U.S. patent application number 13/280687 was filed with the patent office on 2012-02-16 for nasal mask assembly.
This patent application is currently assigned to ResMed Limited. Invention is credited to Anthony M. Ging, Philip R. Kwok, Partick J. McAuliffe, Rachael E. Moore, Gary C. Robinson, Bianto Santoso.
Application Number | 20120037161 13/280687 |
Document ID | / |
Family ID | 36087583 |
Filed Date | 2012-02-16 |
United States Patent
Application |
20120037161 |
Kind Code |
A1 |
Ging; Anthony M. ; et
al. |
February 16, 2012 |
NASAL MASK ASSEMBLY
Abstract
A mask system is provided to fit pre-adult patients, or patients
having facial features that are very small or child-like, e.g.,
patients having dimensions in the lower 5%-10% of the population.
For example, the headgear and/or cushion are dimensioned to
accommodate this range of patients.
Inventors: |
Ging; Anthony M.;
(Christchurch, NZ) ; Kwok; Philip R.; (Chatswood,
AU) ; Robinson; Gary C.; (East Killara, AU) ;
Santoso; Bianto; (Kingsgrove, AU) ; Moore; Rachael
E.; (North Bondi, AU) ; McAuliffe; Partick J.;
(Chatswood, AU) |
Assignee: |
ResMed Limited
Bella Vista
AU
|
Family ID: |
36087583 |
Appl. No.: |
13/280687 |
Filed: |
October 25, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10781949 |
Feb 20, 2004 |
8042538 |
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13280687 |
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60448533 |
Feb 21, 2003 |
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60465790 |
Apr 28, 2003 |
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Current U.S.
Class: |
128/206.24 ;
128/206.21 |
Current CPC
Class: |
A61M 16/0622 20140204;
A61M 16/0616 20140204; A61M 16/06 20130101; A61M 2210/0618
20130101; A61M 16/0683 20130101 |
Class at
Publication: |
128/206.24 ;
128/206.21 |
International
Class: |
A61M 16/06 20060101
A61M016/06 |
Claims
1. A cushion for a respiratory mask assembly to deliver breathable
gas to a patient, the cushion comprising: a side wall structured to
be attachable to a frame; and a seal-forming portion extending away
from the side wall wherein an inner edge of the seal-forming
portion defines an aperture, wherein the aperture has a base
portion with a length in the range of 30-32 mm, sides with a length
in the range of 18-20 mm, and a top portion substantially parallel
to the base portion with a length in the range of 22-24 mm.
2. A cushion according to claim 1, wherein seal-forming portion
includes a contoured notch in a nasal bridge region of the cushion
having a depth in the range of 12-27 mm.
3. A cushion according to claim 1, wherein a contact area between
the seal-forming portion and the patient's face in a nasal bridge
region is greater than a contact area between the seal-forming
portion and lip and cheek regions of the patient.
4. A cushion according to claim 1, wherein the seal-forming portion
is a membrane.
5. A cushion according to claim 4, wherein the cushion has a rim
extending away from the side wall, and the membrane substantially
surrounds the rim.
6. A cushion according to claim 5, wherein the membrane includes a
contoured portion that extends upwardly from the side wall and
curves inwardly along a generally constant radius to terminate at
the inner edge of the membrane.
7. A cushion according to claim 6, wherein, in at least a portion
of a nasal bridge region of the patient, the rim and the membrane
are spaced away from one another to define a gap.
8. A cushion as claimed in claim 7, wherein the rim and membrane
are spaced away from one another in lip and cheek regions of the
cushion to define a gap.
9. A cushion according to claim 7, wherein an inner edge of the rim
defines an aperture, the aperture of the membrane having a smaller
dimension than a dimension of the aperture of the rim.
10. A according to claim 9, wherein the aperture of the rim has a
base portion with a length in the range of 35-42 mm, sides with a
length in the range of 17-20 mm, and a top portion substantially
parallel to the base portion with a length in the range of 29-33
mm.
11. A cushion according to claim 4, wherein the membrane is
structured to engage a patient's face such that forces applied to
the patient's face are substantially evenly distributed around the
entire perimeter of the cushion.
12. A cushion according to claim 1, wherein a radius of curvature
of the seal-forming portion in the nasal bridge region is in the
range of 3-12 mm.
13. A cushion according to claim 1, further comprising: a central
portion between an edge of the side wall and the seal-forming
portion, the central portion having a thickness structured to
withstand buckling forces applied to the cushion when the cushion
is attached to the frame.
14. A cushion according to claim 13, wherein the thickness of the
central portion is in the range of 2-10 mm.
15. A cushion according to claim 13, wherein an end of the side
wall is adapted to be inserted into a channel of a frame so as to
removably attach the cushion to the frame.
16. A cushion according to claim 1, wherein the seal-forming
portion is constructed from silicone.
17. A cushion according to claim 1, wherein the seal-forming
portion is adapted to form a seal on the patient's lip region
positioned below the patient's nose and above the upper lip of the
patient.
18. A respiratory mask assembly for delivering breathable gas to a
patient, comprising: a frame having a front surface and a rear
surface adapted in use to face the patient; and a cushion according
to claim 1 removably attachable to the rear surface of the frame.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Ser. No.
10/781,949, filed Feb. 20, 2004, which claims the benefit of U.S.
Provisional Patent Application Nos. 60/448,533 filed Feb. 21, 2003
and 60/465,790 filed Apr. 28, 2003, each of which is incorporated
herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a nasal mask assembly for use with
non-invasive positive pressure ventilation (NIPPV) applied to small
adults or pre-adults with sleep disordered breathing (SDB).
