Consolidated anesthesia circuit

A sampling adaptor suitable for use in a unilimb breathing system with three or more hoses that includes a breathing hose connector, a swivel to allow the breathing hose connector to rotate freely in relation to the remainder of the adaptor, an angular swivel to allow adjustment of the angular shape of the adaptor, a filter that encloses the sampling end of a flexible sampling hose, a patient end connector, is disclosed herein.

FIELD OF INVENTION 
This invention relates to unilimb breathing circuits and more particularly 
to unilimb breathing circuits with provisions for sampling gases while 
filtering and separating the sample from fluid condensate. 
BACKGROUND 
The sampling of expired gases from breathing circuits in anesthesia is a 
well-known practice. It is desirable that the sample be taken as closely 
as possible to the patient's mouth piece. This helps to minimize mixing of 
the exhaled gases with inspired gases. It is also desirable to minimize 
the number of hoses that run from the patient to the respiratory machine. 
A reduction in the number of hoses that run to the patient, produces a 
corresponding reduction in the likelihood of having hoses become tangled 
or obstructed by torquing of the hoses. 
U.S. Pat. No. 3,856,051 to Bane discloses a double lumen unilimb device 
where the inspired and expired air are contained within one limb that has 
an inner and outer hose. This design reduces the number of external hoses 
between the patient and the machinery from three tubes to two tubes if a 
sampling line is utilized and from four tubes to three tubes if a 
temperature probe or heater is also utilized. A unilimb design for 
respiratory hoses lowers heat loss to the patient. The reduction of heat 
loss occurs due to heat transfer between the exhaled and inhaled gases 
through the walls of the hoses in the unilimb. The unilimb design also 
reduces heat loss from heated inspired air because of the shielding by the 
warm outer expiratory tube. 
U.S. Pat. No. 4,838,258 to Dryden et al. discloses a hose arrangement that 
includes a sampling hose contained inside one of two single lumen 
respiratory hoses. The other respiratory hose runs to the respirator as a 
single hose. 
While the prior art has utilized double lumen unilimb hoses, several 
single-lumen hoses are still required with such unilimb hoses. Therefore, 
there remains a need to further reduce the number of lines between the 
patient and machine and to reduce the possibility of tangling and torquing 
of the breathing hoses. This may be accomplished according to my invention 
by providing a unilimb device that carries all of the required hoses or 
lines to the patient, the inspiratory gas hose, the expiratory gas hose, 
the sampling hose and any other required hoses or lines. 
It is well-known that water vapor condensate interferes with analysis of 
gas samples that are taken from gas sampling hoses. The problem is created 
by the cooling of the moist exhaled gases from the patient, which causes 
water vapor to condense. Various types of water traps have been utilized 
to reduce the amount of condensate that reaches the gas analyzers. U.S. 
Pat. No. 4,717,403 to Choksi is an example of liquid traps utilized to 
prevent liquid condensation collection in gas analyzers. This device uses 
a separation chamber to separate the gas from the liquid. A liquid trap is 
an additional device to be placed in line prior to the gas analyzer to 
provide protection if an analyzer is to be utilized. Many liquid traps are 
not fully effective in preventing condensation from reaching gas 
analyzers. Provision must also be made for the emptying of condensate, for 
the trap to retain its effectiveness. 
The patient on a respirator loses water as well as heat. I have determined 
that a device able to transfer the humidity from the expired air to the 
inspired air would reduce this moisture loss and decrease the problem of 
condensation from exhaled gases. The inspired air would also require less 
moisture to be added prior to inhalation by the patient and, therefore, 
less processing. A combination heat and humidity exchange device present 
in the patient end of the respiratory apparatus would be ideal for the 
patient and healthcare professional. Such a device that is able to 
separate gases from liquid condensate, and that also functions to exchange 
heat and moisture from expired air to the inspired air, and which is also 
part of the gas sampling device, is needed due to distinct advantages in 
terms of efficiency and simplicity of use. Such a device would reduce the 
need to heat and humidify inspired air and reduce the problems of handling 
collected condensates from the expired gas. 
