This application claims priority to European Patent Application No. EP20461557.9, filed on Jul. 30, 2020, the disclosure of which is incorporated herein by reference.
The subject of this invention is a pneumatic compression bandage intended in particular to be used in patients who underwent the implantation of medical devices used for cardiac electrotherapy to minimize or eliminate any hemorrhagic complications, primarily hematomas in the implantation site (device site). The bandage is used to prevent hematomas in the implantation sites of cardiac stimulation devices.
In the prior art, there is a device intended for applying compression to the sites to prevent hematomas after the procedure of medical device implantation in the site and the way of using the said device known under the application no. US 2008319473 (A1). Such a device may include cushions and relevant fasteners, e.g. in the form of a clamp, hinge, brace, clip, spring, a pneumatic or inflatable solution, a tape etc. However, the said device does not have an automatic control and pumping system to preset pressure values, responsible for maintaining the constant pressure.
The document U.S. Pat. No. 5,031,604 discloses a device for applying compression to the patient's limb via a device in the form of a multi-chamber sleeve filled with pressurized fluid. The fluid pressure is increased to the required value by a compressor controlled via a control system which receives data from the manometer situated in the chamber and outside it. The device may fill the chamber to the preset pressure and increase or decrease it in the preset sequence. The compressor control algorithm used is the P-type algorithm based on comparing the pressure in the chamber to the atmospheric pressure. The disclosed control system switches the compressor on when the pressure in the chamber is lower than the preset one based on the ambient pressure or switches it off in the opposite situation.
The document no. WO2018213615A3 discloses a device similar to the one disclosed in the document no. U.S. Pat. No. 5,031,604 which has also sensors detecting the shot or fall, e.g. accelerometric ones. When the control system detects a possible hemorrhage caused by a fall or shot, it activates measures to increase the pressure in the device chamber to the preset value.
The document U.S. Pat. No. 5,779,657 discloses a device similar to the one disclosed in the document U.S. Pat. No. 5,031,604 which is also able to detect the hemorrhage onset and then to activate the device automatically and notify the healthcare practitioners thereof.
In the prior art, there is also a publication no. EP2708215B1 Compression bandage known, concerning in particular its use for preventing hemorrhagic complications following medical device implantations in cardiac electrotherapy, with fasteners and a pneumatic compression cushion containing a pressure sensor connected with a control and pumping system, equipped with an integrated circuit to control pressure in the compression cushion. However, the said device does not have an automatic control and pumping system to preset pressure values, responsible for maintaining the constant pressure using a PID controller.
The aim of this invention was to develop a significantly improved pneumatic compression bandage to minimize or eliminate any hemorrhagic complications, primarily hematomas in the implantation site (device site).
According to the invention, the pneumatic compression bandage particularly for preventing hemorrhagic complications following medical device implantations in cardiac electrotherapy with a cuff having a chamber to be filled with pressurized fluid. It has a harness to fasten the cuff in the wound area and a control and pumping unit connected pneumatically to the chamber in the cuff via a connection hose. The said control and pumping unit includes an electrical pump, an electromechanical valve connected electrically with the control and pumping unit, a pressure sensor connected electrically with the control and pumping unit. The said unit has a memory and a system capable of processing digital information, as well as a user interface in the form of buttons, light and sound indicators. The pneumatic compression bandage according to the invention is characterized by the fact that the controller of the pressure in the cuff chamber is of the PID type, i.e. it contains a proportional, integral and derivative part and is intended for controlling and configured to control the electrical pump to increase pressure in the cuff chamber and the valve to reduce pressure in the said chamber.
Preferably, the harness includes a chest and shoulder strap.
Preferably, the harness also includes an arm strap.
Preferably, the above-mentioned control and pumping unit is programmed to maintain the preset constant pressure level in the cuff chamber, selected from among the predefined pressure settings.
Preferably, the control and pumping unit has a display, preferably an LCD display.
Preferably, the display is capable of showing the value of the current pressure in the cuff chamber or the actual time.
Preferably, the control and pumping unit is battery-powered.