[0004] 2. Description of Related Art
[0005] Sleep-disordered breathing is a general term for a sleep
disorder with apneas and hypopneas. Apneas are generally taken to
be a cessation of airflow for ten seconds or longer. Hypopnea are
generally taken to be a 50% or greater decrease in air flow for ten
seconds or longer. Both apneas and hypopneas cause sleep
arousals--moments when an individual wakes enough to resume
breathing but not enough to remember any interruption of sleep.
Some arousals simply cause the sleeper to shift into a lighter
stage of sleep. In either case, the arousal lessens the quality of
sleep. Apneas and hypopneas may cause blood oxygen levels to drop.
Apneas and hypopneas result from upper airway obstruction, either
full or partial, or a dysfunction of the body's automatic drive to
breathe.
[0006] Obstructive Sleep Apnea (OSA) is a common disorder.
Estimates for the number of Americans with OSA vary depending on
the criteria researchers use for the study. Conservative estimates,
however, put the number of adult Americans with OSA at
approximately 20 million. OSA occurs because of upper airway
obstructions that can cause you to snore or to stop breathing.
Obstructions occur during sleep for two primary reasons: lack of
muscle tone and/or gravity. Excess tissue in the upper airway and
anatomic abnormalities compound these factors. During sleep,
especially in REM sleep, our bodies relax, and muscle tissues like
the tongue and soft palate lose their slight rigidity. Because we
tend to sleep lying down, gravity pulls these tissues toward the
back of the throat and closes the upper airway.
[0007] The use of nasal Continuous Positive Airway Pressure (nasal
CPAP) to treat obstructive sleep apnea (OSA) was taught by Sullivan
in U.S. Pat. No. 4,944,310. Today apparatus for OSA typically
comprises (i) a blower which provides a supply of air or breathable
gas at positive pressure, (ii) an air delivery conduit connected to
the blower, and (iii) a patient interface, such as a nasal mask,
which is connected to the air delivery conduit.
[0008] A variety of nasal masks have been developed. One such mask
is the MIRAGE.RTM. mask, manufactured by ResMed Limited and
described in U.S. Pat. Nos. 6,112,746; 6,357,441; 6,119,693 and
6,463,931, amongst others. Another such mask is the ULTRA
MIRAGE.RTM. mask, also manufactured by ResMed Limited. The ULTRA
MIRAGE.RTM. mask is described in U.S. Pat. Nos. 6,112,746,
6,357,441, 6,374,826, 6,412,487, 6,439,230 and 6,463,931.
[0009] The American Academy of Pediatrics, in a Technical Report on
the Diagnosis and Management of Childhood Obstructive Sleep Apnea
Syndrome (OSAS) (PEDIATRICS Vol. 109 No. 4 April 2002) noted that
"Snoring is a common occurrence in childhood, with reported
prevalence between 3.2% and 12.1%. The prevalence of childhood OSAS
is difficult to estimate, largely because published studies use
different PSG criteria for its ascertainment. Reports range from
0.7% to 10.3%."
[0010] A key factor in the efficacy of therapy and compliance of
patients with therapy is the comfort and fit of masks. Whilst there
are a large number of masks designed for adults, there are
relatively few designed to suit children.
[0011] One mask designed for children is the SULLIVAN.RTM. Nasal
CPAP system, Infant Nasal Bubble Mask System with Sensor tubing,
manufactured by ResMed Limited. See FIG. 1. In addition,
Respironics Inc. manufactures a "Comfort Flap Small Child"
product.
[0012] Other infant masks are shown in the following patents: FR
2775905; GB 2277688; US 2002/0104531; U.S. Pat. No. 3,827,433; U.S.
Pat. No. 4,232,476; U.S. Pat. No. 4,406,283; U.S. Pat. No.
4,774,946; U.S. Pat. No. 4,896,666; U.S. Pat. No. 4,832,015; U.S.
Pat. No. 5,271,391; U.S. Pat. No. 5,318,590; U.S. Pat. No.
5,462,050; U.S. Pat. No. 5,509,408; U.S. Pat. No. 5,535,741; U.S.
Pat. No. 5,813,423; U.S. Pat. No. 5,660,174; U.S. Pat. No.
6,418,929; WO 01/32250 ;WO 02/05883 ;WO 95/09023
[0013] One adult mask is the VISTA.TM. mask, manufactured by ResMed
Limited, and described in Australian Provisional Patent Application
PS1926, filed 23 April 2002; U.S. 60/377,254 filed 3 May 2002; U.S.
60/397,195 filed 22 Jul. 2002; U.S. 60/402,509 filed 12 Aug. 2002;
and U.S. Ser. Nos. 10/391,440, 10/390,682, 10/390,681, 10/390,720
and 10/390,826, all filed 19 Mar. 2003, the contents of which are
hereby incorporated by cross-reference. An ornamental design
applied to the VISTA.TM. mask is shown in design patent application
U.S. Des Pat. No. 29/166,190, the contents of which are hereby
incorporated by reference.
[0014] The VISTA.TM. mask includes a cushion, a frame, an elbow and
headgear including a yoke.
[0015] While the VISTA.TM. mask is particularly suitable for
adults, the problem arises as to how such an adult mask can be
adapted to suit children.
[0016] International Patent Application WO2001/32250 (Sullivan
& Wilkie) describes a mask for supplying gas under pressure to
the nasal airway of an infant human. In that application, the
following is stated: [0017] ". . . until now, infant masks have
been developed on the basis of scaling down the adult mask to
approximate to the infant face and nose. The problems with this
scaling down process are threefold. [0018] First, the adult nose
and middle third of the face is very different in shape from that
of the infant. The adult nose is more elongated than, and protrudes
far more from the surface of the face compared to the infant nose
which is relatively flat with no bridge, with the nares (nostril
passages) pointing outwards. Therefore in order to fit the adult
nose the base of the mask has a triangular shape elongated in the
vertical axis. In contrast, with an infant, the width at the base
of the nose approximates the height from the base of the nose
(nares) to the apex of the nose (nasion). The proportional shape of
the nasal area of an adult is rectangular compared with a square
proportional shape for an infant. In addition to this basic
difference in proportional shape, the adult face has quite marked
contours especially around the nose and cheek area which are absent
in the infant. The adult mask must therefore have acute angles
which accommodate these facial contours. Thus, when an adult mask
is scaled down for an infant, not only are the proportions wrong
for the infant nose and face, but the angles which are
unnecessarily incorporated, inadvertently introduce a new problem.
