Note: Descriptions are shown in the official language in which they were submitted.
Endotracheal Tube Having Outer And Inner Cannulae
Field Of The Invention
This invention relates to improvements in endotracheal tubes, for example,
orotracheal tubes and nasotracheal tubes.
Background Of The Invention
This invention is directed toward the problem of pooling of saliva and other
secretions around the inflated cuff of a tracheal tube, for example, an
endotracheal tube, and the
potential for such secretions to leak past the cuff and into the lungs.
The following are of interest: U. S. Patents: 1,598,283; 2,892,458; 3,688,774;
3,996,939; 4,211,234; 4,223,411; 4,280,492; 4,304,228; 4,305,392; 4,315,505;
4,327,721;
4,449,523; 4,459,984; 4,469,100; 4,573,460; 4,584,998; 4,589,410; 4,596,248;
4,607,635;
4,627,433; 4,632,108; 4,637,389; 4,762,125; 4,834,087; 4,840,173; 4,852,565;
5,056,515;
5,067,497; 5,107,828; 5,123,922; 5,201,310; 5,217,008; 5,218,970; 5,255,676;
5,297,546;
5,329,921; 5,339,808; 5,343,857; 5,349,950; 5,391,205; 5,392,775; 5,458,139;
5,497,768;
5,507,279; 5,515,844; 5,584,288; 5,599,333; RE35,595; 5,687,767; 5,688,256;
5,746,199;
5,771,888; 5,957,978; 6,053,167; 6,089,225; 6,102,038; 6,105,577; 6,135,110;
6,135,111;
6,463,927; 6,722,367; 6,814,007; 7,404,329; U. S. patent publications:
2003/0084905;
2004/0123868; foreign/international patent publications: DE 25 05 123; DE 34
06 294; DE 37
20482; DE 38 13 705; DE 195 13 831; DE 101 09935; WO 99/07428; WO 99/12599; WO
00/32262; other publications: Quick Reference Guide to Shiley's "Quality-Of
Life" Line of
Tracheostomy Products, 1991; Granuloma Associated with Fenestrated
Tracheostomy Tubes,
Padmanabhan Siddharth, MD, PhD, FACS and Lawrence Mazzarella, MD, FACS, Case
Reports, vol. 150, Aug. 1985, pp. 279-280; Technical Support Information
Connections with
the Passy-Muir Tracheostomy and Ventilator Speaking Valves, one sheet;
Tracheostomy and
Laryngectomy Tubes, pp. 568 and 572; Tracheostomy Tube Adult Home Care Guide,
Shiley
Tracheostomy Products, Mallinckrodt Medical pp. 1-40; D. Hessler, MD, K.
Rehder, MD and
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S.W. Karveth, MD, "Tracheostomy Cannula for Speaking During Artificial
Respiration",
Anesthesiology, vol. 25, No. 5, pp. 719-721 (1964). No representation is
intended by this
listing that a thorough search of all material prior art has been conducted,
or that no better art
than that listed is available. Nor should any such representation be inferred.
Summary of the Invention
According to an aspect, an endotracheal tube apparatus includes an outer
cannula
having first and second ends. A fenestration is provided along the length of
the outer cannula
between the first and second ends. An inflatable cuff is formed on the outer
cannula between
the fenestration and the second end. A first conduit extends from the cuff for
introducing an
inflating fluid into the cuff when it is desired to inflate the cuff and
removing inflating fluid
from the cuff when it is desired to deflate the cuff. An inner cannula is
sized selectively to be
inserted into, and removed from, the outer cannula. The inner cannula includes
a second
conduit to evacuate a region of a trachea of a wearer adjacent the cuff. The
second conduit
includes an opening which lies adjacent the closest point in the fenestration
to the cuff when the
inner cannula is selectively inserted into a use orientation in the outer
cannula.
Illustratively, the apparatus further includes a gauge coupled in the first
conduit
for indicating the inflation pressure of the cuff.
