Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/60—Containers for suction drainage, adapted to be used with an external suction source
  • A61M1/61—Two- or three-bottle systems for underwater drainage, e.g. for chest cavity drainage
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/71—Suction drainage systems
  • A61M1/74—Suction control
  • A61M1/742—Suction control by changing the size of a vent
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/71—Suction drainage systems
  • A61M1/74—Suction control
  • A61M1/743—Suction control by changing the cross-section of the line, e.g. flow regulating valves
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/35—Communication
  • A61M2205/3546—Range
  • A61M2205/3569—Range sublocal, e.g. between console and disposable
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/35—Communication
  • A61M2205/3576—Communication with non implanted data transmission devices, e.g. using external transmitter or receiver
  • A61M2205/3592—Communication with non implanted data transmission devices, e.g. using external transmitter or receiver using telemetric means, e.g. radio or optical transmission

Definitions

• the source of suction when used can fail and therefore the apparatus should be constructed to function as gravity drainage apparatus as a precaution against this eventuality so that fluid can still be drained from the patient.
• Display of an accurate suction level reading is also needed so that the physician can readily monitor or easily re-adjust the level of suction during the course of treatment to the patient.
• the prior art typically uses a water seal in the drainage apparatus between the collection chamber and the source of suction, or between the chamber and the atmosphere in the case of gravity drainage, to isolate the patient from the atmosphere and keep air from getting back into the chest.
• the water seal also serves as an indicator of air leakage from the patient when air bubbles through the water, the amount of bubbling serving as a guide to the physician of the degree of air leakage. Also motion of the water level indicates the patency and sampling of the patient.
• Such seals have not been reliable in preventing contamination of the patient and have been inconvenient and unreliable in use, as described below.
• the simplest form of such a drainage apparatus comprises a single bottle partially filled with water and serving as a water seal chamber.
• the bottle has an inlet tube from the patient extending below the water and on outlet tube communicating with the air space above the water. This is a rudimentary arrangement, which provides no control over, or indication of, the pressure in the collection chamber. As the drained material gradually fills the bottle, the resistance to drainage increases.
• a plurality of bottles has been used, connected in series between the patient and a source of suction.
• Normally three bottles are used: the first, connected to the patient as a trap, collects the fluids; the second, partially filled with water, forms the seal; and a the third acts as a pressure regulator by having a tube open to the atmosphere and extending below water in the bottle.
• the dept of this tube below the water determines the maximum amount of suction that can be drawn through the system because once sufficient suction is reached to drain air down the tube from the atmosphere and bubble through the water, increasing the level of suction only increases the rate of bubbling and consequently the level of suction in the apparatus is limited.
• U.S. Patents No. 3.363.626. 3.363.827. 3559.647. 3.683.913 and 3.853.128 show the development of rigid, disposable, plastic drainage apparatus, which has adapted the three-bottle arrangement into a unitary structure.
• a drainage apparatus which includes a water seal requires a relatively long time to set up because the apparatus must be primed with a certain volume of sterile water to generate the and to fill the U shaped manometer chamber. This volume of water is relatively large and usually more than one chamber has to be filled.
• the outlet also includes a float ball gauge calibrated to indicate the suction applied to the patient and connected the atmosphere and the outlet.
• a float ball gauge calibrated to indicate the suction applied to the patient and connected the atmosphere and the outlet.
• these apparatus incorporates an over-negative-pressure relief valve, which vents to atmosphere at a pre-set negative pressure to prevent the vacuum reaching too high a level (60 cm water).
• This valve is set in a passage between the atmosphere and the collection chamber and comprises a one-way spring-loaded valve. Since actuation of the valve allows air from the atmosphere into the collection chamber, which is open to the patient, it is necessary to provide a filter in the passage.
• US 4,889,531 discloses a pressure regulator including high and low pressure chambers separated by a divider having an opening, a closing member biased to a closing position for closing the opening with a biasing force according to a desired pressure differential between the chambers.
• GB 2 077 397 discloses a vacuum regulator comprising a body having parallel passages and a cap attached by a screw thread over one end of the body defining with the body a chamber containing a diaphragm arranged to co-operate with a seating at the end of a passage.
• a such apparatus must be able to function under conditions of gravity drainage or vacuum drainage and, in the latter case, apply stable and acceptable levels of suction to the patient.
• a simple, reliable sensor in the drainage apparatus to indicate accurately the pressure conditions in the collection chamber over a range of negative pressures.