Mucus plugs are commonly encountered in respiratory devices, and frequently 
clog smaller hoses such as gas sampling hoses. These mucus plugs must be 
removed from the hose in order to obtain readings of gas composition from 
the sampling hose. I believe it is desirable to protect the sampling hose 
by preventing mucus from reaching it and thereby reduce the problems of 
mucus clogged hoses. 
It would also be helpful to have a temperature sensor to measure the 
temperature of inspired gases after heat transfer from exhaled gases in 
the unilimb hose and heat transfer from the heat and moisture exchange 
media, to determine the degree of warming required for the inspired gases. 
The temperature may be determined by the use of a temperature probe in the 
region where the inhaled and exhaled gases mix. 
Special connectors are desirable to incorporate my improvements and to 
allow compatibility with standard 15 and 22 mm respiratory connectors. 
Hoses for a unilimb breathing system may become twisted by torquing of the 
hose between the patient and machine. Therefore swivels which allow the 
remainder of the device to remain stationary while the hose connectors are 
free to rotate are helpful in order to eliminate torquing and to retain 
unobstructed airways. U.S. Pat. No. 4,967,744 to Chua utilizes one swivel 
in a swivel patient connector. While a single swivel allows rotation of 
the patient breathing device (mask, endotracheal tube) relative to the 
patient connector, the flexible breathing hose may still undergo torquing 
and may become obstructed unless, and according to one feature of my 
invention, at least one swivel and preferably two swivels are located in 
the patient adaptor (patient connector), one at each end, and at least one 
swivel is located on the machine end adaptor. These additional swivels 
according to my invention allow each end of the flexible breathing hose to 
rotate. The flexible breathing hose may rotate at the patient breathing 
device, the sampling adaptor or at the machine adaptor to prevent hose 
torquing. 
In patient treatment, utilizing a breathing system, it is often necessary 
to vary the orientation of the patient end of the adaptor based on the 
relative position of the patient and the breathing means. In some 
instances, a 90.degree. elbow may be required between the adaptor and the 
breathing means (patient breathing mask or endotracheal tube), and in 
other instances, a straight connection is required. A patient end adaptor 
that is variable from a straight orientation to that of a 90.degree. bend 
is an improvement that I have incorporated to optimize the patient end 
adaptor orientation for each patient's use and to simplify installation of 
the apparatus because extra elbows or adaptors are no longer required. 
SUMMARY OF THE INVENTION 
One aspect of the present invention relates to a sampling adaptor for use 
with a breathing system that includes breathing hose connections, swivels 
to allow the breathing hose connector to rotate in relation to the 
remainder of the adaptor, an angular swivel or angular swivels to allow 
adjustment of the angular shape of the adaptor, a filter that encloses the 
sampling end of a flexible sampling hose to enable particulate and liquid 
contaminants to be removed from the sampled gases, and means to connect 
the adaptor to a breathing mask, endotracheal tube or similar type 
devices. 
It is an object of the present invention to provide a sampling tube adaptor 
for use with unilimb tubing that conveys the inspiratory gas to the 
patient, and the expiratory gas and sampled gas to the appropriate 
machine. 
It is a another object of the present invention to inhibit solid and liquid 
contaminants from reaching the sampling tube. 
It is a further object of the present invention to provide a sampling 
adaptor with means to allow adjustment to provide optimal orientation for 
patient usage. 
It is another object of the present invention to enable use with 
conventional respiratory apparatus. 
