Patent ID: 12186482

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring toFIG.1, a respiratory assistance apparatus of the present invention is generally referenced by arrow100.

The apparatus100comprises a flow generator1. The flow generator1typically comprises a fan or impeller that is rotatably driven by a variable speed motor, and can comprise a centrifugal pump. In preferred embodiments, the flow generator1can generate flow rates of at least about 5 litres per minute, or of at least about 10 litres per minute, or of at least about 15 litres per minute, or of at least about 20 litres per minute, or of at least about 25 litres per minute, or of at least about 30 litres per minute, or of at least about 35 litres per minute, or of at least about 40 litres per minute, or of at least about 45 litres per minute, or of at least about 50 litres per minute, or of at least about 60 litres per minute, or of at least about 70 litres per minute, or of at least about 80 litres per minute. In some embodiments, a filter10may be connected to the flow generator1such that incoming air may be filtered.

The flow generator1supplies air to an intake conduit2.

The intake conduit2has an outlet3to which a patient interface (not shown) may be connected, typically via a further flexible conduit and/or further conditioning equipment. Any suitable patient interface may be used, for example nasal cannulas or nasal masks. In some embodiments, the patient interface can be selected from the group consisting of: a nasal cannula, such as the OPTIFLOW nasal cannula manufactured by Fisher & Paykel Healthcare Limited of New Zealand; a nasal mask, such as the OPUS nasal pillows mask manufactured by Fisher & Paykel Healthcare Limited of New Zealand; a full-face mask, such as the FREEMOTION full-face mask manufactured by Fisher & Paykel Healthcare Limited of New Zealand; a tracheostomy interface, such as the DIRECTCONNECT tracheostomy interface manufactured by Fisher & Paykel Healthcare Limited of New Zealand.

The intake conduit2is provided with a venturi formation4located between the flow generator1and the outlet3. The venturi formation4has a mouth5at an upstream end (that is, fluidically connected to the flow generator1).

The apparatus100has an oxygen inlet7which is in fluid communication, or at least selective fluid communication, with an oxygen supply6. In a preferred embodiment, an adjustable flow controller8, for example a needle valve, is provided in the flow path between the oxygen supply6and the oxygen inlet7. In preferred embodiments, the adjustable flow controller8may be manually adjustable, but, as is described further below, in other embodiments it may be electronically adjustable.

The oxygen inlet7can be positioned and orientated towards the venturi mouth5, such that a jet of oxygen issuing, in use, from the inlet7, is directed into the venturi4, preferably directly into the centre of the venturi mouth5.

As will be appreciated by those skilled in the art, in use the jet of oxygen issuing from the inlet7will tend to entrain air through the venturi4. Accordingly, in some embodiments, a vent or the like may be provided near the venturi mouth5to provide a source of ambient air to be entrained. In preferred embodiments, the flow generator1is adapted to allow air to be entrained there through.

In a preferred embodiment the apparatus100is mountable to, or comprises, a wheeled chassis.

The apparatus100may be used in two modes.

In a first mode, the flow generator1is powered by a mains power connection and pumps ambient air into the intake conduit2. The pressure and/or flow rate of the ambient air supplied by the flow generator1may be adjusted depending on the patient's requirements, but may typically be in the range 0-100 litres/minute, such as about 10 litres per minute, or about 15 litres per minute, or about 20 litres per minute, or about 25 litres per minute, or about 30 litres per minute, or about 35 litres per minute, or about 40 litres per minute; or about 45 litres per minute, or about 50 litres per minute, or about 60 litres per minute, or about 70 litres per minute, or about 80 litres per minute, and at a pressure of between 0-50 cm H2O, such as about 5 cm H2O, or about 10 cm H2O, or about 15 cm H2O, or about 20 cm H2O, or about 25 cm H2O, or about 30 cm H2O, or about 35 cm H2O, or about 40 cm H2O, or about 45 cm H2O, or about 50 cm H2O.

The oxygen supply6is connected to a pressurised oxygen source, for example a centralised oxygen supply or an oxygen bottle. The flow rate of oxygen from the oxygen supply6may be adjusted to suit the patient's requirements, but will typically be such that the oxygen comprises between 21% and 100% of the total volume of gas supplied to the patient.

In a second mode, the flow generator1is not operational. This may be a result of a fault in the pump, a loss of mains power, or because the patient wishes to move the apparatus100away from the bed, such that it is not possible or not desirable to have the apparatus100connected to the mains power.

In the second mode, the oxygen flowing from the inlet7into the venturi4creates an area of below ambient pressure which draws ambient air through the flow generator1. The flow generator1may be configured to minimise the resistance to the ambient air flow in this mode of operation, and may comprise an impeller which offers relatively low resistance to air flow between the pump inlet and cutlet when stationary.