• quantity of air that is evacuated over time which in it self indicates the progress of healing.
• SOC standard of care
• the tubing connecting the patient to the apparatus is preferably of a kink-resistant type that is designed to prevent obstruction to flow of fluid and air from the patient. Such obstruction may otherwise cause development of a tension pneumothorax.
• the pressure measuring means preferably comprises a piezo electric pressure sensor provided in the lid of the chamber, which directly measure the working pressure in the chamber.
• the piezoelectricity is becoming electrically polarized when stress is applied to it and this electrically polarization is translated to a display device to indicate the pressure in the chamber.
• Embodiments include MEMS and silicon sensor technology.
• the apparatus of this invention has means for indicating directly the pressure in the collection chamber and displaying the true level of suction applied to the patient, irrespective of whether an air leak from the patient is passing through the equipment.
• This pressure measuring means comprises preferably a liquid crystal display making a reading easy to accomplish, accurate and reliable, even at high levels of suction.
• the flow measuring means is provided to quantify the volume of evacuated air from the patient during use.
• All data from the flow measuring means and the pressure measuring means is preferably collectible and transferable to a PC/PDA via an infrared (IR) port.
• the collection chamber is provided with features, which make placement, collection and transportation of the device more convenient.
• the collection chamber is provided with suspension means, which serve both to suspend the collection chamber and to carry it, and yet which may also be stored flush against the chamber when not in use.
• Said suspension means preferably comprises VELCRO straps making the suspension adjustable.
• a surgical apparatus for draining fluids from the body, especially from the pleural cavity which comprises a rigid chamber for receiving the fluid.
• the chamber has an inlet for communication with the body, an outlet for connection to a source of suction when desired and a sensor for indicating the pressure in the chamber during use.
• This sensor comprises a piezoelectric sensor or a silicon sensor which is impervious to drained liquids and to air and which is mounted in the chamber lid standing in pressure communication with the inside of the chamber.
• the sensor is connected to means for indicating the pressure. Pressure differentials inside the collection chamber cause the sensor in use to be electrically polarized when stress is applied to it and this electrically polarization is translated to a display device to indicate the pressure in the chamber.
• the indication is achieved by a LCD-display mounted on the lid of the collection chamber.
• a flowmeter which comprises a sensor by means of a thermistor, which is mounted in an air channel for measuring the volume of air passing through the system over time.
• the channel has an inlet for directing the flow of gases from the collection chamber, and an outlet for letting the airflow from the apparatus.
• the sensor comprises in one embodiment a thermistor sensor, which is first heated up and then cooled off by the airflow in the channel. Heat differentials cause the sensor in use to be electrically polarized.
• four thermal resistors of the same nominal resistance is arranged in a row in said channel along a direction parallel to the air flow and with a heating resistance arranged between resistor number two and three.
• Said resistors are electrically coupled in a Wheatstone-like bridge such that the voltages of two voltage dividers are compared i.e., the voltage over resistor number four is compared with the voltage over resistor number 2 and where one current is flowing through resistors one and four, and another current is flowing through resistors three and four.
• the so formed differential voltage is measured under two conditions, i.e, heated with the heating resistor and unheated. The difference between the voltages obtained under heated and unheated conditions are subtracted from each other and the resulting difference is used as representative of the value of the air flow rate.
• a so called “moving vain” sensor is used, where a membrane is influenced by the air stream and this influence is translated to an electrical polarization.
• the electrical polarization is subsequently translated to a display device to indicate the airflow through the apparatus.
• Increasing flow or decreasing flow causes the sensor to be polarized and this polarization is translated to the indicating means via a microprocessor to directly display the airflow in the channel.
• the indication is achieved by a LCD-display mounted in the lid of the collection chamber.
• a pressure relief valve is provided on the lid of the chamber. This valve is activated manually to relive the negative pressure in the collection chamber.
• this pressure relief valve may comprise a spring-loaded or silicone or rubber seal over an opening between the outlet line and the atmosphere.
• the valve may comprise a rubber or silicone body having resilient properties eliminating the need for a conventional spring. A particular level of manual pressure will be sufficient to overcome the force of the spring and the seal will open to admit the atmosphere to the collection chamber and thereby relive the pressure in the collection chamber.
• the atmospheric air is filtered before entering the chamber bye means of a filter, which allows air filtration, and hindering contaminated particles from entering the chamber.
• a one-way valve which allow air to pass out, and not into the chamber.
