Abstract:
An apparatus and method for performing warming therapy is described. In one exemplary embodiment, the apparatus includes a patient support assembly and a pump assembly coupled to the patient support assembly, for providing heated air to a patient. The pump assembly may include one or more heating elements coupled to the sidewalk thereof for providing heating of air flowing through the pump assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/112,383, filed Nov. 7, 2008, the entire contents of which is hereby incorporated by reference, as if fully set forth herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This present invention relates generally to a method and apparatus for performing warming therapy on medical patients. More particularly, the present invention relates to a method and apparatus for providing heating to a medical patient utilizing a pump assembly with heating members integrated into the walls of the assembly. 
       BACKGROUND OF THE INVENTION 
       [0003]    Warming therapy devices are known to provide heated air to an environment surrounding a medical patient (e.g., infant) to promote growth and development. Incubators are a type of warming therapy device that utilize a hood to enclose a patient, and thereby isolate him or her from the outside environment. In many incubators, the various parameters of the microenvironment within which the patient is disposed (i.e., the area inside the hood of the incubator) are controlled using sensors and other devices. For example, heat within the microenvironment is often provided and controlled using standard air pumps (e.g., fans) and convective heaters. In such a scenario, the convective heater generates heat which is carried to the patient by microenvironment air, which is put in motion by the air pump. In many cases, the convective heaters are disposed separately from the air pumps (and in some cases a discrete distance away from the air pumps), which results in hydraulic losses in the air circulation system. For example, convective heaters in warming therapy devices are often equipped with ribs and/or other members which intensify heat exchange between the heater and the microenvironment air, and such members can cause hydraulic losses, which impact the efficiency of the air circulation system. 
         [0004]    For example, U.S. Pat. No. 4,846,783, the disclosure of which is hereby incorporated by reference in this application, as if fully set forth herein, shows a conventional warming therapy device (i.e., incubator) including a fan  2  and heater  4  for supplying heated air to an infant patient disposed on a cot  9  overlying a resting surface  7 . The fan  2  blows air past the heater  4 , where it is heated and provided to an air outlet  21 , and subsequently to the infant patient. The air outlet  21  includes a plurality of guide ribs  24  for guiding the air flow upward through an intermediate space  30 , and into the incubator interior  6 . 
         [0005]    U.S. Pat. No. 5,935,055, the disclosure of which is hereby incorporated by reference in this application, as if fully set forth herein, shows another conventional warming therapy device including a lying surface  1  for a patient, and a housing  8  (i.e., hood) for surrounding the patient. Also included are a fan  4  and electric drive motor  5  for rotating the fan. A circular air heater  6  surrounds the fan  4  and operates to heat the air inside the housing  8 . In particular, heated air is blown by the fan  4  to first and second nozzles  11  (as shown by the directional arrows in  FIG. 2 ), where it is transmitted into the upper part of the housing  8  through parallel slots  7  which run along the two long sides of the housing. Exhaust slots  9  are provided along the two short sides of the housing  8  for collecting the air transmitted to the upper portion of the housing, and for returning such air to the area around the fan  4 . 
         [0006]    However, the air heating and circulation systems associated with conventional warming therapy devices (such as the ones discussed above) often have reduced hydrodynamic efficiency, due to the separation between the respective fans and the heater exchange intensification members (such as ribs). Such conventional systems are also often large in size, due to the separation of the fans and heaters, and also due to ancillary portions of the system (e.g., air guide ribs, heat transfer ribs). Conventional systems including such ancillary portions are also often difficult to clean, due to the location and configuration of such ancillary portions. For example, the air guide ribs discussed above with regard to U.S. Pat. No. 4,846,783 are integrated into the base of the warming therapy device, and thus difficult to access and clean using standardized methods. Because one of the objectives of a warming therapy device is to create a sterile and hygienically sound environment for the patient, an air heating and circulation system, which may be easily disassembled and cleaned is highly desirable. Finally, the air heating and circulation systems associated with conventional warming therapy devices often include electrical connections to the heater, which are exposed in some manner to the oxygen present within the device. Accordingly, any broken connection or wire could potentially cause a fire in an oxygen-rich environment such as inside the warming therapy device. 
