Endotracheal catheter and manifold assembly with improved valve

The present invention relates to an improved flap valve or other internal component for use with respiratory suction catheter and manifold assemblies. This flap valve or other internal component provides the assembly with an improved mechanism for cleaning the tip of the catheter without drawing an excessive amount of air from the respiration circuit to which the endotracheal catheter is attached. More specifically, the present invention relates principally to a closed suction endotracheal catheter system which provides improved cleaning of the catheter while minimizing air drawn from the patient's ventilation circuit by providing at least one protrusion on at least one surface of the flap valve or other internal component. By using a flap valve or other internal component with at least one protrusion, the flap valve or other internal component is strengthened and designed to prevent the flap from scraping mucus or other secretions from the catheter onto the distal surface of the flap during retraction.

FIELD OF THE INVENTION

The present invention relates to an improved flap valve or other internal component for use with respiratory suction catheter and manifold assemblies by providing at least one protrusion on at least one surface of the flap valve or other internal component that may aid in reducing or preventing mucus and similar secretions from collecting on the distal surface of the flap valve or other internal component during retraction of the catheter, thus improving the cleaning of the assembly.

BACKGROUND OF THE INVENTION

In the past twenty years, the medical industry has seen an increased interest in closed suction catheter systems to create artificial airways. Such systems were disclosed in U.S. Pat. No. 3,991,762 (“Radford”), which provided for a catheter within a protective sleeve such that the catheter is only advanced when suctioning is desired. Furthermore, U.S. Pat. No. 4,569,344 (“Palmer”), offered an improved system to reduce the risk of cross-contamination between the patient and the medical personnel using the device. More recently, interest has developed in catheter systems having a flap valve by which the internal passageway of the catheter can be closed off from the manifold.

There are a variety of different circumstances for which a person may be required to have an artificial airway, such as an endotracheal catheter tube, placed in his respiratory system. In some circumstances, such as surgery, the artificial airway's function is primarily to keep the patient's airway open so that adequate lung ventilation can be maintained during the procedure.

Moreover, because the endotracheal tube may be left in the patient for a prolonged period of time, it will become necessary to service these endotracheal catheter tube and manifold assemblies to replace, repair, refit, or otherwise manipulate the assembly. Because patients may need the use of an endotracheal tube to sustain mechanical ventilation for the life of the patient to remove respiratory secretions periodically, it is very useful for the assembly to comprise flap valves and other internal components that aid in the cleaning of the assembly.

In practice, a respiratory suction catheter is advanced through the inner passageway of the catheter and manifold assembly. As the suction catheter is withdrawn, a negative pressure is applied to the interior of the assembly to draw mucus and other secretions from the patient's respiratory system. While a substantial amount of the mucus and other secretions may be withdrawn through the catheter, a portion of the mucus and other secretions remain on the outside of the catheter. Because patient secretions can contain infectious agents, such as streptococcus, pseudomonas, staphylococcus and even HIV, it is important to shield clinicians from contact with the catheter. Likewise, it is important to shield patients' from communicable pathogens in the environment and those that may be carried by the clinician. This is particularly important because patients on mechanical ventilation often have compromised immune systems. Therefore there exists a need to form the internal components of the assembly such as the flap valve such that the withdrawal or retraction of the catheter does not coat the internal components such as a flap valve with mucus and similar secretions such the that cleaning of the assembly is impeded.

SUMMARY OF THE INVENTION

The present invention provides an improved design for internal components for the catheter tube manifold assemblies, including the flap valve of respiratory suction catheter assemblies. The flap valve or other internal component is preferably formed with at least one protrusion on at least one surface such that each protrusion will aid in the positioning of the flap valve or other internal component. By forming the flap valve or other internal component with at least one protrusion sufficient to maintain a space between the flap valve and the distal portion of a catheter that may translate within the assembly, the integrity and working condition of the flap valve or other internal component is protected while improving the cleaning of the assembly. This improved flap valve or other internal component will minimize the amount of mucus and similar secretions that collects or coats the distal surface of the flap valve during retraction or withdrawal of the catheter from the assembly and thus improves removal of mucus and other secretions from the distal tip of the catheter. By automatically separating or otherwise partitioning at least a portion of the assembly to form a cleaning area from the ventilation circuit, each protrusion formed or otherwise attached to the flap valve or other internal component will cause a more efficient cleaning to be affected by ensuring that the majority of the mucus or similar secretions are withdrawn with the catheter into this cleaning area.

Various of the above and other objects of the invention are realized in specific illustrated embodiments of an improved respiratory suction catheter apparatus set forth more fully herein and claimed below. The embodiments of an improved respiratory suction catheter apparatus typically include a manifold for attachment to an artificial airway, such as an endotracheal tube, to form a ventilation circuit, a catheter which is displaceable through the manifold and into the artificial airway to suction secretions from the artificial airway and lungs, and a variation of the flap valve or other internal component valve mechanism of the present invention disposed adjacent the ventilation circuit to minimize the air drawn from the ventilation circuit of a patient while the catheter is being cleaned.

In accordance with one aspect of the invention, the flap valve or other internal component valve mechanism is configured to engage the catheter as it is withdrawn through the manifold to thereby minimize the amount of mucus and similar secretions that may otherwise be scraped onto a distal surface of the flap valve. This flap valve may be configured to lock in a closed position when it is pulled toward the withdrawn catheter to thereby maintain a selective isolation or separation between the catheter tip and the airway through the manifold. Using an air makeup, to allow makeup air into the catheter and thereby ensure proper evacuation of secretions and any liquid used to clean the assembly, may enhance this flap valve or other internal component.