• This one-way valve comprises a membrane that during a particular level of positive pressure will be sufficient to overcome the force of the valve and the seal will open to let air out from the apparatus. A negative pressure in the collection chamber will close the valve preventing air to flow back to the apparatus.
• a capillary breakpoint with increasing area of the capillaries is mounted just before the one-way valve.
• the capillary breakpoint comprises a membrane with large volume of small holes and their circular are is increasing in area, which allows fluids and blood to pass out from the membrane if they have entered the capillary breakpoint.
• the invention also assist in stabilization of the apparatus in use.
• means are provided to limit liquid transformation from one part of the system to another.
• the ergonomic kidney shaped design and labyrinth sectional walls that are designed in such a manner allows this function that they will not only limit the contamination of one-way valve and suction regulator but also allow good ergonomics when carried by the patient or managed by the hospital staff. Due to the kidney shape, the front and back surfaces of the collection chamber is arched, providing a more rigid and strong structure than would be the case e.g. with a plan surface.
• Means are provided to suspend the chamber, such as by Velcro® from a bed or rail.
• the suspension means are mounted on the external surface of the chamber in such a manner that they will not only suspend the chamber but also be nested on the external surface for storage and interlocked to form a carrying handles.
• Another embodiment of the invention include a portable drainage unit in the size of approximately 10 times 8 times 2.5 centimetres or less provided with a one way valve," connection to the patients body cavity, an electronics measuring and display organ for measuring and displaying drainage air flow and suction pressure.
• Said portable drainage unit utilises the body's own ability to provide pressure for pushing out air from a body cavity, i.e., by utilising the flow of air that results from breathing movements and other movemeonts and muscle contractions.
• the unit is provided with a small collection chamber having an absorbent material inside taking care of possible fluid. This type of apparatus is intended for treatment an monitoring of patients with partly healed and less wet pneumothorax.
• Measuring and display means A drainage apparatus according to a preferred embodiment of the invention is provided with measuring and display means providing for high accuracy measurement of the pressure in a body cavity, and the flow from said cavity as mentioned above.
• the embodiment achieve high accuracy combined with low power consumption so that a single solar cell of an area of approximately 2 times 3 centimetres or less is sufficient to provide the needed power. This will allow for almost indefinite shell life.
• a small battery e.g. of button cell type can be used.
• Figure 1 is an explanatory sketch showing the working principle of an embodiment of the present invention.
• Figure 2a shows a suction pressure regulator, partly in cross section, for a drainage device according to an embodiment of the present invention
• Figure 2b shows, in cross section, a suction pressure regulator according to another embodiment of the present invention.
• FIG. 3 shows a an overview of an embodiment of an apparatus according to the present invention
• Figure 4 shows a collection chamber, with the lid removed for clarity, for a drainage device according to an embodiment of the present invention.
• Figure 5b shows, partly in cross section, a detail of the non return valve unit in fig 5a.
• Figure 6 shows a block diagram of a measuring and display unit for use in a drainage device according to an embodiment of the present invention.
• Fig. 7a shows a photograph of a MEMS flow sensor according to an embodiment of the invention.
• Fig. 7b shows an enlargement view of a part of the sensor in fig. 7a shoving four serpentine like sensor resistors
• Fig. 7c shows a bridge circuit of a preferred way of coupling the sensor resistors.
• Fig . 8a shows a circuit diagram of a sensor circuit board for a drainage device according to an embodiment of the present invention
• Fig. 8b is a circuit diagram showing miscellaneous components of the sensor circuit board
• Fig. 9a shows a circuit diagram of a controller circuit board for a drainage device according to an embodiment of the present invention
• Fig. 9b shows a connectors overview.
• Fig. 10 shows a flow chart of a method of obtaining a value representative of an air flow in an apparatus according to one embodiment of the invention.
• FIG. 1 is an explanatory sketch showing the working principle of a drainage apparatus 199 according to an embodiment of the present invention.
• the figure shows a drainage tube 101, preferably of a kink resistant type, having a first and a second end. Said first end is intended to be connected to a patients body to drain fluid from typically a pleural or a pericardial cavity. Said second end is connected to a drainage apparatus 199 having an airtight collection chamber 110.
• the drainage tube 101 is provided with a reinforced part 105 near its second end close to an inlet opening of the collection chamber 110. Fluids that are extracted from the body include blood, pus and protein containing fluids with a high water content.
