WO1991001771A1

WO1991001771A1 - Improved airway adapter with purge means

Info

Publication number: WO1991001771A1
Application number: PCT/US1990/004353
Authority: WO
Inventors: Neil Sheehan; Jeffrey W. Etter
Original assignee: Nellcor Incorporated
Priority date: 1989-08-04
Filing date: 1990-08-01
Publication date: 1991-02-21
Also published as: EP0438583A1; FI911623A0

Abstract

An airway adapter for disposition between an endotracheal tube and an artificial breathing system which includes a central adapter body (100) with a gas pathway therethrough, a sampling port (120) that is disposed from the sidewall of the central body and is in fluid communication with the gas pathway (108), and a hub/filter assembly (200) that is fixed within the sampling port (120) with the filter (230) extending into the gas pathway of the central body section and with the hub/filter (200) assembly being configured for passing therethrough in a first direction a gas sample for analysis and in a second direction purging air to clean the filter.

Description

IMPROVED AIRWAY ADAPTER WITH PURGE MEANS

Technical Field

The present invention relates to the field of airway adapters that are disposed between endotracheal tubes and artificial breathing systems. More particularly, the present invention relates to airway adapters with purging means that are disposed between endotracheal tubes and artificial breathing systems that have means for removing filtered gas samples from the gas stream passing to and from the lungs through the adapter.

Background Of The Invention

During surgery or in an intensive care unit ("ICU") , many patients are intubated or as it is commonly called artificially ventilated. Such patients are usually mechanically intubated through an endotracheal tube. This usually entails disposition of an endotracheal tube through the patients mouth, down the trachea, and into the lungs. The endotracheal tube provides the only ventilation path to the lungs. An airway adapter is connected to the exposed end of the endotracheal tube. The connector for the breathing system is then connected to the adapter. The adapter has means for removing a gas sample for testing. An analysis of the inhaled and exhaled gas mixture provides information about the patient's ventilation.

Generally, airway adapters are of two types: straight or elbow type. Most, if not all, of them have SUBSTITUTESHEET a takeoff or sample port disposed at an angle to the main body that is used for the removal of gas samples for testing. This testing usually is for determining gas constituents and certain breathing events. This analysis can be done, for example, by gas analyzing devices such as those disclosed in U.S. Patent No. 4,817,013 and co-pending application Serial No. 101,931, filed September 25, 1987, both of which are assigned also to the Assignee of this application. More specifically, this testing may be used to determine the timing of inspired and expired breathing events, or the partial pressures of the anesthetic agent, O, or end tidal CO .

The straight adapter has a straight central cylindrical body through which the gas stream between the artificial breathing system and the endotracheal tube to the lungs flows. The sampling port may be disposed from the body perpendicular to the longitudinal axis of the central cylindrical body. The sampling port has a small central opening compared to the cylindrical body opening, through which the gas stream flows. The opening in the sampling port is in fluid communications with the opening through the central cylindrical body. The distal end of the sampling port connects to a sample tube which then connects to the gas analyzer.

The elbow adapter has a "L" shaped central body. It has first and second sections that are disposed perpendicular to each other. The opening in the central body extends through the first and second sections. The gas stream that flows between the artificial breathing system and the endotracheal tube passes through this opening.

The sampling port may be disposed perpen- dicular to the section of the central body that

SUBSTITUTESHEET connects to the artificial breathing system. The sampling port when so disposed is in axial alignment with the section of the central body that connects to the endotracheal tube. The sampling port has a central opening that is in fluid communication with the opening of the central body. The distal end of the sampling port, like its counterpart for the straight adapter, connects to a sample tube that then connects to a gas analyzer. Conventional adapters, both straight and elbow, have an inlet filter disposed across the the sampling port opening where it connects to the opening of the central body. This filter is used to prevent water, mucus, or other material in the gas stream from entering the sampling port and sample tube. However, these materials may occlude the filter. This problem of clogged or occluded filters is acute in ICϋ use since large amounts of water, mucus, and other material are produced by the lungs and pass through the adapter. Generally, airway adapters do not have means to purge occluded filters. Therefore, when the filter becomes occluded, replacement of the adapter is necessary if it is desirable to remove gas samples for testing. Even adapters that do have some means to purge the filter only purge filters of a certain finite area. Co-pending application Serial No. 101,931, filed September 25, 1987, referred to above, discloses an airway adapter with a purgeable inlet filter.

The present invention provides an improved airway adapter for disposition between an endotracheal tube and artificial breathing system.

Summary Of The Invention

The present invention is an improved airway adapter with purge means for use with an endotracheal

SUBSTITUTESHEET tube and artificial breathing system. The improved airway adapter can be configured as an elbow or straight adapter; however, preferably it is configured as an elbow. When the present invention is configured as an elbow, the central body has an "L" shape with one cylindrical section having an open end adapted to connect to an endotracheal tube and a perpendicularly disposed second cylindrical section with an end adapted to connect to the artificial breathing system. The cylindrical sections define a continuous "L" shaped opening through the central body. The gas stream flows through this? opening.

A sampling port is disposed perpendicular to the central body section that connects to the artificial breathing system. When so disposed, the port is aligned axially with the central body section that connects to the endotracheal tube. The opening of the sampling port has an area adapted to receive a hub/filte assembly. The hub/filter assembly includes a hub to which an elongated, hollow filter is attached. The hub body seats in the portion of the sampling port opening adapted to receive it and the elongated filter extends into the "L" shaped opening in the central body. The filter is in axial alignment with the central body section that connects to the endotracheal tube.

The filter is configured as a long tubular membrane to provide greater filter surface area but very little interior dead space. This type of filter is less susceptible to clogging and results in longer filter life. The increased surface area allows the use of filter material of smaller pore size. The filter preferably has a pore size that filters bacteria or viruses. The elongated, hollow filter also has either a protective cage or stiffing strip associated with it

SUBSTITUTESHEET for protection from being bent by water, mucus, or other material passing through the airway adapter.

