Patient support system
A pressure control apparatus for use in a bed including a pressurized air source, an inflatable air sack, and an independently inflatable cell located adjacent the inflatable air sack. A controller is operable to regulate the pressure in the air sack and to independently alternately pressurize and vent the inflatable cell at a selected frequency.
This is a continuation of application Ser. No. 10/190,807, filed Jul. 8, 2002 which is a continuation of application Ser. No. 09/633,599, filed Aug. 7, 2000, now U.S. Pat. No. 6,415,814, which is a continuation of application Ser. No. 08/804,317, filed Feb. 21, 1997, now U.S. Pat. No. 6,098,222, which is a continuation of application Ser. No. 08/501, 274, filed Jul. 17, 1995, now U.S. Pat. No. 5,606,754, which is a continuation of application Ser. No. 08/350,715, filed on Dec. 7, 1994, now abandoned, which is a continuation of application Ser. No. 08/201,042, filed on Feb. 24, 1994, now abandoned, which is a continuation of application Ser. No. 07/898,970, filed Jun. 15, 1992, now abandoned, which is a continuation-in-part of application Ser. No. 07/555,319, filed Jul. 19, 1990, now U.S. Pat. No. 5,121,513, which application is a divisional application of Ser. No. 07/355,755, filed on May 22, 1989, now U.S. Pat. No. 4,949,414, which application is a continuation-in-part Application of Ser. No. 07/321,255, filed Mar. 9, 1989, now abandoned, all the disclosures of which are incorporated by reference herein.
BACKGROUND AND SUMMARY OF THE INVENTIONTherapeutic percussors and vibrators are known and used to stimulate expectoration of mucous from the lungs. It has been found that by applying undulating or vibratory action to the area of the body adjacent to the thoracic cavity, postural draining or coughing up of sputum is induced thereby reducing the amount of mucous that lines the inner walls of the alveoli.
Various pneumatic and mechanical types of percussors are known in the art. For example, U.S. Pat. No. 4,580,107 to Strom et al. discloses a pneumatic percussor for stimulating the expectoration of mucous. Similarly, U.S. Pat. No. 3,955,563 to Maione discloses a pneumatic percussor useful in the therapeutic treatment of cystic fibrosis and other lung disorders.
Low air loss patient support structures or beds are also known in the medical field. The structures essentially consist of a plurality of inflatable sacs disposed on a frame structure. The patient's weight is uniformly distributed over the supporting surface area of the inflatable sacs. Low air loss beds are known in the art claiming therapeutic value in pulmonary and circulatory care. Low air loss beds are also considered helpful in preventing and treating pressure sores. Exemplary low air loss beds relating to wound care management and prevention include the Flexicair and Restcue beds provided by Support Systems International, Inc.
Alternating pressure low air loss beds are also known in the art. For example, U.S. Pat. No. 5,044,029 to Vrzalik discloses a low air loss bed having first and second sets of air bags alternating positioned in an interdigitated fashion. Valves and circuitry are provided for alternately changing the pressure in each of the sets of bags to selectable maximum and minimum pressure above and below a predetermined baseline pressure in repetitive and cyclical fashion. Low air loss beds are also known for turning or rotating a patient from side to side in a cyclic fashion, for instance the Biodyne bed by Kinetic Concepts, Inc.
Support Systems International, Inc. markets the Restcue bed having the ability to operate in a first static mode, a second pulsation mode, and a third patient turning mode. The Restcue Bed employs a uniquely designed inflatable sac, as disclosed in U.S. Pat. No. 4,949,414, to operate in any one of the three modes.
Until now, the vibratory therapeutic treatment of lung disorders, such as cystic fibrosis, has not been combined with the benefits of low air loss technology. Previously, a patient restricted to a low air loss bed, such as the Restcue bed, who also required percussive chest therapy to induce mucociliary clearance required an external mechanical or pneumatic type vibrator, such as the Strom device. This device would be applied directly to the patient's upper torso to loosen the mucous.
It is also known in the art to provide vibratory pads or similar supports upon which a patient can lie or sit. U.S. Pat. No. 4,753,225 to Vogel, for example, discloses an oscillator plate on which a body can sit, lie, or stand. The oscillator plate is made to oscillate by sound waves. U.S. Pat. No. 4,583,255 to Mogaki et al. discloses a massage mat having a plurality of juxtaposed air chambers. A repeated rhythmic wave motion is induced over the entire surface of the mat or in a local surface by repeating a succession of feeding and discharging of compressed air into and from the air chambers. U.S. Pat. No. 4,551,874 to Matsumura et al. discloses a similar pneumatic massage mat.
