WO2004108218A1

WO2004108218A1 - A probe and breathing circuit

Info

Publication number: WO2004108218A1
Application number: PCT/NZ2004/000119
Authority: WO
Inventors: Darin William Walsh; John Edward Fox Fowler
Original assignee: Fisher & Paykel Healthcare Limited
Priority date: 2003-06-11
Filing date: 2004-06-09
Publication date: 2004-12-16

Abstract

A probe (20) and breathing circuit (3) capable of supplying gases, the probe having a stem (21, 31) capable of extending into a port (23) in the circuit, a latching mechanism (27, 30, 36) between probe and circuit capable of locking probe in port, latch may be a protrusion on probe held by lip or ledge of port or vice versa. port may include soft sealing portion to assist retention of probe stem in port.

Description

"A PROBE AND BREATHING CIRCUIT"

FIELD OF INVENTION

This invention relates to probes for breathing circuits for use with breathing or respiratory apparatus. In particular, the present invention relates to a probe that is capable of being fastened to a breathing circuit. BACKGROUND OF THE INVENTION

Patients that are breathing by way of a breathing circuit maintain improved airway condition if they are delivered with a breathing air supply that is more humidified than not. To achieve an optimum level of humidity to the patient a humidifier needs to control the temperature of the gases supply reaching the patient by controlling the breathing circuit. The humidifier also controls the temperature of the gases within acceptable limits so as to not harm or burn the patient. To give accurate control to the humidifier, there needs to be a reliable measure of the temperature and flow of the gases neared to the patient. This can be achieved by way of temperature and flow probes. These probes must be capable of being sealed within a breathing circuit so that the patient receives most of the gases supplied, at the supplied pressure.

At present, prior art probes are pushed into a plastic port in the breathing circuit. The problem with current breathing circuits and probes, is that soon after the probe has been pushed into the breathing circuit, it can become less secure in the port. This is because the plastic of the port starts to creep and relax. Therefore, the hold on the probe decreases. Some existing probes are held in breathing circuits by a standard '1:40 Taper' that relies on the friction between the probe and the plastic port in the breathing circuit. There are instances where probes fall out completely, due to an accidental bump, or a gas leak is formed. In the case where a leak has formed or a probe is not correctly in position the probe may start to made incorrect gas temperature and flow readings.

A related problem to the situation described above is the fact that the circuit port that receives a probe can be manufactured so that it is relatively smaller than the probe diameter. This is to cater for the fact that the plastic will relax and enlarge over time. As a result, this makes it harder for the end user, such as a patient or doctor, to initially push the probe into the correct position. It is often difficult enough to push the probe all the way into a port on the circuit and end users often don't bother to push the probe in correctly. When this occurs, the probe is held less securely and is prone to falling from the breathing circuit and the probe may not take correct measurement readings. SUMMARY OF THE INVENTION

It is an object of the present invention to attempt to provide a probe and/or breathing circuit which goes some way to overcoming the abovementioned disadvantages in the prior art or which will at least provide the industry with a useful choice.

Accordingly in a first aspect the present invention consists in a probe for use with a breathing circuit that supplies gases to a patient said probe comprising: an elongated stem that is capable of extending into said breathing circuit, and a fastener capable of causing said probe to be locked in place in said breathing circuit.

In a second aspect the present invention consists in a breathing circuit for supplying gases to a patient said circuit capable of receiving a probe having an elongated stem to measure properties of said gases, said circuit comprising: a substantially tubular conduit, a port disposed on said conduit capable of receiving said stem of said probe, and a fastener on one of said conduit or said port to lock said probe to said port.

In a third aspect the present invention consists in a breathing assistance apparatus comprising a probe and a breathing circuit, wherein said probe includes an elongated stem that is capable of extending into said breathing circuit, and said breathing circuit includes a substantially tubular conduit and a port disposed on said conduit said port capable of receiving said stem of said probe, wherein said probe and said breathing circuit are fastened together.