The straight adapter of the present invention has a cylindrical central body that defines the opening through the adapter. The gas stream that flows between the endotracheal tube and the artificial breathing system passes through this opening. The sampling port is disposed perpendicular to the central body and is longer than the sampling port of the elbow adapter. The opening through the sampling port is stepped to accommodate disposition of a hub/ filter assembly. The filter that is connected to the hub extends into a portion of the opening between the hub and the central body opening but does not extend into the central body opening.

The hub has a disk-shaped body with a centrally aligned nipple extending from both sides. A continuous orifice extends through both nipples and the body. The nipple that extends from the surface of the body that faces a multi-path connector has a section cut out along its length. This nipple accommodates both the passage of gas samples from the gas stream enroute to the sample line and purge air from the purge line to the filter for cleaning occlusions. It is an object of the present invention to provide an improved airway adapter for disposition between an endotracheal tube and an artificial breathing system.

Another object of the present invention is to provide an improved airway adapter with a hub/filter assembly for use with both straight and elbow adapters. A further object of the present invention is to provide an improved airway adapter that has a hub/filter assembly that accommodates at least two fluid flows.

SUBSTITUTESHEET A yet further object of the present invention is to provide an improved airway adapter that has a filter capable of filtering bacteria and viruses.

A still further object of the present invention is to provide an improved airway adapter with an elongated filter which provides larger filter area and low interior dead space.

These and other objects will be disclosed in the remainder of the specification.

Brief Description Of The Drawings

Figure 1A is a cross-sectional view of the adapter body with an optional support fin and hub/filter assembly of the preferred embodiment of the airway adapter of the present invention, and the ulti- path connector for a double lumen tube in a spaced relationship.

Figure IB is a cross-sectional view along IB-IB of the preferred embodiment of the airway adapter with an optional support fin shown in Figure 1A. Figure 2 is a cross-sectional view of the preferred embodiment of the airway adapter of the present invention assembled and the multi-path connector for a double lumen tube in a spaced relationship. Figure 3 is a top perspective view of the preferred embodiment of the hub of the hub/filter assembly of the present invention.

Figure 4 is a cross-sectional view along 4-4 of the preferred embodiment of the hub shown in Figure 3.

Figure 5 is an exploded, cross-sectional view of the preferred embodiment of the hub/filter assembly of the preferred embodiment of the present invention.

SUBSTITUTESHEET Figure 6A is a cross-sectional view of a second embodiment of the hub of the hub/filter assembly of the preferred embodiment of the present invention.

Figures 6B, 6C, and 6D are cross-sectional views of the three methods of attaching the filter to the second embodiment of the hub of the hub/filter assembly of the preferred embodiment of the present invention.

Figure 7A is a cross-sectional view of a third embodiment of the hub of the hub/filter assembly of the preferred embodiment of the present invention.

Figure 7B is a cross-sectional view of a hub/filter assembly that includes the third embodiment of the hub of the hub/filter assembly of the preferred embodiment of the present invention.

Figure 8 is a cross-sectional view of the adapter body and hub/filter assembly of the second embodiment of the airway adapter of the present invention, and the multi-path connector for a double lumen tube in a spaced relationship.

Figure 9 is a cross-sectional view of the second embodiment of the airway adapter of the present invention assembled and the multi-path connector for a double lumen tube in a spaced relationship. Figure 10 is an exploded, cross-sectional view of the preferred embodiment of the hub/filter assembly of the second embodiment of the present invention.

Figure 11A is a cross-sectional view of a second embodiment of the hub of the hub/filter assembly of the second embodiment of the present invention.

Figures 11B, 11C, and 11D are cross-sectional views of the three methods of attaching the filter to the second embodiment of the hub of the hub/filter

SUBSTITUTESHEET assembly of the second embodiment of the present invention.

Figure 12A is a cross-sectional view of a thir4 embodiment of the hub of the hub/filter assembly of the second embodiment of the present invention. Figure 12B is a cross-sectional view of a hub/filter assembly that includes the third embodiment of the of hub the hub/filter assembly of the second embodiment of the present invention. Figure 13 is a cross-sectional view of the adapter body and hub/filter assembly of the third embodiment of the airway adapter of the present invention, and the multi-path connector for a double lumen tube in a spaced relationship. Figure 14 is a cross-sectional view of the third embodiment of the airway adapter of the present invention assembled and the multi-path connector for a double lumen tube in a spaced relationship.

Detailed Description Of The Drawings The-present invention is a airway adapter with purge means that is used with, and disposed between, an endotracheal tube and artificial breathing system. . The preferred embodiment of the present invention is shown in Figures 1-7B. Figures 1A, IB, and 2 show cross-sectional views of the airway adapter and the multi-path connector of a double lumen tube. The double lumen tube includes a sample line and a purge line. Figures 3 and 4 are views of the preferred hub of the hub/filter assembly. Figure 5 is an exploded view of the preferred embodiment of the hub/filter assembly. And Figures 6A, 6B, 6C, 6D, 7A, and 7B relate to further embodiments of the hub/filter assembly.

SUBSTITUTESHEέT Referring to Figures 1-5, the preferred embodiment of the airway adapter will be described. The airway adapter includes the adapter body 100 and hub/filter assembly 200. Adapter body 100 includes "L" shaped central section 102 having first segment 104 and second segment 106 disposed perpendicular to it. Segment 104 has end 110 configured to mate with the end of the endotracheal tube; and segment 106 has end 112 configured to mate with the end of the artificial breathing system.

Gas pathway 108 extends through "L" shaped central section 102 from end 110 of segment 104 to end 112 of segment 106. The gas pathway includes section 114 in segment 104 and section 116 in segment 106 of central section 102.