The patient care industry has become sensitive to the rising cost of health care in this country. Sophisticated therapy devices such as the low air loss beds described, although very effective in their method, can amount to significant expense if the patient requires sustained use of the bed. The more versatile these beds can be made, the more the expense of the bed can be spread among a wider patient basis. For example, a low air loss bed also incorporating a vibratory therapy mode of operation could be used to treat a first patient suffering from pressure ulcers and a second patient suffering from a lung disorder. The present invention provides such a unique and versatile patient support system and marks a significant advance in the art of low air loss specialty hospital beds.
The accompanying drawings which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference now will be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. As used herein, air tightly is a relative phrase that refers to essentially no air leakage at the operating air pressures of the present invention.
The preferred embodiment of the modular low air loss patient support system is shown in
The patient support system of the present invention preferably includes a frame, indicated generally in
In accordance with the present invention, a plurality, preferably seventeen in the illustrated embodiment (
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Each sack has a pair of restrictive flow passages, one connecting each of the end chambers to the adjacent intermediate chamber. As shown in
In further accordance with the present invention, means are provided for supplying gas, preferably air, to each sack of the patient support system of the present invention. As embodied herein and shown schematically in
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The female connection fitting 108 has an interior configured with a hollow axially disposed coupling opening 110, preferably a cylinder, to receive a coupling in airtight engagement therewith. A cylindrical poppet 97 is disposed in the cylindrical coupling opening and is configured to slide within the cylindrical coupling opening. Poppet 97 is closed at one end, and a spring rests between the bottom 113 of the interior of fitting 108 and the interior of the closed end of poppet 97. The spring-loaded poppet is thereby biased to seal off the entrance 111 of coupling opening 110.
The connection fitting further defines a fitting groove 112 completely around the interior of the fitting and preferably near the entrance 111 of coupling opening 110. The connection fitting also includes a resiliently deformable flexible O-ring 114 held in the fitting groove 112. As shown in
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In keeping with the modular configuration of the patient support system of the present invention, the means for supplying air to each sack further preferably includes a modular manifold for distributing air from the blower to the sacks plugged into the modular sack support member. The modular manifold provides means for mounting at least two pressure control valves and for connecting same to a source of pressurized air and to an electric power source. Because its elongated shape resembles a “log,” such modular manifold is sometimes referred to as the log manifold, and one embodiment is designated by the numeral 128 in
One section of main body 130 defines a mounting wall 140 on which a plurality of pressure control valves 162 (such as shown in
The log manifold further includes a circuit board 150 preferably mounted on the exterior of the main body adjacent the mounting wall 140. As shown in
In further accordance with the patient support system of the present invention, means are provided for maintaining a predetermined pressure in the sacks. The predetermined pressure is kept at a constant predetermined value for each of a number of groups of sacks in the standard mode of operation or may be constantly varying over time in a predetermined sequence in yet other modes of operation of the patient support system of the present invention. As embodied herein and shown schematically in
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Each pressure control valve includes a housing 164, which preferably is formed of aluminum or another light weight material. As shown in
The pressure control valve preferably includes means for connecting the motor to the piston in a manner such that the operation of the motor causes displacement of the piston within the chamber. As embodied herein and shown in
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The microprocessor is programmed to set the reference pressure of each pressure control valve of each body zone into which the patient support system has been divided for purposes of controlling the pressure supplied to air sacks 34 under particular portions of the patient. Based upon the height and weight of the patient, the microprocessor is preprogrammed to calculate an optimum reference pressure for supporting the patient in each body zone. This reference pressure is determined at the valve passage where the pressure transducer of each pressure control valve is sensing the pressure. The circuit card 192 performs a comparison function in which it compares the reference pressure signal transmitted to it from microprocessor 160 via circuit board 150 to the pressure which it has received from the pressure transducer. Depending upon the difference between this signal received from the valve's pressure transducer and the calculated desired signal corresponding to the preset reference pressure, the valve circuit 192 signals the valve motor to open or close the pressure control valve, depending upon whether the pressure is to be increased or decreased. This process continues until the desired reference pressure is sensed by the pressure transducer of the pressure control valve. The microprocessor has parallel processing capability and thus can simultaneously supply each of the pressure control valves with the reference pressure for that particular control valve. Moreover, the speed of each of the microprocessor and valve circuits greatly exceeds the time in which the motors of the pressure control valves can respond to the signals received from the valve circuits. Thus, in practical effect the motor response times limit the frequency with which the pressure control valves can be corrected.
Moreover, the reference pressure calculated by the microprocessor also can depend upon other factors such as whether one or more articulatable sections of the frame is elevated at an angle above or below the horizontal. Another factor which can affect the microprocessor's calculation of the reference pressure for the particular zone is whether the patient is being supported in a tilted attitude at an angle below the horizontal and whether this angle is tilted to the left side of the patient support system or the right side. Still another factor is whether the patient is lying on his/her side or back.