• the collection chamber is intended to be used in an upright position.
• Fluids entering the collection chamber 110 do, owing to gravity, first enter a first compartment 102, a paediatrics measuring chamber 102 having defining walls 113,114. Said chamber 102 is provided to enable a physician, a nurse or other health care personnel to make an optical reading on a first scale 112.
• the material of the collection chamber 110 is of an optically transparent type, e.g polycarbonate plastic or the like, allowing for easy and convenient readout of the fluid level inside the collection chamber 110.
• the paediatrics measuring chamber 102 has a relatively small transverse cross section so that when fluid are filling the chamber the level is increasing relatively much for a certain amount of fluid, making it easy to detect small variations in the fluid level.
• the paediatrics measuring chamber 102 is having its own set of defining walls making assembly easy by allowing for easy sliding the paediatrics chamber 102 into place in e.g. a dovetail slot.
• fluid When treating an adult patient producing a large amount of excess fluid in his pleural or pericardiac cavity, fluid will fill the paediatrics measuring chamber 102 and enter a second compartment 120, having a corresponding measuring scale 130. As fluid levels increase further the second compartment becomes full and the fluid flows over a first dividing wall 140 to a third compartment 121.
• the collection chamber comprises a number of such compartments 121-124 divided by dividing walls 140-143, preferably five to six compartments, allowing for easy readout of up to for example 2500 millilitres of fluid.
• Air evacuated from the patient passes over the dividing walls 140-143 and is sucked away via an outlet of the collection chamber 110, via protective means 105, comprising a capillary breaker 105, further via a non return valve 106, still further via a flow measuring means 107, a suction regulator 108, a high pressure valve 109, and finally via a suction supply tube 180 to an external source of suction pressure.
• protective means 105 comprising a capillary breaker 105
• non return valve 106 still further via a flow measuring means 107, a suction regulator 108, a high pressure valve 109, and finally via a suction supply tube 180 to an external source of suction pressure.
• the pressure measuring means 104 and/or the flow measuring means 107 is of a type connectable to an electronic measuring unit capable of wireless communication, e.g. infrared communication, with a computer 111 for further processing of information.
• a printer 129 can be connected to the computer 111 for the printing of parameters, trend diagrams on the like.
• the apparatus can also be provided with display means, connected to the electronic measuring unit, for displaying actual parameter values, such as collection chamber pressure, and current flow.
• Figure 2a is a view of a suction pressure regulator, partly in cross section, for a drainage device according to an embodiment of the present invention.
• the regulator preferably comprises two main parts, a house 201, and a turnable cap 202.
• the cap 202 has preferably a cylindrical shape so it can be screwed onto the house 201.
• the cap is provided on its inner cylindrical surface with threads 205, and the house is correspondingly on its outer cylindrical surface provided with corresponding threads.
• the threads are airtight in themselves or, in another embodiment, means such as 0-ring are provided to provide an airtight connection between the house 201 and the cap 202.
• the cap 202 is provided with a diaphragm 211 attached inside the cap 202 near an inner surface 217 of a top part 220.
• the inner surface 217 is preferably provided with a rough surface or pimple-like protrusions preventing the diaphragm 211 from adhering to the top inner surface 217.
• the diaphragm 211 is attached to the inner cylindrical walls in an air tight manner.
• the top part 220 is provided with a hole 222 for letting air of atmospheric pressure to enter and leave a small space 230 above the diaphragm 211.
• the house 201 comprises connections 231, 232 for supply suction pressure, and regulated suction pressure respectively.
• the supply connection 231 has a fluid connection through a bottom plate240 of the house 201 to a prolonged nozzle 241 inside the house 201.
• Said nozzle part having a top orifice 242 facing the diaphragm 211 so that an airtight contact can be achieved between the diaphragm 211 and the orifice 242.
• the nozzle part is preferably arranged in the centre of the bottom plate 240.
• the regulated pressure connection 232 preferably comprises a prolonged nozzle part 250 inside the house 201, having an orifice 251.
• the regulator functions as described below.
• the diaphragm In some point in the regulatory process the diaphragm is in air tight close contact to the orifice 242 of the supply nozzle 241. If the pressure inside the house 201 raises, i.e., the suction pressure becomes less, the diaphragm 211 will bend away from the supply orifice 242, thereby open for a supply suction pressure supplied via the nozzle 241, causing the pressure to fall. As the pressure falls, the diaphragm will bend towards the supply orifice 242 again and eventually make close contact to said orifice 242, thereby closing off suction pressure supply. This process is repeated and the pressure is regulated.