The invention consists in the foregoing and also envisages constructions of which the following gives examples. BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the present invention will now be described with reference to the accompanying drawings.

Figure 1 is a block diagram of a humidified breathing assistance apparatus that may use a probe and breathing circuit of the present invention.

Figure 2 is an exploded perspective view of a first form of the probe of the present invention and associated breathing circuit and probe port disposed on the breathing circuit.

Figure 3 is a perspective view of the probe, breathing circuit and port of Figure 2, where the probe has been inserted and fastened in the port in the breathing circuit. Figure 4 is a plan view of the probe, breathing circuit and port of Figure 3. Figure 5 is an end view of the probe, breathing circuit and port of Figure 3. Figure 6 is an exploded perspective view of a second form of the probe and breathing circuit of the present invention, where the breathing circuit includes an elbow portion, a jacket that forms an extended port on the circuit and a soft sealing portion disposed in the port.

Figure 7 is a perspective view of the probe of Figure 6. Figure 8 is a perspective view of the jacket shown in Figure 6. Figure 9 is a perspective view of the soft sealing portion shown in Figure 6. Figure 10 is a perspective view of the breathing circuit elbow shown in Figure 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides improvements in probes and breathing circuits that form part of breathing assistance or ventilation apparatus, which supply gases to a patient. The probe and breathing circuit of the present invention includes a fastener or latch that ensures the probe is fixed in position within a breathing circuit port, and eliminates the possibility of the probe falling from the port and/or improper measurements being taken by the probe.

A breathing circuit and breathing assistance apparatus that would use the probe of the present invention is shown in Figure 1. Although a non-invasive system (using a nasal mask) is shown in Figure 1, the latching probe of the present invention may be used with invasive ventilation apparatus, such as endotracheal ventilation systems or the like. The breathing apparatus of Figure 1 shows a Continuous Positive Airway Pressure (CPAP) System or ventilation system where a patient 1 receives humidified and sometimes pressurised gases through a patient interface 2. The interface 2, which may be a nasal mask, full-face mask, nasal cannula, ET tube or tracheotomy tube, is connected to a breathing circuit 3 that is effectively a humidified gases transportation pathway or conduit. The breathing circuit 3 is connected to the outlet 4 of a humidification chamber 5, which contains a volume of water 6.

The breathing circuit 3 may contain heating means or heater wires (not shown) which heat the walls of the conduit to reduce condensation of the humidified gases within the conduit. The humidification chamber 6 is preferably formed from a plastics material and may have a highly heat conductive base (for example an aluminium base) which is in direct contact with a heater plate of the humidifier 8. The humidifier 8 is provided with a control means or an electronic controller 9, which may comprise a microprocessor based controller executing computer software commands stored in an associated memory. The controller 9 receives input from sources such as a user input means or dial 10 through which a user of the device may, for example, set a predetermined required value (preset value) of humidity or temperature of the gases supplied to the patient 1. The controller will also receive input from other sources, for example the temperature and/or flow velocity sensors (probes) 12, 20, through a connector 13 and a heated plate temperature sensor 14. In response to the user set humidity or temperature value input via dial 10 and the other inputs, controller 9 determines when (or to what level) to energise the heater plate 7 to heat the water 6 within the humidification chamber 5. As the volume of the water 6 within the humidification chamber 5 is heated, water vapour begins to fill the volume of the chamber above the water's surface and is passed out of the humidification chamber outlet 4 with the flow of gases (for example, air) provided from the gases supply means or blower 15 which enters the chamber through inlet 16. Exhaled gases from the patient's mouth are passed directly to ambient surroundings or may pass through an expiratory circuit, back to a ventilator. • The blower or ventilator 15 may be provided with a variable pressure regulating means or variable speed fan 11 which draws air or other gases through blower inlet 17. The speed of the fan 11 is likely to be controlled by the electronic controller 18 (or alternatively the function of the controller 18 could be carried out by the controller 9) in response to inputs from the controller 9 and the user set predetermined required value of the pressure of fan speed by way of dial 19.