Sampling port 120 is disposed perpendicular to the exterior surface of the segment 106. The sampling port has stepped opening 122. Opening 122 is in fluid communications with gas pathway 108 through the central section.

Filter protector structure 134, which extends into section 114 of segment 104 of gas pathway 108 perpendicular to the interior surface of segment 106, is aligned with the openings in sampling port 120 and gas pathway 108. The filter protector structure has a plurality of longitudinally extending slits 138. These slits are for gas within the gas pathway to pass through to reach the filter. Segment 104 of the central body section, filter protector structure 134, and sampling port 120 are axially aligned.

When the adapter is assembled, the filter extends into the filter protector structure. The filter protector structure helps prevent filter damage and gross clogging from water, mucus, or other such materials. It can also prevent filter damage from

SUBSTITUTESHEET fingers, suction catheters, or other such devices being inserted in the end of the central body section. The filter protestor may also have optional support fin 140 whieJh adds additional strength to it and facilitates fabrication.

.-Stepped opening 122 of sampling port 120 includes first step 126 disposed at the distal end. The first step has a first diameter. Annular bead 127 is disposed from the first step at the end of opening 122. Annular depression 129 is disposed in the first step adjacent annular bead 127.

Adjacent the first step is second step 124 which has second diameter that is smaller than the first diameter.- Angled annular ledge 128 is formed between the first and second steps. The first and second steps are used for securing the end of multi- path connector 300 in the sampling port in a locking and fluid-tight relationship.

Third step 136 has a third diameter that is less than^"the second diameter. Annular ledge 130 is formed between the second and third steps. The end of the filter protector structure is disposed adjacent to, and has a diameter less than, the third step. Annular ledge 132 is formed between the third step and the end of the filter protector structure.

Hub/filter assembly 200 includes hub 202 and filter 23 . Referring to Figures 1A, 3, 4A, and 4B, hub 202 will be described. Hub 202 is- stepped. Disk- shaped first step 204 has a diameter slightly less than the diameter of second step 124 of sampling port 120. Disk-shaped second step 211 is disposed from the bottom surface of first step 204. The second step has a diameter less than that of the first step of the hub and slightly less than the third step of sampling port

SUBSTITUTESHEET 120. Annular ledge 210 is formed between the disk- shaped first and second steps of the hub body.

Centrally aligned nipple 214 extends from the side of the hub that faces the multi-path connector when the airway adapter is assembled and centrally aligned nipple 218 that extends from the opposite side of the hub. Orifice 216 extends through the center of the centrally aligned nipples and the hub body. Nipple 214 has a 45° section cut from it. This cut out allows purge air to pass through the hub when a purge operation is being performed to clear an occluded filter.

Nipple 218 has barb 220 disposed at the outside diameter. Barb 220 is in the form of an annular ledge. The single annular ledge can be replaced by a plurality of barbs, which are similar to fish hook barbs, and still be within the scope of the invention.

Concentric with nipple 214 is first annular channel 206. This channel extends into the hub surface that faces the multi-path connector. Between annular channel 206 and nipple 214 is concentric, annular channel 208. Annular channel 208 extends deeper than first annular channel 206 into the hub surface. Filter 230 is an elongated tubular structure with a closed end 232 and open end 234. In assembling the hub/filter assembly, open end 234 is moved onto nipple 218 and over barb 220. Once this is done, the barb prevents the filter from sliding off of the nipple even when purge air of a approximately 8 psi is supplied to clean the filter.

Preferably, the filter is formed from polypropylene hollow fiber that has an inside diameter of 1.8 mm, an outside diameter of 2.25 mm, and a pore size of 0.2 μm. This material is flexible and is

SUBSTITUTESHEET available from ENKA A.G., West Germany. The polypropylene of this pore size is naturally hydrophobic and filters bacteria or viruses. Accordingly, only sterilized gas or air passes through the filter.

It is understood that filter material of the larger pore size can be used. Such filter material, however, .will not have the beneficial sterilization effect that the filter material with a 0.2 μm pore size has. Even if filter material of a larger pore size is used, the system of the present invention has safeguards against contamination from the sample tube and gas analyzer being blown back into the patient during a purge operation as will be discussed. , The elongated tubular filter provides substantially more filter area than conventional disk- shaped inlet filters. This increased area helps prevent occlusions and, therefore, the number of necessary purge operations. When the airway adapter of the present invention is assembled as shown in Figure 2, hub/filter assembly 200 is sealingly disposed within stepped opening 122 of sampling port 120. In doing so, edges 204 and 211 of hub 202 are sealingly fixed to steps 124 and step 136, respectively, of stepped opening 122, and nipple 218 with connected filter 230 extends into filter protector structure 134.

Once the filter is in place, the filter protector structure protects the flexible filter from water, mucus, or other material that may enter the gas pathway. If the structure were not in place, the water, mucus, or other material could bend the flexible filter and prevent its proper operation.

Multi-path connecter 300 will be described referring to Figures 1 and 2. The double lumen tube containing sample line 306 and purge line 304 connect airway adapter 100 to the gas analyzer (not shown) . The series of dots at 302 represent the outer cover which encases sample line 306 and purge line 304. The walls of the sample line, preferably constructed at least in part of Nafion, absorb and then evaporate condensed water vapor in the line. Nafion is commercially available from E. I. du Pont de Nemours and Company, Wilmington, Delaware. Nafion is a trademark of E. I. du Pont de Nemours and Company, Wilmington, Delaware.

Connector body 310 has gripping members 338 which along with locking cap 308 secure outer cover 302 of the double lumen tube to connector body 310. Connector body 310 has annular bead 312 which assists in locking the connector body in the sampling port. O-ring 316 is disposed in annular groove 314. O-ring 316 is used to provide a fluid-tight seal between connector body 310 and the sampling port. Connector body 310 has central bore 322.