Preferably, the control and pumping unit has an additional radio communication interface to communicate with other electronic devices, preferably an NFC (Near Field Communication) interface.
According to the invention, the method of controlling pressure in the pneumatic compression bandage including a cuff with a chamber to be filled with pressurized fluid, the harness to fasten the cuff in the wound area and a control and pumping unit connected pneumatically to the chamber in the cuff via a connection hose. The control and pumping unit contains an electrical pump, an electromechanical valve connected electrically with the control and pumping unit, a pressure sensor connected electrically with the control and pumping unit, as well as the memory and a system able to process digital information, with the user interface in the form of buttons, light and sound alarm devices. The method according to the invention is characterized by the fact that the pressure in the cuff chamber is controlled by a control algorithm of PID type, comprising a proportional, integral and derivative response, by means of a controller, consisting in controlling the electrical pump to increase pressure in the cuff chamber, while the valve is controlled to reduce pressure in the said chamber.
Preferably, the pressure control method in the pneumatic compression bandage covers also at least one of the below stages, and more preferably—all the stages mentioned below:
A) placing the pneumatic compression bandage cuff centrally over the medical device implanted in the patient's body to ensure it covers the whole implanted medical device and the implantation site as much as possible;
B) fastening the cuff to the patient's body using the harness;
C) tightening the harness until the patient feels slight pressure at the site of the implanted medical bandage;
D) starting the pneumatic compression bandage;
E) carrying out the automatic procedure to check the correct operation of the pneumatic compression bandage.
Preferably, stage E covers the following activities:
Preferably, the device emergency state is reported by a sound or light signal.
Preferably, the memory of the control and pumping unit stores the pressure values in the cuff chamber at the intervals lower than or equal to 60 minutes, even more preferably—every 30 minutes, and even the most preferably—every 15 minutes.
Using the PID controller in the solution of the pneumatic compression bandage implies specific benefits for the device functionality and usability, including:
The PID controller used is one of 4 known controller types (P,PI,PD,PID). The PID controller, owing to the fact of using the three modules simultaneously (P for proportional, I for integral and D for derivative) is characterized by the shortest adjustment time in the set of controllers (the time from changing the selected pressure setting or from the interference occurrence to maintaining the preset level value) and the lowest control deviation (the difference between the preset level value and the measured one). In the pneumatic compression bandage, there is a divided actuating system used according to the invention. The controller controls the pump to increase pressure by switching it on, when the pressure value higher than or equal to the preset one is reached, the pump is switched off, and if the value is higher, the electrovalve is opened. Such a control system may be vulnerable to hazardous oscillations likely to result in fast-changing electrical signals and incorrect operation of the device (unstable pressure in the cuff chamber). Selecting the control parameters of the PID controller for systems with unforeseeable characteristics, e.g. a human body, is a difficult task. During the operation, the pneumatic compression bandage will be exposed to the disturbances of the pressure value in the cuff chamber resulting from the ordinary movements of the individual wearing it. To ensure the correct operation and the shortest time to achieve the pressure value in the cuff chamber preset by a doctor, the PID controller is used with control parameters selected experimentally. Thus, the shortest time to achieve the required pressure value in the chamber is obtained. When a patient moves and changes their body position and, consequently, the pressure in the chamber, the control and pumping unit will bring the pressure in the device chamber to the preset pressure value using the PID controller in the shortest time possible. Thus, the time when the wound compression is different than recommended is the shortest.
Now, the invention will be closer presented in the preferable embodiments, with reference to the attached drawings, in which:
The pneumatic compression bandage is a medical device intended for patients after the implantation procedure of medical devices used in cardiac electrotherapy to reduce the hemorrhagic complication risk in the implantation site. The pneumatic compression bandage is particularly recommended in patients using a double antiplatelet therapy or an oral anti-coagulation therapy (VKA, NOAC) in the periprocedural period.
The pneumatic compression bandage includes: a harness, a compression cuff with a connection hose, a pumping unit in a polymer housing (ABS) and two AA 1.5 V batteries delivered separately (included in the packaging).