In a preferred embodiment of the present invention, each protrusion may be connected by a bridge that improves the interaction between the translating catheter and the protrusion formed on flap valve such that withdrawal or retraction of the catheter does not cause mucus or similar secretions from being scraped onto the flap valve in a manner that impedes cleaning of the assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings in which the various elements of the present invention will be given numeral designations wherein like numerals are used to designate like materials throughout. It is to be understood that the following description is only exemplary of the principles of the present invention, and should not be viewed as narrowing the pending claims. Those skilled in the art will appreciate that aspects of the various embodiments discussed may be interchanged and modified without departing from the scope and spirit of the invention. Moreover, the use of reference numerals in each Figure is only to show a preferred embodiment of the corresponding structure and is not intended to limit the scope of the invention as claimed herein.

Referring toFIG. 1, there is shown a cross-sectional view of a manifold10and catheter cleansing mechanism14in accordance with the teachings of the prior art. The manifold has a valve mechanism in the form of a rotatable rod18for selectively isolating a lavage chamber20from the ventilation circuit26. When the distal end of the catheter22is disposed in the lavage chamber20, a lavage solution can be injected through a side port30to help wash the mucus and other secretions from the exterior of the catheter22. Because of the relative size and dimensions of the lavage chamber20, however, there is nothing to force vigorous interaction between the lavage solution and the secretions on the exterior of the catheter. Additionally, because the lavage chamber is not configured for makeup air to enter when the rotatable rod18is closed, a vacuum can be created in the lavage chamber20that interferes with effective suctioning.

An additional disadvantage of the embodiment shown inFIG. 1is that the closure mechanism for such devices typically must be manually activated. If the user fails to close the rotatable rod18, actuation of suction through the catheter will draw air from the ventilation circuit26.

Turning now toFIG. 2, there is shown a cross-sectional view of an alternative embodiment of the prior art. The manifold100is provided with a plurality of ports104. A first port104ais attached to the hub of an endotracheal tube of the patient to conduct respiratory air to and from the endotracheal tube.

Thus the manifold forms part of a ventilation circuit. The air is typically provided to and removed from the manifold through a second port104bwhich is attached to a pair of ventilation tubes via a connector (not shown). The ventilation tubes are, in turn, connected to a mechanical ventilator (not shown) in a manner that will be well known to those skilled in the art.

A third port104cis provided opposite the second port104b. The third port104cis typically covered with a cap108which is removed when “blow-by” is desired to wean a patient from forced ventilation.

The manifold also has a fourth port104d. A coupling112is configured to form a force-fit engagement with the fourth port104dand effectively connects the catheter116and a protective sleeve120to the manifold100. Disposed adjacent a proximal end of the coupling112is a lavage port124through which a cleaning liquid can be injected to rinse the exterior of the catheter116. Such a configuration is advantageous because the lavage port124is positioned adjacent a seal128which is configured to wipe mucus and other secretions from the catheter116as is drawn through the seal. Thus, a user will typically withdraw the catheter116until the distal end116athereof is positioned slightly distally of the seal128, and then the cleaning solution will be injected into the lavage port124to assist in the removal of secretions. While such a method of removing the secretions is generally effective, it can draw more air from the ventilation circuit132than is necessary to effectively clean the distal end116aof the catheter116. Additionally, it is common for respiratory therapists and other clinicians to maintain the suction on as the distal end116aof the catheter116is drawn from the first port104ato a position immediately adjacent the seal128.

Turning now toFIG. 3A, there is shown a cross-sectional view of a portion of an improved endotracheal catheter, generally indicated at200. The endotracheal catheter includes a manifold, generally indicated at204and a catheter208. The manifold204includes a plurality of ports212a–c. A first port212ais configured for attachment to the proximal end of an artificial airway, such as the hub of an endotracheal tube, tracheostomy tube, etc. A second port212bis typically connected to a pair of ventilator tubes (not shown) by means of an adapter (not shown), in accordance with common practice in the art.

As used herein, distal refers generally to the direction of the patient, while proximal refers to the direction of the clinician. Unless otherwise noted, the drawings ofFIG. 2Aare oriented such that the distal (patient) end is toward the top of the page, while the proximal (clinician) end is toward the bottom of the page.

During normal usage, conditioned inspiratory air is forced through one of the ventilator tubes, through the second port212band the first port212aand into the patient's lungs via the artificial airway. Exhaled air is carried through the first port212aand then the second port212band out through the other ventilator tube. Thus, the manifold204forms part of a ventilation circuit214through which respiratory air is cycled.

Also forming part of the manifold204is a third port212c. A cap216typically covers the third port212c. Whenever mechanical ventilation is used, it is the goal to someday return the patient to voluntary or spontaneous breathing. To accomplish this, the patient must usually be weaned from the mechanical ventilation—to spontaneous breathing. To this end, the cap216may be removed from the third port212cso that oxygenated air is passed by the patient's endotracheal tube, but inspiratory air is not forced into the patient's lungs by means of a totally closed circuit. This arrangement commonly called “blow-by,” enables the patient to gradually resume natural or spontaneous breathing.

The manifold204also has a fourth port212d. The fourth port212dis disposed generally opposite the first port212aand is configured to allow the catheter208to slide therethrough and into the first port to enable suctioning of the patient. At the completion of suctioning, the catheter208is pulled back into the fourth port212dto prevent interference with the ventilation circuit214.

Disposed between the wall forming the fourth port212dand the catheter208is a coupling or adapter220. On an outer extreme, the adapter220engages the wall defining the fourth port212d. On an inner extreme, the adapter220engages a collar224that closely surrounds the catheter208so as to leave a small cylindrical space226around the catheter208. Ideally the space between the catheter208and the collar224is between about 0.127 mm (0.005 inches) and about 0.381 mm (0.015 inches). This proximity provides two important advantages. First, if lavage needs to be provided to the lungs of the patient, injecting lavage solution through the lavage port228and into the cylindrical space226causes a stream of lavage solution to be directed out the distal end224aof the collar and through the first port212a. If the spacing between the catheter208and the collar224is too large the lavage solution cannot be thus directed. Second, as the catheter208is drawn back into the collar224after use, the collar helps to wipe any heavy layers of mucus or other secretions from the outside of the catheter.