         [0007]    Accordingly, there is presently a need for a warming therapy device that includes an air heating and circulation system which is small in size, which may be easily disassembled and cleaned, and which is not subject to substantial fire risks, but which also maintains a high hydrodynamic efficiency. 
       SUMMARY OF THE INVENTION 
       [0008]    An exemplary embodiment of the present invention comprises an apparatus including a patient support assembly and a pump assembly coupled to the patient support assembly, wherein the pump assembly includes a volute housing with first and second portions, and a heating element coupled to the first portion of the volute housing. 
         [0009]    An exemplary embodiment of the present invention also comprises an apparatus including a patient support assembly, a mattress tray assembly coupled to the patient support assembly, and a pump assembly coupled to the mattress tray assembly, wherein the pump assembly includes a volute housing with first and second portions, and a heating element coupled to the first portion of the volute housing. 
         [0010]    An exemplary embodiment of the present invention also comprises a method of providing warming therapy to a patient, the method including the steps of providing a mattress tray assembly for supporting a patient, providing a pump assembly in proximity to the mattress tray assembly, the pump assembly including a volute housing with first and second portions, and a heating element coupled to the first portion of the volute housing, and activating the pump assembly to force air through the pump assembly, said air being heated by the pump assembly and being output to the area surrounding the mattress tray assembly for warming the patient. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is perspective view of a warming therapy device according to a first exemplary embodiment of the present invention. 
           [0012]      FIG. 2  is an overhead perspective view of the warming therapy device of  FIG. 1 . 
           [0013]      FIG. 3  is top partial cross-section view of a pump assembly according to a first exemplary embodiment of the present invention. 
           [0014]      FIG. 4  is top partial cross-section view of a pump assembly according to a second exemplary embodiment of the present invention. 
           [0015]      FIG. 5  is a top plan view of the pump assembly shown in  FIG. 4 , without the thermal insulation layer and with the heating element extending the length of the volute. 
           [0016]      FIG. 6  is a perspective view of the pump assembly shown in  FIG. 4 , without the thermal insulation layer and with the heating element extending the length of the volute. 
           [0017]      FIG. 7  is an exploded perspective view of a mattress tray assembly according to an exemplary embodiment of the present invention. 
           [0018]      FIG. 8  is a side cross-section view of the mattress tray assembly shown in  FIG. 7 , with an infant patient disposed therein. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    The present invention relates to a warming therapy device (e.g., incubator, warmer, etc.) including a pump assembly with an integrated heating element. In particular, the warming therapy device includes a pump assembly with a volute for circulating and distributing air which includes heated sidewalls. 
         [0020]    Conventional warming therapy devices use standard air pumps and separate convective heaters. In many cases, the convective heaters are disposed separately from the air pump (and in some cases a discrete distance away from the air pump). Such separation, coupled with the introduction of heat transfer intensification members (e.g., ribs coupled to the heaters), can lead to a loss in hydrodynamic efficiency of the overall heating system. The present invention allows efficient convective heating of air without a corresponding reduction in the hydrodynamic efficiency of the air circulation system. Another advantage of the present invention is reduction in size. Particularly, by combining the air pump and the heater into a single assembly, space inside the warming therapy device is conserved, and thus the overall size of the warming therapy device structure may be decreased. Yet another advantage is the ease of cleaning the pump assembly as compared to conventional pump and heater assemblies. In particular, standard heaters normally use a plurality of ribs to intensify heat transfer from the heater to the surrounding air. These ribs can make heaters difficult to clean, due to their size and placement. The present invention allows heat transfer intensification by positioning the heater in the volute of the air pump (where air velocity is high), so that the walls of the volute are flat, and do not include any ribs or other heat transfer intensification members, making them easier to clean. Yet another advantage of the present invention is a separation of the heated fluid or gas (in the volute) and the electrical connection to the heater (which may be disposed outside the volute). This is an important safety feature when, for example, the gas traveling in the volute is oxygen rich air. 
