Patent Publication Number: US-2022233380-A1

Title: Negative-pressure dome

Description:
TECHNICAL FIELD 
     The present disclosure relates to protective equipment suited for medical procedures performed on a subject&#39;s head, in particular in a subject&#39;s mouth. 
     BACKGROUND 
     When a person infected with a contagious condition exhales aerosols, these aerosols may remain suspended in the surrounding atmosphere for an extended period of time. Generally, social distancing and wearing filtering masks mitigate the dangers to other people in indoor settings. In some situations, however, social distancing and mask-wearing are not feasible. For example, dental work requires close proximity between the dentist and the subject. Also, a filtering mask would obstruct access to the oral cavity. There are other situations, in which a subject&#39;s mouth or nose need to remain accessible. 
     SUMMARY 
     Accordingly, it is desirable to provide a device that mitigates the presence of pathogen-carrying aerosols in the vicinity of an infected person while also providing access to and visibility of the oral or nasal cavities. 
     The present disclosure presents negative-pressure dome comprising a transparent domed shield; a flexible skirt attached to the perimeter of the domed shield; a hose attachment port formed on the domed shield; and access openings in at least one of the domed shield and the flexible skirt. This arrangement allows great visibility of a subject&#39;s face while keeping any exhaled pathogens from entering the space surrounding the negative-pressure dome. The transparent domed shield preferably consists of a clear rigid plastic to provide undistorted visibility. 
     The skirt may be transparent, either to allow outside light to illuminate the space covered by the domed shield or to provide additional visual access. 
     In order to mitigate the required suction power of a vacuum pump creating a negative pressure within the negative-pressure dome, the access openings may be at least partially occluded by flexible flaps that are deflectable to increase an open cross-section of respective access openings when a tool is inserted. 
     For best optical properties, the domed shield forms a partial ovoid, ellipsoid, or sphere. One or more light sources affixed to the domed shield and directed into the domed shield may also enhance the visibility of features within the negative pressure dome. 
     In a first configuration, the access openings are disposed in the domed shield and are sized to have a cross-section between 3 cm 2  and 15 cm 2 . 
     For constituting a space-saving face covering, the domed shield may have a longitudinal length between 20 cm and 30 cm, a lateral width between 15 cm and 25 cm, and a depth between 2 cm and 10 cm. In this configuration, the domed shield may have a padded rim. 
     An arcuate wiper operable to wipe an interior surface of the domed shield via an external actuator may enhance the visual properties by removing potential splatter, for example from dental procedures. The wiper may be pivotably mounted to the domed shield with an operating handle extending out of the domed shield. 
     Alternatively, the access openings may be disposed in the flexible skirt and be sized to have a cross-section between 30 cm 2  and 200 cm 2 . 
     This is in particular useful if the domed shield is sized to extend over ahead and chest of a subject. In such a configuration, the domed shield has a longitudinal length between 50 cm and 100 cm, a lateral width between 30 cm and 80 cm, and a depth between 10 cm and 50 cm. 
     An articulated mount carrying the domed shield keeps the domed shield at such a distance from the subject&#39;s body that a working space is created that allows for easy maneuvering of tools. 
     The articulated mount is attached to the domed shield separately from the hose attachment port so that the hose becomes disposable after every use. In this variation, a hose is in fluid communication with the hose attachment port at a first end of the hose and configured to be connected to a suction port of a vacuum pump at a second end of the hose. The hose is preferably supported by an arm of the articulated mount via a releasable retainer coupling the hose to the arm of the articulated mount. 
     A filter arrangement at the hose attachment port prevents contamination of the parts downstream from the hose attachment port. 
     Alternatively or additionally, a filter arrangement disposed at the suction side of the vacuum pump protects the interior of the vacuum pump from contamination. 
     Further details and benefits of the present disclosure become apparent from the following description of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  shows a first configuration of a negative-pressure dome according to the present disclosure; 
         FIG. 2  shows a partial detail view of the device of  FIG. 1 ; 
         FIG. 3  shows a cross-sectional view through the device of  FIG. 1  along the line III-III; 
         FIG. 4  shows a detail view of a second configuration of a negative-pressure dome according to the present disclosure; 
         FIG. 5  shows the device of  FIG. 4  in an environment of a dental office; and 
         FIG. 6  shows a variation of the second configuration of the negative-pressure dome. 