Injecting sterile saline or cleaning solution through the lavage port228further removes the secretions from the exterior of the catheter208and enhances evacuation by suction in the catheter. This configuration also minimizes the volumes of air and cleaning solution necessary to effect cleaning.

While the collar224configuration shown inFIG. 3Ais beneficial, it is still common to have secretions build up on the distal end208aof the catheter208. If such build up is not promptly removed, it can interfere with the ability of the catheter to properly suction the patient. It can also serve as a culture medium for pathogens within the closed suction catheter system.

As shown inFIG. 3A, a flap valve232is hingedly attached to an annular ring236disposed inside the fourth port212dso as to enable the flap valve232to pivot with respect to the ring to form a self-closing valve member. Of course, the flap valve232could be attached directly to the wall of the manifold204defining the fourth port212dor to the adapter220. The hinged attachment240allows the flap valve232to selectively move while maintaining alignment with the catheter tip, thereby creating a self-closing flap valve. Moreover, during retraction or withdrawal of catheter208, mucus and similar secretions may be scraped from the catheter208and collect in areas that are difficult to clean. For example, these secretions may collect on the distal surface of the flap valve232that is discussed below. As shown inFIG. 3A, valve232further comprises at least one non-planer, outward extruding protrusion280on at least one surface of flap232. As shown, each protrusion280on flap232may be attached or otherwise secured to flap232. Preferably, each protrusion280is formed on at least one surface of flap232during the formation of flap232. At least one protrusion280extends from the proximal surface of flap232and is positioned such that the catheter208contacts at least one protrusion280rather than the proximal surface of flap valve232.

As shown inFIG. 3B, the flap valve232is positioned to align with the distal end208aof the catheter208when the catheter is almost completely withdrawn into the collar224. The hinged attachment240is sufficiently flexible that suction through the distal end208aof the catheter208will draw the flap valve232proximally from a first, distal position into a second, proximal position, wherein the flap valve contacts with the distal end of the catheter208. Thus, the flap valve232and related structures form a self-closing valve wherein no additional external manipulation of the catheter system is needed to close the valve232. As with most closed suction catheters, the catheter208is formed such that a primary aperture244is formed in the distal end208aand one or more lateral apertures248positioned slightly proximal from the distal end may also be formed therein.

As the distal end of catheter208approaches flap232, the distal end of catheter208will contact that flap232. In this arrangement, the proximity to flap232substantially reduces the rate of suction through catheter tip aperture244. This decrease in suction at aperture244effectively increases suction flow in lateral apertures248, thereby increasing the ability of lateral apertures248to evacuate any secretions contained between the outside of catheter208and the interior collar244.

Because the lateral apertures248are generally smaller than the distal aperture244and because airflow to the lateral apertures248is limited by the collar224, the catheter208will increase the evacuation of secretions between the outside of catheter208in the interior of the collar244while not significantly taxing the airflow in the ventilation circuit.

As shown inFIGS. 3A and 3B, the proximal surface232a(i.e., the side opposite the ventilation circuit214) of the flap valve232is generally planar. At least one raised protrusion280on flap valve232extends proximally from this plane. As shown, a single protrusion280remains dormant until the catheter208translates through flap valve232during insertion or retraction periods.

Turning now toFIG. 3C, there is shown a close-up cross-sectional view of the embodiment shown inFIGS. 3A and 3Bwith a slight modification to the flap valve232. Unlike the flap valve232inFIGS. 3A and 3Bwhich is substantially planar save each protrusion280formed or otherwise attached thereto, the flap valve232inFIG. 3Cfurther comprises a channel252formed therein on the proximal surface232a. The channel252, prevents the flap valve232from forming a sealing engagement with the distal end208aof the catheter208. The channel252ensures that a controlled rate of airflow may be drawn into the aperture244at the distal most end208of the catheter.

The measured volume of air is drawn in through the channel252can have an important effect. Specifically, the air increases turbulent airflow both within the catheter208and immediately around its exterior. The turbulent airflow in turn, assists in breaking up agglomerations of mucus and secretions which lavage/cleaning solution alone may not. Thus, the turbulent airflow helps to provide improved cleaning of the distal end208aof the catheter208.

Turning now toFIG. 3D, there is shown yet another variation of the flap valve232shown inFIGS. 3A and 3B. Rather than having a channel formed in a proximal side thereof, the flap valve232has an aperture260formed therein so as to create an additional pathway for air to pass through the flap valve232. As with the embodiment shown inFIG. 3A, the small aperture260creates more turbulent airflow at the distal end208aof the catheter208and thereby improves cleaning. It is currently believed that an aperture260in the flap valve232with a diameter of about 0.76 mm (0.03 inches) is preferred.

Turning now toFIG. 4A, there is shown another embodiment of an improved respiratory suction catheter apparatus, generally indicated at300, with an improved flap336comprising at least one protrusion380made in accordance with the principles of the present invention. The improved respiratory suction catheter apparatus300includes a manifold304and a catheter308. As with the previous embodiment, the manifold304includes a first port312a, a second port312b, an optional third port312c, and an optional fourth port312d.

An adapter320is disposed in the fourth port312din such a manner as to make the manifold304and the catheter308a functionally integrated unit. The adapter320may be adhesively attached to the manifold304, or may be simply force-fit.

Unlike the embodiment discussed withFIGS. 3A–3D, an annular ring is not disposed in the manifold304independent of the adapter320. Rather, an annular ring326extends inwardly from a distal end320aof the adapter320. The annular ring326defines an aperture or opening330through which the catheter308can be extended. Thus, the opening330is slightly larger than the exterior of the catheter308.