         [0021]      FIGS. 1 and 2  show a warming therapy device  10  according to a first exemplary embodiment of the present invention. The warming therapy device  10  includes a radiant heater head  20 , and a patient support assembly  30  including a mattress tray assembly  40 . The mattress tray assembly  40  may include a hood  45  which has a top portion  46  which pivots about one or more axes  47 . The hood  45  may also include one or more sidewalls  48  which may be slideable, removable, pivotable or rotatable. The mattress tray assembly  40  also preferably includes a mattress tray  42 , with a mattress  41  disposed therein. The warming therapy device  10  may optionally include a backplane  50 , to which ventilation hoses and other devices may be coupled through, for example, interconnection nozzles  51 . 
         [0022]      FIG. 2  shows the top portion  46  of the hood  45  rotated up so that it is approximately ninety degrees (90°) with respect to the mattress tray  42 . In the exemplary embodiment shown in  FIG. 2 , the sidewalls  48  of the hood  45  are capable of sliding vertically within a portion of the mattress tray assembly  40 , so that they may become disposed, partially or completely, below the plane of the mattress tray  42 . 
         [0023]    Referring again to  FIGS. 1 and 2 , either of the patient support assembly  30 , or the mattress tray assembly  40  of the warming therapy device  10 , may include a pump assembly  200 ,  300  (as described below) for circulating heated air to a patient disposed on the mattress  41 . For example, the pump assembly may be disposed within the mattress tray assembly  40 , as a position directly underneath the mattress tray  42 .  FIG. 7 , discussed below, shows an exemplary embodiment of how either of the pump assemblies  200 ,  300  may be integrated with a warming therapy device. 
         [0024]      FIG. 3  shows a pump assembly  200  according to a first exemplary embodiment of the present invention. The pump assembly  200  includes a rotor  210  (e.g., fan and motor), a volute housing  220 , a heating element  230 , and a thermal insulation layer  240 . The rotor  210  may include one or more blades  215  for circulating gas (e.g., air, oxygen, etc.) or liquid through the pump assembly  200 . The rotor  210  also includes an inlet or intake  216  passage disposed at the center of the blades  215 . The volute housing  220  includes an outlet passage  225 , where air circulated within the rotor  210  leaves the volute housing. 
         [0025]    The rotor  210  rotates within the volute housing  220 , and pumping action is achieved by rotation of the blades  215  within the gas or liquid-filled area. The rotor  210  may rotate clockwise (as shown in  FIG. 3 ), or counterclockwise. In either rotating direction, gas or liquid enters through the inlet passage  216 , and is pushed towards the outer edges of the rotor  210 , as shown by the smaller “FLOW” lines in  FIG. 3 . The gas or liquid continues to flow out through the outlet passage  225 , as shown by the larger “FLOW” line in  FIG. 3 . As an alternative to the rotor  210  shown in  FIG. 3 , other mechanisms may be used to impose rotation on the gas or liquid, such as a “Tesla” pump, which can circulate gas and/or liquid through viscous friction. The gas or liquid is circulated within the rotor and moved towards the outlet passage  225  of the volute housing  220 . Gas or liquid, which enters the pump assembly  200  through the intake  216 , obtains a dynamic pressure as it is rotated within the rotor  210 . This dynamic pressure is converted into static pressure at the outlet passage  225 . 
