Drainage device with pressure relief valve

Abstract

A drainage device for removing fluid from a body cavity of a patient is provided. The device comprises a drainage tube and a pressure sensing means (24). The drainage tube is connectable to a pump unit configured to apply suction pressure to the fluid in the body cavity, and the pressure sensing means (24) is configured to detect when the applied suction pressure is equal to or above a predetermined threshold level.

Description

Technical Field

[0001] The present invention relates to a drainage device for removing fluid from a body cavity of a patient, and more particularly to a drainage device having a pressure sensing means. The present invention also relates to a method for regulating the suction pressure of such a drainage device. Background Art

[0002] In contemporary medical care, the movement of fluids from a body cavity to another collection point is a routine need and can be performed in several ways. When a tube or conduit is used to carry the fluid during the movement, gravity or a pump can be used to generate and / or maintain the suction pressure required to move the fluid from one point to another.

[0003] Sometimes, fluid from the human body must be moved in a gentle, slow, and steady manner. This gentle, slow, and steady manner can be referred to as "peristalsis." Peristaltic pumping can be performed in a variety of ways, including but not limited to a manual pump or using a peristaltic pump.

[0004] Additional known methods for drainage procedures include plastic vacuum suction bottles and wall / portable suction. These methods generally produce constant suction rather than peristaltic suction. These methods also include plastic bottles that are pre-avacuumed pre-set with vacuum at pressures that cause inadequate suction.

[0005] Since these pumps are not always monitored by medical personnel, problems can occur when an excess of fluid has been removed from the patient. The pump continues to run until it is turned off, and during this time the pumping causes severe pain to the patient.

[0006] From the foregoing it can be appreciated that there is room for improvement and the present invention is directed to solving or at least alleviating the above-referenced and other problems. Summary of the invention

[0007] The object of the present invention is to provide a new type of drainage device, which is improved over the prior art and eliminates or at least alleviates the disadvantages discussed above. More specifically, the object of the present invention is to provide a drainage device with a pressure relief valve, which relieves the pain of patients who need drainage. These objects are achieved by the technology set forth in the attached independent claims and the preferred embodiments defined in the dependent claims related thereto.

[0008] According to an embodiment of the present invention, the above problem is solved by a pressure relief valve provided in the drainage device.

[0009] In a first aspect, a drainage device for removing fluid from a body cavity of a patient is provided. The device comprises a drainage tube and a pressure sensing means. The drainage tube can be connected to a pump unit, which is configured to apply suction pressure to the fluid in the body cavity, and the pressure sensing means is configured to detect when the applied suction pressure is equal to or above a predetermined threshold level. This is advantageous because the patient may experience pain due to pressure exceeding the threshold level. By detecting the pressure, the pain can be relieved.

[0010] In one embodiment, the pressure sensing means is a pressure relief valve. The valve is configured to open when the pressure is equal to or above a predetermined threshold level. By opening the valve, the patient's pain can be relieved.

[0011] In another embodiment, the pressure relief valve is configured to allow air to flow through the drainage tube when opened, thereby reducing the suction pressure. When the suction pressure becomes too high, ie, exceeds a threshold level, the reduced suction pressure relieves the pain experienced by the patient.

[0012] Preferably, the drainage device further comprises a check valve for preventing air from the pressure relief valve from entering the patient. From a patient safety perspective, it is advantageous not to allow air to travel in a direction toward the patient. If air enters the patient, the patient may suffer complications.

[0013] The drainage device can also include a filter unit configured to remove contaminants from the air entering through the pressure relief valve. It is advantageous to remove possible contaminants from the air that might otherwise accumulate inside the drainage device and cause blockages, slow flow rates, or reduced suction pressure.

[0014] In one embodiment, the pressure sensing tool includes a pressure sensor and a memory metal valve configured to control the suction pressure of the fluid applied to the body cavity. This is advantageous because the memory metal is a simple solution that does not require additional sensors or electronics. In addition, the memory metal provides a high level of recoverable plastic strain.

[0015] Preferably, the pressure sensor is configured to transmit an electric current to the valve, thereby causing the valve to expand and form a hole configured to allow air to flow therethrough, thereby reducing the suction pressure.