Because the infant has a relatively flat nose, and virtually no
bridge, the angles promote formation of channels in the sealing
margin of the mask, especially in the region of the nasal bridge.
[0019] Secondly in adult mask designs, the straps of the head
harness connect with lugs on the rigid manifold in the order of 20
mm away from the surface of the face to allow the mask to
accommodate the height of the adult nose. Because of this a
potential fulcrum effect is created. In the adult this fulcrum
effect is not as problematic as in the infant, not only because the
adult is less mobile during sleep . . . but also because the
contours of the adult face and cheeks can offset this rise. In the
infant, when the mask used is merely a scaled down adult mask, the
elevation of the straps lugs above the face is about 12 mm. This by
itself creates a potential fulcrum as it does on the adult but the
effect is enhanced by the fact that there is no offset from the
infant cheek due to the smaller facial area. Consequently, the
straps holding the mask in place come into contact with the side of
the face in the infant, compared to the cheek in the adult. [0020]
Thirdly, because the attachment of the paediatric mask to the face
and head mimics that of the adult mask, the torsional forces are
increased. The greater torsional effect is due to the decreased
surface area of the mask face contact relative to the air delivery
pipe. Thus relatively minor movements can result in sufficient
torsional forces to cause movement at the interface between the
mask and the infants face."
SUMMARY
[0021] In accordance with a first aspect of the invention a mask
assembly suitable for pre-adults is provided.
[0022] In accordance with a second aspect of the invention a system
of cushions, frames, headgear, yokes and other mask components are
provided which fit a wide range of pre-adults with a good seal and
which are economic to bring to market.
[0023] In accordance with another aspect of the invention, a system
of mask cushions is provided for pre-adults in which the cushion
for children aged generally 2-6 years has a shallower nasal bridge
region than the cushion for pre-adults aged generally 6-16
years.
[0024] In accordance with another aspect of the invention, a system
of mask cushions is provided for pre-adults in which the cushion
for children aged generally 2-6 years has larger radius lower
corner edges of the membrane than the cushion for pre-adults aged
generally 6-16 years.
[0025] In accordance with another aspect of the invention, a system
of mask cushions is provided for pre-adults aged generally 6-16
years which are adapted to be mounted to corresponding adult sized
frames.
[0026] In one preferred embodiment, headgear for use with a
respiratory mask includes first and second straps each adapted to
be provided to a mask frame of the mask, where each of the first
and second straps includes a yoke, each said yoke being constructed
and arranged to accommodate at least one of a pre-adult patient or
a small sized adult patient.
[0027] In another embodiment, which can be used with the headgear
described above, a cushion for use with a nasal mask includes an
outer membrane including a face-contact portion to form a seal with
the patient; and an underlying rim positioned below the membrane,
wherein the membrane and the rim are formed and positioned with
respect to one another to accommodate at least one of a pre-adult
patient or a small sized adult patient.
[0028] These and other aspects will be described in or apparent
from the following description.
BRIEF DESCRIPTION OF FIGURES
[0029] Preferred embodiments will be described in relation to the
following drawings, in which:
[0030] FIG. 1 shows related art infant bubble mask;
[0031] FIG. 2 shows a perspective view of a related art VISTA.TM.
mask on an adult patient;
[0032] FIG. 3 shows a side view of the VISTA.TM. mask;
[0033] FIG. 4 shows a front view of the VISTA.TM. mask;
[0034] FIG. 5 shows a side view of a headgear yoke of the VISTA.TM.