Illustratively, the apparatus further includes a one-way valve at an end of
the
first conduit remote from the cuff for preventing escape of inflating fluid
from the cuff.
Illustratively, the cuff comprises a sleeve including a first end, a second
end, and
a third region between the first and second ends. The sleeve is located around
the outer cannula
with at least the first end of the sleeve between the outer cannula and the
third region of the
sleeve.
Illustratively, the first and second ends of the sleeve are both between the
outer
cannula and the third region of the sleeve.
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Illustratively, the apparatus further comprises a first coupler provided on an
outer end of the outer cannula and a second coupler provided on an outer end
of the inner
cannula. Each of the first and second couplers is provided with at least one
cooperating surface
for guiding the inner cannula into a predetermined orientation with respect to
the outer cannula
when the inner cannula is inserted into the outer cannula.
Illustratively, the apparatus further comprises at least one tab provided on
an
outer end of one of the outer cannula and the inner cannula. The at least one
tab includes an
engaging surface. At least one coupler is provided on an outer end of the
other one of the outer
cannula and the inner cannula for engagement by the at least one tab. The at
least one coupler
includes a portion for cooperating with the engaging surface for orienting the
inner cannula in a
predetermined orientation with respect to the outer cannula.
Illustratively, the at least one tab is flexibly formed or mounted to said one
of the
outer cannula and the inner cannula.
According to another aspect, a tracheal tube apparatus includes a cannula
having
first and second ends. An inflatable cuff is formed on the cannula between the
first and second
ends. A conduit extends from the cuff for introducing an inflating fluid into
the cuff when it is
desired to inflate the cuff and removing inflating fluid from the cuff when it
is desired to deflate
the cuff. A gauge is coupled to the conduit for indicating the inflation
pressure of the cuff.
Illustratively, the apparatus further includes a one-way valve at an end of
the
conduit remote from the cuff. The one-way valve prevents escape of inflating
fluid from the
cuff.
Illustratively, the cuff comprises a sleeve including a first end, a second
end, and
a third region between the first and second ends. The sleeve is located around
the cannula with
at least the first end of the sleeve between the cannula and the third region
of the sleeve.
Illustratively, the first end of the sleeve and the second end of the sleeve
are both
between the cannula and the third region of the sleeve.
Brief Description of the Drawings
The invention may best be understood by referring to the following detailed
description and accompanying drawings which illustrate the invention. In the
drawings:
Fig. I illustrates a fragmentary perspective view of a system according to the
invention in a disassembled configuration;
Fig. la illustrates a longitudinal sectional side elevational view of the
anatomy of
the upper airway of a wearer with the apparatus illustrated in Fig. 1 in
place;
Fig. 2 illustrates a perspective view of a portion of the system illustrated
in Fig.
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1;
Fig. 3 illustrates a perspective view of a portion of the system illustrated
in Fig.
1;
Fig. 4 illustrates an enlarged longitudinal sectional side elevational view of
a
detail of Figs. 1 and 3, taken generally along section lines 4-4 of Fig. 3;
Fig. 5 illustrates an enlarged longitudinal sectional side elevational view of
a
detail of Figs. 1 and 2, taken generally along section lines 5-5 of Fig. 2;
Fig. 5a illustrates an enlarged longitudinal sectional side elevational view
of an
alternative detail to the detail illustrated in Fig. 5;
Figs. 6a-c illustrate enlarged front elevational, side elevational and rear
elevational views, respectively, of a detail of Figs. I and 2; and,
Figs. 7a-e illustrate schematic circuit diagrams of the detail illustrated in
Figs.
6a-c.