[0016] In one embodiment, the drainage device further comprises a pressure indicator configured to provide an alert when the pressure is equal to or above a threshold level. This is beneficial to the patient. If the patient feels that the suction pressure is starting to become uncomfortably high, he / she can feel relieved by the indicator confirming that the pressure is actually on the high side and that the pressure will soon decrease. This can help the patient tolerate any pain.

[0017] Preferably, the pressure indicator is one or more of a visual indicator, such as a light, LED, propeller tool, color indicator tool or visible air flow, or an auditory indicator, such as a whistle tool, or a bellows tool. All forms of visual or auditory indicators provide the patient with information about the suction pressure that has reached a threshold level.

[0018] In one embodiment, the first end of the drainage tube can be connected to the patient's patient side tube, and the second end of the drainage tube can be connected to a collection unit for collecting the removed fluid. It is advantageous to use a collection unit to collect the removed fluid. A portable collection unit also means that the patient does not need to be completely still while the drainage procedure is performed.

[0019] The pressure sensing means is preferably arranged between the patient side tube and the drainage tube. This is an advantageous position because this is where the two tubes join.

[0020] In one embodiment, the patient side tube is a chest tube. Fluid is typically drained from the lung region of the patient, and in this case, the patient tube is a chest tube.

[0021] The predetermined suction pressure threshold level is preferably between 20-60 cmH 2 O. For most patients, this is a suitable threshold level.

[0022] In a second aspect, a method of regulating the suction pressure of a drainage device is provided. The method comprises the steps of determining a suction pressure threshold level; providing a drainage device with a pressure sensing means; detecting by means of the pressure sensing means when the applied suction pressure is equal to or above the determined suction pressure threshold level; and then regulating the applied suction pressure. The advantage of the method is that the patient does not need to experience an unnecessarily high level of pain when the suction pressure becomes too high.

[0023] In one embodiment, the regulating step is performed by an open valve or by a sensor communicating with a microprocessor regulating the pump unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Embodiments of the invention will now be described; reference is made to the attached schematic diagram which shows a non-limiting example of how the inventive concept can be reduced to practice.

[0025] Figure 1 is a front view of a patient with pleural effusion;

[0026] Figure 2a is a front view of a drainage device according to one embodiment;

[0027] Figure 2b is a perspective view of a drainage tube and a collection tool according to one embodiment;

[0028] Figure 3a yes Figure 2b A stereoscopic view of a ring of a drainage tube and a first fixing tool;

[0029] Figure 3b is a perspective view of a second fixing tool;

[0030] Figure 3c It is configured around the peristaltic mechanism Figure 3a A stereoscopic view of a ring of a drainage tube in FIG.

[0031] Figure 4 is a perspective view of a drainage device according to one embodiment;

[0032] Figure 5 yes Figure 4 Detailed view of the drainage device in;

[0033] Figure 6 yes Figure 2b A stereoscopic view of the drainage tube and collection tool, and a detailed view of the pressure sensing tool;

[0034] Figure 7 is a side view of a portion of a drainage device;

[0035] Figure 8 is a side cross-sectional view of a pressure relief valve in a closed position according to one embodiment;

[0036] Fig. 9 yes Figure 8 A side cross-sectional view of the pressure relief valve in an open position;

[0037] Fig.10 yes Figure 8-9 Top view of the pressure relief valve in;

[0038] Fig.11a is a top view of a pressure relief valve in a closed position according to one embodiment;

[0039] Fig.11b is in the closed position Fig.11a A side view of a pressure relief valve in FIG.

[0040] Fig.12a is a top view of the pressure relief valve of FIG. 11 in an open position; and

[0041] Figure 12b is a side view of the pressure relief valve of Figures 11-12a in an open position. DETAILED DESCRIPTION

[0042] Specific embodiments will be described in more detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided as examples so that this disclosure will be thorough and complete and will fully convey the scope of the invention, such as defined in the appended claims, to those skilled in the art. If not otherwise stated, the different embodiments can be combined with each other.