Also extending inwardly from the adapter320is a flap336. The flap336is preferably hingedly attached to either the adapter directly or to the annular ring326. When no suction is applied to the catheter308, or when the distal end308aof the catheter is disposed distally from the flap336, the flap336will generally extend distally from the annular ring326and provide virtually no resistance to advancement of the catheter308. In this configuration, at least one protrusion380on the proximal side of flap336will interface with catheter308during this advancement such that the translation of catheter308through the assembly300will cause flap336to be deflected such that at least one protrusion380is the interfacing zone between catheter308and flap336during this period. In this configuration, the advancement of catheter308will cause a distal tip308aof catheter308to encounter and displace flap336by contract with at least one protrusion380. As shown inFIG. 4D, flap336comprising at least one protrusion380is deflected such that flap336remains in working condition and parallel to the advancement of catheter308. The major benefit of each protrusion380is not realized until retraction of catheter308, laden with secretions. This arrangement ensures that catheter308may be advanced with virtually no resistance and the planar surface of flap336will have less interaction with catheter308during retraction. When catheter308is retracted, mucus and similar secretions on catheter308will not be able to coat or collect on flap336, especially the distal surface336bof flap336. Because at least one protrusion380formed or otherwise attached to flap336on its proximal surface336adistances flap336from catheter308during this retraction, flap336is not positioned such that it will scrape this mucus and secretions from catheter308such that this mucus and secretions will not collect on the distal surface336bof flap336. During withdrawal, at least one protrusion380on the proximal side may actually remove some of the mucus and secretions coating catheter308. The mucus and secretions will collect on each protrusion380on the proximal surface336aof flap336. These secretions can be easily removed during the cleaning of the catheter336.

As shown inFIG. 4B, as the distal end308aof the catheter308is withdrawn through the annular ring326while suction is applied vacuum is created that pulls the flap336over the opening330. The suction at the distal end308aof the catheter308is reduced and more of the airflow in the ventilation circuit is available for the attached patient. While the flap336could be configured in the manner shown inFIGS. 3C and 3D, the present configuration does not necessitate the use of makeup air from the ventilation circuit340.

If the catheter308were simply left in the chamber348behind the flap336/annular ring326and lavage were injected into the chamber, it is possible that the cleaning process would be less efficient. Moreover, it may be difficult to suction mucus and other secretions from the chamber once the lavage source had been sucked dry. To overcome these problems with the prior art, the embodiment inFIGS. 4A through 4Dcomprises a makeup air inlet, generally indicated at350, which is formed in a portion of the wall defining the fourth port312dof the manifold and the adapter320. The makeup air inlet350preferably includes a filter354that is selected to substantially prevent cross-contamination between the environment/clinicians and the patient. Disposed adjacent to the filter material is a flexible barrier358which forms a one-way valve360.

As shown inFIGS. 4B and 4C, the one-way valve358will generally be closed when the catheter308is in an extended position such that the catheter308extends through the opening330in the annular ring326. However, once the distal end308aof the catheter308has been withdrawn through the opening330in the annular ring326and the flap336has been drawn closed, a vacuum may develop on the side of the flap336opposite the ventilation circuit340. The vacuum causes the one-way valve358to open and allow a supply of makeup air to enter the chamber. The makeup air flowing past the flexible one-way valve member358helps to create turbulent airflow and facilitate removal of any respiratory secretions on the catheter308. This is preferably accomplished at about the same time the user utilizes the lavage port370to inject lavage/cleaning solution through the space372between the collar374and the catheter308. It will be appreciated that the one-way valve358could be configured to provide very little resistance to air inflow, or could be configured to require a substantial vacuum to be present before makeup air is allowed into the area proximal the flap336.

Turning now toFIG. 5A, there is shown a fragmented, cross-sectional view of an alternate embodiment of an improved endotracheal catheter system, generally indicated at700, incorporating aspects of the present invention. The endotracheal catheter system includes a manifold, generally indicated at704, and a catheter708. As with several of the previous embodiments, the manifold704may include a plurality of ports712a–712d. The first port712ais configured for attachment to the proximal end of an artificial airway, such as the hub of an endotracheal tube, tracheostomy tube, or similar airway. A second port712bis typically connected to a pair of ventilator tubes (not shown) by means of an adapter (not shown), in accordance with common practice in the art. During normal usage, conditioned inspiratory air is forced through one of the ventilator tubes, through the second port712band the first port712aand into the patient's lungs via the artificial airway. Exhaled air is carried through the first port712aand then the second port712band out through the other ventilator tube. Thus, the manifold704forms part of a ventilation circuit714through which respiratory air is cycled.

Also forming part of the manifold704is a third port712c. The third port712cis typically covered by a cap716that may be removed to facilitate “blow-by” and thereby enable the patient to gradually resume spontaneous breathing. Those skilled in the art will appreciate that while the provision of a third port for blow-by is preferred, it is not necessary to the practice of the principles of the invention.

The manifold704also has a fourth port712d. The fourth port712dis disposed generally opposite the first port712aand is configured to allow the catheter708to slide therethrough and into the first port to enable suctioning of the patient. At the completion of suctioning, the catheter708is pulled back into the fourth port712dto facilitate cleaning and to prevent interference with the ventilation circuit714.

Disposed between the wall forming the fourth port712dand the catheter708is a coupling or adapter720. On an outer extreme, the adapter720engages the wall defining the fourth port712d. On an inner extreme, the adapter720engages the catheter708. Alternatively, a collar such as collar224shown inFIG. 3Acould be used between the catheter708and the adapter720.

The adapter720preferably has a cylindrical hollow which forms a first portion720adisposed toward a proximal end thereof, and a second portion720bdisposed toward a distal end thereof. At the first portion720a, the diameter of the cylindrical hollow is substantially the same as the outer diameter of the catheter708so that the first portion720aof the adapter720closely surrounds the catheter.