mask;
[0035] FIG. 6 shows a plan view of a headgear yoke in accordance
with a first embodiment of the invention;
[0036] FIG. 7 is a cross-sectional view taken along section 7-7 in
FIG. 6;
[0037] FIG. 8 is a bottom view of the yoke shown in FIG. 6;
[0038] FIG. 9 is a plan view of a side headgear strap according to
an embodiment of the present invention;
[0039] FIG. 10 is a plan view of a central rear headgear strap
according to an embodiment of the present invention;
[0040] FIG. 11 is a plan view comparing the central rear headgear
strap of FIG. 10 and the VISTA.TM.;
[0041] FIGS. 11a-11c illustrate a headgear crossover according to
an embodiment of the present invention;
[0042] FIG. 12 shows a plan view of a cushion, mounted on a frame,
in accordance with an embodiment (the "Kid cushion") of the
invention;
[0043] FIG. 13 shows a top elevation view of the "Kid" cushion;
[0044] FIG. 14 shows a side elevation view of the "Kid" cushion
(without the frame);
[0045] FIG. 15 shows a bottom elevation view of the "Kid"
cushion;
[0046] FIG. 16 shows a perspective view of the "Kid" cushion;
[0047] FIG. 17 shows a plan view of the "Kid" cushion compared to
other cushion shapes;
[0048] FIG. 18 shows a rear review of an underlying rim of the
"Kid" cushion showing the change in dimension compared with an
adult VISTA.TM.;
[0049] FIG. 19 shows of a membrane of the "Kid" cushion showing the
change in dimension compared with an adult VISTA.TM. cushion;
[0050] FIG. 20 shows the edge of the membrane of the "Kid" cushion
and the more rounded lower corners of the "Mini" cushion;
[0051] FIG. 21 shows a sketch plot of a system of masks in
accordance with an embodiment of the invention;
[0052] FIG. 22 illustrates a rear view of a "Kid" cushion in
accordance with the present invention;
[0053] FIG. 23 illustrates a bottom view of a "Kid" cushion in
accordance with the present invention, in comparison to the
VISTA.TM. and/or other earlier embodiments;
[0054] FIG. 24 illustrates a top view of a "Kid" cushion in
accordance with the present invention;
[0055] FIG. 25 illustrates a side view of a "Kid" cushion in use,
in accordance with the present invention;
[0056] FIG. 26 illustrates features of the upper lip design for a
cushion according to an embodiment of the present invention;
[0057] FIG. 27 illustrates a sample fitting chart plotting nose
width v. nose or bridge height in accordance with the present
invention, comparing the VISTA.TM., the Kidsta Small and the Kidsta
Extra Small;
[0058] FIG. 28 illustrates cross-sectional views comparing the
cushions of the "Kid", the Kidsta Small and the VISTA.TM.;
[0059] FIG. 29 illustrates partial plan views comparing the "Kid",
Kidsta Small and VISTA.TM. cushions;
[0060] FIG. 30 illustrates a sample fitting chart based on bridge
center depth, in accordance with an embodiment of the present
invention;
[0061] FIG. 31 illustrates partial cross-sectional views comparing
the cushions of the "Kid", Kidsta Small and VISTA.TM.;
[0062] FIG. 32 illustrates a plan view of a Kidsta Small cushion in
accordance with an embodiment of the present invention;
[0063] FIG. 33 is a rear view thereof;
[0064] FIG. 34 is a side view thereof;
[0065] FIG. 35 is a cross-sectional view taken along section 35-35
in FIG. 32;
[0066] FIGS. 35a-35g illustrate exemplary cross-sections shown in
FIG. 32, including dimensions and/or to-scale relative locations of
the membrane relative to the rim;
[0067] FIG. 36 is a detailed view taken from FIG. 35;
[0068] FIG. 37 is another detail view taken from FIG. 35;
[0069] FIG. 38 illustrates a plan view of a Kidsta Extra Small
cushion in accordance with an embodiment of the present
invention;
[0070] FIGS. 38a-38f are various cross-sections thereof;
[0071] FIG. 39 is a rear view thereof;
[0072] FIG. 40 is a side view thereof;
[0073] FIG. 41 is a cross-sectional view taken along section 41-41
of FIG. 38;
[0074] FIG. 42 is a detail view (scale: 2 to 1) taken from FIG.
41;
[0075] FIG. 43 is a top view of a frame in accordance with an
embodiment of the present invention; and
[0076] FIG. 44 shows the frame of FIG. 43 in a different
position.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0077] FIGS. 2-5 illustrate a related art mask known as the
VISTA.TM., manufactured by ResMed Incorporated. Mask assembly 100
comprises (i) a soft face-contacting cushion 110, (ii) swivel elbow
130, (iii) headgear clips 140, (iv) a frame 120 adapted to receive
the cushion 110 and support swivel elbow 130 and headgear clips
140, and (v) headgear 150 including straps 160 and a headgear yoke
170.
[0078] Stabilization of the cushion 110 and frame 120 on the face
220 of an adult patient 200 is assisted by the size, shape and
positioning of the yoke 170 on the headgear 150. In spite of the
problems identified by Sullivan & Wilkie concerning the fulcrum
and torsional effects of prior art masks, greater stability can be
achieved in pre-adults with a mask in accordance with the present
invention. In one embodiment, the present inventors have redesigned
the VISTA.TM. mask in FIGS. 2-5 to be suitable for use with
pre-adults, or adults with small or child-like facial features.
[0079] FIGS. 6-16 illustrate components of a mask system for use
with pre-adults, in accordance with preferred embodiments of the
present invention, in which like elements are referenced by like
elements compared to the VISTA.TM. shown in FIGS. 2-5.
[0080] The US Food & Drug Administration (FDA) makes the
following classifications for pre-adults:
TABLE-US-00001 TABLE 1 Neo-natal 0-1 month Infant 1 month-2 years
Child 2 years to 12 years Adolescent 12 years to 16 years
[0081] In accordance with an aspect of the invention, a mask system
is provided which uses a different classification:
TABLE-US-00002 TABLE 2 Infants 0-2 Mini 2-6 Kid 6-16
[0082] The mask system can fit the same range of pre-adults defined
by the FDA, however, four separate mask systems are not
required.
[0083] In adults, a system of masks suitable for fitting a range of
people should take into account body mass and racial nose
characteristics. For example, the East Asian-shaped nose typically
has a lower nasal bridge region compared to the Caucasian-shaped
nose. However, below the ages of 5-7 there are few racial
distinctions in children. In particular, neo-nates, infants and
young children have no nasal bridge. Not only do children have
smaller heads and faces than adults, their heads and faces are
differently shaped. In accordance with an aspect of the invention,
a system of mask & headgear sizes has been developed in which a
minimal set of components can be used to fit the widest range of
people:
TABLE-US-00003 TABLE 3 Cushion 110 Frame 120 Yoke 170 Clips 140
Elbow 130 Mini (2- 2-3 sizes 50-70% of Extra- 50-70% of 50-70% of
6YO) standard small standard standard Kid (6- 2-3 sizes Standard
Small Standard Standard 16YO)
[0084] An advantage with the mask system described herein is that a
very wide range of pre-adults can find a mask which fits well with
little leak, is comfortable, and yet is economic for manufacturers
to produce and bring to market. Since the pediatric, small adult,
or pre-adult market is relatively small in comparison to the
standard adult market, there is a reduced economic incentive for
business to bring product to the market. However, when a system in
accordance with the invention is produced, it becomes more
economically viable to produce such masks.