     
    
    
     The drawings are provided herewith for purely illustrative purposes and are not intended to limit the scope of the present invention. 
     DETAILED DESCRIPTION 
     The present disclosure describes the overall concept of protection against airborne pathogens exhaled by a subject undergoing a facial or oral procedure, such as dental work while ensuring visibility of and access to the target site. The device may also be used for transporting subjects in an ambulance or for subjects in a stationary setting such as in a hospital or a nursing home or home to protect the environment from airborne pathogens in the air exhaled by the subject suffering from or suspected of a contagious respiratory disease. 
     All discussed configurations and variations have in common that a transparent, preferably clear, domed shield in combination with a skirt and a hose attachment creates an individual negative-pressure dome. 
     The protection is effective for subjects sitting upright or in a reclined position as customary in dentist chairs. The protection is limited to the individual subject positioned under or behind the negative-pressure dome so that medical or service personnel is free to move around the subject or to leave the room as needed without endangering other individuals. 
     In this application, the term “negative pressure” defines a pressure lower than the environmental (ambient) atmospheric pressure. Accordingly, the term “negative pressure” indicates a relative pressure compared to the atmosphere, not an absolute pressure: Mathematically subtracting the atmospheric pressure from the pressure inside the negative-pressure dome results in a negative value. 
     The present disclosure presents two configurations of a negative-pressure dome  10  and  110  with some common and some different features. Where the features differ, features of one of the two configurations may replace the different feature in the other configuration so that this disclosure also encompasses hybrid constructions composed of features from different embodiments. In summary, the two configurations  10  and  110  involve the following features: 
     In the first configuration shown in  FIGS. 1-3 , the negative-pressure dome  10  includes a transparent domed shield  12  attached to a vacuum source (not shown) via a hose  14 . The transparent domed shield consists of a clear rigid plastic and is preferably coated with a scratch-resistant clear coating to mitigate potential scratches from tools. The hose  14  is configured to be connected to a vacuum source, such as a vacuum pump equipped with a suitable filter, e.g. a HEPA filter, at or upstream of the suction port of the vacuum source. The vacuum pump creates suction at the unidirectional air flow through the air exchange arrangement within the range of 2,500 liter per minute through 11,000 liter per minute, wherein openings in the flexible skin and surrounding the flexible skin allow for an air flow compensating for the unidirectional air flow through the air exchange arrangement. 
     The hose may be a corrugated hose configured to withstand vacuum forces without collapsing. While a vacuum source is not shown in  FIGS. 1-3  for the first configuration, it is shown as a compact vacuum pump  116  in  FIGS. 5 and 6  in connection with the second configuration  110 . The hose  14  is attached to the domed shield  12  via a hose attachment port  18  to establish a fluid communication from the interior space of the domed shield  12  to the hose  14 . The domed shield  12  of the first configuration is dimensioned to cover a human face and thus has a longitudinal length L between 20 cm and 40 cm, lateral width W between 15 cm and 30 cm, and a depth D between 2cm and 10 cm 
     The negative-pressure dome includes a skirt  20  attached to the rim  22  of the domed shield  12 . The attachment of the skirt  20  to the rim  22  is preferably achieved by releasable connectors  24  and may, for example, be formed by hook-and-loop connections (known as Velcro®) or snaps distributed along the rim. The domed shield  12  is placed over a subject&#39;s face and may be held in place with clips attaching the skirt to the chair, on which the subject rests. While it is possible to leave the skirt  20  hanging freely, such a skirt  20  would need a sufficient weight and stiffness not to collapse from the applied vacuum. In the shown first configuration, it is not crucial that the skirt  20  is transparent because the domed shield  12  provides a wide viewing angle onto the subject&#39;s face  26  (shown in  FIG. 2 ). A transparent or clear skirt will, however, enhance the illumination of the subject&#39;s face from external light sources. Thus, in addition to transparent flexible films, suitable materials for the skirt  20  are woven, nonwoven, or bonded textiles, including Tyvek®. 
