Patent Publication Number: US-2009223519-A1

Title: Ventilation mask

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-in-part Application of U.S. application Ser. No. 11/393,182, which is a Continuation-in-part Application of U.S. application Ser. No. 10/966,062. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a ventilation mask for the ventilation of a patient, which has a mask base and a contour element that fits on the patient&#39;s face. 
     2. Description of the Related Art 
     A ventilation mask with a separate expiratory constituent is described, for example in DE-OS 199 03 732. The base of the mask is rigidly connected into a coupling element, which can be coupled with the expiratory constituent. The expiratory constituent can be fitted with a hose adapter, which connects the breathing mask to a ventilation unit via a ventilation hose. A ventilation mask of this type is suitable especially for use in CPAP therapy. 
     Another ventilation mask is described in DE-OS 101 58 066. A ventilation hose is connected with the ventilation mask by a joint shaped like a spherical segment. An outflow channel for respiratory gas is jointly bounded by an expiratory constituent, on the one hand, and by a coupling element connected with the mask, on the other hand. 
     It is also known that an expiratory system can be realized in the area of a breathing mask by providing several expiratory openings, which are formed as holes or slots, directly in the base of the mask. However, this produces relatively large expiratory noises directly in the area of the patient&#39;s head. This is unacceptable, especially if the mask is to be used during the night. 
     In general, previously known ventilation masks and expiratory systems are relatively loud, since the expiratory openings have relatively compact geometries and thus do not promote sufficiently diffuse outflow. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to construct a ventilation mask of the aforementioned type in such a way that sound emission during expiration is low, a small number of parts are used, and a high level of wearing comfort is achieved. 
     In accordance with the invention, this object is achieved by providing at least one outflow channel for respiratory gas in a transition zone between the base of the mask and the contour element. 
     Locating the outflow channel in the transition zone between the base of the mask and the contour element helps to provide an outflow channel with a relatively elongated shape, so that low flow velocities of the gas and thus low sound emissions are promoted. Furthermore, this location of the outflow channel makes it possible to dimension the outflow channel relatively narrowly to promote a diffuse outflow of the respiratory gas. Due to the elongated dimensioning of the outflow channel, its narrow dimensioning does not lead to an unfavorable increase in flow resistance, but rather a sufficiently large outflow area is provided. 
     The arrangement of the outflow channels in the transition zone between the base of the mask and the contour element also supports favorable manufacture of the parts from the standpoint of tool technology. Furthermore, it provides a very high degree of functionality and effective washing out of carbon dioxide, since the outflow channel is positioned relatively close to the patient&#39;s nose. 
     To prevent closure of the outflow channel by deformations of the structural members bordering the outflow channel, it is proposed that the outflow channel be divided by at least one spacing element. 
     The production of an outflow channel border that can withstand a large load is supported by bounding the outflow channel at least in some areas with a spacing ring arranged between the base of the mask and the contour element. 
     Simple manufacturing from the standpoint of tool technology is assisted by arranging at least one of the spacing elements in the area of the spacing ring. 
     Taking typical material properties into consideration, it is found to be advantageous for the spacing element to be arranged in the area of a spacing ring contact surface that faces the base of the mask. 
     In accordance with another embodiment, at least one of the spacing elements is arranged in the area of the base of the mask. 
     In another fabrication variant, the spacing element is arranged in the area of a spacing ring contact surface that faces the contour element. 
     The shape is defined by the fact that the spacing ring bounds an essentially triangular base area with rounded corner regions, which takes typical facial anatomy into consideration. 
     Favorable flow conveyance is promoted if the outflow channel is bounded in the area of at least one of the triangular legs of the spacing ring. 
     The production of an outflow channel that is as elongated as possible is assisted by bounding the outflow channel in the area of each triangular leg of the spacing ring. 
     In a typical selection of materials, the spacing ring is made of a harder material than the contour element. 
     Simple assembly and handling are assisted by forming the spacing ring and the contour element as a single piece. 
     Injection of the spacing ring on the contour element is an especially helpful way to contribute to simpler handling. 
     Another design variant consists in the spacing ring and the contour element being adhesively bonded to each other. 
     It is also possible for the spacing ring and the contour element to be welded together. 
     A modular design of the device can be realized by detachably fastening the spacing ring and the base of the mask to each other. 
     Simple assembly is also assisted by fastening the spacing ring and the base of the mask to each other by a snap connection. 