Headgear Yoke Design
[0085] FIGS. 6-8 illustrate (left hand) headgear yoke 170 suitable
for pre-adults in accordance with an embodiment of the invention.
Yoke 170 includes vertical finger 310, ladder lock 320 to receive a
headgear strap, lower yoke finger 330 and key-shaped recess 311 to
receive a clip 140 (see FIG. 3). Headgear yoke 170 preferably
should have one or more of the following features: [0086] 1. yoke
vertical finger 310 located midway between eye-line 230 and earlobe
240 (refer to FIG. 2). [0087] 2. yoke ladderlock 320 located 1/3 of
the distance between the eye-line 230 and crown of the head 250.
[0088] 3. a gap of 5 mm maintained between lower yoke finger 330
and lowest point of earlobe 240. [0089] 4. lower yoke finger 330
positioned about 15 mm behind the lowest point of the earlobe 240.
[0090] 5. a lower yoke finger 330 positioned at an angle of about
15-20.degree., preferably 17.degree., like the VISTA.TM..
[0091] Table 4 compares dimensions of related art VISTA.TM.
headgear yoke with two "small" headgear yokes, referred to as the
"Mini" and "Kid," in accordance with preferred embodiments of the
invention. The first row of Table 4 identifies four features (A, B,
C and D) of the headgear yoke. These features are shown in FIG. 6,
while FIGS. 7 and 8 show additional views of the yoke 170. The
dimension values can be varied up to .+-.20%, and preferably up to
.+-.10%, of the dimensional values listed in Table 4 below and
shown in the Figures. For example, distance A can be about 90-100
mm, distance B can be about 80-100 mm, distance C can be about
25-40 mm, and distance D can be about 45-55 mm, although other
distances are possible.
[0092] FIGS. 11a-11c illustrate a headgear crossover 80 that can be
used instead of the crossover shown in FIG. 4. The crossover 80
includes a main body 82 which may have a substantially square
appearance, although other shapes are possible. Each side may
include a slot 84 to receive one of the straps 160 shown in FIGS.
10 and 11. Exemplary dimensions are shown in FIGS. 11a-11c,
although other dimensions are possible. Crossover 80 has an
improved appearance compared to crossover in FIG. 4. Further,
crossover 80 provides greater friction to the straps running
through it and so resists slipping out of place more than the
crossover in FIG. 4. For example, the sliding force for the
crossover 80 may be increased between about 100-150%.
TABLE-US-00004 TABLE 4 Yoke Comparison "A" (mm) "B" (mm) "C" (mm)
"D" (mm) VISTA .TM. (related art) 130 110 43 48.5 "Small" 1st 100
86 28 46 embodiment - "Mini" "Small" 2.sup.nd 100 95 37 49
embodiment - "Kid" "Small 3.sup.rd 100 90 37 49 embodiment -
"Kidsta-S"
Headgear Strap Design
[0093] FIG. 9 illustrates a side headgear strap 162 suitable for
use with yoke 170 shown in FIG. 6. Strap 162 includes vertical
portion 163 and lower portion 164. The yoke is mounted on strap 162
in a manner similar to that shown in relation to the VISTA.TM. yoke
and strap, as shown in FIG. 5. For example, the yoke and strap can
be secured to one another via stitching, adhesives, etc.
[0094] The headgear strap 162 may include the dimensions as shown
in FIG. 9. However, those dimension are exemplary only, as other
dimensions could be used instead. For example, the strap 162 could
have dimensions that are varied up to .+-.20%, but preferably no
more than up to .+-.10%, of the dimensional values shown in the
example in FIG. 9. Other variations to the yoke are described
below, which may also impact the dimensions of the headgear
strap.
[0095] FIG. 10 shows a center strap 160 for the headgear 150.
Preferred dimensions of the center strap 160 are illustrative only,
and may be adjusted up to +/-10%-20% of the values shown. FIG. 11
shows the center strap 160 of the "Kid" in side-by-side comparison
with the VISTA.TM. center strap. The rear width of the center strap
150 shown in FIG. 10 can be reduced by about 30 mm, as compared to
the VISTA.TM. center strap. Further, the center strap 150 can
accommodate a label (in label area 161) and ladder locks.
Cushion Design
[0096] FIGS. 12-16 illustrate a cushion 110 in accordance with an
embodiment (e.g., the "Kid") of the present invention. FIGS. 12-13
and 15 show the cushion mounted on a standard VISTA.TM. frame 120.
Cushion 110 includes a double-walled face contacting portion. As
shown in FIG. 12, the double wall includes a thin flexible outer
membrane 910 which forms a sealing structure, and an underlying rim
920 which forms a support structure. In FIG. 12, the rim 920 is
indicated with a broken line as it is seen through and/or below the
membrane 910. As shown in FIG. 13, a top view, cushion 110 has a
patient contacting region 1110 and a frame-engaging region 1120.
The cushion 110 and frame 120 are adapted to engage with one
another as in the VISTA.TM. mask, as described in U.S. Patent
Application No. 60/402,509, or other ones of the applications
listed above, although other engagement methods are possible. Both
the membrane 910 and rim 920 preferably include a nasal bridge
notch 930, a pair of side portions 940, and a curved lip region
950, as shown in FIG. 12.
[0097] The cushion 110 is constructed from a silicone material,
such as that used for the VISTA.TM. mask, although other materials
could be used, e.g., gel, foam, silicone and combinations
thereof.
[0098] In accordance with an embodiment of the invention, 2-3 "Kid"
cushion sizes and 2-3 "Mini" cushion sizes can be used to fit
pre-adults from 2 to 16 years.