The second portion720bof cylindrical hollow of adapter720has a larger diameter than the first portion720aof adapter720. This larger diameter forms a collection area in which mucus and other secretions can collect as the catheter708is drawn proximally through the adapter720.

As has been mentioned previously, in accordance with one of the principles of the present invention it has been found that selective obstruction of the airflow into the distal end708aof the catheter708can significantly improve catheter cleaning. Additionally, it has been found that such a mechanism for improved cleaning also minimizes the withdrawal or air from the ventilation circuit714.

As shown inFIG. 5A, a flap732is hingedly attached to an annular ring736disposed inside the fourth port712dso as to enable the flap732to pivot with respect to the ring. Alternatively, flap732could be attached directly to the wall of the manifold704defining the fourth port712dor to the adapter720. The hinged attachment740allows the flap732to selectively move while maintaining alignment with the distal end708aof the catheter708, thereby creating a flap valve. As shown, flap732comprises at least one protrusion780on the proximal surface of flap732that may interface or otherwise engage catheter708at distal tip708a. Flap732may comprise an aperture760formed in flap732to provide a conduit for a controlled amount of air to enter catheter708at distal end708a. As with previous embodiments, the aperture760also allows a small amount of air to enter the catheter708and further facilitate cleaning without drawing excessive air from the inhalation circuit of the patient.

With the flap732significantly reducing of the airflow into the distal end708aof the catheter708, suction will increase at the lateral openings738, partially shown inFIG. 5A, which are formed in the catheter proximal from the distal end708aand ultimately improve the cleaning of the catheter708.

One significant difference between the flap732and those shown in previous embodiments is the manner in which it engages the ring736. On one end, the flap732is pivotally attached to the ring736to enable movement as a flap valve as discussed above. At an opposing end, the flap732is configured to engage a flange764that extends inwardly from the ring736. More specifically, the ends of the flap732and the flange764are configured to complement one another so as to nest in one another or otherwise form a locking engagement. Thus, as shown more clearly inFIG. 5B, the end764aof the flange764is provided with a V-shaped groove and the complimentary end732aof the flap732is V-shaped projection.

As the catheter708is withdrawn through the adapter720to the point where the distal end708aof the catheter is disposed behind the ring736, the suction of air through the tube will cause the flap732to be pulled toward the distal end708aof the catheter708and thereby improve cleaning of the catheter as has been discussed with previous embodiments. As previously discussed, at least one protrusion780on the proximal surface732aof flap732will significantly reduce the interaction between catheter708and flap732during retraction and prevent the accumulation of mucus and similar secretions on the distal surface732bof flap732.

Once the catheter708is sufficiently-withdrawn through the adapter720, the end732cof the flap732will nest in the groove in the end764aof the flange764, thereby locking the flap732in a closed position. With the flap732locked closed, the risk of mucus or other secretions seeping into the ventilation circuit714is significantly reduced.

Thus, the engagement between the flap732and the flange764provides a locking mechanism which prevents flap732from being moved from the nearly closed position (FIG. 5B) to the open position wherein the flap732does not interfere with distal movement of the catheter708. As shown in prior embodiments, suction maintained the flap732in the closed position. In contrast, the present embodiment provides a positive retention of flap732.

When suctioning is desired, flap732may be opened by advancing the distal end708aof the catheter708to contact at least one protrusion780on flap732and force the end732aof flap732out of engagement with the flange764. The amount of force required is minimal above that normally exerted to advance the catheter708for suctioning.

While not shown inFIGS. 5A and 5B, a lavage port could be used with the adapter720to enhance cleaning of the catheter708. The lavage port could be placed along the first or second portions,720aor720b, depending on the tolerances thereof.

Turning now toFIG. 6A, there is shown a fragmented, cross-sectional view of an alternate embodiment of an improved endotracheal catheter system, generally indicated at800. As with the previous embodiment, the endotracheal catheter system includes a locking valve mechanism, generally indicated at810.

The endotracheal catheter800includes a manifold, generally indicated at804and the catheter808. The manifold includes first, second, third and fourth ports,812a–812dwhich define a ventilation circuit814and otherwise function in the same manner as the first through fourth ports712a–712ddiscussed above inFIG. 5A.

An adapter820is disposed in the fourth port812din a manner similar to that discussed with respect to the prior embodiment. The adapter820may include first and second portions820aand820bhaving different diameters to facilitate collection of mucus and other secretions, and to otherwise improve the workings of the device.

Also disposed in the fourth port812dis a flap832that is configured to approach the distal end808aof the catheter808. As with the previous embodiments, at least one protrusion880is preformed on at least the proximal surface of flap832to prevent the direct communication between catheter808and flap832. This arrangement not only protects flap832from being deformed during the translation of catheter808by focusing the pressures of the advancement of catheter808onto protrusion880but also improves the cleaning of catheter808by preventing the planar surface of flap832from scraping the mucus and secretions onto the distal surface of flap832. Flap832is pivotally attached to a ring836disposed in the fourth port812d. Alternatively, the flap832could be directly connected to the wall defining the fourth port812d. As with several of the previously discussed embodiments, the flap832is drawn into contact with the distal end808aof the catheter808via at least one protrusion880as suction is applied through the catheter808. Preferably, forming at least one aperture860in flap832provides an additional conduit for airflow. This reduced airflow improves cleaning. The size of the aperture860is preferably about 0.76 mm (0.03 inches) in diameter.

Also disposed on the ring836is an inwardly extending projection864that forms a catch. Preferably, the projection864is disposed on the ring836opposite the location at which the flap832is attached to the ring. As with the flap832, the projection may be directly mounted on in the fourth port812d.

As the flap832is drawn proximally by suction through the catheter808, the flap passes over the projection864which extends inwardly slightly further than the end832aof the flap. Thus, once the flap832has moved proximally beyond the extreme inward point of the projection864, distal movement of the flap is restricted by the projection. Thus, the flap832becomes frictionally engaged behind the projection864until is forced distally past the projection by advancement of the catheter808. Alternatively, those skilled in the art will appreciate that the flap832could be configured to bias the flap832into the proximal or closed position.