If the patient desires to move around then the oxygen supply6may be connected to a bottle of pressurised oxygen which, in a preferred embodiment, may be mounted to the apparatus100. In this way the patient can receive a source of oxygen enriched air while moving around. This may be beneficial in encouraging the patient to maintain or regain mobility after a period of enforced bed rest.

In some embodiments, the apparatus100can be provided with a controller11which can be in communication with one or more sensors12. The sensors12can include: one or more pressure sensors; one or more flow rate sensors; one or more temperature sensors; one or more oxygen concentration sensors.

In some embodiments, the apparatus100can also include a display unit13on the apparatus. The display unit13can be adapted to show measurements from one or more of the sensors12. Additionally or alternatively, the measurements can be communicated to a remote monitoring station using known wired or wireless communications methods.

A portable power source14, such as a battery, may be provided to enable the sensors12and/or display unit13to function, or at least to generate alerts or alarms, when the apparatus100is disconnected from the mains. The size and capacity of the portable power source14can be much smaller than would be required to power the pump1for a substantial length of time.

If the flow generator1ceases operating unexpectedly then the controller11may sound an alarm to alert the patient and/or medical staff. However, the patient will still be supplied with a flow of oxygen enriched air. Although the flow rate of oxygen through the inlet7(and hence the flow rate of oxygen enriched air) may be increased if desired, this may not be required in some cases.

Those skilled in the art will appreciate that if apparatus100has only a single oxygen inlet7then the range of oxygen enrichment in the air supplied to the patient when in the second mode of operation will be relatively limited. However, in an alternative embodiment the apparatus100may be provided with a second oxygen inlet9. The second inlet9may be provided upstream of the venturi4, but is preferably not orientated directly towards the mouth5of the venturi4, so that a flow of oxygen through the second oxygen inlet9does not cause a corresponding increase in the flow rate of the ambient air. In a preferred embodiment the second oxygen inlet9is directed substantially orthogonally to the direction of air flow in its immediate vicinity, and more preferably is provided in the wall of the venturi4at the throat.

When in the second mode, oxygen flowing through the second inlet9can be used to increase the concentration of oxygen in the combined flow supplied to the patient.

Referring next toFIG.3, in a preferred embodiment the apparatus100is connectable to a humidification apparatus15. An exemplary humidification apparatus15is described in U.S. Pat. No. 6,349,722, the contents of which are included herein in their entirety by reference. In some embodiments, the humidification apparatus15can be one of the MR810, MR850, MR880 humidifiers, all manufactured by Fisher & Paykel Healthcare Limited of New Zealand.

The humidification apparatus15preferably comprises a chamber16which holds a volume of humidification fluid18(which can be water). The chamber16can be formed of a plastic material, and will preferably have a thermally conductive base17(such as a metal base) connected thereto. The chamber16can be thermally coupled to a heater19, which, in use, heats the humidification fluid18within the chamber16to increase its rate of evaporation.

The chamber has an inlet20which is connectable to the outlet3of conduit2, and an outlet21which is connectable to a patient interface, typically via a flexible conduit22. In preferred embodiments, the conduit22comprises an integral heating means to reduce the risk of condensation in the conduit22. The heating means is typically a heater wire23. The heater wire23can be disposed within the gas path of the conduit22, can be located within the wall of the conduit22, can be wrapped helically around the outside of the conduit22, and/or any other suitable means as is known in the art.

A controller controls the heat input into the humidification fluid18from the heater19, in order to generate a required level of humidity in the gases stream at the outlet21. In a preferred embodiment the controller11may be adapted to communicate with and/or control the humidification apparatus15. The communication may be by any suitable wireless protocol, or there may be a wired connection between the humidification apparatus15and the oxygen respiratory therapy apparatus controller11, in one embodiment the humidification inlet20and the outlet3may be provided with respective complementary sockets and plugs, so that an electrical connection is established between the controller11and the humidification apparatus15at the same time as the gases flow path is established between them.

Referring next toFIG.4, in another embodiment, generally referenced101, the apparatus100and the humidification apparatus15may be incorporated into a single integrated unit. In this embodiment the portable power source14(not shown inFIG.4), if provided, may also power the heater19for a period of time if the mains power source is interrupted for any reason. In some embodiments the controller11may allow the humidity at the outlet21and/or the temperature of the gas at the outlet21to drop to a lower level if the mains power is interrupted, so that the power consumed by the heater19is reduced. The heater wire23may also be powered when the mains power is interrupted, although possibly at a lower power level. However, if the controller lowers the humidity of the gas leaving the humidification apparatus15then, depending on the ambient temperature, it may not be necessary to power the heater wire at all. In such a case the controller may switch off the power to the heater wire in order to conserve power.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”.

Where in the foregoing description, reference has been made to specific components or integers of the invention having known equivalents, then such equivalents are herein incorporated as if individually set forth.

Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the spirit or scope of the invention.