Yet another factor that can affect the reference pressure calculated by the microprocessor is whether the patient comfort adjustment buttons 216 have been manipulated via the control panel to adjust the pressure desired by the patient in a particular zone to a pressure slightly above or slightly below the reference pressure that the microprocessor is preprogrammed to set for that particular zone under the other conditions noted, including, elevation angle, side lying or back lying, and tilt attitude. As shown in
One form of sack pressure algorithm which is suitable for use by the microprocessor to calculate the reference pressures for different configurations of the patient support system of the present invention is as follows:
Pressure=C1 x Weight+C2 x Height+C3
Table 1 provides parameters suitable for several elevation configurations, patients lying on his/her back, side lying, and all five zones. For example, the constants C1, C2 and C3 for each zone are the same for elevation angles 0 degrees through 29 degrees with the patient lying on his/her back. The values of C1, C2 and C3 for side lying are the same for elevation angles of 0° through 29°.
The weight of the patient is supported by the surface tension of the air sack as well as the air pressure within the sack. Thus, values of C1, C2, and C3 can vary with air sack geometry or the properties, such as stiffness, of the materials used to form the air sacks Different air sack geometries may provide more or less stiffness in the air sack.
Typically, a ribbon cable 218 electrical connector (
In further accordance with the present invention, there is provided means for switching between different modes of pressurizing the sacks. As embodied herein and shown schematically in
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The so-called switching disk is rotatable for the purpose of changing the path defined by the inlets and outlets. As shown in solid lines in
As shown by the dotted line configuration of the flow pathways, when the switching disk is rotated 90 degrees counterclockwise to the dotted line position (R), the first flow pathway connects channel A to channel C, and the second flow pathway connects channel B to channel D. Thus, first inlet 224 of first pathway 222 is connected to channel C, and second inlet 230 of second pathway 228 is connected to channel B. First outlet 226 of first pathway 222 becomes connected to channel A, and second outlet 232 of second pathway 228 becomes connected to channel D. In the dotted line configuration shown in
The use of the diverter valves by the present invention enables the support system to be operated in either a pulsation mode of operation or a rotation mode of operation with a minimum number of valves and air flow conduits. The diverter valve allows the air flow paths of the support system to be reconfigured between two distinctly different ways of connecting the pressurized air source through the pressure control valves to individual air sacks of the patient support system.
The patient support system of the present invention can be operated to automatically rotate the patient, i.e., turn the patient to one side or the other, at preset intervals of time. Referring to the control panel shown in
In addition, right button 240 allows the operator to select the attitude of the patient in the right-tilted s position. There are a number of illumination bars disposed above the right button. Each illumination bar corresponds to a different attitude to which the patient can be tilted to the right. The operator selects the desired attitude by continuously pressing the triangular buttons above and below id right button 240 until the bar adjacent the desired attitude is illuminated. For example, the maximum attitude of tilt requires the operator to continue pressing the downward pointing triangular button beneath right button 240 until the lowermost bar above the right button is lit. The same procedure is followed to set the attitude for the left-tilted position.
Moreover, as shown schematically in
In accordance with the present invention, the control over blower 66 preferably includes a blower control circuit which controls the power supplied to blower 66. Microprocessor 160 provides a blower control voltage to blower control circuit 67 which controls the power supply to blower 66 according to this blower control voltage signal received from microprocessor 160. A pressure transducer 246 measures the pressure preferably at the blower and communicates a signal corresponding to the measured blower pressure to the microprocessor 160 via blower control circuit 67 and circuit board 150.
Microprocessor 160 has a blower control algorithm which enables microprocessor 160 to calculate a desired reference pressure for the blower. The blower control algorithm preferably calculates this blower reference pressure to be 3 to 4 inches of standard water higher than the highest pressure in the air sacks. Typically, the seat zone (Zone III) has this highest pressure for a given height and weight setting (provided by the operator to the microprocessor) regardless of the elevation of the head and chest sections and whether the patient is lying on his/her side or back. However, a patient with abnormal body mass distribution (which could be caused by a cast for example) may require the highest sack pressure in one of the other zones. If Zone III has the highest sack pressure, as the elevation angle increases, the sack pressure in Zone III increases, and the reference pressure for the blower also increases to equal 3 to 4 inches of standard water above the pressure of the sacks in Zone III.