Plug 336 is disposed in one end of the connector body. Purge line 304 and sample line 306 extend through plug 336 in separate holes therethrough.

Insert 330 is disposed in the other end of central bore 322. Insert 330 has centrally disposed orifice 332 which connects to larger diameter end opening 324. The end of sample line 306 is disposed in orifice 332 so that it is in fluid communication with end opening 324. Purge line 304 passes through plug 336 and terminates in central bore 322. Purge line 304 is in fluid communications with central bore 322. Channels 318 and 320 provide a fluid communication path between central bore 322 and at least annular channels 206 and

SUBSTITUTESHEET 208 of hub 202 when the connector is detachable fixed within the sampling port.

When connector body 310 is inserted into sampling port 120, annular bead 127 at the end of first step 126 moves over annular bead 312 of connector body 310. Annular.bead 312 then rests in annular depression 129. When this happens, O-ring 316 moves into sealing contact with the wall of second step 124 of opening 122. These actions lock the connector body within the sampling port and seal the connection against fluid leaks. Also, when the connector body is inserted into the sampling port, end opening 324 of the connector body fits over nipple 214 of hub 202 but does not completely cover the 45° cut out in the nipple. Accordingly, both sample line 306 and purge tube 304 are in fluid communication with the respiratory gas stream through orifice 216 and filter 230.

During normal sampling operations, a sample pump of the gas analyzer (not shown) draws a gas sample through filter .230, orifice 216, and sample line 306. The suction level is approximately 8 psi. Since a valve at the other end of the purge line is closed, the gas sample does not enter the purge line nor does an appreciable amount of air from the purge line enter the sample line.

When the filter becomes occluded and purging is required to clear it, a valve at the end of the sample line is closed and purge air is supplied through orifice 216 of hub 202 and filter 230. The purge air does not enter the sample line because the sample line is closed at the other end.

Purge air is filtered room air which has passed through the purge line not the sample line. Therefore, if there is any contamination in the sample

SUBSTITUTESHEET line or the gas analyzer, it will not be backflushed to the patient via the purge air.

Figures 6A-6D, and 7A-7B are the second and third embodiments, respectively, of the hub/filter assemblies of the preferred embodiment of the present invention. The filter and at least some portions of the second and third embodiments of the hub/filter assemblies are the same as disclosed for the preferred embodiment shown is Figures 1-5. Therefore, in describing the second and third embodiments, the like portions will pointed out first, then the differences will be described.

Figure 6A shows the hub of the second embodiment of the preferred embodiment of the hub/filter assembly generally at 400. This hub is the same as hub 202 of the preferred embodiment except that nipple 402 that extends from the bottom of the hub does not have barb 220 at the outside surface.

Figures 6B, 6C, and 6D show three methods for connecting filter 230 to nipple 402. In Figure 6B at 404, open end 234 of filter 230 is heat sealed to nipple 402. In Figure 6B at 406, open end 234 of filter 230 is secured to nipple 402 by a piece of tube chemically expanded and evaporation shrunk over open end 234 once it is disposed over the nipple. In

Figure 6D at 408, open end 234 of the filter is secured to nipple 402 by a an O-ring disposed over the filter once it is disposed over the nipple.

Figures 7A and 7B show the third embodiment of the preferred embodiment of the hub/filter assembly. Referring to Figure 7A, hub 450 has a top portion that is the same as the preferred embodiment of the hub shown in Figures 1-5, but the bottom is different.

Hub 450 has disk-shaped central section 452. Nipple 456 with straight sides extends from the bottom of the central section. Concentric with nipple 456 is annular member 454. Annular groove 458 is formed between nipple 456 and annular member 454. In assembling the third embodiment of the hub/filter assembly, open end 234 of filter 230 is slid over nipple 456 and secured in that position by potting material that is placed in annular groove 458.

It is to be understood that the sampling port may be configured to support the connection of a connector that has a gas sample line but does not have a purge air line and still be within scope of the present invention. The hub of the sampling port is configured with a nipple that is like nipple 214 except that the 45° section is not cut from it to accommodate the passage of purge air through the hub. A sampling port configured in this manner still makes use of the advantages associated with using the elongated, tubular filter to filter the respiratory gas sample from the gas pathway. Further, when only the sampling line is to be connected to the sampling port, the connector may be a standard luer fitting or other conventional type of connector. These further aspects of the present invention apply.-equally to the other embodiments disclosed herein. The second embodiment of the airway adapter of the present invention is shown in Figures 8-12B. Figures 8 and 9 show cross-sectional views of the airway and the multi-path connector. Figure 10 is an exploded view of the hub and filter. And Figures 11A, 11B,.11C, 11D, 12A, and 12B relate to further embodiments of the hub/filter assembly.

Referring to Figures 8-10, the second embodiment on the airway adapter of the present invention will be described. The airway adapter of the second ^"embodiment is similar to the preferred

SUBSTITUTESHEET embodiment except that the filter protector structure is not part of the central body section and the hub includes a stiffening strip that is disposed in the filter. The stiffening strip prevents the filter from being damaged by water, mucus, or other material that pass through the gas pathway.

The airway adapter of the second embodiment includes the adapter body 500 and hub/filter assembly 700. Adapter body 500 has "L" shaped central body section 502 that includes first segment 504 and second segment 506 disposed perpendicular to it. Segment 504 has end 510 configured to mate with the end of the endotracheal tube; and segment 506 has end 512 configured to mate with the end of the artificial breathing system.

Gas pathway 508 extends through "L" shaped central body section 502. The gas pathway includes section 514 in segment 504 of central body section 502 and section 516 in segment 506 of the central body section.

