Abstract:
A collapsible reservoir system is disclosed herein. The collapsible reservoir system includes a first tube pneumatically connected to the collapsible reservoir, and a second tube pneumatically connected to the collapsible reservoir. The second tube is configured to generally remain open in the absence of an externally applied compressive force. The second tube is positioned relative to the collapsible reservoir such that a compressive force applied to the collapsible reservoir can also compress and thereby restrict the second tube. A corresponding method for controlling the pressure of a collapsible reservoir system is also provided.

Description:
FIELD OF THE INVENTION 
       [0001]    This disclosure relates generally to a collapsible reservoir to store and control the delivery of fluid. As medical device, it can be use as a resuscitation system or in conjunction with a medical ventilator system to manually augment patient breathing. 
       BACKGROUND OF THE INVENTION 
       [0002]    In general, medical ventilator systems are used to provide respiratory support to patients undergoing anesthesia and respiratory treatment whenever the patient&#39;s ability to breath is compromised. The primary function of the medical ventilator system is to maintain suitable pressure and flow of gases inspired and expired by the patient. Medical ventilator systems used in conjunction with anesthesia generally include an automatic system comprising a bellows and a manual system comprising a collapsible reservoir configured to allow a clinician to deliver manual breaths to the patient. 
         [0003]    The manual system is implemented to ventilate a patient by repeatedly compressing and releasing the collapsible reservoir. When the collapsible reservoir is compressed, inhalation gas is transferred to the patient. When the collapsible reservoir is subsequently released, the patient passively exhales due to the lungs&#39; elasticity. Fresh gas is generally continuously introduced into the system, and at least a portion of the patient&#39;s exhaled gas can be recycled and transferred back to the patient. A pressure release valve is traditionally provided to limit the pressure level in the manual system and thereby regulate the volume of inhalation gas transferred to the patient during each compression of the collapsible reservoir. 
         [0004]    As an operator compresses and releases the collapsible reservoir to manually ventilate a patient, her or she typically must also operate the pressure release valve in order to maintain optimal ventilator system performance. The operation of the pressure release valve must be coordinated with the compression and release of the collapsible reservoir. For example, an operator may have to constantly adjust the pressure release valve between a low relief pressure setting for spontaneous only breathing, and a higher pressure setting to enable augmented positive pressure synchronous with patient inhalation. The problem is that the operation of the pressure release valve in the manner described unnecessarily burdens the operator and is also subject to operator error. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    The above-mentioned shortcomings, disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification. 
         [0006]    In an embodiment, a collapsible reservoir system includes a collapsible reservoir, a first tube pneumatically connected to the collapsible reservoir, and a second tube pneumatically connected to the collapsible reservoir. The second tube is configured to generally remain open in the absence of an externally applied compressive force. The second tube is positioned relative to the collapsible reservoir such that a compressive force applied to the collapsible reservoir can also compress and thereby restrict the second tube. 
         [0007]    In another embodiment, a collapsible reservoir system includes a first tube that is pneumatically connectable to an inlet hose of a patient circuit, a collapsible reservoir that is pneumatically connectable to the first tube, and a second tube that is pneumatically connectable to an outlet hose of the patient circuit. The second tube is configured to generally remain open in order to release excess pressure from the collapsible reservoir system. The second tube is also configured to automatically occlude when a compressive force is applied to the collapsible reservoir. 
         [0008]    In another embodiment, a method for controlling the pressure of a collapsible reservoir system includes providing a collapsible reservoir in fluid communication with a patient circuit, providing a first tube in fluid communication with the patient circuit, and providing a second tube in fluid communication with the patient circuit. The method also includes compressing the collapsible reservoir and generally simultaneously compressing the second tube such that the second tube becomes occluded and at least a portion of the contents of the collapsible reservoir are transferred to the patient circuit. The method also includes releasing the collapsible reservoir after the collapsible reservoir has been compressed. Wherein releasing the collapsible reservoir also opens the second tube such that excess pressure in the collapsible reservoir system can be released therethrough. 