Microprocessor 160 stores the signal from transducer 246 corresponding to the measured blower pressure in the microprocessor memory, which is updated preferably only once every three seconds. Microprocessor 160 calculates the reference blower pressure about four times each second and compares it to the stored measured pressure about once each second. If the measured pressure is more than about one inch of standard water higher than the reference pressure calculated by microprocessor 160, microprocessor 160 decreases the control voltage by an increment of {fraction (1/256)} of the maximum control voltage signal that microprocessor 160 is programmed to provide to blower control circuit 67. This maximum voltage corresponds to the maximum output of blower 66. If the measured blower pressure is more than about one inch of standard water lower than the reference pressure, then microprocessor 160 increases the control voltage signal by an increment of {fraction (4/256)} times the maximum control voltage. The increase or decrease, if any, occurs about once each second. Pressure deficits are of a greater concern, and thus correction of such deficits occurs four times faster than correction of excess pressures. The pressure changes resulting from the blower control sequence occur no more frequently than once each second and are no greater than {fraction (1/256)} of the maximum pressure for decreases and {fraction (4/256)} times the maximum pressure for increases. Moreover, the microprocessor's three second delay in updating the measured pressure used in the calculations assures that changes in the measured pressure that have very short durations will not lead to pressure instability because of control loop exacerbation of short-lived pressure fluctuations. This three second time interval can change depending upon the pressure dynamics and control dynamics of the system.
The selection of the rotation mode of operation on control panel 210 causes the microprocessor to signal the diverter valves to align their pathways for rotational operation of the support system. Once the parameters of operation in the rotation mode have been inputted, the microprocessor recalculates an optimum reference pressure for each pressure control valve. The microprocessor determines the appropriate tilt reference pressure based upon the height and weight of the patient and the angle of tilt selected by the operator. This is accomplished such that the pressure in the low pressure side of the sack and the pressure in the high pressure side of the sack average out to the pressure that would be set for the same sacks in the normal mode of operation, i.e., without any rotation. Thus, the average pressure over the entire sack during the rotational mode of operation is the same as it would be in the non-rotational modes of operation.
The operator initiates the rotation by pressing the RUN button on panel 210 in
In accordance with the present invention, a method is provided for turning the patient on a low air loss patient support system as in the present invention. As embodied herein, the turning method includes the step of grouping all of the sacks 34 into at least two body zones that correspond to at least two different zones of the patient's body. Each zone of the patient's body is preferably supported by one or more sacks in one of the two body zones. Preferably five body zones are involved.
The next step in the method for turning a patient is to pressurize all of the sacks according to a first pressure profile that provides each sack in each body zone with a respective first air pressure. This first air pressure has been chosen so as to provide a first respective level of support to that portion of the patient's body supported by the sacks in that body zone. The level of support is predetermined depending upon the height and weight of the patient and calculated accordingly by the microprocessor. The height and weight data also affect the respective first air pressure that is chosen for the sacks in that particular body zone.
The terms “pressure profile” are used to refer to the fact that the pressure in each body zone may be different because of the different support requirement of that particular body zone. If the individual pressures in the sacks of all the body zones were to be represented on a bar graph as a function of the linear position of the sacks along the length of the patient support, a line connecting the tops of the bars in the graph would depict a certain profile. Hence the use of the term “pressure profile” to describe the pressure conditions in all of the sacks at a given moment in time, either when the pressures are changing or in a steady state condition.
The next step in turning the patient involves separately controlling the air pressure that is supplied to each side of each of the sacks. This preferably is accomplished by supplying the chambers on one side of the sacks in each body zone via a first pressure control valve and supplying the chambers on the other side of the sacks via a separate pressure control valve, and connecting each pressure control valve to a four-way diverter valve. The diverter valve can then be configured to ensure that the air pressure being supplied to the chambers on one side of each sack is being controlled by one of the pressure control valves, and the pressure being supplied to the chambers on the other side of the sack of a particular zone is being supplied through a separate pressure control valve.
The next step in turning the patient involves lowering the pressure in the chambers on the side of the sacks to which the patient is to be tilted. Specifically, the pressure must be lowered in the chambers of one side of the sacks from a first pressure profile, previously established, to a predetermined second pressure profile. The second pressure profile is predetermined according to the height and weight of the patient and also according to the attitude to which the patient is to be tilted. The greater the angle below the horizontal to which the patient is to be tilted, the lower the predetermined second pressure profile.
Another step in the method of turning the patient requires raising the pressure in the chamber on the side of the sacks that is opposite the side to which the patient is being tilted. This involves raising the pressure in the chamber of the non-tilted side of each of the sacks to a predetermined third pressure profile. The raised pressure profile in the non-tilted sacks compensates for the lower pressure profile in the side of the sacks to which the patient has been tilted. When the overall pressure being supplied to support the patient has been reduced in half of the sack, as occurs during tilting, that portion of the patient's body in that particular body zone would not be maintained at the desired level of support without increasing the pressure in the non-tilted side of the sack.