Sampling port 520 is disposed perpendicular from the exterior surface of the segment 506. The sampling port has stepped opening 522 which is in fluid communications with gas pathway 508 of the central body section. Segment 504 of the central body section and sampling port 520 have the same longitudinal axis.

Stepped opening 522 includes first step 526 with a first diameter that is disposed at the distal end of the sampling port. Annular bead 527 is disposed from the first step at the end of opening 522. Annular depression 529 is disposed in the first step adjacent annular bead 527.

Adjacent first step 526 is second step 524 which has a second diameter that is smaller diameter than the first diameter. Angled annular ledge 528 is

SUBSTITUTESHEET formed between the first and second steps. The first and second steps are used in locking the multi- path connector in the sampling port in a fluid-tight relationship. _ Third step 536 has a third diameter less than that of the second diameter. Annular ledge 530 is formed between the second and third steps. Fourth step 534 has fourth diameter less than that of the third diameter. The fourth step forms the opening between the gas pathway and the stepped opening of the sampling port. Annular ledge 532 is formed between the third and fourth steps.

Hub/filter assembly 700 includes hub 702 and filter 730. Referring to Figures 8 and 10, hub 702 will be described. Hub 702 is substantially the same as hub 2p2 of the preferred embodiment except for the inclusion of stiffening strap 720. The hub will now be described.

Hub 702 is stepped. Disk-shaped first step 704 has a diameter slightly less than the diameter of second step 524 of sampling port 520. Disk-shaped second step 711 is disposed from the bottom surface of first step 704. The second step has a diameter less than that of the first step of the hub and slightly less than the third step of sampling port 520. Annular ledfie 710 is formed the first and second steps.

Centrally aligned nipple 714 extends from the side of the hub that faces the multi-path connector and centrally aligned nipple 718 that extends from the opposite side of the hub. Orifice 716 extends through the center of the centrally aligned nipples and the hub body.

Stiffening strap 720 is disposed from the distal end of nipple 718. The stiffening strap, however, does not in any way obstruct orifice 716.

TITUTE SHEET Nipple 714 has a 45° section cut from it. The cut out provides a path for purge air from the purge line to travel through the hub to the filter to be cleared. Nipple 718 has barb 722 disposed at the outside diameter. The barb is an annular ledge. As previously discussed, it is also contemplated that the single barb can be replaced with a plurality of barbs and still be within the scope of the invention.

Concentric with nipple 714 is first annular channel 706. The first annular channel extends into the hub surface that faces the multi-path connector. Between first annular channel 706 and nipple 714 is concentric, annular channel 708. Annular channel 708 extends deeper than annular channel 706 into the hub surface.

In Figure 10, among other things, a cross- section of filter 730 is shown. The filter material is the same as described for the preferred embodiment and those descriptions are incorporated here by reference. The cross-section of elongated filter 730 has open ends 734 and 736. In assembling the hub/filter assembly, open end 734 is moved over stiffening strip 720, onto nipple 718, and over barb 722. After this, end 736 of the filter material and the end of the stiffening strip are heat sealed together to form closed end 732 of the hub/filter assembly. Thus, in the finished assembly, the barb and heat sealed end 732 prevent end 734 of the filter material from sliding off nipple 718 and stiffening strip 720, even when purge air at approximately 8 psi is supplied to the filter to clean it. Furthermore, the stiffening strip prevents the filter from being bent or damaged should water, mucus, or other material enter the gas pathway and contact the filter.

SUBSTITUTE SHEET When the second embodiment of the airway adapter of the present invention is assembled as shown in Figure 9, hub/filter assembly 700 is sealably disposed within stepped opening 522 of sampling port 520. In doing so, edges 704 and 711 of hub 702 are sealably fisced to steps 524 and 536, respectively, of stepped opening 522, and nipple 718 and stiffening strip 720, with connected filter 730, extend into section 514 of gas pathway 508. Multi-path connecter 300 shown in Figures 8 and 9 is the same as the one described for the preferre embodiment and, therefore, has the same reference number. Accordingly, the descriptions for the multi-path connector of the preferred embodiment are incorporated here by reference.

When multi-path connector 300 is inserted into sampling port 520, annular bead 527 at the end of first step 526 moves over annular bead 312 of connector body 310. Annular bead 312 then rests in annular depression 529. When this happens, O-ring 316 moves into sealing contact with the wall of second step 524 of opening 522. These actions lock the multi-path connector within this sampling port and seal the connection against fluid leaks. Also, when the connector body is inserted into the sampling port, end opening 324 of the connector body fits over nipple 714 of hub 702 but does not completely cover the 45° cut out in the nipple. Accordingly, both sample line 306 and purge line 304 are in fluid communication with the respiratory gas stream through orifice 716 and filter 730. formal sampling operations for the second embodiment are like those for the preferred embodiment. Accordingly, a sample pump of the gas analyzer (not shown) draws a gas sample through filter 730, orifice

SUBSTITUTESHEET 716, and sample line 306. The gas is drawn at about 8 psi. Since valve at the other end of the purge line is closed, the gas sample does not enter the purge line nor does any appreciable amount of air from the purge line enter the sample line.

When the filter becomes occluded with water, mucus, or other material, the filter must be purged. With a valve at the other end of the sample line closed, the purge air is supplied through orifice 716 of hub 702 and filter 730. The purge air does not enter the sample line because the sample line is closed at the other end.

As discussed, the purge air is filtered room air with no association to the sample line. Therefore, if there is any contamination in the sample line or the gas analyzer, it will not be backflushed to the patient.

Figures 11A-11D, and 12A-12B are the second and third embodiments, respectively, of the hub/filter assemblies of the second embodiment of the present invention. The filter and at least some portions of the second and third embodiments of the hub/filter assemblies are the same as disclosed in Figures 8, 9, and 10. Hence, in describing the second and third embodiments, the like portions will pointed out first, then the differences will be described.

