WO 2007/004898 PCT/NZ2006/000166
A breathing assistance apparatus with a manifold to add auxiliary gases to ambient gases.
BACKGROUND OF THE INTENTION
Field of the Invention
This invention relates to a gases supply and gases humidification apparatus
including a manifold that allows for the addition of oxygen to the gases supply.
Summary of the Prior Art
A number of methods are known in the art for assisting a patient's breathing.
Continuous Positive Airway Pressure (CPAP) involves the administration of air under
pressure to a patient, usually by a nasal mask. It is used in the treatment of snoring and
Obstructive Sleep Apnoea (OSA), a condition characterised by repetitive collapse of the
upper airway during inspiration. Positive pressure splints the upper airway open,
preventing its collapse. Treatment of OSA with nasal CPAP has proven to be both
effective and safe, but CPAP is difficult to use and the majority of patients experience
significant side effects, particularly in the. early stages of treatment.
Upper airway symptoms adversely affect treatment with CPAP. Mucosal drying is
uncomfortable and may awaken patients during the night. Rebound nasal congestion
commonly occurs during the following day, simulating a viral infection. If untreated,
upper airway symptoms adversely affect rates of CPAP use.
Increases in nasal resistance may affect the level of CPAP treatment delivered to
the pharynx, and reduce the effectiveness of treatment. An individual pressure is
determined for each patient using CPAP and this pressure is set at the patient interface.
Changes in nasal resistance affect pressure delivered to the pharynx and if the changes are
of sufficient magnitude there may be recurrence of snoring or airway collapse or reduce the
level of pressure applied to the lungs.
CPAP is also commonly used for treatment of patients with a variety of respiratory
illnesses or diseases, including Chronic Obstructive Pulmonary Disease (COPD).
Oxygen is the most common drug prescribed to hospitalized patients with
respiratory or other illnesses. The delivery of oxygen via nasal cannula or facemask is of
benefit to a patient complaining of breathlessness. By increasing the fraction of inspired
oxygen, oxygen therapy reduces the effort to breathe and can correct resulting hypoxia (a
low level of oxygen in the tissues).

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The duration of the therapy depends on the underlying illness. For example,
postoperative patients may only receive oxygen while recovering from surgery while
patients with COPD require oxygen 16 to 18 hours per day.
Currently greater than 16 million adults are afflicted with COPD, an umbrella term
that describes a group of lung diseases characterized by irreversible airflow limitation that
is associated mainly with emphysema.and chronic bronchitis, most commonly caused by
smoking over several decades. When airway limitation is moderately advanced, it
manifests as perpetual brcathlessness without physical exertion. Situations such as a
tracheobronchial infection, heart failure and also environmental exposure can incite an
exacerbation of COPD that requires hospitalization until the acute breathlessness is under
control. During an acute exacerbation of COPD, the patient usually experiences an
increase in difficulty of breathing (dyspnea), hypoxia, and increase in sputum volume and
purulence and increased coughing.
Oxygen therapy provides enormous benefit to patients with an acute exacerbation
of COPD who arc hypoxic, by decreasing the risk of vital organ failure and reducing
d)'spnea. The major complication associated with oxygen therapy is hypercarpnia (an
elevation in blood carbon dioxide levels) and subsequent respiratory failure. Therefore, the
dose of oxygen administered is important.
To accurately control an oxygen dose given to a patient, the oxygen-enriched gas
must exceed the patient's peak inspiratory flow to prevent the entrainment of room air and
dilution of the oxygen. To achieve this, flows of greater than 20 L/min are common. Such
flows of dry gases cause dehydration and inflammation of the nasal passages and airways
if delivered by nasal cannula. To avoid this occurrence, a heated humidifier may be used.
The majority of systems that are used for oxygen therapy or merely delivery of
gases to a patient consists of a gases supply, a humidifier and conduit. Interfaces include
facemasks, oral mouthpieces, tracheostomy inlets and nasal cannula, the latter then having
the advantage of being more comfortable and acceptable to the patient than a facemask.
It is usual for the gases supply to provide a constant, prescribed level of gases flow
to the humidifier. The humidifier and conduit can then heat and humidify the gases to a set
temperature and humidity before delivery to the patient. Many patients using blowers or
continuous positive pressure devices to treat COPD are on long term oxygen therapy.
Such patients often need in excess of 15 hours per day of oxygen therapy and as such the