• the cap 202 is turned clockwise or anticlockwise like a knob so that a distance between the diaphragm 211 and the supply pressure nozzle orifice 242 becomes less or more.
• Another feature of the regulator is the feature of handling the problem of temporary formation of condensation water. Air coming from the human body normally contains 100% humidity at 37 degrees Celsius. As the temperature falls this humidity will fall out as water. To lower the risk of influence of such water in the regulator the hight H2 of the regulated pressure prolonged nozzle 250 is approximately half the hight Hl of the supply pressure nozzle 241. Water formed inside the regulator house 201 will stay at the bottom of the house, or leaving towards a collection chamber via the regulated pressure inlet 232, without affecting the diaphragm.
• Figure 2b shows, in cross section, a pressure regulator according to another embodiment of the invention.
• Those parts having a corresponding part in fig. 2a have the corresponding reference numerals with the addition of "prim" (').
• the embodiment in fig. 2b is based on the same principle as the embodiment in fig.2a i.e., the pressure is adjusted by moving a membrane (211, 211') closer to or further away from a suction pressure supply nozzle (241, 241').
• the regulator 200 comprises a regulator house 201' and an adjustable cap 202', where said cap is provided with a membrane 211' arranged close to its closed end 220' .
• the membrane is provided with a bellow 212 allowing the membrane to move in a downward-upward direction following the orifice of the prolonged nozzle 241' when the cap 202' is turned, and the pressure is adjusted is described above.
• the membrane 211 ' is also provided with a rim 213 providing structural stability an a means for being able to be kept on place.
• the membrane 211 ' is clamped between the upper part 220' of the cap 202' and a slide ring 215, which is kept in position by means of a conical spring 214.
• Said conical spring 214 serves the double purpose of on the one hand to provide means of keeping the membrane 211 ' in position, and on the other hand to provide means for keeping the cap 202' and the house 201' in a firm relationship avoiding loose or play between said cap 202' and house 201 ' that may otherwise adversely affect the pressure regulatory functioning.
• the conical spring has a large and a small end, the large end abuts the slide ring, while the small end abuts a shoulder 243 on the prolonged nozzle 241 ' .
• the spring 214 is designed to function in the following way: starting with an unloaded spring; when the axial load increases, the turns having the greatest radii is the most active.
• FIG. 3 shows an overview of an embodiment of a drainage apparatus 300 according to the present invention.
• a collection chamber 310 is provided with an airtight lid 384 having an inlet connection 380 connectable to a drainage tube from the patient, and an suction pressure supply connection 381.
• the suction pressure supply connection 381 is connected via internal channels in the lid 384 to a suction pressure regulator 387. Regulated suction pressure is connected to the internal of the collection chamber 310 via a non-return valve and a capillary breaker (not shown in fig. 3)
• a electronics unit 385 is provided in the lid having a pressure display, a air flow display and one or more solar cells for supplying all the power needed to power the electronics unit 385.
• the unit 385 is made easy removable allowing environmentally correct disposal of different kind of waste when the apparatus is to be disposed.
• FIG. 4 shows a collection chamber 400, with a lid removed for clarity, for a drainage device according to an embodiment of the present invention.
• the chamber 400 has a cross section providing an indentation running from a bottom part 402, not visible, to the lid, preferably giving the chamber 400 a kidney shaped cross section adding to the stability and rigidness of the chamber 400.
• Said chamber 400 is divided into compartments by a number of separating walls 405,410,415, 420..
• the separating walls are provided with fluid passing cuts near the lid to allow fluid to flow from a full compartment to a not yet full compartment.
• separating walls and cuts are arranged in a labyrinth manner preventing or reducing the risk of fluids from entering further compartments if the chamber accidentally falls on the side or otherwise is tilted in a non upright position.
• Two nearby separating walls have their fluid passing cuts formed at opposing sides i.e. near the indented side or near the non indented side. Some of the walls are also provided with cuts to give room for the lid and the electronics in the lid
• the two oute ⁇ nost dividing walls 405, 420 are provided with longitudinal running bends 406, 421 to further add to rigidness and stability.
• the lid is air tightly sealed to the collection chamber by means of silicone seal, plastic welding or other suitable method.
• the chamber 400 is provided with fastening means for a strap with VELCRO adjustment means or the like for easy suspension and carrying of the drainage device.