The operator begins by lowering the pressure in one side of the all of the sacks until the patient has been tilted to the desired attitude of tilt beneath the horizontal. As this is occurring, the microprocessor is increasing the pressure in the non-tilted sacks such that one-half of the sum of the pressure in the tilted sacks plus the pressure in the untilted sacks equals the base line pressure of the sacks before the tilting procedure began. In the case just described, the base line pressure corresponds to the pressure in the sack at the first pressure profile. Preferably, the raising and lowering of the pressures in the chambers of opposite sides of the sacks occurs practically simultaneously. Since preferably the microprocessor has parallel processing capability and thus can control each of the pressure control valves simultaneously, the speed with which the tilting is effected (or any other pressure changes in the sacks) is primarily limited by the flow restrictions in the pneumatic circuit, which is primarily a function of the air sack volume and the pressure level in the sacks.
In further accordance with the present invention, the patient is maintained in the selected tilted position for a predetermined length of time. At the end of this predetermined length of time, which is clocked by the microprocessor, the patient is returned to the horizontal position by simultaneously increasing the pressure in the side of the sacks to which the patient previously had been tilted while decreasing the pressure in the non-tilted side of the sacks until the pressure in both sides of the sacks returns to the first predetermined pressure profile. The changes in pressure from low to high or from high to low preferably occurs over a time interval of about three minutes. This is done to reduce the likelihood that the patient will experience any uncomfortable sensation during these pressure changes.
In still further accordance with the present invention, the method of turning a patient can maintain the patient in the horizontal position for a predetermined interval of time. At the end of this predetermined interval of time, the patient then can be tilted to the side of the patient support system that is opposite the side to which the patient had been tilted prior to being maintained in the horizontal position. Moreover, the amount of time which the patient spends in a particular position, namely, left-tilted, horizontal, and right-tilted, can be preselected so that the patient can be maintained in one of the three positions for however long is deemed therapeutic.
It is during the turning, i.e., rotation or tilting, mode of operation that the grommet which defines the hole 64 connecting each intermediate chamber 54 with each end chamber 46 of each sack 34 plays a particularly important role. As the pressure control valve controlling the side of the sack to which the patient is to be tilted begins to close and reduce the pressure being supplied to this side of these sacks, the weight of the patient above the depressurizing intermediate chamber 54 squeezes the air from the intermediate chamber through the grommet and into the end chamber 46 to compensate for the reduced pressure being supplied to the end chamber via the pressure control valve. Thus, the reduction in pressure initially serves to deflate the intermediate chamber while maintaining the end chamber as fully inflated as before the pressure control valve began to reduce the pressure supplied thereto. The pressure in the end chamber of course is being reduced. However, the end chamber remains completely inflated, unlike the connecting intermediate chamber which is being squeezed by the weight of the patient that no longer is being supported by the same level of air pressure as was present when the sacks were being maintained according to the first pressure profile that was first set to maintain the patient in the horizontal position atop the sacks. Moreover, since the end chamber remains inflated, it acts as a passive constraint to prevent the patient from rolling past the end chamber and off of the patient support.
To operate the support system of the present invention in the pulsation mode, the operator pushes the SET UP button on the control panel illustrated in
In further accordance with the present invention, a method is provided for periodically relieving the pressure of the patient support system against the patient's body. This method preferably is accomplished by pulsating the pressure in the sacks of the low air loss patient support system having a plurality of sacks disposed transversely across the length of the support system. The pressure in a first group of sacks comprising every alternating sack is depressurized relative to the remaining sacks, which are provided with an increase in pressure. The pressure differential between the two separate sacks is maintained for a predetermined interval of time. At the end of this time interval, the pressure profiles switch so that the other set of alternating sacks becomes depressurized while the first set of alternating sacks receives a slight increase in pressure. This opposite pressurization condition is also maintained for a predetermined interval of time, whereupon the cycle repeats itself until the pulsation mode of operation is discontinued.
Prior to the initiation of the pulsation mode of operation, all of the sacks in the patient support will be maintained at a first pressure profile according to the height and weight of the patient, the various angles of inclination of any of the articulating sections of the frame, and any tilt angle imposed upon the sacks. However, preferably, the pulsation method will not be operated in conjunction with any tilting of the patient, and thus activation of the pulsation method automatically discontinues operation in the tilting mode.
The steps of the method for pulsating the pressure in the sacks of the low air loss patient support system include configuring the air supply means of the patient support to define two separate groups of alternating sacks. A first group of sacks includes either every odd number sequenced sack in order from one end of the patient support to the opposite end of the patient support or every even number sequenced sack. For purposes of this description, the first of the two groups of sacks will be chosen to be the odd number sequenced sacks. In a preferred embodiment, the sacks are further grouped into body zones to support the patient's body at a predetermined pressure for all of the sacks in the body zone. Thus, all of the sacks in a particular body zone will be pressurized at the same first pressure, and accordingly the individual first pressure will be applied to all of the sacks in each body zone. This step of configuring the sacks is preferably accomplished by configuring a plurality of diverter valves to connect every alternating sack in a body zone.