[0099] Since the "Kid" range of cushions fit adult VISTA.TM.
frames, e.g., see frame 120 in FIGS. 2-5, 12, 13 and 15, they have
a generally inwardly sloping outer wall 1130 (see FIGS. 13-16) that
provides a transition between the relatively smaller
patient-contacting region 1110 and the frame-engaging portion 1120
of the cushion 110. The outer wall can also be stepped as well. In
either case, the area of the bottom of the cushion (where it
connects to the frame) is projected wider than the area where the
membrane contacts the facial tissue. The difference in area (i.e.,
the projected area of the bottom of the cushion) can help reduce
the pressure needed to maintain a seal with the face. This is an
advantage especially in regard to fitting pre-adult or small adult
patients, where the available patient contact area may be
limited.
[0100] Moreover, the smaller area covered by the Kidsta Small and
Kidsta Extra Small masks results in reduced headgear loading. The
smaller area of face exposed to the air pressure in the mask
results in a smaller overall reaction force, as force is equal to
pressure by area. The reaction force from the pressure in the mask
is a significant component of the load on the mask, especially at
higher air pressures. Hence the total load on the mask, and the
headgear strap loads required to match this load, will be less with
the small mask area.
[0101] Both the "Kid" and "Mini" range of cushions are not only
smaller than adult range of VISTA.TM. cushions, they have a
different shape. For example, both the "Kid" and "Mini" cushions
have relatively shallower notches in the nasal bridge region and
relatively shallower curves in the lip region compared to an adult
VISTA.TM. cushion. See also FIGS. 27, 28, 31, 32 and 34.
[0102] Table 5 shows the change in size of a "Kid" cushion in
accordance with one embodiment of the invention. The membrane 910
of the cushion 110 has an orifice 975 (FIGS. 12 and 17) defined by
the edge 970 of the membrane 910. There is a corresponding orifice
985 (visible through the membrane 910) defined by the edge 980 of
the rim 920. In use, the nose of the patient 200 passes through the
orifice 975.
[0103] As compared to the VISTA.TM. cushion, the orifice 985 of the
rim 920 is about 3 mm smaller all around its perimeter, however the
membrane 910 is smaller by an amount varying from about 0 to 3 mm.
FIG. 17 shows broken line 972 which indicates the general position
of the edge of the membrane in a corresponding adult size VISTA.TM.
cushion with its corresponding larger orifice. FIG. 18
schematically shows relative changes of the rim of the "Kid"
cushion compared to the VISTA.TM. cushion, while FIG. 19
schematically shows relative change in the membrane of the "Kid"
compared to the VISTA.TM.. The relative changes in height of the
cushion reflect the relatively shallower notch in the nasal bridge
region and the relatively shallower curve in the lip region.
TABLE-US-00005 TABLE 5 "Kid" v. VISTA .TM. - Cushion Comparison
Membrane Rim Orifice span 0 mm in nasal -3 mm in all regions bridge
region -2 mm in lip region -3 mm in side region Height of patient
+6 mm in nasal +3 mm in nasal contacting region bridge region
bridge region from frame- +3 mm in lip region +3 mm in lip region
engaging portion. +2 mm in side region +1 mm in side region Kid
Orifice span nasal bridge region - 23 nasal bridge region - 35 lip
region - 31 lip region - 33 side region - 19 side region - 43 Kid
Height of nasal bridge region - 28 nasal bridge region - 14 patient
contact- lip region - 20.7 lip region - 16 ing region from side
region - 34 side region - 26 frame-engaging portion
[0104] In accordance with another embodiment of the invention, a
"Kid" cushion has a further 3-4 mm increase in height of the
membrane in the patient contacting-portion from the frame-engaging
portion in the nasal bridge region, hence a total of 9-10 mm when
compared to an adult cushion. There is a corresponding change in
the rim.
[0105] In accordance with another embodiment of the invention, a
"Mini" cushion has a further 6-7 mm increase in height of the
membrane in the patient contacting-portion from the frame-engaging
portion in the nasal bridge region, hence a total of 12-13 mm when
compared to an adult cushion. There is a corresponding change in
the rim. In this way, a "Mini" cushion has an even shallower notch
in the nasal bridge region compared to a "Kid" cushion. Since a
"Mini" cushion uses a smaller frame than a "Kid" cushion, it does
not have the generally sloping outer wall in the transition region
between the face-contacting portion and the frame-engaging portion.
Furthermore, the "Mini" cushion is generally closer to the face for
better stability. Such a shallower notch is indicated by broken
line 990 in FIG. 15. Furthermore, as shown in FIG. 20 the lower
corners of the "Mini" cushion 1510 are more rounded (i.e. larger
radius) than the corresponding corners of the "Kid" cushion. The
cushion includes a nasal ridge region, a top lip region and two
side regions. In this example, the membrane and rim each have an
orifice in which a width of the membrane orifice is between about
30 and 32 mm in the lip region, between about 18 and 20 mm in each
side region, and between about 22 and 24 mm in the nasal bridge
region, a width of the rim orifice is about 34 and 36 mm in the
nasal bridge region, between about 32 and 34 mm in the lip region,
and between about 42 and 44 mm in each side region of the cushion.
The membrane and the rim each have a height as measured from a
portion of the cushion that engages the frame. The membrane height
is about 27 and 35 mm in the nasal bridge region, between about 19
and 22 mm in the lip region, and between about 33-35 mm in each
said side region, the rim height is between about 13 and 18 mm in
the nasal bridge region and the lip region, and the rim height in
each said side portion is between about 25 and 27 mm.
[0106] In general the materials used to construct a mask assembly
in accordance with the invention are the same as those used to
construct the VISTA.TM. mask.