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only practical method to expose these patients to several hours humidification therapy per
day as well as oxygen therapy is to combine the oxygen therapy and humidification
therapy. As the oxygen therapy is known to dry the airways there are likely to be benefits
from combining the treatments.
Currently CPAP systems are commonly integrated with oxygen flow systems to
provide increased fraction of oxygen for the treatment of respiratory disorders. These
systems commonly combine the oxygen source on the high pressure (flow outlet) side of
the blower. This results in three main disadvantages. Firstly, by integrating the oxygen on
the high pressure side, a connection port with a sealing cap is required to seal off the
oxygen inlet port and avoid high pressure gases escaping when the oxygen flow source is
not connected. Secondly, in the event that the oxygen source is turned on before the
blower is turned on the breathing circuit, humidification chamber and blower become
flooded with 100% oxygen. This is likely to create a fire safety risk if sparking should
occur within the blower or heated breathing tube when turned on. Thirdly, if the oxygen
gases source is added at the outlet of the humidification chamber, the oxygen gas, when
mixed with other gases delivered to the patient, lowers the overall humidity of the gases
delivered.
DISCLOSURE OF THE INVENTION
If is an object of the.present invention to provide a breathing assistance apparatus
that goes some way to overcoming the abovementioned disadvantages or that at least
provides the public or industry with a useful choice.
Accordingly in a first aspect the present invention consists in a breathing assistance
apparatus adapted to deliver humidified gases to a patient comprising:
a gases supply having an inlet in which gases are drawn through,
humidification means including a humidification chamber having an outlet, said
gases flowing from said inlet through said humidification chamber and out said outlet, and
manifold on or about said gases supply inlet that enables oxygen or other gases to
be added to said gases.
Preferably said manifold includes an oxygen inlet port capable of being connected
to an oxygen supply.
Preferably said manifold is substantially rectangular.

WO 2007/004898 PCT/NZ2006/000166
Preferably said manifold includes at least one aperture to allow the drawing of
other gases into said manifold.
Preferably said gases supply includes an internal sensor that is capable of sensing
the fraction of oxygen flowing through said breathing assistance apparatus.
Preferably said gases supply includes a controller connected to said internal sensor.
Preferably said gases supply includes a display controlled by said controller and
said controller causes said fraction of oxygen to be displayed and updated on said display.
To those skilled in the art to which the invention relates, many changes in
construction and widely differing embodiments and applications of the invention will
suggest themselves without departing from the scope of the invention' as defined in the
appended claims. The disclosures and the descriptions herein are purely illustrative and
are not intended to be in any sense limiting.
In this specification where reference has been made to patent specifications, other
external documents, or other sources of information, this is generally for the purpose of
providing a context for discussing the features of the invention. Unless specifically stated
otherwise, reference to such external documents is not to be construed as an admission that
such documents, or such sources of information, in any jurisdiction, are prior art, or form
part of the common general knowledge in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
One preferred form of the present invention will now be described with reference to
the accompanying drawings.
Figure 1 is an illustration of the breathing assistance apparatus that may utilise the
manifold of the present invention.
Figure 2 is a rear view of a blower and humidifier apparatus with a manifold of the
present invention installed.
Figure 3 is a rear view of the manifold of the present invention.
Figure 4 is a first perspective view of the manifold of Figure 3.
Figure 5 is a second perspective view of the manifold of Figure 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The breathing assistance apparatus of the present invention includes a manifold that
is preferably provided with or retrofittable to gases supply and humidifying devices. The
manifold allows gases from an oxygen concentrator to be combined with the flow through