It is a further object of the invention to allow use of the invention with 
closed or semi-closed rebreathing systems or with non-rebreathing systems.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
For the purposes of promoting an understanding of the principles of the 
invention, reference will now be made to the embodiment illustrated in the 
drawings and specific language will be used to describe the same. It will 
nevertheless be understood that no limitation of the scope of the 
invention is thereby intended, such alterations and further modifications 
in the illustrated device, and such further applications of the principles 
of the invention as illustrated therein being contemplated as would 
normally occur to one skilled in the art to which the invention relates. 
The present invention includes a unilimb breathing assembly that contains 
at least three hoses. The unilimb contains an outer expiratory hose, an 
inner inspiratory hose and a sampling hose. The present invention also 
includes heat and humidity exchange media, swivels to help reduce torquing 
of the unilimb, a filtered sampling hose and also includes an angular 
swivel to vary the angular relationship of the sampling adaptor to the 
patient breathing device. The patient breathing device may be a mask or an 
endotracheal tube. 
Referring now to FIG. 1, a sampling adaptor 12 is illustrated that has a 
breathing hose connector 13 having an outer breathing hose connector 13A 
with a lip 28A and an inner breathing hose connector 13B with a lip 28B, a 
patient end connector 14, a patient end hose swivel 15, a breathing hose 
connector swivel 16, with a breathing hose connector section 16A and a 
main body section 16B. The sampling adaptor also has three angular 
rotatable swivels 17A, 17B, and 17C that connect four relatively rotatable 
sections 18A, 18B, 18C and 18D defined by the angular swivels. This 
rotation allows a sampling adaptor conformation that is straight as in 
FIG. 5 or that may be varied by a 180.degree. rotation of the several 
sections around the swivels to provide a 90.degree. elbow as in FIG. 6. 
This embodiment of the invention also has filters in four sections, filters 
21A, 21B, 21C and 21D. Filter 21A is contained in the section 18A, 21B is 
in section 18B, 21C is in section 18C and 21D is in section 18D. Filter 
21A is contained by apertured supports 22A and 22B (See FIGS. 1 and 2). 
Apertured support 22A acts as a screen to prevent the movement of filter 
21A into the patient end connector, and apertured support 22E prevents 
filter 21D from moving past the main body portion of the angular swivel. 
Apertured supports 22B and 22C also help retain the filters in the 
appropriate sections. 
The sampling adaptor 12 also contains a sampling hose 23 that runs from the 
sampling adaptor to the machine adaptor 31 and is provided with sufficient 
length to avoid sampling hose tension which might otherwise be caused by 
the stretching of the flexible breathing hoses. This can be done by 
arranging the sampling hose 23 as was done for tube 21 in Dryden et al. 
U.S. Pat. No. 4,838,258, discussed above. The patient end 25 of the 
sampling hose 23 is contained within filter 21D and is held in the center 
of the sampling adaptor on center line 20 by the apertured support 22E 
(See FIG. 3). An apertured support 22F (See FIG. 4) connects the inner 
breathing hose connector 13B with the outer breathing hose connector 13A. 
A temperature sensing probe 24 is enclosed by filter 21D. A wire 26 runs 
from the probe to exit at the machine adaptor 31. The temperature probe is 
located in the filter material where the heat and humidity exchange occurs 
to provide data about the temperature of inspired gases. This data may be 
used to control an external heat and humidity exchange chamber 95 (See 
FIG. 10) to optimize the heat and humidity of the inspired gas. 
The flexible outer breathing hose 27 is utilized to conduct expired gases 
from the sampling adaptor 12 to the machine adaptor 31 and the flexible 
inner breathing hose 29 is used to convey inspiratory gases from the 
machine adaptor 31 to the sampling adaptor 12. The flexible outer 
breathing hose 27 and the flexible inner breathing hose 29 are connected 
to the machine end adaptor 31 by the breathing hose connector 33. The 
outer breathing hose connector 33A connects the outer breathing hose 27 
and the inner breathing hose connector 33B connects the inner breathing 
hose 29. 