The next step includes reducing the air pressure being supplied to the sacks in the first group. This is accomplished as the microprocessor controls the pressure control valve of this first group to attain a second pressure profile. The second pressure profile corresponds to a decreased pulsation reference pressure calculated by the microprocessor when the degree of depressurization was selected by the operator. The microprocessor controls the pressure control valves supplying air to the sacks in the first group until the decreased pulsation reference pressure has been attained by the sacks in this first group.
The next step occurs simultaneously with the first step and includes supplying air pressure to the sacks in the second of the two groups, namely, the group including every even number sequenced sack in order from one end of the patient support to the opposite end of the patient support, at a third pressure profile. This third pressure profile corresponds to an increased pulsation reference pressure which the microprocessor calculated for each pressure control valve controlling the sacks in the second group for each individual body zone. This increased pulsation reference pressure also has been calculated by the microprocessor depending upon the degree of depressurization selected by the operator.
This third pressure profile is designed to compensate for the loss of pressurization by the first group of sacks so that the patient support can continue to maintain the patient at the same level of horizontal support during the depressurization of the first group of sacks. In other words, while the pressures in the alternate groups of sacks are changing, the vertical height of the patient above the floor is not changing significantly from what it was prior to the onset of the pulsation mode of operation. Thus, the microprocessor maintains the pressures in the two groups of sacks such that one-half the sum of the second and third pressure profiles equals the first pressure profile.
The two steps involving the changes in pressurization of the two groups of sacks, occur simultaneously over a first time interval.
The method for pulsating the pressure in the sacks further includes the step of maintaining the second and third pressure profiles being supplied to the two groups of sacks during a second interval of time. This is accomplished by the microprocessor controlling the pressure control valves to maintain the increased or decreased pulsation reference pressures calculated by the microprocessor for the respective group of sacks over the time interval selected by the operator.
After the predetermined lower pressure has been maintained for the sacks in the one group for the second interval of time, the next step is to increase the pressure being supplied to this one group during a third interval of time until each sack in this one group attains a higher individual pressure corresponding to the third pressure profile. At the same time that the sacks in the first group of sacks are attaining the higher individual pressure, the pressure being supplied to the sacks in the other of the two groups is being decreased to the lower pressure corresponding to the second pressure profile. The pressure in the other of the two groups is decreased until the predetermined lower pressure is being provided to each individual sack in this other group. The pressure decreases over this third interval of time.
Finally, the third pressure profile in the one group and the second pressure profile in the other group are maintained during a fourth interval of time.
Preferably, all of the first, second, third, and fourth intervals of time are of equal duration. However, in some embodiments of the method of pulsating the sacks of the present invention, the first interval of time preferably equals the third interval of time, and the second interval of time preferably equals the fourth interval of time.
In yet another embodiment of the method of pulsating the sacks of the present invention, not only are the first and third time intervals equal to each other as well as the second and fourth time intervals being equal to each other, but the first and third time intervals are shorter than the second and fourth time intervals. In other words, the time which the sacks spend alternately changing pressures is less than the time during which the sacks remain at the steady state higher or lower pressures. Similarly, in yet another embodiment of the method of pulsating the sacks of the present invention, the second and fourth time intervals can be equal to each other and shorter than the first and third time intervals, which also are equal to each other.
In accordance with the present invention and as illustrated in the figures in general, particularly
The vibratory patient support system 300 may be similar to the low air loss patient support system previously described with the addition of vibrating means A for vibrating at least a portion of the low air loss patient support system. In a preferred embodiment of system 300, inflatable sacs 34 are disposed transversely across support frame 30, as depicted generally in
Vibrating means A may be external to inflatable sacs 34 or disposed internal to at least one sac 34 as depicted generally in
Additionally, the vibratory patient support system of the present invention is not limited to a low air loss configuration. Inflatable sacs 34 may comprise low air loss sacs but, this is not a requirement of the invention.
A multi-modal low air loss patient support system has already been described. The multi-modal system includes means for pressurizing inflatable sacs 34 in a first constant pressure mode, means for pressurizing inflatable sacs 34 in a second pulsation mode, and means for pressurizing inflatable sacs 34 in a third turning mode. In a preferred embodiment of vibratory patient support system 300 according to the invention, vibrating means A are included with the multi-mode low air loss patient support system as described. In this embodiment, vibratory patient support system 300 is switchable from any one of the modes of operation of the low air loss configuration described to any other mode of operation with vibrating means A being independently actuable and controllable from any one of the modes of operation. The modes of operation of the low air loss configuration system have already been discussed in detail in the specification and need not be repeated.