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a gases supply and humidifying device, most usually air. The combined output of oxygen
and other breathing gases (air) is then humidified.
The breathing assistance apparatus and manifold of the present invention provides a
safe method to add oxygen to the input air stream of a gases supply and humidifying
device and reduces the amount of accumulation of oxygen within the gases supply device,
reducing fire risk should sparking occur within the device.
The present invention provides a breathing assistance apparatus where the flow of
gases passes in sequence through a gases supply means or flow driver (such as, a blower,
fan or compressor), humidification chamber, heated delivery circuit, then to a patient
interface, such as that shown in Figure 1.
Gases are passed to the patient 1 by way of a patient interface 2. The patient
interface used with the apparatus of the present invention may be a full-face mask, nasal
mask, nasal cannula, oral mouthpiece or tracheostomy connection, but the description
below and figures disclose the use of a nasal cannula.
With reference to Figure 1 the humidification apparatus of the present invention is
shown in which a patient 1 is receiving humidified and pressurised gases through nasal
cannula 2. The cannula 2 is connected to a gases transportation pathway or inspiratory
conduit 3 that in turn is connected to an integrated gases supply and humidifying device 4
(including a humidification chamber 5). In the preferred embodiment of the blower-
humidifying device 4, the gases supply or blower is combined in one housing with the
humidifier and humidification chamber.
In the preferred embodiment, the humidification chamber 5 extends out from the
housing 10 and is capable in use of being removed and replaced (by a slide on movement)
by the patient or other user. Also, the inlet port (not shown) to the humidification chamber
5 is internal within the housing 10. It must be appreciated that the embodiment described
above in relation to the housing and Figure 1 merely illustrates one form of the housing of
the integrated gases supply and humidifying device. In other forms the gases supply or
blower and humidifier may be in separate housings.
The inspiratory conduit 3 is connected to an outlet 8 of the humidification chamber
5 that contains a volume of water 6. Inspiratory conduit 3 contains heating means or heater
wires 7 that heat the walls of the conduit to reduce condensation of humidified gases
within the conduit and the patient interface (nasal cannula 2). The humidification chamber

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5 is preferably formed from a plastics material and may have a highly heat conductive base
(for example an aluminium base) that is in direct contact with a heater plate (not shown but
located at the base of the chamber 5, within the blower housing). The gases supply and
humidifying device 4 is provided with control means or an electronic controller that may
comprise a microprocessor based controller executing computer software commands stored
in associated memory. The controller receives input from sources such as user input
means or dial (not shown) through which a user of the device 4 may, for example, set a
predetermined required value (preset value) of humidity or temperature of the gases
supplied to patient 1.
In response to the user set humidity or temperature value input via dial (or buttons)
and other possible inputs such as internal sensors that sense gases flow or temperature, or
by parameters calculated in the controller, the controller determines when (or to what
level) to energise heater plate to heat the water 6 within humidification chamber 5. As the
volume of water 6 within 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 8 with the flow of gases (for example air) provided from a
blower part of the device that has entered the device 4 through an inlet 9 on the back of the
gases supply and humidifying device 4.
The gases supply within the device 4 is preferably a variable speed pump or fan
that draws air or other gases through the blower inlet 9. The speed of variable speed pump
or fan is preferably controlled by the control means or electronic controller described
above in response to inputs entered into the device 4 by the user.
As discussed above it would be advantageous to provide oxygen therapy with
humidification therapy to patients that suffer from COPD and other respiratory disorders.
The breathing assistance apparatus of the present invention provides this by having a
manifold that is attachable to existing gases supply and humidifying devices, such as, the
SleepStyle™ 600 series CPAP devices of Fisher & Paykel Healthcare Limited. It must be
noted that any CPAP, auto PAP, bi-level or other flow generating device that provides high
gases flow and potentially humidification of gases may utilise a manifold as described
below. The manifold allows the output from an oxygen concentrator to be combined with
the flow from a gases supply and humidifying device and the combined output of oxygen
and other breathing gases can then be humidified.