         [0026]      FIG. 4  shows a pump assembly  300  according to a second exemplary embodiment of the present invention. The pump assembly  300  is similar in many respects to the pump assembly  200  described above, and like reference numerals denote like elements. One difference between the pump assembly  300  and the pump assembly  200  is the placement of the heating element and thermal insulation layers. Particularly, the heating element and thermal insulation layer are both disposed on an outer side of a wall of the volute housing. The pump assembly  300  includes a rotor  310  (e.g., fan and motor), a volute housing  320 , a heating element  330 , and a thermal insulation layer  340 . The rotor  310  may include one or more blades  315  for circulating gas (e.g., air, oxygen, etc.) or liquid through the pump assembly  300 . The rotor  310  also includes an inlet or intake passage  316  disposed at the center of the blades  315 . The volute housing  320  includes an outlet passage  325 , where gas or liquid circulated within the rotor  310  leaves the volute housing. As with the pump assembly  200 , the rotor  310  rotates within the volute housing  320 , and pumping action is achieved by rotation of the blades  315  within the gas or liquid-filled area. 
         [0027]    As noted above, the heating elements  230 ,  330  may be coupled to the wall of the respective volute housings  220 ,  320  on the inside, as shown in  FIG. 3 , or on the outside, as shown in  FIG. 4 . Alternatively, the heating elements  230 ,  330  may be coupled to the inside wall of the respective volute housings  220 ,  330  using over-molding or other equivalent technologies. The heating elements  230 ,  330  may comprise electrical heating elements, such as flexible flat heating elements which can be coupled to the walls of the respective volute housings  220 ,  320  through adhesive, glue, or other equivalent attachment means. Alternatively, the heating elements  230 ,  330  may comprise electrical or non-electrical heating elements, such as a Peltier thermoelectric element, resistive heating elements mounted into the volute wall, or any other surface which provides heating, which can be shaped in the form of the walls of the respective volute housings  220 ,  320 . 
         [0028]    In operation, the heating elements  230 ,  330  may heat the rotors  210 ,  310  and blades  215 ,  315  through thermal radiation, in which case the gas or liquid within the respective assembly is further heated by the rotors. The gas or liquid within the pump assemblies  200 ,  300  should be substantially transparent to thermal radiation for efficient heating of the rotors  210 ,  310 , but such is not a requirement of the present invention. For example, air has a high transparency to thermal radiation, and therefore will provide a good medium for operation of the pump assemblies  200 ,  300 . Alternatively, gases and liquids with lower infrared transparency such as water or water vapor will be heated directly by thermal radiation from the volute wall heaters. 
         [0029]    As noted above, the thermal insulation layers  240 ,  340  may be coupled to the outside wall of the respective volute housings  220 ,  320 , as shown in  FIG. 3 , or to an outer surface of the heating element  330 , as shown in  FIG. 4 . In either embodiment, the thermal insulation layers  230 ,  330  substantially prevent excessive heat loss from the pump assemblies  200 ,  300 . 
         [0030]    Although  FIGS. 3 and 4  show the heating elements  230 ,  330  and the thermal insulation layers  240 ,  340  terminating near the respective outlet passages  225 ,  325  of the volute housings  220 ,  320 , those of ordinary skill in the art will realize that the heating elements  230 ,  330  and/or the thermal insulation layers  240 ,  340  may continue on, depending on the length of the outlet passages  225 ,  325 , and the amount of heating required. For example,  FIGS. 5 and 6  show an exemplary pump assembly, which is similar to the pump assembly  300  shown in  FIG. 4 , where the heating element  330  is disposed on an outer wall of the volute housing  320 . The pump assembly shown in  FIGS. 5 and 6  includes a volute housing  320  with an extended outlet passage  325 , where the heating element  330  extends the entire length of the volute housing. 
         [0031]      FIG. 7  shows an exploded perspective view of a mattress tray assembly  400  according to an exemplary embodiment of the present invention, which includes at least one of the above-described pump assemblies  200 ,  300  disposed within a support base  481 . The mattress tray assembly  400  is similar to the mattress tray assembly  40  shown in  FIGS. 1 and 2 , and like reference numerals denote like elements. 