     The domed shield  12  has access openings  28  for treating the subject with various tools. The access openings have cross-sections between 3 cm 2  and about 15 cm 2  and have an elliptical or circular basic shape  30 . Optionally, one or more of the access openings may be enlarged by slits  32  extending away from the elliptical or circular basic shape  30  to ease the introduction and movement of tools. 
     Flexible flaps  34  may be disposed in the access openings  30  to operate as self-closing valves to limit the overall open cross-section in communication with the surroundings. The flexible flaps  34  are deflectable to increase an open cross-section of the access openings  30 . The flaps  34  don&#39;t need to seal the access openings  30  completely as influx of surrounding air into the interior of the domed shield  12  is part of the operating principle. The suction of the vacuum pump creates a unidirectional air flow through the hose  14  of several hundreds of liters per minute, wherein the access openings  28  in the domed shield  12  and gaps at the edge of the skirt  20  allow for an air flow of surrounding air into the negative-pressure dome. 
     Vacuum suction is applied through the hose  14  at a sufficient flow rate to draw room air into the domed shield  12  through gaps between the skirt  20  and the surface on which it rests and through the open cross-sections of the access openings  30 . The hose  14  leads to a HEPA filter and the suction port of the suction device as mentioned above. The domed shield  12  can be sterilized and reused. The skirt  20 , the hose  14 , and the HEPA filter may be of single-use and disposable after each use. 
     Further optional features of the negative-pressure dome  10  of the first configuration include light sources  36  attached to the outside or to the inside of the domed shield  12 . The light-sources may be LEDs consuming little energy that can be supplied by small batteries, for example button cell batteries, that do not obstruct the field of vision. 
     Additionally, especially for implementations involving splatter, a wiper  38  operable from the outside may be installed inside the domed shield  12 . The wiper  38  shown is pivotably arranged behind the domed shield  12 . an operating handle or crank  40  enables an external operation to swing the wiper up ( FIG. 1 ) or down ( FIG. 2 ) out of the field of vision. The wiper  38  has a curvature adapted to make a line-shaped contact with the interior surface of the domed shield  12  over a range different angular positions so that at least a working area can be cleared of splatter without removing the negative-pressure dome  10 . 
     The rim  22  may be equipped with elastomeric padding  42 , for example made of soft silicone or closed-cell foam, that allows surface cleaning and does not trap pathogens in crevices. this may facilitate comfortable support of the domed shield  12  on a subject&#39;s head or head rest without cutting into the subject&#39;s neck. The padding is not intended to form a seal  42  because environmental air needs to enter the domed shield  12  past the padding  42 . 
     Now referring to the second configuration shown in  FIGS. 4-6 , a larger domed shield  110  may be more feasible for applications requiring greater movements or larger tools. In the second configuration  110 , the domed shield  112  is sized to extend over a subject&#39;s head and chest. The domed shield  110 , exclusive of the skirt  120  has dimensions in the following ranges: a longitudinal length L between 50 cm and 100 cm, a lateral width W between 30 cm and 80 cm, and a depth D between 10 cm and 50 cm. It is placed at a greater distance from the subject to provide more maneuvering space within the negative-pressure dome  110 . As the domed shield  112  is placed at a greater distance from the subject&#39;s head than in the first configuration, the skirt  120  is preferably made of a clear transparent material. The domed shield is preferably transparent or clear as well. 
     Rather than in the domed shield  112 , in this configuration, the access openings  128  are disposed in the skirt  120  so that the operator can reach the subject through the access openings  128  or from under the skirt  120 . The number, size and location of access openings  128  can be tailored for various procedures as needed. Generally, each access opening  128  has an opening cross-section between 30 cm 2  and 200 cm 2  because not only the tip of a tool needs to be inserted, but typically the operator&#39;s gloved hand as well. 
     The skirt  120  around the perimeter of the domed shield  112  has a length dimensioned to rest on the subject&#39;s upper torso and to hang down behind the subject&#39;s head. If desired, the skirt  120  of the second configuration may be pre-molded into a desired approximate shape with enough flexibility to adapt to the subject&#39;s body shape. 
