Beds – Mattress – Having confined gas
Reexamination Certificate
1998-11-24
2003-05-13
Grosz, Alexander (Department: 3673)
Beds
Mattress
Having confined gas
C005S706000, C005S714000, C005S709000, C005S905000, C005S655300, C250S297000, C362S276000, C362S318000, C340S555000
Reexamination Certificate
active
06560804
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to monitoring and controlling therapeutic beds and mattress systems. More particularly, the invention relates to a system and methods for detecting and monitoring the distance between a patient and a reference point on a mattress and for controlling the mattress in relation to such distance.
BACKGROUND OF THE INVENTION
For years those who suffer from limited mobility due to age, disease or immobilizing physical condition have sought relief from decubitus ulcers, cramping and discomfort as a result of being bedridden for long periods of time. A wide range of therapeutic supports for bedridden patients, such as inflatable mattresses, mattress overlays and mattress replacements, have been made commercially available in the United States. One such support is commercially available from Kinetic Concepts, Inc. (of San Antonio, Tex.) under the “TheraKair” designation, as a mattress which provides pulsating action through inflatable support cushions as described in U.S. Pat. No. 5,267,364.
Therapeutic mattresses are often designed to reduce “interface pressures,” which are the pressures that are exerted by a mattress on skin of the patient (or vice versa) while the patient is lying on the mattress. Given time, elevated interface pressures can reduce local blood circulation around the skin and, as a result, may contribute to bedsores and other complications. With inflatable mattresses, as the inflation air pressure decreases, a patient's susceptibility to encountering elevated interface pressures also tends to decrease, thereby reducing the likelihood that the patient will develop bedsores.
A problem with deflation, however, is the increased risk of “bottoming-out”, which is a widely known effect where the upper surface of an air mattress converges and comes into direct contact with the lower surface. Bottoming out can negate much of the benefit of an air mattress by increasing the patient's pressures at the point of bottoming-out and, therefore, increase the risk of bedsores. Abrupt bottoming-out, such as when the patient is initially positioned on the mattress, could increase the risk of further injury to an already frail, bedridden patient. There has been a long felt need to have an inflatable mattress which self-adjusts the air pressure in inflatable cushions for optimal therapeutic purposes while significantly diminishing the risks of bottoming-out.
Some concepts of regulating air supply within a mattress for the prevention of bedsores and some concepts for the mitigation of bottoming-out effects are known. For example, U.S. Pat. No. 4,694,520 describes methods for detecting inadequate inflation while the patient is situated on the mattress. By contrast, the present invention detects the patient not only when positioned on the bed but also before the patient is even placed on the bed, thereby preventing the risks of rapid bottoming-out by “pre-inflating”.
U.S. Pat. No. 4,873,737 provides for the detection of mattress thickness to supply a mean air pressure while the patient is situated thereon.
U.S. Pat. Nos. 4,745,647 and 4,768,249 provide force activated sensors to detect whether a patient has bottomed-out on a mattress but does not contemplate detecting the patient as the patient nears the bed.
U.S. Pat. No. 4,542,547 provides for mattress inflation through the detection of reflected and pulsed light while the present invention, by contrast, detects diffuse light.
SUMMARY OF THE INVENTION
It is an object of the present invention to enhance patient care and to overcome the obstacles and inadequacies of the prior art.
The present invention includes features and/or components that have been invented or selected for their individual and combined benefits and superior performance as an apparatus and a method for minimizing patient interface pressures by sensing patient distance and, if necessary, adjusting that distance to some predetermined or calculated level to optimize the therapeutic effects of the patient's mattress. The system is a combination of components and methods that together have new and novel features. Each of the individual components work in association with the others and are optimally mated for performances.
The present invention circumvents current laborious requirements of manually adjusting a mattress for optimal therapeutic inflation or allowing a patient to be filly positioned on the bed before sensing means are activated. The present invention offers a unique “hands-free” approach to controlling a mattress's air supply while a patient is lying thereon. Through the use of a heterodyning proximation detector similar benefits are achieved even before a patient lies upon the mattress. With such benefits there is less need for extra personnel and training costs to operate a mattress's air supply system. In addition, the present invention further reduces any risks for rapidly bottoming-out as a patient is initially placed on a mattress. Accordingly, the heterodyning proximation detector detects a patient as the patient nears a mattress and allows for air supply in the mattress to be increased before the patient is ever positioned atop the mattress.
The heterodyning proximation detector is an improved version of a somewhat obscure musical instrument that had been developed in the United States during the 1920s called a “Theremin”. The present invention improves on the musical instrument's ability to sense a human's natural reactance, or electrical characteristics, and applies this improvement to therapeutically regulating an air mattress. The heterodyning proximation detector is effectively an antenna referenced to a conducting plate with a large surface area that variably responds to the dielectric constants of different materials. The heterodyning proximation detector may also be used to control air supply while the patient is on the mattress along with, or separately from, a force-responsive distance sensing apparatus or a light-responsive distance sensing apparatus, thus reducing the risks for gradual bottoming-out as well.
Aspects of the present invention feature a force-responsive distance sensing apparatus for continuously determining how high the patient is being supported on the mattress in real-time while the patient is on the mattress. The depth that the patient sinks into the mattress is used for controlling air supply to the mattress. The patient's height (or depth) distance is represented as variations in height of a compliant, force transmitting member that is placed relative to the mattress. Thus, a change in height of the patient generates a change of force applied to a force sensitive component coupled to the force transmitting member.
Other aspects of the present invention relate to a light-responsive distance sensing apparatus using either visible light or infrared radiation. The mattress upon which the patient rests may be physically divided into sections, such as independently inflatable air-cells, or logically divided into sections, where no physical barrier isolates the air inside the mattress. A section, logical or physical, of the mattress's initial shape becomes deformed in response to a patient being set atop the air mattress. A light emitter and light detector are situated in a fashion such that a deformation in the mattress shape reduces the amount of light that reaches the detector from the emitter, thereby generating a control signal to adjust the air pressure within the mattress accordingly. The preferred embodiments contain certain elements which include, but are not limited to:
a frame for supporting a mattress;
a therapeutic mattress set upon the frame where both frame and mattress cooperate in tandem to define a therapeutic bed;
a controlled air supply for selectively inflating one or multiple air cells upon receiving data relating directly or indirectly to the height of the patient relative to the bottom of the air mattress.
In one preferred embodiment, a heterodyning proximation detector is significantly influenced by
Boynton Thomas A.
Lina Cesar Z.
Wise William M.
Zheng X. Lu
Grosz Alexander
KCI Licensing Inc.
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