• FIG. 5a and 5b shows, in cross section, a non return valve unit according to an embodiment of the present invention.
• the evacuated air enters an atrium 501 having a floor 502 and vertical walls 503.
• the atrium 501 is upwardly defined by a capillary breaker 510 in the form of a horizontal wall 510 having a number of conical holes 505 in it.
• the holes 505 have a smaller and a wider end, and the smaller end is directed downwards in fig. 5a and 5b such that air streaming through the atrium 501 and the capillary breaker 510 will have a less water content after the breaker than before said breaker 510.
• the wall 503 is preferably continued upwards and a central column 512 is formed that holds a horizontal membrane 514 preferably of rubber of another flexible material.
• a non return valve is formed as the membrane forms an air tight seal with an upper part 516 of the vertical wall 503, as long as the pressure is lower on the side of the membrane 514 that is facing the capillary breaker than on the other side.
• the evacuated air then enters a measuring channel inlet 520 having vertical wall 522 of a height h that together with an airtight cover 530 forms a condense trap 524 further reducing the possible water content of the evacuated air.
• FIG. 6 shows a block diagram of a measuring and display organ 600 for use in a drainage device according to an embodiment of the present invention.
• Said measuring and display organ 600 include a pressure sensor 605 for measuring the pressure in a pressure measuring part of the drainage device that is in pressure connection with the body cavity.
• Said measuring and display organ 600 also include an airflow sensor 615 for measuring the airflow in an airflow measuring part of the drainage device, representative of the airflow from said body cavity.
• the sensors 605, 615 are connected to a processor 630 and send signals representative of said pressure and flow to said processor 630.
• Said processor processes the signals from the sensors 605, 615. Such processing may include analogue to digital conversion of signal values, compensations for nonlinearities etc.
• the processor 630 also transforms pressure and flow values to signals suitable to drive a display unit 670.
• the processor is connected to a display unit 670.
• Said display unit 670 receives signals from the processor 630 representing the pressure and flow values.
• the display unit 670 displays said values preferably in both a digital and in an analogue format making the values clearly readable for medical personnel handling the nursing and treatment of the patient, making parameters of progress as well as deterioration in the recovery process easily quantifiable.
• a button is arranged,, so that when pressed, the cumulative airflow, representative of the last hours cumulative air leakage is shown on the display 670.
• the processor 630 is preferably of the flash type, i.e., it has an internal flash memory which contributes to low power consumption.
• the measuring and display organ 600 is powered from a solar panel 650 provided with a power regulator 655. In an alternative embodiment the organ 600 is powered from a battery 665.
• the processor 630 is preferably connected to an IR port 640 for transferring information to an external device such as a personal computer or personal digital assistant. In another embodiment the data transferring is accomplished by wireless BLUETOOTH-means.
• the display unit 670 is preferably of a liquid crystal display (LCD) type or another low power consumption type and may be connected to the processor over a latch 675.
• the pressure value is preferable displayed as a two-digit number representative of the pressure in centimetres water column.
• the air flow is preferably displayed as a two digit number expressed in litres per minute.
• the pressure sensor 605 is preferably of a micro electromechanical system (MEMS) type.
• MEMS micro electromechanical system
• a suitable sensor is for example the MS761D from Intersema Sensoric SA 5 BEVAIX 5 SWITZERLAND (http://www.intersema.ch) .
• the pressure sensor 605 include a small rectangular area provided with a measuring resistance along each of the four sides. Electrical connections may be provided at all four corners.
• the pressure sensor is provided with means to withstand liquids such as water with ions, e.g. salt.
• the micro-controller is programmed such that when the operator presses the DEL button for 5 seconds the pressure and flow data stored in the memory, but not the sensor/controller ID, will be erased.

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• Health & Medical Sciences (AREA)
• Heart & Thoracic Surgery (AREA)
• Biomedical Technology (AREA)
• Vascular Medicine (AREA)
• Engineering & Computer Science (AREA)
• Anesthesiology (AREA)
• Hematology (AREA)
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• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Pulmonology (AREA)
• External Artificial Organs (AREA)

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• 2004
  • 2004-04-26 WO PCT/SE2004/000637 patent/WO2004110523A1/fr not_active Ceased
  • 2004-04-26 EP EP04729566A patent/EP1644058A1/fr not_active Withdrawn
  • 2004-04-26 AT AT07121511T patent/ATE476206T1/de not_active IP Right Cessation

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