[0043] Figure 1 A patient 28 is shown having a lung 29. The lung 29 is surrounded by the lung lining, or pleura 30. When the patient 28 suffers from a disease such as various forms of cancer, fluid may accumulate between the lung 29 and the lung lining 30. This condition is known as a pleural effusion 31. This condition is treated by drainage via a drainage device 16, which will be described below. Since such a device 16 is not always monitored by medical personnel, problems may arise when excess fluid has been removed from the patient 28. The drainage device 16 continues to operate until it is turned off, and during this time the continued suction pressure causes the lung to become collapsed, causing severe distress to the patient 28.

[0044] Figure 2a and 2b A front view of a drainage device 16 and a perspective view of a portion of the device 16 are shown, respectively, according to one embodiment. The drainage device is also referred to below as a drainage device or drainage system. The system / device 16 is disposable. This means that it is used only once and then discarded to avoid spreading infection between patients 28.

[0045] like Figure 2a As shown, the drainage device 16 comprises a housing 1 for accommodating the main components of the device 16, which are a preferably flexible drainage tube 3 and a peristaltic mechanism 2. The drainage tube 3 has a first end 7a having a patient-side connector 4 for connecting the device to an access port (not shown) of a patient 28, and a second end 7b having a device-side connector 5. A collection unit 8 is preferably provided, which can be connected to the device-side connector 5 of the drainage tube 3.

[0046] The drainage device 16 can also include a pressure regulator 17 .

[0047] The depicted device also includes at least one liquid property indicator 9, a peristaltic movement indicator 10, a peristaltic regulator 11, a peristaltic regulator button 11a, a power button 12, a battery level indicator 13. In addition, a sample port 15 is provided at the bottom end of the collection unit 8 to enable extraction of a sample from the drained fluid for further testing.

[0048] The drainage tube 3 is inserted through the peristaltic mechanism 2 and fixed in its operating position by first fixing means 6 which fix the operating position of said drainage tube 3 and provide optimal operating peristaltic conditions.

[0049] When the drainage tube 3 and the two connectors 4, 5 are in place, the device can be activated by pressing the power button 12. The device is thus ready for use.

[0050] Connect the patient's access port to the patient-side connector 4 to use a drainage device.

[0051] The drainage program is activated by pressing the peristaltic regulator button 11, and the peristaltic pumping is indicated by the peristaltic movement indicator 10. As the body fluid is drained from the body cavity, it enters the first portion 7a of the drainage tube 7 via the patient-side connector 4, passes through the peristaltic mechanism 2 into the second end 7b of the drainage tube 3, and then enters the collection unit 8 via the device-side connector 5.

[0052] The peristaltic regulator 11 controls the peristaltic motor in a preprogrammed manner to perform what can be referred to as a "drainage cycle." In order to provide this preprogrammed control, the peristaltic regulator 11 is constructed to include an acceleration phase in which the peristaltic motor is controlled to accelerate from a rpm of zero revolutions per minute to a predetermined operating rpm in a first predetermined time period.

[0053] The peristaltic regulator 11 is also configured to subsequently regulate the motor to maintain a predetermined operating rpm for a second predetermined period of time.

[0054] The peristaltic regulator 11 is also configured to subsequently decelerate the peristaltic motor from the operating rpm to a rpm of zero revolutions per minute over a third predetermined period of time.

[0055] The first predetermined time period can preferably be selected in the interval of 20-40 seconds, the second predetermined time period can preferably be selected in the interval of 150 to 250 seconds, and the third predetermined time period can preferably be selected in the interval of 20-40 seconds. Most preferably, the predetermined time periods are selected to be approximately 30, 200 and 30 seconds, respectively.

[0056] The peristaltic motion indicator 10 is configured to indicate to the user how much peristaltic motion capacity has been used. The peristaltic mechanism is rotating, and the regulator 11 controls the speed of rotation. If the battery power supply reaches a critical level, the battery power indicator 13 reminds the user to charge the battery.

[0057] As the fluid is transported through the second portion 7b of the drainage tube 3 and discharged into the collection unit 8 through the device-side connector 5, it will contact the fluid property indicator 9 and fluid properties such as pH and lactate and the total accumulation are measured.

[0058] The liquid property indicator 9 is provided for determining the liquid property of the drainage, for example by means of a chemical indicator arranged inside the preferably transparent collecting unit 8 .