     Optimum utilization of this component geometry is achieved by providing this fastening in the transition zones between the triangular legs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       In the drawing: 
         FIG. 1  is a schematic illustration of a ventilation device with a ventilation mask; 
         FIG. 2  is a perspective view of a base of the ventilation mask; 
         FIG. 3  is a perspective view of the base of the mask in accordance with  FIG. 2  together with a spacing ring and a contour element; 
         FIG. 4  shows a top view in viewing direction IV in  FIG. 3 ; 
         FIG. 5  is a schematic illustration of the spacing ring 
         FIG. 6  is a schematic view of the mask and a patient showing inhalation; 
         FIG. 7  is a view as in  FIG. 6  showing exhalation; 
         FIG. 8  is a perspective view showing exhalation; and 
         FIG. 9  is a view as in  FIG. 6  showing a transition phase in connection with exhaling of the patient and before inhaling begins. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows the basic construction of a ventilation device. In the area of the unit housing  1 , which has an operating panel  2  and a display  3 , a respiratory gas pump is installed in an internal space in the unit. The connecting hose  5  is attached by a coupling  4 . An additional pressure-measuring hose  6 , which can be connected with the unit housing  1  by a pressure input connection  7 , can run along the connecting hose  5 . To allow data transmission, the unit housing  1  has an interface  8 . 
       FIG. 1  also shows a ventilation mask  10 , which is designed as a nasal mask. The mask can be fastened on the head of a patient by a head fastening device  11 . A coupling element  12  is provided in the expanded region of the ventilation mask  10  that faces the connecting hose  5 . 
       FIG. 2  shows a perspective view of the base  13  of the ventilation mask  10 . The base  13  of the mask has a mounting component  14  for the coupling element  12 . In the embodiment shown in  FIG. 2 , the mounting component  14  is designed to receive a part of the coupling element  12  which has the form of a ball joint. The mounting component  14  circumscribes an inlet opening  15  of the base  13  of the mask. 
     An opening  16  is provided, which faces away from the inlet opening  15  and is bordered by an edge  17 . The edge  17  has an essentially triangular contour with three legs that are rounded at their points of transition into each other.  FIG. 2  also shows a mounting component  18  for the head fastening device  11  shown in  FIG. 1  or for comparable strap-like fastening devices and mounting components  19 ,  20  for a forehead support, which is not shown in the drawings. 
       FIG. 3  shows a perspective view of the base  13  of the mask in accordance with  FIG. 2  in a rotated position together with a spacing ring  21  and a contour element  22 . The spacing ring  21  is shaped to conform to the shape of the edge  17  and thus likewise has an essentially triangular base contour with rounded corner regions. In the region of the border of the spacing ring  21  that faces the base  13  of the mask, the triangular legs  23 ,  24 ,  25  of the spacing ring  21  are provided with spacing elements  26 , which are formed essentially as webs. The spacing elements  26  extend essentially transversely to the longitudinal direction of the triangular legs  23 ,  24 ,  25 . 
     The base  13  of the mask and the spacing ring  21  are typically made of a hard or moderately hard plastic. The contour element is made of a relatively soft plastic, so that it fits comfortably on the patient&#39;s face. The flexibility of the contour element  22  is supported especially by sealing lips  28  provided on the contour element  22  in its expanded region that faces away from the base  13  of the mask. 
     Alternatively to the arrangement of the spacing elements  26  in the area of the spacing ring  21 , they can also be formed on the edge  17  of the base  13  of the mask. It is also conceivable to provide both the spacing ring  21  and the base  13  of the mask with spacing elements  26  in their facing expanded regions. 
       FIG. 4  again illustrates the shape of the base  13  of the mask. In addition, portions of the sealing lips  28  of the contour element  22  are visible through the inlet opening  15 . 
       FIG. 5  shows a top view of the spacing ring  21 . The drawing shows the surfaces of the triangular legs  23 ,  24 ,  25  that bound the outflow channels  27 . The spacing elements  26  are not shown in  FIG. 5 . 
     The ventilation mask is suitable for carrying out different types of ventilation. For example, CPAP ventilations, APAP ventilations, bilevel ventilations, home ventilation as well as emergency ventilation shall be mentioned. Typically, the ventilation gas is made available from a pressurized gas source and is conducted through a ventilation gas hose to the ventilation mask. For example, the pressurized gas source may be provided with a blower for building up pressure and for conveying the necessary volume flow of ventilation gas. 