The probe of the present invention is likely to be used in place of the probe, indicated as 12 or 20, described above and the probe will function (that is, measure either temperature or flow or both) in a similar fashion to that of the flow probe as described in United States Patent Number 6349722 and United States Patent Number 6272933, both of Fisher & Paykel Healthcare Limited, the contents of which are incorporated herein. The probe as described in these patents is capable of providing both temperature and flow rate sensing of the gases flow through a breathing circuit conduit by incorporating two sensors (preferably thermistors). Alternatively, the probe of the present invention may merely be of the singular type that only measures either temperature or flow. The probe of the present invention will now be described with reference to Figures 2 to

5, where a first form of the probe 20 is illustrated. This probe is shown in Figure 1 as being near to the humidifier but could be used at any appropriate point along the breathing circuit, either on the part of the circuit (conduit) between the blower and the humidifier or on the part of the circuit (conduit 3) between the humidifier and the patient. The probe 20 has a stem 21 that houses at least one sensor. When the probe is in use, the stem 21 extends into the breathing circuit conduit 22 and the sensor measures the flow, temperature or other characteristics of the gases flow through the conduit 22. The stem is preferably tapered and fits into a port 23 formed in the conduit 22. The port 23 may have an internal (and possibly integral) soft sealing portion (not shown but described below), such as a small ring or grommet, disposed inside the port that assists in retaining the probe 20 within the port 23 and provides for easier insertion of the probe stem into the port 23. The probe 20 is connectable to a control means, such as controller 9 or 18 as described above, by way of electrical wiring, housed within a cable 24, which is connected to the sensors within the probe 20. An additional cable 25 extends from the probe 20; this cable may house wiring that provides power to the sensors within the probe.

The probe 20 has a body 26 that is moulded about the soldered joints of the sensors and wiring, such that the probe body and stem form a T shape. A shoulder or ledge 27 is formed, preferably during the moulding process but may be fastened separately to the body 26, on the body 26. The ledge 27 is effectively a protrusion capable of fastening or latching with a complimentary lip or protrusion formed on the breathing circuit.

In other forms of the present invention a shoulder or ledge may be formed on the breathing circuit, near a port and a lip or protrusion formed on the probe, where these cause the fastening of the probe and circuit together.

The conduit port 23 is preferably circular in shape and extending alongside it has a elongated extension 28 that is preferably integrally moulded with the port 23 and conduit 22, but may be separately fastened, by appropriate means, for example by gluing to the conduit 22. One end of the extension 28 is fastened or moulded to the conduit 22 and the distal end 29 has formed on it a lip or protrusion 30, such that the extension is an inverted L shape.

As shown in Figure 3 when the probe 20 is inserted in the conduit port 23 the ledge 27 abuts the lip 30 on the extension 28, effectively fastening, latching or locking the probe 20 in position within the port 23. When the ledge 27 latches with the extension 28 there is an audible click alerting a user that the probe is correctly connected with the conduit. The probe

20 cannot be knocked out of the port 23 and cannot inadvertently come loose, even with a small expansion of the port 23 that may occur. The extension 28 is preferably made from a hard plastics material such as an acetyl resin or other appropriate materials commonly used where positive latching is required. The extension is preferably made from a material that has a high tensile strength, so that the extension 28 can be flexed without breaking, in order to remove the probe 20 from the port 23. The breathing circuit and port are preferably made from a plastics material, such as polyethylene, whereas the ring or grommet within the port is preferably made from a synthetic rubber or elastomer, that is soft and flexible and which provides sealing capability. The ring or grommet therefore has the function of ensuring there is a seal between the probe stem 21 and the port 23, so that gases cannot escape from the breathing circuit conduit. The material making up the ring or grommet 55 has as a characteristic less "creep" than conventional plastics.