The machine end adaptor 31 also has an outer swivel 35A and an inner swivel 
35B. The machine end adaptor 31 has an apertured support 22G which is 
fixed to and supports the inner 33B and outer 33A hose connectors. 
Apertured support 22H is fixed to and supports outer and inner connectors 
41A and 41B, respectively, of the machine end connector 41. The sampling 
hose is connected to a sampling port 37 that includes a Luer Lock 
connector 39. The port 37 is fixed to connector 41A and 41B by a solvent 
seal. The Luer Lock connector allows the attachment of a Luer Lock line to 
any currently used gas analyzers in order to analyze the patient expired 
gases. 
This invention is adaptable to a closed or semi-closed absorption system, 
if the absorber has function directional valves and active soda lime. The 
invention is also adaptable as a non-rebreathing circuit when the 
inspiratory hose is connected to a fresh gas flow from the gas machine and 
the expiratory gas hose is attached to an out-flow system that includes 
the overflow control valve, breathing bag, and scavenge system by means of 
a tee adaptor that fits a 22 mm. bag nipple. 
The flexible breathing hoses 27 and 29 that are attached to the sampling 
adaptor 12 may be coaxial (See FIG. 1) or they may run separately. The 
flexible breathing hoses may be connected to the breathing hose connectors 
and/or the Luer Lock ports by use of a solvent seal (as shown with the 
sampling port 37) or by friction fit over an expanded lip (as shown by 
outer flexible breathing hose 27 fitted over lip 28A). The flexible 
breathing hoses may be with or without reinforcing corrugated spiral 
ridges. The filters 21A, 21B, 21C and 21D utilized in this embodiment of 
the invention, may be composed of a fibrous material or polymeric foam 
having a comparatively large surface area that is capable of filtering out 
dust size particles and mucus plugs and is suitable for separating liquid 
condensates from gaseous compositions. 
The sampling hose may be run in either the inner flexible breathing hose 
(as shown) or between the inner and outer flexible breathing hose. If the 
sampling hose is run between the inner and outer flexible breathing hoses, 
the sampled gas will be warmed by the expired gases and will have less 
condensation from the cooling of the sample. If it is preferred to allow 
condensation to occur prior to the exit of the sampling hose from the 
unilimb, the sampling hose may be run in the inner flexible hose where the 
inspired gases may cool the sampled gas more quickly to achieve greater 
extraction of moisture from the sampled gas. 
An inventive method for use of the device described in FIG. 1 is performed 
by attaching the machine end adaptor portion 31 to a respirator gas input 
and output, by attaching the sampling port to a gas analyzer by Luer Lock 
compatible connectors, by attaching the sampling adaptor to a patient gas 
mask or endotracheal tube, by adjusting the angular swivel to provide 
optimum orientation of the sampling adaptor for use by the patient, by 
filtering the gas sample of expired gases through the filter prior to 
analysis by the gas analyzer to remove solid and liquid contaminants, by 
analyzing the expired gases and the gas analyzer and by adjusting the 
composition of inspired gases to provide optimal composition for the 
patient as determined by the analysis of the expired gases. 
FIGS. 2, 3 and 4 illustrate the apertured supports 22. The hoses and 
connectors are not shown, to simplify the figures. FIG. 2 illustrates 
apertured supports 22A, 22B, 22C and 22D and the basic structure of the 
apertured supports which are comprised of spokes 43 and apertures 45 
between the spokes. FIG. 3 illustrates the apertured support 22E which has 
spokes 43, apertures 45 and a sampling hose support 47 that surrounds and 
retains the sampling hose in place. FIG. 4 illustrates apertured supports 
22F, 22G and 22H which have spokes 43, apertures 45 and inner hose support 
49 that supports the inner hose connector assembly within the outer hose 
connector assembly to which the outer section of the spokes are attached. 