         [0009]    Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the accompanying drawings and detailed description thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic diagram of a collapsible reservoir system in accordance with an embodiment; 
           [0011]      FIG. 2  is a schematic diagram of a collapsible reservoir system in accordance with another embodiment; and 
           [0012]      FIG. 3  is a schematic diagram of a collapsible reservoir system in accordance with another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments that may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken as limiting the scope of the invention. 
         [0014]    Referring to  FIG. 1 , a collapsible reservoir system  10  is schematically depicted in accordance with an embodiment. The collapsible reservoir system  10  may, for example, be implemented as a component of a medical ventilator system (not shown). The collapsible reservoir system  10  includes a collapsible reservoir  12 , a first tube  14  and a second tube  16 . It should be appreciated that the second tube  16  may include one or more tubes. The collapsible reservoir system  10  will hereinafter be described in accordance with the exemplary embodiment depicted in  FIG. 1  wherein the first tube  14  is configured to transfer gas to and receive gas from a patient  18 , and the second tube  16  is an exhaust tube configured to release gas to atmosphere or transfer it to a scavenging system (not shown). It should, however, be appreciated that the first tube  14  and the second tube  16  may be configured for alternate purposes. 
         [0015]    According to the exemplary embodiment of  FIG. 1 , the collapsible reservoir system  10  is operatively connected to a patient circuit  15  configured to transfer gas to and from the patient  18 . The patient circuit  15  is pneumatically connected to a single inlet/outlet hose  17  through which the patient  18  can inhale and exhale. The patient circuit  15  is a “semi-open circuit” such as a Bain circuit, or a “semi-closed circuit” such as a “water to and fro circuit” wherein gas exhaled by the patient  18  is transferable to the collapsible reservoir  12 , and can thereafter be re-circulated from the collapsible reservoir  12  back to the patient  18 . The first tube  14  is pneumatically connected to the inlet/outlet hose  17  via the patient circuit  15 . A fresh gas supply  24  that is constrained to one-way flow replenishes oxygen consumed by the patient  18 . A conduit  26  pneumatically connects the fresh gas supply  24  to the patient circuit  15 . While it is preferable that conduit  26  be connected to the patient circuit  15  via a pneumatic coupling proximal to the inlet/outlet hose  17 , this connection can be made anywhere along the patient gas breathing passage including a direct pneumatic coupling to the tube  14  or the inlet/outlet hose  17 . Similarly, the collapsible reservoir  12  can be pneumatically connected to work with a more sophisticated configuration of the patient circuit  15 , such as a “circle breathing circuit” commonly used in anesthesia machines. For purposes of this disclosure, the terms “pneumatic connection” and “pneumatic coupling” are defined in a non-limiting manner to include an attachment of two or more components that is adapted to facilitate the transmission of a gas between or through the attached components. 
         [0016]    The collapsible reservoir  12  generally comprises a pliable bladder or bag that is repeatedly compressed and released in order to manually ventilate a patient. The collapsible reservoir  12  is commonly referred to as a hand bag, and is so named because an operator typically uses his or her hand to compress and release the collapsible reservoir  12 . The collapsible reservoir  12  includes a first opening  20  configured to pneumatically couple the collapsible reservoir  12  with the first tube  14  such that the first tube  14  is in fluid communication with the collapsible reservoir  12 . The collapsible reservoir  12  also includes a second opening  22  configured to pneumatically couple the collapsible reservoir  12  with the second tube  16  such that the second tube  16  is in fluid communication with the collapsible reservoir  12 . For purposes of this disclosure, the term “fluid” is defined to include any continuous, amorphous substance whose molecules move freely past one another and that has the tendency to assume the shape of its container. Accordingly, a “fluid” may include a liquid or a gas. 
         [0017]    The second tube  16  is comprised of a pliable material that can be manually compressed to restrict fluid flow therethrough. At least a portion of the second tube  16  is in contact with or in close proximity to an outer surface  13  of the collapsible reservoir  12 . Therefore, when an operator squeezes the collapsible reservoir  12  in order to manually ventilate the patient  18 , the operator is also likely to engage and thereby restrict the second tube  16 . 