Figure 11A shows hub 750 of the second embodiment of the hub/filter assembly. This hub with stiffening strap 754 is the same as hub 702 except that nipple 752 which extends from the bottom of the hub does not have a barb at the outside surface.

Figures 11B, 11C, and 11D show three methods for connecting end 734 of filter 730 to nipple 752, with stiffening strip 754. It is understood that in each method bottom end 736 of the filter is heat sealed to the end of stiffening strip 754 as described. In Figure 11B at 760, open end 734 of the filter is heat sealed to nipple 752. In Figure 11B at 762, open end 734 of the filter is secured to nipple 752 by a piece of tube chemically expanded and evaporation shrunk over the open end that is disposed over the nipple. In Figure 11D at 764, open end 734 of the filter is secured to nipple 752 by an O-ring disposed over the filter that is disposed over the nipple. Figures 12A and 12B show the third embodiment of the hub/filter assembly. Referring to Figure 12A, hub 780 has a top portion that is the same as the hub shown in Figures 8, 9, and 10, but the bottom is different. Hub 780 has disk-shaped central section 782. Nipple 786 with straight sides and extends from the bottom of the central section. Stiffening strip 790 extends from the distal end of nipple 786. Concentric with nipple 786 is annular member 784. Annular groove 788 is formed between nipple 786 and annular member 784. In assembling the third embodiment of the hub/filter assembly, open end 734 of filter 730 is moved over stiffening strip 790 and forced over nipple 786 and secured in that position by potting material that is placed in annular groove 788.

Figures 13 and 14 show the third embodiment of the airway adapter of the present invention, and the multi-path connector. Figure 13 shows an exploded view, and Figure 14 shows an assembled view of the airway adapter.

Referring to Figures 13 and 14, the third embodiment will be described. The third embodiment is a straight airway adapter. Adapter body 900 includes straight central body section 902 and sampling port assembly 912. Central body section 902 has gas pathway

^SUBSTITU TE SHEET 908 through it, and has end 904 configured to mate with the exposed end of the endotracheal tube and end 906 configured to mate with the connector of the artificial breathing system. Sampling port assembly 912 comprises elongated cylindrical section 914 and sampling port 918, and is disposed perpendicular to central section 902. Sampling port 918 is disposed at the distal end of the assembly. The sampling port has stepped opening 920 which is in fluid communications with elongated cylindrical section 914 which in turn is in fluid communications with gas pathway 908 of the central section.

Stepped opening 920 includes first step 924 at the distal end which has a first diameter. Annular bead 929 is disposed from the first step at the end of opening 920. Annular depression 931 is disposed in the first step adjacent annular bead 929.

Adjacent the first step is second step 922 which has a diameter less than the first diameter. Angled annular ledge 926 is formed between the first and second steps. The first and second steps are used for securing the end of the multi-path connector in the sampling port in a locked and fluid-tight relationship. The third step 927 has a diameter less than that of the second diameter. Annular ledge 928 is formed between the second and third steps. Fourth step 932 has a diameter less than that of the third diameter. The fourth step forms the opening between the cylindrical section and the stepped opening of the sampling port. Annular ledge 930 is formed between the third and fourth steps.

Elongated cylindrical section 914 has opening 916 which extends from fourth step 932 of the sampling port to gas pathway 908 of central body section 902.

SUBSTITUTESHEET The length of the cylindrical section is such that when the hub/filter assembly is disposed in the sampling port, the end of the filter will not extend into the gas pathway through the central body section. The hub/filter assembly and the multi-path connector that are preferably used in the third embodiment of the airway adapter of the present invention are the same as the ones described for the preferred embodiment. Therefore, hub/filter assembly 200 and multi-path connector 300 are individual for this embodiment. The descriptions of the hub/filter assembly and multi-path connector for the preferred embodiment apply here and are incorporated by reference-. As indicated above, preferably, hub/filter assembly 200 is used in the third embodiment. It is also contemplated that the further embodiments of the hub/filter assembly shown in Figures 6B, 6C, 6D, and 7B can be used^" in the third embodiment. These embodiments are contemplated for use with this embodiment since the flexible fϋter is disposed in the elongated cylindrical section 914 which protects the filter from bending and damage. However, if for some reason it is desired to use the hub/filter assembly shown in Figures 8_r 11B, 11C, 11D, and 12B can be done without detrimental effect.

. It is contemplated also that some type of struction may be disposed across the end opening of the elongated cylindical section to prevent water, mucus, or other material from entering the elongated section. For example a single strap could be disposed across the opening.

When the third embodiment of the airway adapter of the present invention is assembled as shown in Figure 14, hub/filter assembly 200 is sealingly

SUBSTITUTESHEET disposed within stepped opening 920 of sampling port 918. In doing so, edges 204 and 211 of hub 202 are sealingly fixed to steps 922 and 927, respectively, of stepped opening 920, and nipple 218 with connected filter 230 extends into opening 916 in cylindrical section 914. Opening 916 has a diameter larger than the outside diameter of the filter; however, it is only larger by an amount that will allow proper sampling and purging operations, yet have low dead space volume. When multi-path connector 300 is inserted into sampling port 920, annular bead 929 at the end of first step 924 moves over annular bead 312 of connector 310. Annular bead 312 then rests in annular depression 931. When this happens, O-ring 316 moves into sealing contact with the wall of second step 922 of opening 920. These actions lock the multiple connection within the sampling port and seal the connection against fluid leaks. Also, when the connector body is inserted in the sampling port, end opening 324 of the connector body fits over nipple 214 of hub 202 but does not completely cover the 45° cut out. Hence, both sample line 306 and purge line 304 are in fluid communication with the respiratory gas stream through orifice 216 and filter 230. In normal sampling operations, a sample pump of the gas analyzer (not shown) draws a gas sample through filter 230, orifice 216, and sample line 306. The sample gas is withdrawn at approximately 8 psi. Since a valve at the other end of the purge tube is closed, the gas sample does not enter the purge line nor does an appreciable air from the purge line enter the sample line.