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Figure 2 shows a gases supply and humidifying device 4 with a manifold 11
installed. The manifold 11 is shown in further detail in Figures 3 to 5. The manifold 11 is
preferably a substantially rectangular insert that is capable of being inserted into the inlet
port 9 on the device 4. The manifold 11 has a recessed edge 12 that fits into a
complementary lip on the inlet port 9 and has an oxygen inlet port 13 to which tubing 14 or
the like can be attached that feeds to an oxygen supply tank or the like. The oxygen port
13 preferably extends from the side of the manifold 11. The manifold 11 has an extended
area 15 that includes at least one aperture (although two apertures 16, 17 are shown in
Figures 3 to 5. The apertures 16, 17 allow for ambient air to be drawn into the device 4 by
the action of the pump or fan. The ambient air plus oxygen gases are mixed within the
device 4 and exits the chamber outlet 8 as humidified air plus oxygen that is then passed to
the patient via the conduit 3.
A filter, (not shown) for example, a substantially rectangular piece of meshed filter
material or the like, may be placed inside the apertures 16, 17, such that it fits within the
inner part of the extended area 15 and filters all gases entering the blower inlet.
Advantages
This breathing assistance apparatus and manifold of the present invention provides
a safe method to add oxygen to the input air stream of a gases supply and humidifying
device. The full oxygen output from the tubing feeding oxygen to the manifold is drawn
into the device when the device is in use, but if the device is switched off oxygen that is
fed into the manifold disperses through the apertures 16, 17 and therefore remains outside
the device 4. Therefore, oxygen does not accumulate within the device (for example, a
gases supply such as a blower) and create a fire risk. Consequently, the manifold lowers
the fire hazard risk should a spark occur inside the blower or breathing conduit.
By adding oxygen to the inlet of the flow generation device this oxygen can be
fully humidified along with the other gases delivered to the patient. Prior art systems
usually add oxygen after humidification of gases thus reducing the overall humidification
of the gases that reach the patient.
Furthermore, adding oxygen on the inlet side of the flow source makes it is possible
to sense inside the device 4 the fraction of oxygen in the combined gas flow and display
this fraction on a display on the flow source. Therefore, in a further embodiment the gases
supply (blower or integrated blower and humidifying device 4) includes an internal sensor

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(not shown) that is capable of sensing the fraction of oxygen through the device 4. The
internal sensor is preferably connected to the controller within the device (as described
above) and the controller causes the fraction of oxygen measurement sensed by the internal
sensor to be displayed on the display 18 (see Figure 2) that is preferably disposed on the
top of the device 4. As the fraction of oxygen changes and this is sensed by the internal
sensor preferably this change is updated on the display in real time.
The breathing assistance apparatus with the manifold of the present invention does
not require one way valves or sealing caps when an oxygen circuit is not connected to the
apparatus and is safe and simple for a patient to operate.

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WE CLAIM:
1. A breathing assistance apparatus adapted to deliver humidified gases to a patient
comprising:
a gases supply having an inlet that ambient gases are drawn through,
manifold on or about said inlet that enables auxiliary gases to be added to said
ambient gases.
2. A breathing assistance apparatus according to claim 1 wherein said breathing
assistance apparatus further comprises humidification means including a humidirication
chamber having an outlet, where said ambient and auxiliary gases flow from said inlet
through said humidification chamber and out said outlet.
3. A breathing assistance apparatus according to claim 1 or 2 wherein said manifold
includes an inlet port capable of being connected to an auxiliary gases supply.
4. A breathing assistance apparatus according to any one of claims 1 to 3 wherein said
manifold includes at least one aperture to allow the drawing of ambient gases into said
manifold.
5. A breathing assistance apparatus according to any one of claims 1 to 4 wherein said
at least one aperture is an air intake when said gases supply is supplying gases and a gases
outlet to allow auxiliary gases to spill to ambient when said gases supply is not supplying
gases.
6. A breathing assistance apparatus according to any one of claims 1 to 5 wherein said
auxiliary gases are oxygen.
7. A breathing assistance apparatus according to any one of claims 1 to 6 wherein said
gases supply includes an internal sensor that is capable of sensing a fraction of oxygen
flowing through said breathing assistance apparatus.
8. A breathing assistance apparatus according to claim 7 wherein said gases supply
includes a controller connected to said internal sensor.
9. A breathing assistance apparatus according to claim 7 or 8 wherein said gases
supply includes a display controlled by said controller and said controller causes said
fraction of oxygen to be displayed and updated on said display.
10. A breathing assistance apparatus according to any one of claims 1 to 9 wherein said
manifold includes a filter disposed over said at least one aperture.

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

The breathing assistance apparatus of the present invention includes a manifold that is provided with or retrofittable
to gases supply and humidifying devices. The manifold allows gases from an oxygen concentrator to be combined with the flow
through a gases supply and humidifying device, most usually air. The combined output of oxygen and other breathing gases (air) is
then humidified. The breathing assistance apparatus and manifold of the present invention provides a safe method to add oxygen to
the input air stream of a gases supply and humidifying device and reduces the amount of accumulation of oxygen within the gases
supply device, reducing fire risk should sparking occur within the device.