         [0018]    According to one embodiment, the second tube  16  is secured directly to the outer surface  13  of the collapsible reservoir  12 , and extends generally along the length of the collapsible reservoir  12 . Advantageously, this configuration extends the contact region for the second tube  16  such that an operator does not need to find a specific point of contact in order to operate the device. According to another embodiment, the second tube  16  is disposed about the periphery of the collapsible reservoir  12  in a pattern adapted to increase the likelihood that the second tube  16  will be engaged during collapsible reservoir  12  compression. For example, with reference to  FIG. 2 , it can be seen that by disposing a second tube  16   a  about the periphery of the collapsible reservoir  12  in a generally spiraled pattern, an operator can engage the second tube  16   a  regardless of the orientation at which his or her hand (not shown) approaches the collapsible reservoir  12 . 
         [0019]    According to the exemplary embodiment of  FIG. 1 , the second tube  16  remains open in the absence of an externally applied force such as, for example, a compressive force applied by an operator&#39;s hand (not shown). Allowing the second tube  16  to generally remain open in the manner described prevents the accumulation of excess pressure in the collapsible reservoir system  10 . This operational mode of the second tube  16  functionally replaces a more conventional pressure release valve. 
         [0020]    When an operator generally simultaneously squeezes both the collapsible reservoir  12  and the second tube  16 , the second tube  16  becomes occluded in response to the external force applied by the operator&#39;s hand (not shown) such that all or most of the contents of the collapsible reservoir  12  are directed to the patient  18 . When the collapsible reservoir  12  is subsequently released the patient  18  passively exhales due to the elasticity of his or her lungs. The act of releasing the collapsible reservoir  12  also releases and thereby opens the second tube  16  such that any excess pressure can be released therethrough. According to one embodiment, a backpressure can be exerted to keep the collapsible reservoir  12  inflated. Such backpressure can be exerted by the flow restriction provided by the second tube  16 , or by an optional valve (not shown) which is well known to those skilled in the art, in order to provide positive end expiratory pressure (PEEP). The exhaled gas from the patient&#39;s lungs is transferred back to the collapsible reservoir  12  where it may be recycled during a subsequent collapsible reservoir  12  compression or exhausted through the second tube  16 . 
         [0021]    A primary purpose of the collapsible reservoir system  10  is to transfer a desired quantity of gas to the patient  14  as a means for providing respiratory support and/or anesthesia. Closing the second tube  16  during collapsible reservoir  12  compression is critical to the operation of the collapsible reservoir system  10 . As an example, if the second tube  16  remained open during collapsible reservoir  12  compression, gas within the collapsible reservoir  12  could escape through the exhaust system thereby interrupting the transfer of gas to the patient  14  and defeating the primary purpose of the collapsible reservoir system  10 . By providing the second tube  16  configured in the manner previously described, the collapsible reservoir system  10  can effectively provide respiratory support and/or anesthesia without accumulating excess pressure. It should also be appreciated that the collapsible reservoir system  10  having a second tube  16  that automatically opens and closes is easier to operate than conventional collapsible reservoir systems incorporating a pressure release valve that must be manually opened and closed in a coordinated manner. 
         [0022]    Referring to  FIG. 3 , a collapsible reservoir system  30  is schematically depicted in accordance with an embodiment. The collapsible reservoir system  30  may, for example, be implemented as a component of a medical ventilator system (not shown). The collapsible reservoir system  30  includes a collapsible reservoir  32 , a first tube  34  and a second tube  36 . It should be appreciated that the second tube  36  may include one or more tubes. The collapsible reservoir system  30  will hereinafter be described in accordance with the exemplary embodiment depicted in  FIG. 3  wherein the first tube  34  is configured to transfer gas to and receive gas from a patient  38 , and the second tube  36  is an exhaust tube configured to release gas to atmosphere or transfer it to a scavenging system (not shown). It should, however, be appreciated that the first tube  34  and the second tube  36  may be configured for alternate purposes. 