When the filter becomes occluded with water, mucus, or other material, a valve at the other end of the sample line is closed and purge air at

SUBSTITUTESHEET approximately 8 psi is supplied through orifice 216 of hub 202 and filter 230. The purge air does not enter the sample line because the sample line is closed at the other end. The purge air is filtered room air as described for the other embodiments and does not backflush any contaminants in the sample line or the gas analyzer back into the patient.

The terms and expressions which are used herein are used as terms of expression and not of limitation. And there is no intention in the use of such terms and expressions of excluding the equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible in the scope of the invention.

SUBSTITUTESHEET

Claims

1. An airway adapter for use with a system for measuring respiratory gases in a patient respiratory path, comprising: an adapter body with gas pathway therethrough; a port disposed from a sidewall of the adapter body that is in fluid communications with the gas pathway, with the port being adapted to mate with a connector means of apparatus that can cause fluid flow through the connector; fluid passage means for disposition across the port, with the fluid passage means having means that mates with the connector means for effecting passage of fluid through the fluid passage means; elongated, cylindrical filter means associated with the fluid passage means, with fluid communications between the gas pathway and the port being through the filter means and fluid passage means; and protection means associated with the filter means to protect it from material passing through or entering the gas pathway.

2. The adapter as recited in claim 1, wherein the adapter body is "L" shaped having a first and a second section.

3. The adapter as recited in claim 2, wherein the port is disposed perpendicular to the second section.

4. The adapter as recited in claim 3, wherein the port and first section of the adapter are axially aligned.

SUBSTITUTESHEET

5. The adapter as recited in claim 1, wherein the port has a stepped opening therethrough with means for receiving the fluid passage means.

6. The adapter as recited in claim 1, wherein the port has means for securing the connector means therein.

7. The adapter as recited in claim 1, wherein the fluid passage means further comprises a disk-shaped, stepped body with a centrally aligned first nipple that extends outwardly from a first surface and a second nipple that extends outwardly from an opposite second surface of the disk-shaped, stepped body, with a centrally aligned bore that extends through the nipples and the disk-shaped, stepped body, with the first nipple having means for effecting fluid passage through the fluid passage means from at least a first means associated with the connector means.

8. The adapter as recited in claim 7, wherein the first nipple has means for effecting fluid passage through the fluid passage means from a first and a second means associated with the connector means.

9. The adapter as recited in claim 7 or 8, wherein attachment means fix the elongated, cylindrical filter means to the second nipple.

10. The adapter as recited in claim 9, wherein the attachment means is a barb disposed at the outside diameter of the second nipple.

SUBSTITUTESHEET

11. The adapter as recited in claim 9, wherein the attachment means is the elongated, cylindrical filter means being heat sealed onto the outside diameter of the second nipple.

12. The adapter as recited in claim 9, wherein the attachment means is a sleeve of material being chemically expanded and evaporation shrunk on the elongated, cylindrical filter means disposed on the outside diameter of the second nipple.

13. The adapter as recited in claim 9, wherein the attachment means is an O-ring disposed over the elongated, cylindrical filter means disposed on the second nipple.

14. The adaptor as recited in claim 9, wherein the attachment mean includes potting material to secure the elongated, cylindrical filter means to the outside diameter of the second nipple.

15. The adapter as recited in claim 8, wherein the first nipple has a longitudinally extending segment removed therefrom such that fluid from a first and a second means are in fluid communications with a gas pathway.

16. The adapter as recited in claim 7, 8 or 15, wherein the first means of the connector means is a sample gas line and the fluid associated with the first means is respiratory gas from the sample gas line.

17. The adapter as recited in claim 8 or 15, wherein the second means of the connector means is a purge air line and the fluid associated with the second

SUBSTITUTESHEET means is purge air for purging occlusions in the elongated, cylindrical filter means.

18. The adapter as recited in claim 1 wherein the elongated, cylindrical filter means is a tubular member with a proximal end with means conected to the fluid passage means and a distal end that is sealed.

19. The adapter as recited in claim 1 or 18, wherein the elongated, cylindrical filter means is constructed from polypropylene.

20. The adapter as recited in claim 1 or 18, wherein the elongated, cylindrical filter means is flexible.

21. The adapter as recited in claim 1 or 18, wherein the elongated, cylindrical filter means has a 0.2 μm pore size.

22. The adapter as recited in claim 1 or 18 wherein the elongated, cylindrical filter means is hydrophobic.

~~

23. The adapter as recited in claim 3, wherein the protection means further comprises an elongated, hollow structure with a plurality of openings, with the structure being fixed to the inside diameter of the second section of the adapter body and extending into the first section of the adapter body with the structure, first section, and port being axially aligned.

SUBSTITUTESHEET

24. The adapter as recited in claim 1, wherein the protection means is a stiffening member that is connected to the fluid passage means and disposed within the elongated, cylindrical filter means.

25. The adapter as recited in claim 1, wherein the elongated, cylindrical filter means is attached to the fluid passage means with a barb associated with the fluid passage means.

26. The adapter as recited in claim 1, wherein the elongated, cylindrical filter means is attached to the fluid passage means by the elongated, cylindrical filter means being heat sealed onto fluid passage means.

27. The adapter as recited in claim 1, wherein the elongated, cylindrical filter means is attached to the fluid passage means by a sleeve of material being chemically expanded and evaporation shrunk over a portion of the filter means and a portion of the fluid passage means.