[0059] The pH value of the drained fluid can be measured, for example, by means of a pH indicator in the form of an acid-chromogenic compound, allowing visual determination of the acidity or alkalinity. Another option for determining the pH of the drained fluid is by means of an electronic circuit configured to receive and process signals from a pH sensor disposed on the inner surface of the collecting unit 8, where the pH sensor is printed.

[0060] As described above, the liquid property indicator 9 is capable of determining the presence of lactate, which reflects metabolic stress. This can be done with the aid of a test strip containing an immobilized substrate, L-lactate, and visually determined by its color intensity, or with the aid of an electronic circuit configured to receive and process signals from a lactate sensor disposed on the inner surface of the collection unit 8, where the sensor is printed.

[0061] The human drainage system is preferably provided with a display unit (not shown), and the system is configured to display the pH and / or lactate measurement values ​​on the display unit. The display unit can be arranged on or as an integral part of the drainage device 16 or the housing 1, or can alternatively be arranged at a stand or hanger for the collection unit 8 (not shown).

[0062] Figure 3a Shown is a loop of drainage tube 3 and first fixing means 6. Tube 3 is firmly attached to fixing means 6, which does not allow any sliding between them. First fixing means 6 is preferably provided with mechanical protrusions, notches or other suitable means so that the tube 3 forming the loop can only be assembled in a specific position.

[0063] like Figure 3b As shown, the second fixing means 21 is preferably also provided with mechanical protrusions, notches or other suitable means, which are inverted relative to those of the first fixing means 6, so that the first fixing means 6 and the ring can only be assembled in a predetermined position and to prevent the first fixing means 6 from being assembled in the second fixing means 21 in a wrong way. For patient safety, it is important that the fixing means 6, 21 are not assembled in a wrong way, as this may result in fluid being pumped into the patient 28 instead of being pumped out of the patient.

[0064] Figure 3cA loop of drainage tube 3 is shown assembled around peristaltic mechanism 2. It can also be seen how first fixing means 6 is assembled with second fixing means 21 to hold drainage tube 3 in place for effective pumping. In human drainage device 16, the portion of drainage tube 3 arranged around peristaltic mechanism 2 has a length of tube corresponding to an arc length of 80 to 190 degrees of rotational revolution of peristaltic mechanism 2, so that the rollers of peristaltic pump 18 compress this portion of tube 3 in the course of its action. This portion of tube 3 preferably includes a length of tube corresponding to an arc length of 80 to 140 degrees, or more preferably 80 to 100 degrees, and most preferably 85 to 95 degrees of rotation of the peristaltic mechanism.

[0065] Figure 4-7 The above-mentioned drainage device 16 is shown, which is provided with a pressure relief valve arrangement 20, and Figure 8-10 A valve arrangement 20 is shown. The pressure relief valve is configured to reduce the pressure applied by the drainage device 16 to the body cavity 31 of the patient 28. The discomfort and pain experienced by the patient 28 is thereby alleviated.

[0066] exist Figure 6 and 8 The pressure relief valve arrangement 20, best seen in Figure 10, comprises a pressure relief valve, a filter unit 27, a tap 23, a first connector 25 and a second connector 26. The valve unit further comprises a housing 36 from which the connectors 25, 26 protrude.

[0067] The filter unit 27 is arranged on the first surface 36a of the housing 36. The filter 27 is permeable to air, allowing ambient air to enter the interior of the valve housing 36, but is impermeable to contaminants removed from the air entering the device 16.

[0068] The valve is provided with a valve membrane 37 inside the housing 36. The membrane 37 is connected to an actuator 38. The actuator is implemented as a spring, preferably a coil spring, for example. A partitioning tool 39 is further provided inside the housing 36, which is preferably implemented as a plate. The plate 39 divides the interior of the housing 39 into a first part 41 and a second part 42. The first part 41 accommodates the valve membrane 37 and the spring 38. The second part 42 is a flow channel for the fluid to be diverted.

[0069] The partition plate 39 is provided with through holes 40. The number of through holes 40 can vary between different embodiments and valve sizes. Fig.10The number of holes 40 shown in the figure is seven and is to be regarded as an example only. The inlet area 40a of the hole 40 is located on the side of the first part 41 of the separation tool 39 facing the interior of the housing 36. The outlet area 40b of the hole 40 is located on the side of the second part 42 of the separation tool 39 facing the interior of the housing 36. The shape of the hole 40 is a truncated cone. Therefore, the inlet area 40a is larger than the outlet area 40b. The hole 40 and its use will be further described below.