FIG. 5 and 6 illustrate two conformations of the sampling adaptor. FIGS. 5 
and 6 illustrate the result of rotation of sections 18A, 18B, 18C and 18D 
about the angular swivels 17A, 17B and 17C which allow an unlimited range 
of configuration of the sampling adaptor from straight (FIG. 5) to a 
90.degree. bend (FIG. 6). 
FIG. 7 illustrates an alternative embodiment of the sampling adaptor. 
Sampling adaptor 51 has a breathing hose connector 53 comprised of an 
outer breathing hose connector 53A and an inner breathing hose connector 
53B. The breathing hose connector 53 is attached to a breathing hose 
swivel 59. A patient end connector 55 is attached to a patient end swivel 
57. Angular swivels 65A, 65B and 65C allow rotation of patient end 
sections 63A, 63B, 63C and 63D about the angular swivels. In this 
embodiment, the sampling adaptor contains a filter in sections 63A and 
63B. Filter 69A is retained between apertured support 71A and apertured 
support 71B and is located in section 63A. Filter 69B is located in 
section 63B and is retained between apertured support 71B and 71C. 
A sampling hose 73 passes from filter 69B toward the breathing hose 
connector 53 and is supported in the center of apertured support 71C and 
71D. The sampling hose 73, in this embodiment, is supported and retained 
by the apertured support as described in previous figures. The patient end 
75 of the sampling hose 73 is centered in filter 69B and is surrounded by 
filter material on all sides to ensure filtration of all sampled gas. A 
temperature sensing probe 70 is enclosed by filter 69B. A wire 72 runs 
from the probe toward the machine adaptor where it exits the hose. The 
outer flexible breathing hose 77 is connected to the outer breathing hose 
connector 53A and the inner flexible breathing hose 79 is connected to the 
inner breathing hose connector 53B. 
Referring to FIG. 8, an alternate embodiment of a machine end adaptor 81 is 
illustrated which has an outer swivel 85A and an inner swivel 85B. Machine 
end adaptor 81 adapts the multi-line unilimb by connectors for the 
attachment of standard single lumen hoses. For example, machine end 
adaptor 81 has a inspiratory gas connector 83 and exhaled gas connector 87 
that are compatible with standard connectors and which allows connection 
of a standard 22 mm breathing hose 93 thereto. In this illustration, the 
inner flexible breathing hose 84 is connected to the inner breathing hose 
connector 82B by a lip 90B. In this embodiment, the inspiratory gases flow 
from the inspiratory gas connector 83 to the inner flexible breathing hose 
84. The outer flexible breathing hose 86 is connected to the outer 
breathing hose connector 82A by a lip 90A. Exhaled gases flow from the 
outer flexible breathing hose 86 to the exhaled gas connector 87. The 
sampling hose 88 which runs to a sampling hose port 89 is attached by a 
solvent seal to adaptor 81, and the wire 92 for the temperature probe to a 
terminal 91 for the temperature probe. 
FIG. 9 is a cross-sectional view of the machine end adaptor 81. This view 
illustrates the inspiratory gas connector 83, the exhaled gas connector 
87, the sampling hose 88 and the wire 92 for temperature probe 70 (in FIG. 
7). 
FIG. 10 illustrates an external heat and humidity adding chamber. Based 
upon the requirements of the patient, the inspiratory gases from the 
respirator may be run into the chamber 95 for addition of heat and 
humidity which consists of an input adaptor 97 and an output adaptor 99 
and a chamber to provide heat and humidity 100. As depicted, water for a 
humidifier and electric power for a heater are supplied to the chamber. 
Dry cool gases enter and warm moist gases leave the external heat and 
humidity adding chamber. This device may be controlled by a servo 
mechanism and a temperature probe in the sampling adaptor. 