28. The adapter as recited in claim 1, wherein the elongated, cylindrical filter means is attached to the fluid passage means by an O-ring disposed over a portion of the filter means and a portion of the fluid passage means.

29. The adapter as recited in claim 1, wherein the elongated, cylindrical filter means is attached to the fluid passage means with potting material.

SUBSTITUTESHEET

30. An airway adapter for use with a system for measuring respiratory gas in a patient respiratory path, comprising: an adapter body with gas pathway therethrough; a port assembly disposed from a sidewall of the adapter body that is in fluid communications with the gas pathway, with the port assembly having first and second segments, with the first segment being adapted to mate with a connector means of an apparatus that can cause fluid flow through the connector; fluid passage means for disposition across in the first segment of the port assembly, with the fluid passage means having means that mates with the connector means for effecting passage of fluid through the fluid passage means; and elongated, cylindrical filter means associated with fluid passage means and disposed in the second segment, with fluid communications between the gas pathway and the first segment of the port assembly port being through the second segment, filter means, and fluid passage means.

31. The adapter as recited in claim 30, wherein the adapter body is straight.

32. The adapter as recited in claim 29, wherein the port assembly is disposed perpendicular to the adapter body.

33. The adapter as recited in claim 32, wherein the second segment of the port assembly is an elongated, cylindrical segment.

SUBSTITUTESHEET

34. The adapter as recited in claim 30, wherein the inside diameter of the second segment of the port assembly is a predetermined amount larger than the outside diameter of the filter means to provide low dead space volume.

35. The adapter as recited in claim 30, wherein the first segment of the port assembly has a stepped opening therethrough with means for receiving the fluid passage means.

36. The adapter as recited in claim 30, wherein the first segment of the port assembly has means for securing the connector means therein.

37. The adapter as recited in claim 30, wherein the fluid passage means further comprises a disk-shaped, stepped fluid passage body with a centrally aligned first nipple that extends outwardly from a first surface and a second nipple that extends outwardly from an opposite second surface of the disk- shaped, stepped body, with a centrally aligned bore that extends through the nipples and the disk-shaped, stepped body, with the first nipple having means for effecting fluid passage through the fluid passage means from at least a first means associated with the connector means.

38. The adapter as recited in claim 37, wherein the first nipple has means for effecting fluid passage through the fluid passage means from a first and a second means associated with the connector means.

SUBSTITUTESHEET

39. The adapter as recited in claim 37 or 38, wherein attachment means fix the elongated, cylinrical filter means to the second nipple.

40. The adapter as recited in claim 39, wherein the attachment means is a barb disposed at the outside diameter of the second nipple.

41. The adapter as recited in claim 39, wherein the attachment means is the elongated, cylindrical filter means being heat sealed onto the outside diameter of the second nipple.

42. The adapter as recited in claim 39, wherein the attachment means is a sleeve of material being chemically expanded and evaporation shrunk on the elongated, cylindrical filter means disposed on the outside diameter of the second nipple.

43. The adapter as recited in claim 39, wherein the attachment means is an O-ring disposed over the elongated, cylindrical filter means disposed on the second nipple.

44. The adapter as recited in claim 30, wherein the attachment means includes potting material to secure the elongated, cylindrical filter means to the outside diameter of the second nipple.

45. The adapter as recited in claim 38, wherein the first nipple has a longitudinally extending segment removed therefrom such that fluid from a first and second means are in fluid communications with the gas pathway.

SUBSTITUTESHEET

46. The adapter as recited in claim 37, 38, or 45, wherein the first means of the connector means is a sample gas line and the fluid associated with the first means is respiratory gas from the sample gas line.

47. The adapter as recited in claim 38 or 45, wherein the second means of the connector means is a purge air line and the fluid associated with the second means is purge air for purging occlusions in the elongated, cylindrical filter means.

48. The adapter as recited in claim 30, wherein the elongated, cylindrical filter means is a tubular member with a proximal end with means conected to the fluid passage means and a distal end that is sealed.

49. The adapter as recited in claim 30 or 48, wherein the elongated, cylindrical filter means is constructed from polypropylene.

50. The adapter as recited in claim 30 or 48, wherein the elongated, cylindrical filter means is flexible.

51. The adapter as recited in claim 30 or 48, wherein the elongated, cylindrical filter means has a 0.2 μm pore size.

52. The adapter as recited in claim 30 or 48, wherein the elongated, cylindrical filter means is hydrophobic.

SUBSTITUTESHEET

53. The adapter as recited in claim 30, wherein the second segment of the port assembly is a filter protection means.

54. The adapter as recited in claim 30, wherein the adapter further includes a stiffening member, with the stiffening member being connected to the fluid passage means and disposed within the elongated, cylindrical filter means.

55. The adapter as recited in claim 30, wherein means are disposed across the opening between the gas pathway and the second segment of the port assembly to prevent the ingress of materials other than sample gas into the port assembly.

56. The adapter as recited in claim 30, wherein the elongated, cylindrical filter means is attached to the fluid passage means with a barb associated with the fluid passage means.

57. The adapter as recited in claim 30, wherein the elongated, cylindrical filter means is attached to the fluid passage means by the filter means being heat sealed onto fluid passage means.

58. The adapter as recited in claim 30, wherein the elongated, cylindrical filter means is attached to the fluid passage means by a sleeve of material being chemically expanded and evaporation shrunk over a portion of the elongated, cylindrical filter means and a portion of the fluid passage means.

59. The adapter as recited in claim 30, wherein the elongated, cylindrical filter means is

SUBSTITUTESHEET attached to the fluid passage means by an O-ring disposed over a portion of the filter means and a portion of the fluid passage means.

60. The adapter as recited in claim 30, wherein the elongated, cylindrical filter means is attached to the fluid passage means with potting material.

SUBSTITUTESHEET