The probe body 26 is preferably made of a plastics material, such as polypropylene, which provides good electrical insulating properties, whereas the probe stem 21 is preferably made from a plastics material such as polycarbonate. The material making up the probe should be able to withstand chemical cleaners, as the probe is meant to be able to be cleaned and reused. In particular the material making up the stem should have good strength retention at elevated temperatures, should be high tensile, shear, and have flexural strength, while having a low coefficient of thermal expansion.

A second form of the probe of the present invention will now be described with reference to Figures 6 to 10. The probe 31 is of a very similar form as that described above with relation to Figure 2, it has a stem 32 and body 33, as well as cables 34, 35 extending from the body 33, where the cables 34, 35 house wiring extending through to the sensors housed in the stem 32.

Most importantly, the probe 31 has a ledge 36 formed on the body 33 that enables fastening or latching of the probe 31 into a breathing circuit conduit, which in Figures 6 to 10 is in the form of an elbow connector 40, having three ports 41, 42, 43. The first port 41 fits into a breathing circuit connected to a patient interface. The second port 42 houses a heater wire plug (this is where the heater wire starts) and port 43 is connected to the chamber outlet. This type of elbow connector 40 is used with ventilation systems, for use for CPAP therapy or oxygen therapy, where a patient' s breathing is assisted by a ventilation device, and effectively breathes for the patient or assists the patients breathing.

Referring to Figure 7, the probe 31 also includes a positioning means 37, which is a triangular shaped protrusion formed on the stem 32 of the probe 31. The protrusion 37 assists is orienting the probe 31 into the conduit port 44 as it meets with a complimentary shaped aperture 45 formed in the wall of the port 44. The triangular protrusion 37 and aperture 45 enable a user to easily and correctly position the probe in the conduit, so that accurate measurements of the gases characteristics are sensed. The protrusion 37 also helps with the removal of the probe 31 as the triangular protrusion 37 rides up the aperture 45 as the probe stem is twisted out of the port.

Referring now to Figure 8 a conduit port jacket 38 is shown. The jacket 38 is shaped to conform to the circular shape of the port 44 formed in the elbow connector 40. The jacket 38 has a body portion 39 and a port portion 46. The port portion 46 receives the port 44 of the elbow connector 40 and the body portion 39 extends about the elbow connector 40. The body portion 39 has at least one, but preferably two clips 47, 48 that enable the securing of the jacket 38 to the elbow connector 40. These clips 47, 48 clip into arced extensions 49, 50, formed in the elbow connector 40, that each has an aperture that receives one of the clips 47, 48 on the jacket 38.

Extending from the port portion 46 on the jacket 38 is an elongated extension 51 that has a lip 52. As with the first form of the probe, when the probe of the second form, probe 31 , is inserted in the port portion 46 on the jacket 38, the probe ledge 36 abuts the lip 52 on the extension 51. Therefore, the probe 31 is effectively latched or locked in position within the port portion 46, such that the probe stem 32 extends into the elbow connector 40. The port portion 46 has a similar aperture 54 formed in it to that of the port 44, the aperture 54 meets with the triangular protrusion 37 on the probe 31.

The jacket 38 also has a port cap 53 that fits into the port portion 46 to seal the port when the probe is not inserted. The cap 53 is preferably attached to the jacket body portion 46 by a flexible arm 54 that can be bent to enable the cap 53 to be inserted in the port when the probe is not in use. The jacket is preferably made of a plastics material, such as an acetyl resin.