Referring specifically toFIG. 6B, there is shown a close-up view of the locking valve mechanism and locking structure discussed above. As shown, the end832aof the flap832is tapered to a point832bthat is formed on the distal side of the flap832. The projection864tapers toward a point disposed at the proximal end864athereof. Such a configuration enables the end832aof the flap832to slide proximally over the projection864, while requiring additional effort to move the flap distally past the projection864.

FIG. 7Ashows a cross-sectional view of yet another embodiment of an improved endotracheal catheter generally indicated at900. The catheter900includes a manifold904and a catheter908. The manifold904includes first, second, third and fourth ports,912a–912d, the first and fourth of which are aligned to allow advancement of the catheter908through the manifold.

An adapter920is disposed in the fourth port912dand functions as a guide for the catheter908as it is advanced and retracted. The adapter920preferably includes a first portion920ahaving a inner diameter approximately the same size as the outside diameter of the catheter908, and a second portion920bhaving a diameter which is larger than that of the first portion.

Also disposed in the fourth port912dis a pair of rings936aand936b. A flap932is attached to the ring936band extends inwardly so as to be disposed perpendicular to the travel path of the catheter908as it is advanced through the manifold904. The flap932preferably has a small hole960to allow a small amount of air through the flap932. As with the previous embodiments, flap932may further comprise at least one protrusion980on at least the proximal surface of flap932. In this configuration, protrusion980prevents catheter908from sliding on the planar surface of flap932during translation. During the arrangement shown inFIGS. 7A–7B, suction is reduced at aperture944in the distal tip908aof catheter908. This reduces suction at aperture944and increase suction at aperture948shown inFIG. 7Afor cleaning catheter908and a portion of manifold904.

Referring more specifically toFIG. 7B, the flap932is pivotally attached to the ring936bso that as the distal end908aof the catheter908is withdrawn through the fourth port912d, suction from the catheter draws the flap932into contact with the distal end908a. In such a manner, the flap932functions as a flap valve to substantially occlude the distal end908aof the catheter908.

Also shown more clearly inFIG. 7Ba catch964is attached by an arm968to the ring936a. The catch964is configured to engage the flap932to lock the flap in a desired location. As the catheter908is withdrawn through the fourth port912b, the flap932is drawn by the suction effect at the distal end908a. The end932aof the flap932opposite the attachment arm940between the flap932and the ring936bengages the catch964and causes the catch to be deflected out of the way. Once the end932aof the flap932has passed by the catch964, the catch moves back into its normal position. In such a position, the catch964engages the end932aof the flap932and locks the flap932in a proximal, closed position. To release the flap932, the catheter908is advanced with sufficient force to cause the catch964to deflect out of the way. The flap932may then pivot distally and the catheter908advanced.

Turning now toFIG. 7C, there is shown an end view of the flap932, the rings (shown jointly as936) and associated structure. The flap932is attached to the ring936by two arms948, each forming an attachment point940. The opposite end932aof the flap932engages the catch964that is attached to the ring936by an arm968. The catch940effectively locks the flap932in a proximal position until the user forcibly advances the catheter in a distal direction, causing the catch to release the flap. As shown, a plurality of protrusions980is formed on at least one surface of flap932.

Those skilled in the art will appreciate that numerous modifications could be used to accomplish the principles of the present invention. As an example, a single arm948could be used with the flap932, and multiple catches964could be used. Likewise, a single ring could be used rather than the first and second rings936aand936bto support the flap932and the catch968. Furthermore, as is shown inFIG. 7D, modifications can be made the flap932ato provide other benefits.

As shown inFIG. 7D, a pair of arms948attaches the flap932to the ring936. As mentioned above, the arms948could be configured to bias the flap932into the closed position. The flap932is generally circular, but has two rounded projections950which extend outwardly and are spaced approximately 90 degrees apart. The projections serve two important purposes. First, even if the generally circular portion of the flap932were slightly smaller than the distal opening of the endotracheal tube, the projections950would prevent the flap from entering the endotracheal tube. Second, the projections950would cause the flap to align for airflow to continue to the patient without lying flat to cover any passage which might interfere with airflow to or from the patient.

Also shown inFIG. 7Dis the aperture960that is formed in the generally circular portion of the flap932a. As shown the aperture960is between about 0.76 mm (0.03 inches) and about 1.02 mm (0.04 inches) in diameter. While shown as being circular or disk-shaped, those skilled in the art will appreciate, in light of the present disclosure, that other shaped apertures could also be used. As shown, a plurality of protrusions980are be formed on at least the proximal surface of flap932.

Turning now toFIG. 8A, there is shown a side cross-sectional view of an improved endotracheal catheter, generally indicated at1000. The improved endotracheal catheter1000includes a manifold, generally indicated at1004, and a catheter1008. The manifold1004includes first, second, third and fourth ports1012a–1012das set forth above.

An adapter1020is disposed in the fourth port1012dand facilitates advancement and withdrawal of the catheter1008through the manifold1004. While shown as having a first portion1020awith a smaller diameter and a second portion1020bwith a larger diameter, the adapter1020could be made with a uniform interior diameter. In the alternative, the wall defining the fourth port1012dcould be configured to eliminate the need for an adapter1020.

Also disposed in the fourth port1012dis a flap1032that is connected to a ring1036. The flap1032extends inwardly from the ring1036and is configured to be disposed perpendicular to the long axis of the catheter1008. As shown, flap1032further comprises at least one protrusion1080formed on at least the proximal surface of flap1032. In this configuration, protrusion1080interfaces with catheter1008such that the planar surface of flap1032cannot scrape the mucus and other secretions coating catheter1008during retraction.