The harness 8 is composed of fastening straps 1, 2, 3 with a special structure which enable to adjust the compression cuff 4 correctly to the medical device implantation site. The harness 8 is made from a material ensuring comfortable and hygienic use, as well as protecting the skin from chafing and abrasion. The entire harness is disposable use.
The compression cuff 4 with the connection hose 5 is the proper component of the pneumatic compression bandage 7, responsible for the compression of the site, i.e. the place where the medical device for cardiac electrotherapy was implanted. The cuff is composed of the chamber 9 of the cuff 4 and a trimming enabling to merge the cuff with the harness 8. The compression cuff 4 with the connection hose 5 is disposable use.
The pumping unit 6 with an ABS polymer housing and batteries. The pumping unit has a membrane keypad which enables to control and manage the device operation. Replaceable alkaline batteries AA 1.5V are supplied separately (included in the packaging). Once the operation is completed, batteries should be removed (and disposed of in line with the applicable regulations). The ABS housing ensures further protection of the pump unit against mechanical damage, impact and scratches. The pumping unit is disposable use.
The pneumatic compression bandage 7 is designed to restrict everyday activities of the patient to the smallest degree possible, preventing any hemorrhagic complications in the site where the medical device was implanted.
The compression bandage 7 ensures the constant compression force, selected by the user, in the compression cuff due to the operation of the pump and the valve. The control is automatic thanks to the control algorithm implemented in the software.
Power supply system—this is the part of the electronic system which supplies voltage to the individual electronic system components.
Microcontroller—this is a programmable system used in the device, containing the device programme and controlling its operation.
Chamber 9 of the cuff 4 or, in other words, cushion 9 of the cuff 4—the part of the cuff 4 in the form of an inflatable rubber chamber, which the pressure control system is connected to Pressure control system—is a set of components composed of a pump, valve, pressure sensor and tubes connecting it with the cuff cushion
Pump—is a component of the pressure control system pumping air to the harness chamber
Valve—is a component of the pressure control system enabling to release excess air from the system and reduce pressure in the cuff cushion
Pressure sensor—is a component of the pressure control system enabling to measure the current pressure in the cuff cushion
The control and pumping unit 6 termed also the pumping unit 6—a part of the device in the polymer housing, containing a microcontroller and the pressure control system
Pressure—it is a current pressure in the pressure control system
Pressure indicator—it is a field in the software which stores the current value of pressure in the pressure control system
LED light indication—LED operation with a specific frequency where the LED voltage is low for one half of the time and high for the other half, wherein the number of light signals specified as the number of LED operation periods
Pressure setting—this is one of predefined pressure level values in the cuff cushion corresponding to the compression force expected by the user
Pressure sensor calibration—a calibration process consisting in calculating the correct value of the pressure indicator in the pressure control system based on the value returned by the pressure sensor
Settings calibration to the compression force—a calibration process consisting in adapting the pressure in the cuff cushion to the appropriate levels of the compression force of the cuff on the patient's body
State—this is a set of device information which enables to specify the position in the device operation scenario
The device operation scenario—this is the expected sequence of the device state changes
Self-Check—a test carried out automatically by the device to check its correct operation and the correctness of the stored dates
Date and time of the first start—this means a field in the software where the date and time saved following the successful completion of the first-started Self-Check test are kept
Calibration date and time—this means a field in the software which stores a date and time saved after the calibration process is completed
Current date and time—this means a field in the software which stores the current date and time of the device
PID—this is a part of the software controlling the valve and pump based on the pressure indicator and pressure setting values. It is a controller.
There are 4 basic types of controllers used in practice:
It is a hybrid of all the above components.
The device should be supplied from the main battery supply system and have an extra source of battery power supply, enabling to provide power supply to the integrated device clock to maintain the current date and time in the device.
The PID controller programmed in the device, controlling the pump and valve system to control pressure, should be responsible for controlling the compression force exerted by the cuff cushion. Pressure settings are predefined.
The compression force can be selected manually by controlling the pressure.