         [0023]    According to the exemplary embodiment of  FIG. 3 , the collapsible reservoir system  30  is operatively connected to a patient circuit  35  configured to transfer gas to and from the patient  38 . The patient circuit  35  is pneumatically connected to an inlet hose  37  through which the patient  38  can inhale and an outlet hose  39  through which the patient  38  can exhale. The first tube  34  is pneumatically connected to the inlet hose  37  via the patient circuit  35 , and the second tube  36  is pneumatically connected to the outlet hose  39  via the patient circuit  35 . 
         [0024]    The collapsible reservoir  32  generally comprises a pliable bladder or bag that is repeatedly compressed and released in order to manually ventilate a patient. The collapsible reservoir  32  includes an opening  40  configured to pneumatically couple the collapsible reservoir  32  with the first tube  34  such that the first tube  34  is in fluid communication with the collapsible reservoir  32 . 
         [0025]    The second tube  36  is comprised of a pliable material that can be manually compressed to restrict fluid flow therethrough. At least a portion of the second tube  36  is in contact with or in close proximity to an outer surface  33  of the collapsible reservoir  32 . Therefore, when an operator squeezes the collapsible reservoir  32  in order to manually ventilate the patient  38 , the operator is also likely to engage and thereby restrict the second tube  36 . 
         [0026]    According to one embodiment, the second tube  36  is secured directly to the outer surface  33  of the collapsible reservoir  32 , and extends generally along the length of the collapsible reservoir  32 . Advantageously, this configuration extends the contact region for the second tube  36  such that an operator does not need to find a specific point of contact in order to operate the device. According to another embodiment, the second tube  36  may be disposed about the periphery of the collapsible reservoir  32  in a manner similar to that of the second tube  16   a  (shown in  FIG. 2 ) in order to increase the likelihood that the second tube  36  will be engaged during collapsible reservoir  32  compression. 
         [0027]    The second tube  36  operates similarly to the previously described second tube  16  (shown in  FIG. 1 ). More precisely, the second tube  36  generally remains open in the absence of an externally applied force and is adapted to close when an operator compresses the collapsible reservoir  32  in a manner similar to that described in detail hereinabove with respect to the second tube  16 . 
         [0028]    When an operator generally simultaneously squeezes both the collapsible reservoir  32  and the second tube  36 , the second tube  36  becomes occluded in response to the external force applied by the operator&#39;s hand (not shown) such that all or most of the contents of the collapsible reservoir  32  are directed to the patient  38 . When the collapsible reservoir  32  is subsequently released the patient  38  passively exhales due to the elasticity of his or her lungs. The act of releasing the collapsible reservoir  32  also releases and thereby opens the second tube  36  such that gas exhaled from the patient&#39;s lungs is transferred therethrough. The exhaled gas in the second tube  36  may, for example, be released to atmosphere or may be directed to a scavenger system (not shown). 
         [0029]    The collapsible reservoir system  30  may also include a first valve  42  and a fresh gas supply  44  that are both operatively connected to the first tube  34 . The first valve  42  may comprise a check valve configured to restrict fluid flow from the patient back to the collapsible reservoir  32 . The first valve  42  may also be configured to provide a selectable amount of resistance within the first tube  34  in order to ensure the collapsible reservoir  32  remains inflated with gas from the fresh gas supply  44 . According to one embodiment, the fresh gas supply  44  is configured to deliver gas at a higher pressure level than that which is attainable by squeezing the collapsible reservoir  32  such that gas from the collapsible reservoir  32  is prevented from entering the fresh gas supply  44 . The patient  38  can spontaneously inhale and thereby draw gas from the fresh gas supply  44  and the collapsible reservoir  32 . The collapsible reservoir system  30  can also include a second valve  46  operatively connected to the second tube  36 . The second valve  46  is optional and may be implemented to provide positive-end expiratory pressure (PEEP). 
         [0030]    While the invention has been described with reference to preferred embodiments, those skilled in the art will appreciate that certain substitutions, alterations and omissions may be made to the embodiments without departing from the spirit of the invention. Accordingly, the foregoing description is meant to be exemplary only, and should not limit the scope of the invention as set forth in the following claims.