[0070] The pressure relief valve is preferably a negative pressure relief valve. This means that the valve opens when the pressure difference between the interior 41, 42 and the exterior of the drainage device 16 becomes too large, i.e. exceeds a certain threshold level. The first connector 25 is preferably a barbed tube fitting and is adapted to be connected to the drainage tube 3. The second connector 26 is adapted to be connected to a chest tube of the patient 28.

[0071] Fluid drained from patient 28 passes through the chest tube, enters the valve via second connector 26, travels through flow channel 42 in the direction of arrow F, and exits the valve via first connector 25. Figure 8 Shown in.

[0072] When the suction pressure of the drainage device 16 applied to the body cavity 31 of the patient 28 is equal to or higher than a predetermined threshold level, the pressure relief valve opens, such as Fig. 9 As shown. This is accomplished by selecting the spring stiffness of the spring 38. When the suction pressure exceeds the spring stiffness of the spring 38, it compresses. The compressed spring 38 brings the valve membrane 37 toward the plate 39. Thus, a space is formed between the filter 27 and the membrane 37, thereby providing the air flow A to the first part 41 inside the housing 36. The air flow A is guided into the second part 42 inside the housing 36 through the hole 40. Thus, the air flow A is directed into the fluid flow channel 42, where it mixes with the fluid and continues to enter the drainage tube 3 via the first connector 25, thereby reducing the suction pressure applied to the patient 28. The truncated cone shape of the hole 40 prevents capillary forces on the fluid and thus prevents the fluid from entering the first part 41.

[0073] When / if the suction pressure normalizes, ie when the pressure drops below a threshold pressure level, the valve membrane 37 returns to its closed position. The air flow A is thus stopped.

[0074] The suction pressure applied by the pump unit 18 pushes the air A in the direction of the collecting unit 8. Thus, the air A is prevented from entering the patient 28. For additional patient safety, the device 16 can be equipped with a non-return valve 32, which is preferably an in-line non-return valve. Once the air A enters the collecting unit 8, it remains therein.

[0075] The tap 23 is preferably a three-way tap. The tap 23 is used to turn off the pressure regulation. Even if the default setting is to use the pressure regulation, in some embodiments, it may be desirable not to use it. Then, the tap 23 becomes useful.

[0076] In one embodiment, the filter unit 27 is a microporous filter. Since the air needs to overcome the flow resistance before it can pass through the filter, the filter itself acts as a valve. As long as the resistance in the tube is less than the resistance through the filter, no air will enter. When the resistance through the tube increases, air will begin to pass through the filter 27, i.e., enter the device 16 through the valve. Therefore, the suction pressure acting on the patient 28 is reduced. In this embodiment, the actuator and the valve membrane are redundant. However, the partition plate 39 is preferably arranged so that the filter unit 27 is not in direct contact with the fluid of the drainage. Therefore, the filter 27 is configured at a distance from the fluid, for example, by means of the plate 39. If the filter 27 contacts the fluid, the flow resistance through the filter may become too large, so that air cannot pass, which means that the filter cannot be opened.

[0077] The drainage device 16 includes a pressure indicator 35, which indicates when a threshold pressure is reached. This can be a signal to the user 28 that sufficient drainage has been achieved. The pressure indicator 35 is, for example, a visual pressure indicator, or an auditory pressure indicator, which alerts the user with the aid of sound. The visual pressure indicator can take the form of an LED or a lamp, or alternatively, or in addition, the visual pressure indicator 35 includes a color indicating means. The color pressure indicator 35 is configured to change its color when it comes into contact with air. Therefore, when the pressure relief valve opens and lets air through, the color pressure indicator 35 changes color and alerts the user.

[0078] Another visual option for the pressure indicator 35 is a propeller tool. The propeller tool 35 is configured to rotate when the pressure is reduced, i.e. when the pressure relief valve is open. When the pressure is normalized, the propeller tool 35 is stationary. Therefore, it is obvious to the user 28 when the valve is open. If the propeller tool is made to make a noise while rotating, a combination of visual and audible indication is obtained.