Vibrating means A and the means for variably controlling vibrating means A according to the invention preferably includes an operator interface means, such as control panel 308 as shown in
Control panel 308 depicted in
The relationship of circuit board 150, microprocessor 160, and blower control 67 has already been described in detail. The means for variably controlling vibrating means A preferably comprises an interface with microprocessor 160 and circuit board 150. Microprocessor 160 includes software means for controlling the frequency of vibrating means A through power distribution board 150. This relationship is depicted generally in
Vibrating means A according to the invention may comprise a pneumatic vibrating system or means B, as in
Pneumatic vibrating system B may further comprise at least one inflatable cell 304. Cell 304 may be disposed within at least one inflatable sac 34, as shown particularly in
In one preferred arrangement, cell 304 comprises a tubular pod which extends generally lengthwise within sac 34, as shown in
As described, each inflatable sac 34 has an upper surface 36. Preferably, inflatable cells 304 are disposed within sac 34 just below surface 36 so that when inflatable cells 304 are rapidly inflated and vented, they impart a vibrational force to upper surface 36. Thus, the frequency of the vibrational forces imparted to the patient support surface depends upon the frequency inflatable cells 304 are alternately inflated and vented. Alternatively, cells 304 may be external to sac 34 and still impart vibrational forces to the patient support surface.
Means are further provided for connecting inflatable cells 304 to the source of pressurized air. Preferably, device 322 is provided similar to the hand detachable air-tight connection 126 for supplying pressurized air to sacs 34, as previously described. However, any suitable air-tight connection can employed as device 322. Flexible tubing or other like material may be used to convey the pressurized air internally through sac 34 to inflatable cell 304. When inflatable cells 304 are disposed within a multi-chambered sac 34, as illustrated in
Pneumatic vibrating system B according to the present invention may also include controllable valve means C disposed between the source of pressurized air or blower 66 and inflatable cell 304. Valve means C operate to alternately supply pressurized air from the pressurized air source to inflatable cell 304 and to vent pressurized air from inflatable 304 at a predetermined frequency. In this manner, inflatable cell 304 expands and contracts thereby pneumatically vibrating just below upper surface 36 of sac 34, thereby imparting vibrational forces to the patient support surface.
Controllable valve means C may comprise solenoid valves 314, 310, and 312 as shown in
Controllable valve means C may comprise conventional timer control circuits with relay outputs for controlling the frequency of operation of the solenoid valves. In this embodiment, the timer control circuit need not be interfaced with microprocessor 160. Preferably though, appropriate software is embodied in microprocessor 160 for controlling the valves.
The software for control of controllable valve means C may be embodied in an appropriate chip carried within microprocessor 160. The control of solenoid valves through appropriate software and power distribution boards is well-known to those skilled in solid state electronic control systems and need not be described in detail here. In summary though, an operator may interface with microprocessor 160 through, for instance, control panel 308 of
As embodied in
It should be understood that the solenoid valves 310, 312, and 314 are only examples of suitable controllable valves for use with the vibrating therapy system of this invention. Other values or valve configurations are suitable and within the scope of this invention. For instance, a spool valve or solenoid diaphragm type valve may also be utilized.
Means are also preferably provided for controlling the amplitude or magnitude and sequence of vibrational forces imparted to upper surface 36. This may be accomplished by, for instance, varying the source of pressurized air to cells 304 or the timing of the pressurization of the cells. In the embodiment of the invention depicted in the figures, blower 66 supplies air to inflatable cell 304. The magnitude or amplitude of vibrational forces of cell 304 can be varied by controlling the speed of blower 66 through blower control circuit 67. Preferably, an operator interface is provided by, for example, control panel 308, for varying the output of blower 66.
It is a desirable feature of the vibrational therapy device according to the present invention that vibrating means A, for example, pneumatic vibrating system B, be separately actuable and controllable in any of the modes of operation of the patient support system. If vibratory patient support system 300 of the present invention includes the low air loss patient support system described earlier, it is desired to be able to actuate and control vibrating means A so as not to interfere with or affect the operational mode of the low air loss system. For example, it may desired to actuate vibrating means A while the low air loss patient support system is simultaneously rotating the patient from side to side. Additionally, it may only be necessary to actuate vibrating means A for only brief periods of time at preselected intervals. In this manner, it is desired to have a timing control circuit, within microprocessor 160 for example, for establishing and controlling the period of operation of vibrating means A regardless of the mode of operation of the low air loss patient support configuration.