         [0032]    The mattress tray assembly  400  may include a hood  445  for creating an incubation chamber, and may also include a mattress tray  412  for receiving a mattress (not shown). The support base  481  may include one or more rotors  460 , which form part of the above-described pump assemblies  200 ,  300 . The rotors  460  may be inserted within the support base  481  as shown, and sealed by a rotor cover  470 . The support base  481  may also include a cover  482 , and a weight scale  483  disposed beneath the mattress tray  412 . Although the exemplary embodiment shown in  FIG. 7  includes only one rotor  460  (and correspondingly one pump assembly and/or volute housing), those of ordinary skill in the art will understand that two or more rotors  460  may be disposed within the support base  481 , each corresponding to a respective pump assembly or volute housing. As will be further understood by those of ordinary skill in the art, when utilizing multiple rotors  460 , the volute housings (e.g.,  220 ,  320 ) of the pump assemblies (e.g.,  200 ,  300 ) may be formed as separate units, or as a unitary member. The use of a pump assembly with two or more volutes, or the use of two or more pump assemblies, provides the benefits of efficiency and scalability. In particular, if only a small amount of heating is required, only one of the rotors  460  need be activated, which may in turn circulate heated air in only one of the pump assemblies and/or volute housings, thus conserving energy. Alternatively, if a large amount of heating is required, one or more of the additional rotors  460  may be activated, which in turn circulates heated air in the additional pump assemblies and/or volute housings, decreasing the overall time required to heat the associated warming therapy device, and thus conserving energy. 
         [0033]      FIG. 8  is a side cross-section view of the mattress tray assembly  400 , showing the placement of the pump assembly (e.g., pump assembly  200  or  300 ), and an infant patient  480  disposed thereon. As shown, either pump assembly  200 ,  300  may be disposed within the mattress tray assembly  400  at a position underneath the mattress tray  412 , and the infant patient  480 .  FIG. 8  also shows a mattress  443  disposed on the mattress tray  412 , on which is disposed the infant patient  480 .  FIG. 8  also shows an optional convective heater  460  which may be disposed within the mattress tray assembly  400 , and used for additional heating, if necessary. As shown, air is drawn in from outside the mattress tray assembly  400  by the pump assembly, and then circulated to the microenvironment surrounding the infant patient  480 . Due partially to the configuration of the hood  445 , the heated air passes over the body of the infant patient  480 , and back into the pump assembly. This process creates a heated microenvironment of the desired temperature for the infant patient  480 . 
         [0034]    As will be noted by those of ordinary skill in the art, the pump assemblies  200 ,  300  according to first and second exemplary embodiments may be integrated into a warming therapy device such as the device  10  shown in  FIG. 1 . For example, the pump assemblies  200 ,  300  may be formed inside the patient support assembly  30  at a position underneath the mattress tray  42 . 
         [0035]    Further, although the pump assemblies  200 ,  300  according to the first and second exemplary embodiments are shown and described above with reference to an associated warming therapy device  10  of a specific configuration, those of ordinary skill in the art will realize that the pump assemblies  200 ,  300  may be integrated into any suitable incubator, warmer, medical treatment device or other equivalent apparatus. Those of ordinary skill in the art will also realize that the pump assemblies  200 ,  300  may be used in other medical or non-medical applications, where efficient convective heating is required without significant losses in hydraulic efficiency. Further, although the pump assemblies  200 ,  300  are described above with reference to air or oxygen comprising the circulated gas or liquid, those of ordinary skill in the art will realize that the any liquid or gas may be heated and circulated using the pump assemblies  200 ,  300  according to the present invention. 
         [0036]    Although exemplary embodiments of the present invention has been described above for use in procedures involving infant patients, those of ordinary skill in the art will realize that the warming therapy device  10 , and pump assemblies  200 ,  300 , according to the exemplary embodiments of the present invention, may be used for other types of operations and procedures, including for children and adults without departing from the scope of the present invention. 
         [0037]    Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly to include other variants and embodiments of the invention which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention. This disclosure is intended to cover any adaptations or variations of the embodiments discussed herein.