[0079] Another visual pressure indicator 35 is the air flowing through the draft tube 3 when the pressure relief valve is open.

[0080] The audible pressure indicator 35 can include a bellows tool. The bellows tool 35 has an expansion mode and a contraction mode. When the pressure is too low, the bellows tool 35 contracts and makes a sound. When the pressure is normalized again, the bellows tool 35 returns to its expansion mode.

[0081] An alternative audible pressure indicator 35 is a whistle tool. When air enters through the whistle tool 35, ie when the pressure relief valve is open, a sound is emitted. The whistle tool can, for example, comprise a ball organ which emits a sound when air passes through.

[0082] In one embodiment, reference Fig.11a , 11b , 12a and 12b, the valve configuration 200 includes a filter unit 270 and a valve membrane. The pressure relief valve membrane includes a switch formed of a memory metal. The memory metal can also be referred to as one of SMA, smart metal, memory alloy, muscle wire, and smart alloy. The valve membrane of the memory metal is configured to be operably connected to the pressure sensor 340.

[0083] like Fig.11a and 11b As shown, the valve is closed when the suction pressure recorded by the pressure sensor 340 is below the threshold pressure level. Fluid travels through the conduit 300 in the direction of arrow F. No air passes through the valve.

[0084] refer to Figure 12a-12b , when the pressure detected by the pressure sensor 340 exceeds a predetermined threshold, a current 430 flows from the pressure sensor 340 to the valve. The current 430 heats the metal of the valve, causing the memory metal to expand. As a result, the hole 400 in the valve is opened. As a result, air A is able to flow through the filter unit 270, through the hole 400 and into the fluid flow F, and thus in combination with the above Figure 8-10 Relieve suction pressure in the same manner as described.

[0085] The connection between the valve arrangement 200 and the tube 300 is only schematic. Preferably, the connection comprises any suitable type of connector valve. The valve arrangement 200 can be combined with Figure 8-10 Features of the valve arrangement 20 are shown and described in conjunction with these drawings.

[0086] In one embodiment, the drainage device 16 comprises a microcontroller 33, which is preferably arranged in the pump unit 18. The suction pressure applied by the drainage device 16 can be controlled by means of the microcontroller 33. The pressure regulation is performed by means of, for example, an in-line pressure sensor 34, which is configured to communicate with the pump unit 18 via the microcontroller 33.

[0087] In one embodiment, the pressure relief valve is replaced by a pressure sensor 34. When the pressure sensor 34 detects a pressure exceeding a predetermined threshold level, it transmits a signal to the pump unit 18, thereby disconnecting the pump unit 18. Alternatively, or additionally, the suction pressure applied by the pump unit 18 is adjusted to a lower pressure.

[0088] The preferred pressure threshold level for the interrupted suction pressure is between 20-60 cmH2O. One possibility is to set the suction pressure threshold level to 50-60 cmH2O. This pressure level interval causes effective drainage. Another possibility is to use a lower threshold level. This is suitable for patients with higher sensitivity 28. A cancer patient may experience a lot of pain, so it is best not to make him / her suffer unnecessary pain. Therefore, in this case, the preferred threshold level is 20-40 cmH2O. The predetermined threshold pressure can be preset, or can be selected from various preset pressures, or can be freely selected, or the selections can be combined.

[0089] The foregoing description of embodiments of the invention has been given for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and it is apparent that many modifications and variations are possible. Such modifications and variations that are apparent to one skilled in the art are intended to be included within the scope of the invention as defined by the appended claims. For example, in connection with other medical conditions, fluid may accumulate in other regions of the human body other than the lungs. Therefore, the present invention is not limited to drainage of the lung region.