     The outflow channel  27  is made available in the area of the ventilation mask, wherein the outflow channel  27  defines the outflow opening. This provides for a defined leakage of ventilation gas. Ventilation gas and/or gas expired by the patient can continuously flow off through this leakage. 
     The ventilation mask is constructed as a passive component which is not provided with a valve for actively interrupting or deflecting a gas flow of expired gas. A patient carrying the ventilation mask has to perform only little expiration work or no expiration work at all because the ventilation gas is supplied to the patient with pressure support and the patient therefore does not have to blow the expired air from the mask. However, the expired gas is rinsed out through the expiration gap by the subsequent pressurized fresh ventilation gas and, thus, the expired gas is removed from the area of the ventilation mask. Typically, the used ventilation gas is mixed with fresh ventilation gas in order to accelerate the rinsing process. The fresh incoming ventilation gas which is under excess pressure ensures an effective rinsing of carbon dioxide. 
     The outflow opening is typically dimensioned in such a way that a pressure range of 0 to 35 mbar is covered by a suitable selection of the length, the width and the height. By optimizing the dimensions, it is possible to use the ventilation mask up to a pressure of 50 mbar. With respect to time, the flow resistance to the ventilation gas is essentially constant. In at least one state of operation, an excess pressure of at least 2 mbar prevails in the interior of the mask, wherein the pressure may increase up to a pressure of 35 mbar. 
     As illustrated in  FIG. 5 , the outflow opening is arranged distally relative to the inflow opening and is therefore located at the area of the greater circumference of the mask. As a result of this shape of the ventilation mask, it is possible to achieve a sound level of less than 31 dBa at a distance of one meter from the ventilation mask. This also makes possible a good compliance by the patient. 
     The flow through the outlet opening typically is 10-30 l/min at a pressure of about 4 hpa. In accordance with a preferred embodiment, the outflow opening extends over more than a third of the circumference of the outer limit of the mask, as illustrated in  FIG. 5 . The outflow gap typically has a length extension of at least 30 mm. A length extension of at least 40 mm is preferred in order to make available a large outflow area. 
     The outflow channel has a small width in relation to the length and, consequently, has a narrow shape. A typical width is at most 1.5 mm, preferably at most 1 mm. Particularly preferred is a range of 0.1 and 0.4 mm. The width of the outflow channel is predetermined by the spacer ribs used. The narrow configuration of the outflow channel makes it possible in combination with the large outflow area to provide a diffuse and quiet outflow of the ventilation air. 
     No further structural elements which could influence the flow are arranged in the outflow channel between the spacing ribs. As illustrated in  FIG. 3 , the outflow channel has an outflow angle which is directed away from the patient. The outflow angle is formed by the geometry of the transition from the mask body to the spacing element or from the spacing element to the contour element. Moreover, the outflow channel is constructed with a slightly greater length because of the selected outflow angle, so that the sound emission is further reduced. 
     In order to adapt the ventilation mask to the anatomy of a user, the mask has in the area of its contact surface with the face of the user an essentially triangular basic configuration. 
     The ventilation mask is composed of only three components. This makes it possible to quickly and easily disassemble the mask for cleaning purposes. Because of the low number of structural components, the manufacturing costs are also low. 
     The configuration of the ventilation mask of three releasably connected structural components provides the additional advantage that the individual structural components can be easily exchanged. Any structural component which may be defective can be replaced while the other components can be reused. 
     In accordance with another embodiment, it is also possible to replace the contour element with an alternative transition element, wherein the alternative transition element has a different shape from the originally used contour element. The different shape may refer, for example, to the use of a sealing lip, the material selection or the material hardness. 
     As a result, an individual adjustment to a face contour of the respective user is possible. 
     It is also feasible to replace the spacing ring against another differently shaped spacing ring. The differently shaped spacing ring has the purpose of making available different geometries of the outflow channel. Consequently, depending on the therapy pressure required for the respective user, the outflow channels can be adapted to the ventilation gas flow. 
     Consequently, this provides the advantage for the user that an adjustment of the rinsing of carbon dioxide and the minimization of sound emission can take place which is adapted to the individual requirements of the user in an optimum manner. Such an optimization can be effected by means of providing different heights of the spacer elements which define the outlet channel. 
     In accordance with another embodiment, it is also possible to further reduce the number of structural components by using the two-component technology. For example, the spacer ring can be adapted with the use of the two-component technology to the contour element and/or the mask body. 