The device is switched on by pressing and holding the OK button for a prolonged time, e.g. 3 s. The device should be able to be started normally (to ensure normal operation) only after both calibration processes are completed. Once switched on, the device should enter the state when the Self-Check is carried out automatically.
It consists in undergoing the automatic test of the device correct operation. This test should be carried out by the device immediately after it is started. Depending on the start parameter value, the appropriate option of the Self-Check is selected.
During the first start, the device carries out the Self-Check procedure where the following parameters are checked in a sequence:
Following the Self-Check tests, the device awaits the operation start. After the OK button is pressed, the device selects the first value in the setting sequence as the pressure setting and enables the user to select any of the predefined settings. The device checks if the pressure control error falls is within the limits of the pump and valve control errors. If it is not the case, the device starts the operation of the PID controller to reach the required pressure setting, avoiding pressure oscillations in the cuff cushion. The pressure is controlled by the operation of the pump and the valve. Summarizing, during the normal operation, the device checks the pressure in the cuff cushion and starts to control when the pressure is too high or too low. The PID controller itself operates based on a specific control strategy.
The control strategy is the adopted way of controlling and reaching the preset value in a way limiting the use of the valve because of its high inertia.
The device should have a permissible control error implemented, being the control error value below which the controller should not perform an action, with different error values defined for the pump (e.g. 300 Pa) and different for the valve (e.g. 500 Pa).
Control with energy quanta. The control consists in selecting quanta of electricity from the power supply delivered to the valve and pump. The sampling frequency is constant.
Pressure error e(t) between the pressure sample v(t) and the setting w(t) is analyzed by the PID controller. If the error value belongs to the permissible control error range, we stop the control. Depending on whether the error is positive or negative, we decide to control the pump or the valve. The controller returns the u(t) value in the form of the valve or pump launching time. Thus, the speed of reaching the steadiness is achieved basing on the Kp, Ki and Kd parameters of the PID controller. Because of such control, we get quanta of energy sent in the form of pressure to the cuff if the y(t) value deviates from w(t) a lot.
The cuff 4 with the harness 8 of the pneumatic compression bandage 7 is first applied in the operating theater by the doctor or another person authorized to carry out such activities immediately after the medical device (e.g. a stimulator or a cardioverter) implantation procedure is completed and after the wound is protected with a standard, sterile dressing. The procedure of applying the pneumatic compression bandage:
1) Ensure the postoperative wound is protected correctly with a sterile dressing
2) Place the compression cuff 4 of the pneumatic compression bandage 7 centrally over the implanted medical device to ensure it covers the entire implanted device and the implantation site as much as possible.
3) In the above position, the compression cuff 4 should be fixed using the adjustment of straps 1, 2, 3 of the harness 8. First, adjust the length of the chest strap 1, then of the shoulder strap 2 to ensure stable and fixed location of the cuff over the implantation site. Finally, fix the arm strap 3 preventing arm abduction.
4) The harness 8 should be fitted tight, i.e. the patient should feel a slight pressure on the area of the stimulator/cardioverter site even before the chamber 9 of the compression cuff 4 is filled automatically.
To start the pumping unit of the pneumatic compression bandage, press the OK button of the inactive device and hold it for 3 seconds. If the device is started for the first time, it undergoes an extended automatic Self-Check test. In any other case the device carries out solely the fast automatic Self-Check test (lasting ca. 1 second). Once the test is completed, the device reports its readiness for the operation by a repeating sequence of the green LED lighting: 2 seconds lit and 2 seconds break. Then, press OK to start the device operation.
If the device is started again after its parameters have been set and the keypad has been locked, right after the Self-Check test it starts to operate with the preset parameters and the device keypad is locked automatically.
The device has 6 predefined settings of the compression force. The compression force can be increased/decreased by pressing the “UP”/“DOWN” button when the device operates with the unlocked keypad. The device indicates the currently selected setting by the number of the green LED blinks (0 to 5). To confirm the selection, press “OK”. The device will automatically control the pressure in the cuff to the selected compression force.