Claims

1. A drainage device for removing fluid from a body cavity of a patient, the device (16) comprising a drainage tube (3) and a pressure sensing means (24; 370), the drainage tube (3) being connectable to a pump unit (18), the pump unit (18) being configured to apply suction pressure to the fluid in the body cavity (31), and the pressure sensing means (24; 370) being configured to detect when the applied suction pressure is equal to or above a predetermined threshold level, and wherein the pressure sensing means comprises a pressure sensor (340) and a memory metal valve configured to control the suction pressure applied to the fluid in the body cavity (31), The pump unit (18) of the drainage device (16) is a peristaltic pump, comprising a peristaltic regulator (11) and a peristaltic motor, wherein the peristaltic regulator (11) of the peristaltic pump is configured to control the peristaltic motor of the peristaltic pump in a preprogrammed drainage cycle, the cycle comprising an acceleration phase within a first predetermined time period, adjusting the motor to maintain a predetermined operating rpm within a second predetermined time period, and a deceleration phase within a third predetermined time period, wherein the first predetermined time period is selected within the range of 20-40 seconds, the second predetermined time period is selected within the range of 150-250 seconds, and the third predetermined time period is selected within the range of 20-40 seconds.

2. The drainage device according to claim 1, wherein the pressure sensing means (24) is a pressure relief valve, the valve being configured to open when the pressure is equal to or above the predetermined threshold level.

3. The drainage device according to claim 2, wherein the pressure relief valve is configured to allow air (A) to flow through the drainage tube (3) when opened, thereby reducing the suction pressure.

4. The drainage device according to any one of claims 2-3, further comprising a check valve (32) for preventing air from the pressure relief valve from entering the patient (28).

5. The drainage device according to any one of claims 2-3, further comprising a filter unit (27) configured to remove pollutants from the air entering through the pressure relief valve.

6. The drainage device according to any one of claims 1 to 3, wherein the pressure sensor (340) is configured to transmit an electric current (430) to the valve, thereby causing the valve to expand and form a hole (400), wherein the hole is configured to allow air (A) to flow therethrough, The suction pressure is thereby reduced.

7. The drainage device according to any one of claims 1 to 3, further comprising a pressure indicator (35), the pressure indicator being configured to issue a reminder when the pressure is equal to or higher than the threshold level.

8. The drainage device according to claim 7, wherein the pressure indicator (35) is one or more of a visual indicator or an audible indicator.

9. The drainage device of claim 8, wherein the visual indicator is a light, a propeller tool, a color indicating tool, or a visible air flow.

10. The drainage device of claim 9, wherein the light is an LED.

11. The drainage device of claim 8, wherein the auditory indicator is a whistle tool or a bellows tool.

12. A drainage device according to any one of claims 1 to 3, wherein the first end (7a) of the drainage tube (3) is connectable to a patient-side tube (19) of a patient (28), and the second end (7b) of the drainage tube (3) is connectable to a collection unit (8) for collecting the removed fluid.

13. The drainage device according to claim 12, wherein the pressure sensing means (24; 34) is arranged between the patient-side tube (19) and the drainage tube (3).

14. The drainage device according to claim 12, wherein the patient-side tube (19) is a chest tube.

15. The drainage device according to claim 13, wherein the patient-side tube (19) is a chest tube.

16. A drainage device for removing fluid from a body cavity of a patient, the device (16) comprising a drainage tube (3) and a pressure sensing means (24; 370), the drainage tube (3) being connectable to a pump unit (18), the pump unit (18) being configured to apply suction pressure to the fluid in the body cavity (31), and the pressure sensing means (24; 370) being configured to detect when the applied suction pressure is equal to or higher than a predetermined threshold level, and wherein the pressure sensing means (24) is a pressure relief valve, the valve being configured to open when the pressure is equal to or higher than the predetermined threshold level, and The drainage device further comprises a check valve (32) for preventing air from the pressure relief valve from entering the patient (28). The pump unit (18) of the drainage device (16) is a peristaltic pump, comprising a peristaltic regulator (11) and a peristaltic motor, wherein the peristaltic regulator (11) of the peristaltic pump is configured to control the peristaltic motor of the peristaltic pump in a preprogrammed drainage cycle, the cycle comprising an acceleration phase within a first predetermined time period, adjusting the motor to maintain a predetermined operating rpm in a second predetermined time period, and a deceleration phase within a third predetermined time period, wherein the first predetermined time period is selected within the range of 20-40 seconds, the second predetermined time period is selected within the range of 150-250 seconds, and the third predetermined time period is selected within the range of 20-40 seconds.

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