     To create a suitable working space, the domed shield  112  is suspended or otherwise supported above the subject&#39;s face. As shown in  FIG. 5 , illustrated to resemble a dental operatory, the negative-pressure dome  110  is held by an articulated mount  144  supported by a floor stand  146 . The floor stand is only schematically illustrated and is generally designed to provide sufficient counter weight to prevent toppling of the assembly. In a variation, the articulated mount  144  may be mounted to a wall or to the ceiling. The articulated mount allows tilting of the domed shell  112  in all directions and may include a universal joint (also called cardan joint) or a ball joint, especially a hollow ball joint as customary in shower heads. 
     In a first variation of the second configuration as shown in  FIG. 5 , the articulated mount  144  includes an interior air flow lumen  148  in fluid communication with the hose attachment port  118  at a first end of the interior air flow lumen  148 . The interior air flow lumen leads through the arm of the articulated mount to the suction port  150  of the vacuum pump  116 . In the variation shown in  FIG. 5 , the vacuum pump  116  may be integrated in the floor stand of the articulated mount. 
     Because the hose attachment port  118  doubles as coupling for the articulated mount  144 , the articulation of the articulated mount  144  is constructed to surround the air flow lumen and to allow an unrestricted air flow from the interior of the domed shield  112  to the vacuum pump  116 . Further, the hose attachment port  118  includes a filter compartment  152  for a suitable particle filter, such as a HEPA filter. 
     A light source  136  may be integrated in the housing of the hose attachment port  118  or of the filter compartment  152  and may be powered by wiring extending through the articulated mount  144  or, alternatively, by a battery accommodated at or in the housing of the filter compartment  152  or of the hose attachment port  118 . 
     In another variation shown in  FIG. 6 , the articulated mount  144  is attached to the domed shield  112  separate from the hose attachment port  118 . Accordingly, a separate hose  114  is connected to the hose attachment port and leads to the suction port  150  of the vacuum pump  116 . The hose  114  is supported by an arm  154  of the articulated mount  144  via a releasable retainer  156  coupling the hose  114  to the arm  154  of the articulated mount  144 . The retainer  156  may be a strap with a snap closure as shown or with a hook-and-loop connection. Alternatively, the retainer  156  may be a resilient Ω-shaped bracket attached to the arm  154  and configured to grip the hose  114  upon insertion. This variation permits the use of a customary arm  154  for the articulated mount  144  of the negative-pressure dome  110  as it is already available for other devices, such as the work light  158 , including electric wiring. In all other aspects, the variation of  FIG. 6  corresponds to the variation of  FIG. 5 . The hose  114  is held in place, so it does not interfere with the field of vision. 
     Both variations have in common that a filter compartment  152  may be disposed upstream of the hose attachment port  118  so that potentially exhaled pathogens are confined to the domed shell  112  and don&#39;t enter the air flow lumen  148  or the hose  114 , respectively. Additionally or alternatively, the suction port  150  may include a suitable filter, especially if the hose  114  is separate from the articulated mount  144  and is disposed after every use. The suction of the vacuum pump  116  creates a unidirectional air flow through the hose  114  or through the air flow lumen  148  amounting to at least 1000 liters per minute, wherein the access openings  128  in the skirt  120  and gaps at the edge of the skirt  120  allow for an air flow of surrounding air into the negative-pressure dome  110 . 
     In all configurations and variations, the vacuum pump  116  generates a sufficient pressure gradient to draw surrounding air into the negative-pressure dome  10  or  110  and draw the inside the negative-pressure dome  10  or  110  out through a HEPA filter. The domed shield  12  or  112  can be sterilized and reused, while he HEPA filter is intended for single-use. The skirt  120  and the hose  114  of the second configuration  110  may be reused, or, if cleaning the skirt  120  is considered too time-consuming, the skirt  120  may also be disposable. In the first configuration  10 , in which the hose  14  is positioned upstream of the filter, the hose  14  is intended for single use only and may be disposed after each use. 
     While the above description pertains to the preferred embodiments of the present invention, the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.