To switch on the manual mode, press the appropriate combination of buttons when the device operates with an unlocked keypad, e.g. pressing and holding the “UP” and “DOWN” buttons simultaneously for 3 seconds. It is indicated by 3 rapid beeps. The compression force is controlled by pressing and holding the button: “UP” increases the compression force by adding more air to the compression cuff and “DOWN” decreases the compression force by opening the discharge valve. The compression force value set by the above control should be accepted by pressing the “OK” button which will result in turning on the automatic mode in which the pumping unit will maintain the constant compression force set with the above programming. Pressing the “UP” or “DOWN” button will result in returning to the last predefined value in the automatic mode and a shift to the adjacent setting (higher/lower depending on the button pressed).
The pneumatic compression bandage provides the possibility of locking the keypad. The device with a locked keypad maintains the appropriate pressure in the cuff but no longer responds to other key combinations (apart from the unlocking combination). This prevents any changes of settings by unauthorized people. The keypad can be locked during normal device operation by pressing an appropriate combination of buttons, e.g. pressing and holding the “UP” button and pressing the “DOWN” button 3 times simultaneously (the keypad is unlocked in the same way).
The pumping unit is switched off by pressing and holding the “OK” button for a longer time, e.g. 3 seconds. If the device keypad is locked, the device can be switched off by removing the cuff connection hose from the control unit, waiting ca. 1 minute until the device starts emitting the emergency sound signal and the red LED is lit, then pressing the “OK” button and holding it for 3 seconds. The device will switch off.
The procedure describes the start and selection of the compression force of the device immediately after the operation.
1) Connect the cuff connection hose to the pumping unit.
2) Switch the device on.
3) Wait ca. 1 minute until the device automatically completes the Self-Check test (the successful Self-Check is signaled by the green LED lighting in the sequence of 2 seconds lit and 2 seconds break).
4) Switch the device off.
5) Put on the compression cuff
6) Switch the device on again.
7) Press the “OK” button.
8) Select the appropriate compression force in the automatic or manual mode
9) Wait for a while until the device stabilizes pressure in the cuff and ensure the site compression is appropriate.
10) Lock the keypad.
11) After the above activities are completed, the device is ready for further automated operation and it can be handed over to the patient.
When the pneumatic compression bandage 7 is used, it may be necessary to replace the standard sterile dressing. Before doing it, switch off the pumping unit. Next, remove the compression cuff 4 and change the sterile dressing. After you put on a new sterile dressing, put the cuff 4 on again (as described above), connect the cuff connection hose 5 to the pumping unit 6 and start the device. The started pneumatic compression bandage 7 seeks to reach the setting before it was switched off and maintains it.
In the pneumatic compression bandage solely the battery/rechargeable battery power supply is permitted. Preferably, power is supplied to the device from 2 AA 1.5 V alkaline batteries. If the device batteries are discharged, they must be replaced by new ones. Low battery is indicated by a relevant emergency signal. To replace batteries, switch off the device, remove the cover at the device bottom, remove the empty batteries and replace them with new ones. Then close the cover, connect the cuff to the pumping unit again and start the device. If the battery level is too low, the device will not start normal operation. After the operation is completed, remove batteries from the device.
The control and pumping unit 6 has an integrated wireless communication interface using radio waves, preferably in the NFC (Near Field Communication) standard. Using the device with the NFC communicator and a controlling application, e.g. a smartphone, the user can communicate with the control and pumping unit 6 to send, read or modify the current configuration of the unit 6 settings. Preferably, this communication will enable also to send or read the information on the patient and therapy administered. Communication using the NFC standard is a touchless, hygienic communication method which enables to read the data saved in the control and pumping unit without the need to touch the device, open the housing or connect the cables.
During the device operation an emergency situation can occur which is indicated by a red LED lighting and an emergency beep. In such a case the device switches off the pump automatically, opens the valve and switches to the emergency state indication mode. In that mode, the device operation is limited to the periodic repetition of the emergency signal. The emergency state mode can be quit by switching the device off. Possible emergency states:
Number | Date | Country | Kind |
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EP20461557.9 | Jul 2020 | EP | regional |