Like the previous embodiment, the end1032aof the flap1032engages a catch mechanism1064which extends inwardly. As shown more clearly inFIG. 8B, the catch mechanism1064is formed by at least one projection1068which extends proximally and inwardly from the ring1036. As the flap1032is drawn proximally by the catheter1008, the end1032aof the flap is drawn over the projection1068that temporarily deflects. Once the flap1032has moved a sufficient distance proximally, the projection1068returns to its normal position and thereby locks the flap in the proximal position.

FIG. 8Cshows an end view of the ring1036and the flap1032. The flap1032is attached to the ring1036by a single arm1048. A pair of catch mechanisms1064in the form of projections1068are spaced apart at 120 degree intervals. Having the catch mechanisms1064spaced helps to stabilize the flap1032when in the locked position. As shown, at least one protrusion1080may be formed on at least the proximal surface of flap1032.

FIG. 9Ashows a cross-sectional view of yet another embodiment of an endotracheal catheter system1300that incorporates aspects of the present invention. The endotracheal catheter system1300includes a manifold, generally indicated at1304which forms a fitting for connecting the endotracheal catheter1300to the artificial airway (i.e. endotracheal tube) of a patient. The endotracheal catheter system1300also includes an elongate catheter1308.

The manifold1304includes a first port1312a, a second port1312b, and a third port1312c. The first port1312ais configured to engage an artificial airway, such as an endotracheal tube. The second port1312bprovides inspiratory and expiratory airflow to and from the patient. Typically, a Y-shaped adapter is attached to the second port1312b. However, many configurations are used in the clinical setting and those skilled in the art will appreciate the different combinations that are available.

The third port1312cis disposed opposite the first port1312a. It is aligned such that the catheter1308can pass through the third port1312c, through the manifold1304, and through the first port1312ainto the artificial airway. As shown inFIG. 9A, the first and second ports1312aand1312bmay also have swivel structures1314to enable the manifold1304to swivel with respect to adjoining structures and thereby improve patient comfort and flexibility.

Connected to the third port1312cis a coupling or adapter1320. On the outer surface of the distal end1320a, the adapter1320engages the wall defining the third port1312c. The inner surface of the adapter1320forms a chamber about the distal end1308aof the catheter1308. This chamber assists in cleaning the distal end of the catheter in a manner that will be discussed more fully below.

Disposed adjacent to the distal end1320aof the adapter1320is a collar1324which has a frustoconical bore1328extending therethrough. Those skilled in the art will appreciate that the collar1324could be formed integrally with the adapter1320if desired.

When lavage solution is injected through a lavage port1330and a side opening1332into the frustoconical bore1328, the collar1324helps to channel the lavage solution along the catheter1308, through the first port1312aand into the artificial airway.

The distal end1324aof frustoconical bore forms an orifice in the distal end of the collar1324. A flap1340, supported by a support ring1344disposed in the third port1312cselectively engages the orifice to substantially occlude the orifice when the two are engaged. As with prior embodiments, the flap1340preferably has one or more holes1348formed therein to allow a small amount of air through the flap. Also, like prior embodiments, the flap1340may be biased in the occluding position, or may be drawn into the occluding position by suction through the catheter1308. Importantly, flap1340comprises at least one protrusion1380on the proximal surface of flap1340for the reason disclosed herein.

Disposed at the opposing, proximal end of the collar1324is a first wiper seal1352. Preferably, a narrowed portion1320bof the adapter1320supports the wiper seal1352. Those skilled in the art, however, will appreciate that other mechanism for holding the wiper seal1352could be used. As the catheter1308is withdrawn past the first wiper seal1352, the wiper seal removes major secretions. While discussed herein as a wiper seal, some other structure having close tolerances (i.e. one that would remove most secretions) could also be used.

From the wiper seal1352, the adapter1320extends proximally and forms a cleaning chamber. Disposed adjacent a proximal end1320cof the adapter1320is a second wiper seal1356. As with the first wiper seal1352, the object of the second wiper seal1356is to remove secretions from the exterior of the catheter1308as it is withdrawn from the artificial airway of the patient. However, the second wiper seal1356will typically have a smaller diameter opening so that the second wiper seal more closely engages the exterior of the catheter1308than the first wiper seal1352.

Conventionally, a single wiper seal has been used. The wiper seal was placed in the location of the second wiper seal1356to wipe secretions from the catheter as it was withdrawn. The distal end1308aof catheter1308, however, was never physically wiped. Instead, the operator attempted to clean this portion with solution injected through a lavage port.

Turning now toFIG. 9B, there is shown a side cross-sectional view of the endotracheal catheter1300in which the catheter1308has been withdrawn through the manifold1304into a cleaning position. As the catheter1308is withdrawn, the flap1340closes—either due to a bias or the suction through the catheter—to occlude the opening in the collar1324without having the opportunity to scrape mucus or secretions onto the distal surface of flap1340because of protrusion1380on the proximal surface of flap1340.

As the catheter1308is withdrawn proximally out of the collar1324and past the wiper seal1352, the distal end1308aof the catheter is wiped by the wiper seal1352so that most secretions thereon are removed. The secretions that are removed by the wiper seal1352are then carried through the catheter1308. It is useful to note that protrusions1380will scrape some of these secretions that may be suctioned using catheter1308during retraction.

Once the distal end1308aof the catheter1308has advanced beyond the first wiper seal1352, a bottle1360is attached to the lavage port1330and a cleaning liquid (typically sterile saline solution) is supplied through the side opening1332in the collar1324. The cleaning liquid flows around the distal end1308aof the catheter1308, indicated by arrow1364, and cleans those secretions which were not removed by the first wiper seal1352from the distal end of the catheter.

At the same time, the holes1348in the flap1340allow a small amount of air into the catheter, thereby facilitating better removal of the secretions. If desired, a make-up air valve could be disposed on the side of the adapter1320to allow the inflow of additional air.