Detailed Descriptions Of Illustrative Embodiments
Referring now particularly to Figs. 1 and la, an endotracheal tube system 10,
here an orotracheal tube system, includes an outer cannula 12 for insertion
through the mouth of
a wearer 20, down the wearer 20's pharynx 24, through the wearer 20's glottis
22 and into the
wearer 20's trachea 18. Outer cannula 12 includes an inflatable cuff 16. Cuff
16 lies in the
trachea 18 of the wearer 20 below the wearer 20's glottis 22. Outer cannula 12
also includes a
first port 26 which resides outside the mouth of the wearer 20 during use and
a second port 28
which resides inside the trachea 18 of the wearer 20 below cuff 16 during use.
The cuff 16 is
inflatable through a conduit 30 once the outer cannula 12 is in place in the
trachea 18 to
minimize the passage of secretions 32 from the upper respiratory tract
downward into the lungs
of the wearer 20. Such secretions 32 pool above the cuff 16 (that is, on the
side of the cuff 16
opposite the lungs) when the cuff 16 is inflated in place. The construction of
the cuff 16 as a
sleeve 42, Fig. 5, with its upper and lower ends 44, 46, respectively, tucked
under, rather than
extending beyond the cuff 16 up and down the outer sidewall of the outer
cannula 12, is aided
by the use of thin-walled material for the cuff 16. In an alternative
embodiment, illustrated in
Fig. 5a, only upper end 44' is tucked under, rather than extending beyond the
cuff 16 up the
outer sidewall of the outer cannula 12'. The constructions illustrated in
Figs. 5 and 5a provide
certain benefits which will be discussed subsequently.
The outer cannula 12 includes (a) fenestration(s) 56. Although two such
fenestrations 56 are illustrated, it should be understood that any number of
fenestrations 56 may
be provided in the outer cannula 12 for this purpose. The construction of cuff
16, with its
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doubled-over upper and lower ends 44, 46, respectively, (Fig. 5) or doubled-
over upper end 44'
(Fig. 5a), permits location of the fenestration(s) 56 low (that is, more
toward the lungs of the
wearer 20) on the outer cannula 12. The proximity of the cuff 16 to the
fenestration(s) 56 also
provides some additional protection of the tissue of the trachea 18 against
irritation and damage
occasioned by contact with the edges of the fenestration(s) 56 by virtue of
the standoff provided
by the inflated cuff 16.
Referring now particularly to Figs. 1 and 3, an inner cannula 60 is inserted
into
the lumen 62 of the outer cannula 12. To evacuate pooling secretions 32, a
conduit 70 extends
down the sidewall of inner cannula 60. Conduit 70 terminates at an open end 72
at the
bottommost extent of fenestrations 56 to expose the secretions 32 to suction
at open end 72 of
tube 70 provided by a suction source 73 at the outer end of inner cannula 60.
Owing to the
construction of cuff 16 with its doubled-under end 44, this location generally
coincides with the
top of the cuff 16 at the bottommost extent of fenestration 56. Owing to this
construction,
extraction of secretions 32 is somewhat more predicable and complete.
In addition, it is contemplated that replacement of the inner cannula 60 may
occur more frequently and with less difficulty and without much of the trauma
that might attend
replacement of outer cannula 12, which is typically placed in the trachea for
a longer term.
Typically, both the outer 12 and inner eannulae 60 are constructed from
suitable filled and/or
unfilled resin(s) and/or polymer(s). Inner cannula 60 typically can be
relatively
straightforwardly replaced by disconnecting it from the ventilator 74
(illustrated
diagrammatically) to which the outer end 76 of inner cannula 60 is attached in
use and
withdrawing inner cannula 60 from outer cannula 12. Because of the relative
ease with which
inner cannula 60 can be removed, disposed of if appropriate, and replaced with
a fresh cannula
60 having a fresh tube 70, providing tube 70 on inner cannula 60 rather than
on outer cannula
12 affords somewhat more reliable patency of tube 70 than if the tube 70 were
to be provided in
outer cannula 12 which, as noted above, is typically not so readily removed
for cleaning or
replacement.
