days for superficial burns
- the preparation period for self-dermoplasty and the first day after self-dermoplasty in case of deep burns, frostbite and trophic ulcers.

 During the initial period of treatment, the formation, on the burned surface, of a "crust" (in the case of superficial burns) begins, and the taking of the auto transplant (in the event of deep burns).

 After said initial period, the entrapment of the traumatized surface begins by cyclic variation of the temperature of the air flow of the blowing air. By keeping the maximum value of the air temperature unchanged at 320C (using the setpoint device 12), the minimum value of the temperature is regularly and progressively lowered from 1.5 to 20C per day by increasing the insensitivity zone using the regulator 10. In this case, the temperature of the air flow blowing the traumatized surface varies cyclically during each day, from the maximum value (which remains invariable) to the minimum value defined by the insensitivity zone adjusted on the regulator 10 of the insensitivity zone.

 At a value of the insensitivity zone equal to 100C, the minimum value of the temperature varying cyclically reached around the sixth or the eighth day at 220C, which corresponds to normal room temperature. This thermal cycle obtained is kept invariable during the subsequent treatment.

 FIG. 2 illustrates the described variation of the temperature cycle of the abacterial air in temperature-duration coordinates. As already mentioned, the cycle time increases as the lower temperature drops.

 The recommended cycle time is 2 to 3 minutes during the initial treatment period in the temperature range of abacterial air from 30 to 320C, and 18 to 20 minutes in the final treatment period in the temperature range of 20 to 32 C.

 The methods for measuring the absolute value of the cycle time have been described above.

 The installation for treating thermal lesions with abacterial air, produced in accordance with the present invention, has passed clinical tests. The treatment results are positive, there is a significant reduction in treatment time. When the treated limbs are removed from the treatment enclosure, no local chills or itching, ie "withdrawal syndrome", is observed. It was noted that the possibility of thermal entrainment of the traumatized surface is obtained thanks to the simple organization of the proposed installation, which is easy to use.

Claims (1)

 Installation for treating thermal lesions with abacterial air, of the type comprising, successively arranged in the order of the air treatment operations, an air blower (i) for the air intake and the blowing thereof on the traumatized part of the body, a filter system (2 and 3) comprising a bacterial filter (3), an electric heater (4) and, connected to the latter, a control unit (5) with a temperature regulator and a temperature sensor (6) mounted in an enclosure (8) for treating the patient, as well as a device for supplying abacterial air <7> into the treatment enclosure (8), characterized in that the regulator The temperature block (9) of the control unit (5) has two positions and contains a regulator (10) for its insensitivity zone, connected to a comparison block (11) which is part of the two - position temperature regulator (9 ), for a cyclic variation of the temperature from a maximum value predetermined by a dis positive (12) temperature setpoint, connected to the comparison block (11), during the initial treatment period, up to gradually decreasing temperature values determined by the insensitivity zone regulator (10) according to the processing steps, this decrease being made simultaneously with a corresponding increase in the duration of the temperature variation cycle.