As shown inFIG. 10A, a pair of arms948attaches the flap932to the ring936. As previously mentioned above, the arms948could be configured to bias the flap932into the closed position. The flap932is generally circular, but has two rounded projections950which extend outwardly and are spaced approximately 90 degrees apart. The projections serve two important purposes. First, even if the generally circular portion of the flap932were slightly smaller than the distal opening of the endotracheal tube, the projections950would prevent the flap from entering the endotracheal tube. Second, the projections950would cause the flap to align for airflow to continue to the patient without lying flat to cover any passage which might interfere with airflow to or from the patient.

Also shown inFIG. 10Ais the aperture960that is formed in the generally circular portion of the flap932. As shown the aperture960is between about 0.76 mm (0.03 inches) and about 1.02 mm (0.04 inches) in diameter. While shown as being circular or disk-shaped, those skilled in the art will appreciate, in light of the present disclosure, that other shaped apertures could also be used. As shown, a plurality of protrusions980may be formed on a surface of flap932. Of note in this preferred embodiment, each protrusion980is integrally formed with a bridge981that connects each protrusion980to one another. This bridge981is designed to scrape mucus and secretions from a retracting catheter and help prevent flap932from deforming during translation of the catheter. Moreover, bridge981limits the interaction of the catheter with the proximal surface of flap932and strengthens flap932to reduce the risk of deformation of flap932during the translation of catheter908(not shown).

Moreover, as shown in the top and side cross-sectional views of the flap932inFIGS. 10B and 10C, flap932is preferably formed with uniform and similar protrusions980on both the proximal and distal surfaces of flap932. This configuration allows for more flexibility and quality control in the manufacture of assemblies comprising flap932or similar internal components. By forming flap932with identically positioned protrusions980, and bridges981if included, on both the proximal and distal surfaces of flap932, flap932may be incorporated into an assembly with less concern as to the orientation of flap932in the manufacturing process.

Those of skilled in the art will recognize that the internal components such as the valve may be formed of a variety of different compositions. For instance, they may be comprised of such synthetic resins as polyurethanes, ethylene vinyl acetate copolymers, polyvinyl chlorides, polyamide/polyethers, polysilicones, polyamides, such as nylon, polyethylene, including those of the high density, low density, intermediate density and linear low density variety, ethylene α-olefin copolymers (such as ethylene propylene copolymers), polyesters, polycarbonates, acrylonitrile-butadiene-styrene copolymers, polyether-polyester copolymers, and polyether polyamide copolymers are desirable. Further desirable are low pressure, relatively soft or flexible polymeric materials, such as thermoplastic polymers including thermoplastic elastomers.

Injection molded medical grade synthetic resinous materials are preferable for such internal components. Especially preferred are polyamide/polyether polyesters including those sold commercially as Pebax® by Atochem North America, Inc., Philadelphia Pa. Most preferred are the Pebax® 33 polyamide/polyether polymers, such as Pebax® 3533 SA 00 polymers. Such polymers have a Shore D, ASTM D2240, hardness of about 35, a Shore A, ASTM D2240, hardness of about 85, and a flexural modulus, ASTM D790, of about 19995500 Pa (2,900 PSI), a softening point, ASTM D1525, of approximately 73° C. (165° F.) and a melting point of between about 109° C. (228° F.) and about 154° C. (309° F.).

Further preferred is Pebax® 5533 SA 00 polyether block amide polymer characterized by a Shore D, ASTM D2240, hardness of about 55, a flexural modulus, ASTM D790, of about 165480000 Pa (24,000 PSI), a softening point, ASTM D1525, of approximately 144° C. (291° F.). And a melting point of between about 128° C. (262° F.) and about 170° C. (338° F.).

Thermoplastic elastomeric polymers which render excellent results as the internal components for use in the invention include those sold under the Monprene® name, a trademark of QST, Inc., including Monprene® MP-2870M, having a Shore A hardness, ASTM D2240, of about 70; Santoprene® name, a trademark of Advanced Elastomer Systems, including Santoprene® MP-2870M, having a Shore D hardness, ASTM D2240, of about 40; polyurethane (polyether) elastomers, such as those sold under the Pellathane™ name, a trademark of Dow Plastics, including Pellathane® 2363-80AE, having a Shore A hardness, ASTM D2240, of about 85; ethylene vinyl acetate polymer sold under the Elvax® name, a trademark of E.I. du Pont Packaging & Industrial Polymers, including Elvax® 150 (33% vinyl acetate) and Elvax® 360 (25% vinyl acetate), Elvax® 450 (18% vinyl acetate) or Elvax® 750 (9% vinyl acetate); low density polyethylene polymers, such 3447500 Pa (500 PSI); the low density polyethylenes sold under the Petrothene® trademark by Equistar Chemicals, L.P., such as Petrothene® NA 270-000 low density polyethylene polymer; polyvinyl chlorides commercially available under the Unichem™ trademark by Colorite Plastics Company, such as Unichem™ 7811G-015 polyvinyl chloride polymer, Unichem™ 8511G-015 flexible polyvinyl chloride polymer, Unichem™ 6511G-015 flexible polyvinyl chloride polymer; the styrene ethylene butylene styrene block copolymers commercially available under the Kraton™ trademark by Shell Chemical Company, such as the Kratomm™ G-7705 styrene ethylene butylene styrene block copolymer; and the density polyethylene polymers commercially available under the Tenite™ trademark by Eastman Chemical Company, such as the Tenite™ 1870A low density polyethylene polymers.

By use of these various configurations, the cleaning of the distal end of a catheter may be enhanced while minimizing or eliminating the air drawn from the ventilation circuit of the patient. Those skilled in the art will appreciate modifications that can be made without departing scope and spirit of the present invention. The appended claims are intended to cover such modifications.