       FIG. 6  shows an arrangement of the breathing mask  10  next to the head of a patient, whereby for the purposes of illustrating the flow directions the breathing mask  10  is shown at a distance from the patient&#39;s head. When actually used the breathing mask  10  would rest against the patient&#39;s face with the sealing lips  28 . 
       FIG. 6  shows the flow of breathing gases during inhalation by the patient. Fresh air is drawn through the coupling element  12  and flows into an interior space  29  of the mask. Via the mask interior  29 , the fresh breathing gas reaches the mouth and nose of the patient, and can be inhaled. A quantity of breathing gas beyond what is needed by the patient is guided out to the surrounding environment through the outflow channels  27 . The outflow channel  27  provides a permanent leakage for the breathing mask  10 . 
       FIG. 7  shows the same arrangement as in  FIG. 6 , during exhaling. Used air flows out of the patient&#39;s nose into the interior  29  of the mask and from there flows mainly out of the outflow channels  27  into the environment surrounding the breathing mask  10 . A small portion of the exhaled air flows into the coupling element  12 . 
       FIG. 8  shows the exhaling phase as in  FIG. 7  in a further perspective view in which the breathing mask is shown, contrary to an actual use position, at a distance from the head to better illustrate the air flow. Here it is again shown that the used air flows out through the outflow channels  27  in the region of the spacing ring  21 . 
       FIG. 9  shows the transition phase after exhaling of the patient and before the beginning of inhalation. Fresh air subsequently flowing through the coupling element  12  draws inhaled used breathing air into the inner chamber of the coupling element  12 . This drawn-in air, together with the further used air collected in the interior chamber  29  of the mask, is exhausted through the outflow channels  27  by the following fresh air into the environment surrounding the ventilation mask  10 . Thus, at the beginning of inhalation of a patient the proportion of used air in the interior chamber  29  of the mask is greatly reduced so that the patient at the beginning of inhalation received mainly fresh and thereby oxygen rich air. 
     The fresh air is guided to the coupling element  12  by a typical connecting hose  5  and has an overpressure, typically in a range of 2-45 hpa. The outflow channels  27  that are arranged in the ventilation mask  10  provide a permanent leakage, which does away with the need for a controllable valve in the region of the coupling element  12  or the ventilation mask  10 . The mask  10  can thus be manufactured with a reduced weight relative to conventional masks. 
     The size of the outflow channels  27  or the number of outflow channels  27  is selected so that a majority of the used air is rinsed from the interior chamber  29  of the mask prior to a following inspiration. In particular it is therefore possible to avoid the collection of large amounts of carbon dioxide in the interior chamber  29  of the mask. 
     The used air present in the interior chamber  29  of the mask or in the coupling element  12  is thus directly mixed with following fresh air, diluted and at least to a major extent rinsed out through the outflow channels  27 . 
     Due to the cooperation of components, particularly, as shown in  FIG. 3 , the spacing ring  21  and the spacing elements  26 , gap-like outflow channels  27  are formed between the spacing ring  21  and the base  13  of the mask. The height of these gaps, which height corresponds essentially to the height of the distance elements  26 , is at most 2 mm, preferably at most 1 mm, at most preferably 0.1-0.4 mm. 
     The length of the outflow gaps in a typical flow direction is generally at most 12 mm, preferably less than 9 mm, and most preferably less than 7 mm. The width of the outflow channels measure along the perimeter of the spacing elements  26  is at most 20 mm, preferably at most 15 mm, and most preferably at most 10 mm. 
     The short reduction of at most 12 mm of the length of the outflow channels  27  in the direction of the flow results in a rapid rinsing out of the used air through the outflow channels  27 . 
     Coupling elements for fastening the head band of  FIG. 1  can be molded onto or into the spacing ring  21  by injection molding so that they are integral with the distance ring  21 . 
     Due to the previously mentioned triangular geometry of the spacing ring  21 , the outflow channels  27  are preferably arranged in the region of the base and in the region of the legs of the triangular shape. 
     Connecting elements can be provided in the region of the corners of the triangular shape, which connecting elements serve to connect the spacing ring  21  onto the base  13  of the mask and/or onto the contour element  22 . 
     As fastening elements, snap hooks can be used, for example, and formed on or attached to the spacing ring  21 . The snap hooks could engage by clamping in corresponding engagement elements in the region of the base  1  of the mask and/or the contour element  22 . 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.