Referring now to Fig. 1, the inner cannula 60 is releasably fixed to an outer
cannula 12 by one or more (two in the illustrated embodiment) locking tabs 100
which may be
formed with, and from the same material as, the coupler 76 of cannula 60 by
which cannula 60
is coupled to the ventilator 74. The tabs 100 are flexibly formed or mounted
to the coupler 76
of inner cannula 60. The tabs 100 are provided with engaging surfaces 106. A
coupler 108 is
provided at the proximal end 54 of outer cannula 12. The coupler 108 includes
a notch 114 for
receiving the portion of each tab 100 which extends beyond engaging surfaces
106 and portions
116 for capturing engaging surfaces 106. This configuration also promotes
correct orientation
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of inner cannula 60 with the fenestration(s) (56 in Fig. 1) of outer cannula
12 when inner
cannula 60 is inserted into outer cannula 12.
Referring to Figs. 1 and 2, a digital pressure gauge 304 is inserted into the
conduit 30 between a fitting 302 and cuff 16 by a fitting 306 provided on
gauge 304. Fitting
302 is configured complementarily to a fitting on a source 307 of compressed
air, such as a
syringe. Such a fitting might be, for example, a Luer lock fitting or other
suitable fitting to
couple the compressed air source to fitting 302 for this purpose. Fitting 302
may also include a
one-way valve of a suitable type, such as, for example, a ball valve, to
prevent the escape of
cuff 16-inflating air, permitting the compressed air source 307 to be
disconnected from fitting
302 once cuff 16 is inflated to a suitable pressure.
The schematic and block circuit diagram descriptions that follow identify
specific integrated circuits and other components and in many cases specific
sources for these.
Specific terminal and pin names and numbers are generally given in connection
with these for
the purposes of completeness. It is to be understood that these terminal and
pin identifiers are
provided for these specifically identified components. It is to be understood
that this does not
constitute a representation, nor should any such representation be inferred,
that the specific
components, component values or sources are the only components available from
the same or
any other sources capable of performing the necessary functions. It is further
to be understood
that other suitable components available from the same or different sources
may not use the
same terminal/pin identifiers as those provided in this description.
The gauge 304 removed from its housing 305 is illustrated in Figs. 6a-c. An
electrical schematic of gauge 304 is illustrated in Figs. 7a-e. As illustrated
in Figs. 1, 2, 6a, 6b
and 7a, gauge 304 includes a two digit (seven segments each) liquid crystal
display (LCD) 310
which illustratively is a Glory Sound (Asia) Ltd., AE359 type DS-M2684-F
display. Referring
to Figs. 6b and 7b, the driver 312 for display 310 illustratively is a
Freescale Semiconductor
MC9S08QB4QFN microcontroller (ttC). Pins 1-4, the Vdd, Vrefh, Vrefl and Vss
terminals,
respectively, of driver 312 are coupled to the gauge 304's +Vbat, +Vbat,
common and common
terminals, respectively. Vrefh is coupled to +Vbat through a 1.81.tH inductor.
+Vbat and
common are the + and - terminals, respectively, of, for example, a 3V lithium
PC 2 pin mount,
170 mAh coin cell 313 such as, for example, a Renata SA type 614-CR2025FH-MFR-
LF coin
cell. See Figs. 6a-c.