In further accordance with the present invention, a vibratable inflatable sac 318 is provided. Vibratable sac 318 may be utilized, for example, with other sacs in a inflatable patient support system, such as a low air loss patient support bed. As illustrated in
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims
1. A bed for supporting a patient, comprising:
- a bed frame; and
- an inflatable patient support assembly supported on the bed frame, the assembly having at least one inflatable zone including:
- first and second interlaced sets of generally adjacent inflatable air sacs defining a patient support surface, each air sac in the first set inflating collectively with other sacs in the first set, each air sac in the second set inflating collectively with the other sacs in the second set, the first set of air sacs being inflated independently relative to second set of air sacs, and
- a vibrational therapy system configured to impart a vibrational force to the patient support surface.
2. The bed of claim 1, wherein the at least one zone has first and second sets of generally adjacent inflatable air sacs, each air sac in the first set inflating collectively with other sacs in the first set, each air sac in the second set inflating collectively with the other sacs in the second set, the first set of air sacs of the at least one zone being inflated independently relative to the second set of air sacs of the at least one zone.
3. The bed of claim 1, further including a controller having software to alternately inflate the first set and second set of air sacs.
4. The bed of claim 1, wherein the vibrational therapy system includes an impact cell.
5. The bed of claim 4, wherein the impact cell is positioned within an air sac.
6. A bed for supporting a patient, comprising:
- an inflatable patient support assembly, the assembly having:
- first and second interlaced sets of generally adjacent inflatable air sacs defining a patient support surface, and
- a controller including a pulsating mode of operation where air pressures within the first set of air sacs and the second set of air sacs are successively and alternately pulsated, and a rotational mode of operation where the patient support surface is laterally rotated.
7. The bed of claim 6, wherein the controller further includes a vibrational therapy mode where a vibrational force is imparted to the patient support surface.
8. The bed of claim 7, further comprising an impact cell in communication with the controller and configured to provide the vibrational force to the patient support surface.
9. The bed of claim 6, wherein the controller further includes a pressure relief mode where the first set of air sacs and the second set of air sacs are maintained at a substantially constant pressure to support the patient in a relatively static condition.
10. A method of providing therapy to a patient, the method comprising the steps of:
- providing an inflatable patient support assembly having first, second, third, and fourth generally adjacent inflatable air sacs and a controller;
- providing alternating pressure therapy by inflating the first and third air sacs and at least partially deflating the second and fourth air sacs; and
- providing lateral rotation therapy by providing inflation to a first chamber of the air sacs that is greater than the inflation provided to a second chamber of the air sacs.
11. The method of claim 10, wherein the patient support assembly includes a plurality of independently controlled zones, each including first, second, third, and fourth generally adjacent inflatable air sacs.
12. The method of claim 10, further comprising the step of providing vibrational therapy by imparting a vibrational force to a patient support surface defined by the air sacs.
13. A method of providing therapy to a patient including the steps of:
- providing an inflatable patient support assembly having first, second, third, and fourth generally adjacent inflatable air sacs defining a patient support surface;
- providing alternating pressure therapy by inflating the first and third air sacs and at least partially deflating the second and fourth air sacs; and
- providing vibrational therapy by imparting a vibrational force to the patient support surface.
14. The method of claim 13, wherein the patient support assembly includes a plurality of independently controlled zones, each including first, second, third, and fourth generally adjacent inflatable air sacs.
15. The method of claim 13, further comprising the step of providing lateral rotation therapy by altering inflation levels of the air sacs.
16. A patient support apparatus for use with a source of pressurized air, comprising:
- a first support zone and a second support zone, each support zone including a plurality of inflatable bladders for supporting a portion of the patient, the plurality of inflatable bladders in each support zone configured such that every alternate bladder is coupled together in a first group and every other alternate bladder is coupled together in a second group;
- a plurality of pressure control valves, each pressure control valve associated with a respective group of inflatable bladders, each respective pressure control valve configured to regulate the pressure of the respective group of inflatable bladders; and
- a microprocessor configured to control the plurality of pressure control valves such that:
- the first support zone is inflated to a first reference pressure and subsequently pulsating the pressure in the first group and the second group in the first support zone; and
- the second support zone is inflated to a second reference pressure which is substantially maintained in the first group and the second group of the second support zone.
17. The patient support apparatus of claim 16, wherein the microprocessor is further configured to control the pressure control valves such that a first chamber of the air sacs have a pressure greater than a second chamber of the air sacs.
18. The patient support apparatus of claim 16, further comprising a vibrational therapy system controlled by the microprocessor.
19. The patient support apparatus of claim 18, wherein the vibrational therapy system includes an impact cell.
20. The patient support apparatus of claim 19, wherein the impact cell is positioned within an air sac.
Type: Application
Filed: Sep 23, 2004
Publication Date: Feb 17, 2005
Inventors: Barry Hanh (Mount Pleasant, SC), Robert Novack (Charleston, SC), Donald Williamson (N. Charleston, SC), James Stolpmann (Charleston, SC), Kenith Chambers (Charleston, SC)
Application Number: 10/947,743