The filters present in the sampling adaptors of FIGS. 1 and 7 serve to 
filter and separate gases from liquid condensate, and enable condensation 
from exhaled gases to evaporate and hydrate the relatively drier inspired 
air. The filters function to exchange humidity from the expired gas to the 
inspired gas due to their relatively large surface area. As a large 
surface area buffer between respirations, the filters also act to exchange 
heat between the expired gases and the inspired gases. Thus, the filters 
also act as humidity and heat exchange media, as well as, serve to filter 
the sampled gases to prevent clogging of the sampling hose. 
The inventive method of delivering a variable mixture of gases for patient 
inhalation requires the inventive devices, a respiratory machine, patient 
breathing means, which may be a mask or endotracheal tube, gas analyzer 
and may require several standard respiratory hoses depending upon the set 
up. The respiratory machine is attached to the machine end adaptor and the 
sampling port is attached to the gas analyzer. The sampling adaptor is 
attached to the patient breathing means, and the angular swivels on the 
sampling adaptor are adjusted for optimal conformation relative to the 
patient breathing means and the sampling adaptor. 
As shown in FIG. 11, the consolidated anesthesia circuit may be utilized as 
a closed or semi-closed absorption system or may be utilized as a 
non-rebreathing circuit. The non-rebreathing circuit may be set up by 
connecting the inspiratory gas hose to a fresh gas flow from the gas 
machine and attaching the expiratory gas hose to an out-flow system that 
includes the over flow control valve, breathing bag and scavenge system by 
means of a tee adaptor that fits a 22 mm bag nipple. 
Referring further to FIG. 11, a consolidated anesthesia circuit 200 is 
shown. A gas sample from the patient is filtered through the filter (not 
shown) prior to analysis to remove solid and liquid contaminants. The 
sampled gas passes through the sampling hose 201 through the sampling port 
203 through a second sampling hose 204 to the gas analyzer 205. The 
patient gases are analyzed and the composition of the inspiratory gases is 
adjusted to provide optimal composition for the patient as determined by 
the analyzer. A gas cylinder 207 contains gas for addition to the 
consolidated anesthesia circuit 200. A gas output line 209 runs from the 
gas cylinder 207 to a carbon dioxide absorber inlet port 213 of a 
conventional gas machine 215. In the present embodiment, the gas flow is 
adjusted by the anesthesiologist manually adjusting valves in the gas 
machine, based upon the gas readings from the analyzer. In other 
embodiments, the amount of fresh gas may be adjusted by valves at a 
separate location. 
In the present embodiment, by having the gas output line 209 run through 
the carbon dioxide absorber inlet port 213, fresh gas can be warmed and 
moistened by the soda lime in the carbon dioxide absorber of the gas 
machine 215. The carbon dioxide absorber is utilized in a closed or 
semi-closed rebreathing system, but is unnecessary in non-rebreathing 
systems. In the system as shown, expired gases leave the exhaled gas 
connector 218 of the machine end adaptor 217 via an expiratory hose 219. 
The expiratory hose 219 runs to a tee connector 221 to which a breathing 
bag 223 is attached. The tee is attached to an input arm 225 of the carbon 
dioxide absorber in the gas machine. The input arm also has an adjustable 
overflow valve 229 and a scavenge port 231. 
An inspiratory limb 233 on the carbon dioxide absorber in gas machine 215 
allows gases to pass from the machine into the heat and humidity adding 
chamber 235 (see FIG. 10). An electrically conductive wire 237 runs from a 
temperature probe such as 24 in FIG. 1 or 70 in FIG. 7 in the sampling 
adaptor, into a control unit at the heat and humidity adding chamber 235. 
The amount of heat and humidity may be varied according to the temperature 
of the gases at the probe. The inspiratory hose 239 runs from the heat and 
humidity adding chamber to the inspiratory gas connector 241 on the 
machine end adaptor 217. 
While the invention has been illustrated and described in detail in the 
drawings and foregoing description, the same is to be considered as 
illustrative and not restrictive in character, it being understood that 
only the preferred embodiment has been shown and described and that all 
changes and modifications that come within the spirit of the invention are 
desired to be protected.