[0107] As shown in FIG. 21, there may be some overlap in ages
between the different masks and cushions. For example, some
pre-adults aged 7 years may find a "Mini" (shown as "Mini-" in FIG.
21) mask too small and it may be appropriate for them to be fitted
with a "Kid" (shown as "Kid" in FIG. 19). Of course, the Mini and
Kid may be used for adult patients having smaller facial shapes or
pre-adult features.
Further Embodiments
[0108] Further cushion embodiments of the invention are described
in relation to FIGS. 22-45. These embodiments also relate to
shrinking and/or re-proportioning the VISTA.TM., Kid or Mini
cushion to create "small" ("Kidsta Small") and "extra small"
("Kidsta Extra-Small (XS)") cushion sizes, while preferably
maintaining the same basic architecture for fitting the cushion to
the VISTA.TM. mask frame. The new embodiments have been developed
as a result of conducting testing on the "Kid" and "Mini" cushions
described above.
[0109] The underlying rim 920 should preferably have the same cross
section as the VISTA.TM., e.g., where it attaches to the frame as
shown in FIG. 37, while the cross section of the membrane 910
and/or its relationship with the underlying rim 920 should be very
similar to the VISTA.TM., bearing in mind that both should be
tweaked at the nasal bridge area 930--the membrane 910 in
particular. The cushion height (e.g., the distance measured from
the underlying rim 920 (i.e., the upper lip (below the nose) to the
top of the cushion as shown in FIG. 22) should be maintained if at
all possible the same as the height of the VISTA.TM., keeping in
mind that the height may be affected by having to fit the cushion
110 onto the frame 120.
[0110] As to the underlying rim 920, one aspect is to reduce the
size of the opening 985 substantially along an entire extent
thereof so that the width and effective height dimensions
correspond to Table 6, all dimensions being in mm. For example, the
width of the Kidsta S and XS may be in the range of about 30-42 mm,
the effective height may be in the range of about 32-42 mm, and the
effective bridge depth may be about 13-24 mm, although other
dimensions are also possible. See FIG. 22, which shows the width
and height of opening 985. The membrane 910 size follows the
underlying rim 920 if proportions are maintained.
TABLE-US-00006 TABLE 6 VISTA .TM., Kidsta S + Kidsta XS - Cushion
Width Eff. Height Bridge Depth VISTA .TM. 45 about 30 <11 KIDSTA
- S 39-40 about 35 <15 KIDSTA-XS 34-35 about 40 20
[0111] The top lip 950 area should be raised so that a distance z
is about 2 mm. See FIG. 23. The membrane bridge 930 should have an
effective depth (i.e., the distance from the underlying rim 920 to
the bottom of the nasal bridge region of the membrane 910, as shown
in FIG. 24) that is preferably adjusted as shown in Table 6. See
FIG. 24. The underlying rim 920 may be raised too if this helps
with seating to frame 120. It may be desirable to adjust only the
vertical dimension, although additional adjustment may be
desirable.
[0112] FIG. 25 shows a side view of the "Mini" or "Kid" described
above, in use on a pre-adult. As shown, the vertical finger 310 of
the yoke 170 may be too close to the user's eyes, and/or the yoke
lower finger 330 may impinge on the lower part of the ear lobe.
Accordingly, for the Kidsta-S, the dimension "C" from Table 4 can
be increased by about 9 mm (i.e., a total of about 37 mm) to move
the vertical finger closer to the ear, thereby increasing field of
view. To better avoid or help avoid impinging on the lower ear
lobe, dimensions "B" and/or "D" from FIG. 6 can be altered, for
example, by increasing these dimensions by about 4 mm each, i.e.,
total dimension "B" would be about 90 mm and total dimension "D"
would be about 50 mm (or a bit less than the VISTA.TM.). The lower
finger 330 may include a full radius.
[0113] The "Kid" or "Mini" can also be better dimensioned and/or
shaped to avoid leak at the nasal bridge region, especially for
kids under age 11 years old, to avoid intrusion into the eyes, to
avoid discomfort stemming from a "hard-edged" cushion, and/or to
reduce the size of the cushion, e.g., to avoid dead air space.
[0114] To better avoid intrusion into the eyes, the Kidsta XS
cushion can be further shortened (compared to the Kidsta S) by
about 5 mm to avoid the eye sockets. As mentioned, the frame size
preferably remains the same.
[0115] The Kid or Mini cushion depth was about 3 mm deeper than the
VISTA.TM., which may introduce possible instability and make
headgear difficult to fit. In the Kidsta S, the height is reduced
approximately to the height of the VISTA.TM..
[0116] In the Kid or Mini, the radius was smaller across the top
lip (compared to the VISTA.TM.) with no leaks or discomfort
reported. Thus for the Kidsta S according to the present
embodiment, maintain the 2 mm smaller radius compared to the
VISTA.TM.. For the Kidsta XS, the radius should be further reduced
another 2 mm, in proportion, which may help accommodate patients
with smaller lips. See FIG. 26.
[0117] As for sizing strategy, one aim is to use only 2 sizes with
roughly equal population coverage. The dimensions which have the
most impact on sizing are the maximum nose width (limits mask
width), the minimum nose height from septum to eye line (limits
mask height) and the minimum nasal bridge depth (limits shallowness
of the mask). The inventors have found that width and height growth
is approximately linear for the 5-16 age group. The masks are
designed to fix approximately 5 year age blocks, and to fit the
largest width and smallest height within each block. The data from
the middle of the nasal bridge region is not widely available, so
it is also assumed to be linear within each block. See Table 7,
below.
TABLE-US-00007 TABLE 7 Bridge Depth Inner Cushion Inner Cushion
Difference (Nose) Width (Nose) Height c.t. Vista VISTA .TM.