A small ring such as a grommet 55 made from a soft and flexible material, such as synthetic rubber or elastomer, may be fitted into the port 44 on the elbow connector 40. The grommet is shown in Figures 6 and 9. The grommet 55 has the purpose of assisting in forming a seal between the probe 31 and the elbow connector port 44. The grommet 55 has a complimentary shape to that of the port 44 and is capable of being fitted inside the port 44. As with the port 44 the grommet is tapered and has a triangular shaped aperture 59 that receives the triangular protrusion 37 on the probe 31. To prevent the grommet 55 from falling into the elbow connector 40 and gases stream flowing through it, a circular retaining step or ledge 56 is moulded into the inside wall of port 44 (see Figure 10). Furthermore, the grommet 55 has a flange 56 that sits on the upper edge 57 of the port 44. When assembled the flange 56 is sandwiched between the jacket 38 and the upper edge 57 of the port 44. When the probe 31 is inserted into the grommet 55 a seal is formed between the grommet 55 and elbow connector 40. The grommet 55 also allows for easier insertion of the probe stem 32 or port cap 53 into the port portion 46. To allow for correct alignment of the grommet 55 within the port 44 the grommet 55 has a key 58. The key is an elongated protuberance 58 that fits into a complementary shaped elongated recess 59 formed in the port 44.

The elbow connector 40 is preferably made from a plastics material such as a polyethylene resin. In particular the connector 40 must be strong and light in weight. hi other forms of the latching probe of the present invention a lip may be provided on the probe body or stem and a complimentary protrusion on the breathing circuit, for example on the port, and a latching of the lip and protrusion may occur in the same manner as described above.

Claims

WE CLAIM:

1. A probe for use with a breathing circuit that supplies gases to a patient said probe comprising: an elongated stem that is capable of extending into said breathing circuit, and a fastener capable of causing said probe to be locked in place in said breathing circuit.

2. A probe according to claim 1 wherein said probe further comprises a body portion and said fastener is disposed on said body portion.

3. A probe according to claim 1 or 2 wherein said fastener is a protrusion capable of being latched and held by a lip or ledge on said breathing circuit.

4. A probe according to claim 1 or 2 wherein said fastener is a lip or ledge on said probe that is capable of being latched and held by a protrusion on said breathing circuit.

5. A probe according to any one of claims 1 to 4 wherein said breathing circuit includes a port that receives said stem, said port including a soft sealing portion to assist in retaining said probe in said port.

6. A probe according to claim 5 wherein said soft sealing portion is a small ring, such as a grommet.

7. A breathing circuit for supplying gases to a patient said circuit capable of receiving a probe having an elongated stem to measure properties of said gases, said circuit comprising: a substantially tubular conduit, a port disposed on said conduit capable of receiving said stem of said probe, and a fastener on one of said conduit or said port to lock said probe to said port.

8. A breathing circuit according to claim 7 said fastener is a protrusion capable of being latched and held by a lip or ledge on said probe.

9. A breathing circuit according to claim 7 wherein said fastener is a lip or ledge capable of being latched and held by a protrusion on said probe.

10. A breathing circuit according to any one of claims 7 to 9 wherein said port includes a soft sealing portion to assist in retaining said probe in said port.

11. A breathing circuit according to claim 10 wherein said soft sealing portion is a small ring, such as a grommet.

12. A breathing assistance apparatus comprising a probe and a breathing circuit, wherein said probe includes an elongated stem that is capable of extending into said breathing circuit, and said breathing circuit includes a substantially tubular conduit and a port disposed on said conduit said port capable of receiving said stem of said probe, wherein said probe and said breathing circuit are fastened together.

13. A breathing assistance apparatus according to claim 12 wherein one of said conduit and said port has a protrusion capable of latching with a lip or ledge on said probe thereby achieving the fastening of said probe and said breathing circuit.

14. A breathing assistance apparatus according to claim 12 wherein one of said conduit and said port has a lip or ledge capable of latching with a protrusion on said probe thereby achieving the fastening of said probe and said breathing circuit.

15. A breathing assistance apparatus according to any one of claims 12 to 14 wherein said port includes a soft sealing portion to assist in retaining said probe in said port.

16. A breathing assistance apparatus according to claim 15 wherein said soft sealing portion is a small ring, such as a grommet.

17. A probe as herein described with reference to the accompanying figures.

18. A breathing circuit as herein described with reference to the accompanying figures.

19. A breathing assistance apparatus as herein described with reference to the accompanying figures.