Referring again to Fig. 7b, the parallel combination of a 2.2 ttE capacitor
and a
100 nF capacitor is coupled across pins 1 and 4 of C 312. The parallel
combination of a 2.2 F
capacitor and a 100 nF capacitor is coupled across pins 2 and 3. Pins 5-24,
terminals
PB7/EXTL, PB6/XTL, PB5, PB4, PC I, PCO, PB3/AD7, PB2/AD6, PB1/TXD/AD5,
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PBO/RXD/AD4, PA7, PA6, PA3/AD3, PA2/AD2, PA1/AD1, PAO/ADO, PC7, PC6, PA5/*RST,
and PA4/BKGD, respectively, of driver 312 are coupled to LCD COM, LCD segment
1G, LCD
segment 1F, LCD segment 1E, LCD segment 2B, LCD segment 2A, LCD segment 1D,
LCD
segment IC, LCD segment 1B, LCD segment 1A, LCD segment 2G, LCD segment 2F,
LCD
segment 2E, not connected, the gauge 304's TEMPerature terminal, the gauge
304's
NET _PRESSure terminal, LCD segment 2D, LCD segment 2C, through a 100 nF
capacitor to
gauge 304's common terminal, and through a 4.7 Ko, resistor to +Vbat. Another
4.7 KQ
resistor is coupled between pin 23 of driver 312 and +Vbat.
Referring to Figs. 6b, 6c and 7c, pressure at port 306, which is the cuff 16
inflation pressure, is monitored by a pressure sensor 320, illustratively a
Freescale
Semiconductor type MPX10 or MPX12 uncompensated silicon pressure sensor.
Sensor 320
pins 1-4 are coupled respectively to the gauge 304 common, through a 10 1(5-2
resistor to the
non-inverting (+) input terminal, pin 3, of a differential amplifier 322, to
gauge 304's +Vbat
terminal, and through a 10 KL2 resistor to amplifier 322's inverting (-) input
terminal, pin 2.
Amplifier 322 illustratively is one-fourth of a National Semiconductor type
LMC6464AIM
quad differential amplifier. Feedback is provided from the output terminal,
pin 1, of amplifier
322 to the - input terminal of amplifier 322 through a 100 KQ resistor. Pin 4
of amplifier 322 is
coupled to +Vbat. Pin 11 of amplifier 322 is coupled to common. The parallel
combination of
a 2.2 ?IF capacitor and a 100 nF capacitor is coupled across +Vbat and common.
Pin 1 of
amplifier 322 is coupled to a + terminal, pin 5 of a differential amplifier
324. An output
terminal, pin 7, of amplifier 324 is coupled to amplifier 324's - input
terminal, pin 6,
configuring amplifier 324 as a unity gain buffer. Pin 7 of amplifier 324 forms
the gauge 304's
NETPRESSure terminal. Amplifier 324 illustratively is one-fourth of a National
Semiconductor type LMC6464AIM quad differential amplifier.
Referring to Fig. 7d, a 10 KQ, 1% thermistor 330, such as a Vishay type 71-
TFPT1206L1002FV thermistor, and a 10 KQ, 1% resistor are coupled in series
between +Vbat
and common. The common terminal of thermistor 330 and the 10 K.Q resistor is
coupled to the
+ input terminal, pin 12, of a differential amplifier 332. An output terminal,
pin 14, of amplifier
332 is coupled to amplifier 332's - input terminal, pin 13, configuring
amplifier 332 as a unity
gain buffer. Pin 14 of amplifier 332 forms the gauge 304's TEMPerature
terminal. Amplifier
332 illustratively is one-fourth of a National Semiconductor type LMC6464AIM
quad
differential amplifier. Referring to Figs. 6a, 6b and 7e, +Vbat is supplied to
the illustrated
circuitry through a suitable switch 334, such as a Snaptron dome switch.
The topography of gauge 304 can best be understood by referring to Figs. 6a-c,
where the relative locations of fitting 306, LCD 310, driver 312, battery 313,
pressure sensor
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320 and switch 334 can be readily ascertained. Gauge 304 is configured to be
reliable yet
inexpensive in keeping with the philosophy that inner cannula 60 be rendered
disposable.
However, gauge 304 can be provided with a T-junction and conduit 30 and
fitting 302 with
appropriate complementary fittings, so that the T-junction can readily be
disconnected from and
reconnected into the conduit 30 between cuff 16 and fitting 302, should it be
appropriate to
retain the gauge 304 and dispose of the inner cannula 60. In such embodiments,
gauge 304
could be reused as long as it remained operable.
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