Standard 45 40 0 Kid or Mini 40 36 5.5 Kidsta Small 40 35 8.5
Kidsta Extra Small 35 30 12.5
[0118] FIG. 27 is a sizing chart based on nose width and nose or
bridge height. In accordance with an aspect of the invention, a
mask (e.g., the Kidsta Small or the Kidsta XS) can be selected for
a patient by measuring or otherwise obtaining one or more nose
dimensions. For example, a Kidsta S or XS would be selected for a
pre-adult or small sized adult patient having a nose width of less
than about 40 mm and/or a nose/bridge height of less than about 35
mm. The Kidsta S and XS include cushions and/or headgear that are
structured to provide a good fit for those patients. If the nose
width is below about 35 mm and/or the nose/bridge height is below
about 30 mm, then the Kidsta XS would appear to be the appropriate
mask for that patient.
[0119] FIGS. 28-29 show various other features of the Kidsta S in
conjunction with other cushions, for comparison purposes, VISTA.TM.
and the Kid or Mini.
[0120] FIG. 30 shows the bridge center depth versus cushion type,
e.g., of the Kidsta S, Kidsta XS, the Kid or Mini, the VISTA.TM.
(S-W) and the VISTA.TM. (Standard). The information in FIG. 30 can
be combined with the information in FIG. 27 to select the most
appropriate mask given one or more dimensions (and/or the age)of
the patient. Compared to the Kid or Mini, the nasal bridge depth is
reduced by about 3 mm for the Kidsta S, and 7 mm for the Kidsta XS.
Also, the vent is the same as or similar to VISTA.TM.. See FIG.
31.
[0121] FIGS. 32-37 show various views of the Kidsta S, while FIGS.
38-42 show various view of the Kidsta XS, including exemplary
dimensions. The dimensions can be changed up to about .+-.20%, but
preferably no more than up to about .+-.10%, of the exemplary
values shown. FIGS. 32-42 are drawn to scale, or at least shown the
relative distances between cushion parts to scale.
[0122] As shown in FIGS. 32 and 38, the cushion may include one or
more markers 911, e.g., in the form of a diamond or other shape.
The markers may be provided in conjunction with similar or
complimentary markings on the frame, to provide a visual indication
to facilitate alignment.
Headgear Clip
[0123] The headgear clip 140 as shown in the VISTA.TM. (FIGS. 2-5)
can be made of PBT, a plastic, resilient material, although other
materials can be used. For the present embodiments, the clips can
be made of polypropylene, preferably available under the trade name
"BOREALIS." Clips made for polypropylene can be more flexible than
PBT, which facilitates operation, e.g., assembly and disassembly,
of the clip, especially by pre-adults, e.g., 5 year old girls can
operate polypropylene clips. This can help increase compliance of
the patient.
Frame
[0124] The existing VISTA.TM. type frame 120 includes cheek pieces
(see FIGS. 2-5) that support the mask both vertically and from side
to side movement. These cheek pieces preferably remain in light
contact with the cheeks and/or jowls to provide the maximum
stability with maximum comfort.
[0125] A problem may arise because different people have different
face widths. A frame width that provides optimal contact for one
person will be too tight for another person and too loose for a
third.
[0126] If the frame is too tight, the patient may suffer from pain
or skin damage, or will adjust the mask so that it is no longer too
tight, but it will no longer seal or provide effective treatment.
If the mask is too loose, the mask will have excessive side to side
movement, especially when the patient turns to the side and presses
one cheek into the pillow.
[0127] Another aspect of the invention is to chose a size that
suits the largest number of patients, with a bias towards being too
loose in preference to being too tight. It is envisaged that a
range of sizes may be introduced so that customers may choose from
a narrow, medium or wide mask frame.
[0128] FIGS. 43-44 show a frame 120 having movable rather than
rigid connections 121 between the cheek pieces 123 and the main
body 125 of the mask frame. This enables the width of the frame
between the cheek pieces to be adjusted to fit the patient.
[0129] There are a number of different ways that this idea can be
implemented. For example, the cheek pieces 123 can be mounted on a
hinge so that they can swing in or out. The cheek pieces 123 may be
either free to move or they could be locked into one or more
predetermined positions, via detents, friction, and/or a pin and
slot arrangement.
[0130] Alternatively, the cheek pieces 123 can be flexibly mounted,
so that they can bend in or out without requiring much force. If
they are set so that the neutral position is wider than the
patient's face, the tension in the headgear will pull the cheek
pieces in towards the ideal position for that person.
[0131] In a further alternative, if the cheek pieces 123 are set so
that the neutral position is narrower than the patient's face, the
cheeks will push the cheek pieces out towards the ideal position
for that person. In another method, the cheek pieces could be
adjusted in or out using some sort of adjustment mechanism, such as
a screw adjustment.
[0132] With movable cheek pieces, the mask can be more comfortable
for a wider range of patients. Those patients with wide faces would
no longer suffer from excessive pressure on the cheeks.
[0133] It would also be more securely mounted on the face,
resulting in less mask movement for those with thin faces, or for
people with wide faces who may adjust the mask poorly in an attempt
to make it more comfortable. This greater security will result in
less leakage, leading to greater comfort and more effective
treatment.
[0134] This will make the VISTA.TM. type mask easier to fit onto a
variety of different face shapes. Because one mask will fit such a
large range, less inventory will be required.
[0135] Use of an adjustable mask frame will stop the need for
having more than one frame size. This will reduce inventory and
tooling costs.
[0136] The ease of fitting a wide variety of facial shapes will
increase the range of people to whom the masks will be attractive.
Although the invention has been described with reference to
particular embodiments, it is to be understood that this embodiment
is merely illustrative of the application of the principles of the
invention. Numerous modifications may be made therein and other
arrangements may be devised without departing from the spirit and
scope of the invention.
* * * * *