Surgery: splint – brace – or bandage – Orthopedic bandage – With light – thermal – or electrical application
Reexamination Certificate
2000-07-05
2001-09-04
Nasser, Robert L. (Department: 3736)
Surgery: splint, brace, or bandage
Orthopedic bandage
With light, thermal, or electrical application
C602S014000, C607S096000, C607S114000
Reexamination Certificate
active
06283931
ABSTRACT:
CROSS-REFERENCES TO RELATED PATENT AND COPENDING APPLICATIONS
This application contains material related to the following commonly assigned pending U.S. patent applications:
Ser. No. 07/900,656 filed Jun. 19, 1992, for “THERMAL BODY TREATMENT APPARATUS AND METHOD”;
Ser. No. 08/342,741, filed Nov. 21, 1994, for “WOUND TREATMENT DEVICE”;
Ser. No. 08/356,325, filed Feb. 21, 1995, for “WOUND COVERING”;
Ser. No. 08/785,794, filed Jan. 21, 1997, for “NORMOTHERMIC HEATER WOUND COVERING”;
Ser. No. 08/786,713, filed Jan. 21, 1997, for “NORMOTHERMIC TISSUE HEATING WOUND COVERING”;
Ser. No. 08/786,714, filed Jan. 21, 1997, for “NEAR HYPOTHERMIC HEATER WOUND COVERING”; and
Ser. No. 08/838,618, filed Apr. 11, 1997, for “FLEXIBLE NON-CONTACT WOUND TREATMENT DEVICE”;
Ser. No. 08/843,072 filed on Apr. 11, 1997 entitled “FLEXIBLE NON-CONTACT WOUND TREATMENT DEVICE WITH A SINGLE JOINT”;
Ser. No. 09/056,191, filed Apr. 6, 1998, “WOUND TREATMENT APPARATUS WITH A HEATER, A HEAT CONDUCTIVE BANDAGE, AND A HEAT-SPREADING MEANS ACTING BETWEEN THE HEATER AND BANDAGE”;
Ser. No. 09/055,725, filed Apr. 6, 1998, “WOUND TREATMENT APPARATUS WITH INFRARED ABSORPTIVE WOUND COVER”;
Ser. No. 09/056,063, filed Apr. 6, 1998, “WOUND TREATMENT APPARATUS WITH IR-TRANSPARENT OR IR-TRANSMISSIVE WOUND COVER”; and
Ser. No. 09/055,597, filed Apr. 6, 1998, “WOUND TREATMENT APPARATUS WITH A HEATER ADHESIVELY JOINED TO A BANDAGE”.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wound treatment device with a bandage and heater that are essentially planar, yet flexible, and are connected or joined by an attachment device that promotes heat transfer from the heater through the bandage to a treatment area where the temperature of tissue is maintained by control of the heater's operation in a normothermic temperature range.
2. Description of the Related Art
The “normal” range of temperature for the human body is 37° C.±1° C. (36° C.-38° C.). This is termed the “normothermic” range. Humans exhibit a thermoregulatory response to core temperature changes as little as ±0.1° C., wherein “core” as used herein refers to interior portions of the body. This extremely tight temperature control is necessary because virtually all cellular functions, chemical reactions and enzymatic reactions are optimum at normothermia.
Surface tissue varies in temperature according to where on the body it is located. The skin of the torso is usually hypothermic, while the skin of the legs is always hypothermic. The normal skin temperature of the distal leg is approximately 32° C., which is considered to be “moderately hypothermic”. The skin temperature of the distal leg of a patient with vascular insufficiency may be as low as 25° C., which is “severely hypothermic”. The hypothermic condition of wounds and ulcers inhibits healing. Severely hypothermic skin or wound tissue is in a state that may be termed “suspended animation”. In suspended animation, tissue is living, but cellular functions necessary for cell division and collagen deposition are slowed or even stopped. Further, the immune system is inhibited,. The local application of heat to hypothermic skin will cause some degree of vasodilatation, resulting in an increase in local blood flow. Increased blood flow increases the subcutaneous oxygen tension (PsqO
2
) which, in turn, increases both collagen deposition and immune function.
Many references report that the immune system is inhibited by hypothermia and activated by mild hyperthermia (fever). Persp Biol Med:439-474, Spring 1980, reports that local body temperature is a critical factor determining host susceptibility, the location of lesions and contracting infectious diseases. New Eng J Med 305:808-814, 1981, reports that animals exposed to cold environments are more susceptible to infectious diseases, whereas exposure to high ambient temperatures often produces a beneficial result. Wound Rep Reg 2:48-56, 1994 and Acta Anaesth Scand 38:201-205, 1994, report that infections caused by a standard inoculum of
e. coli
or
s. aureus
were significantly more severe in hypothermic guinea pigs than in normothermic control animals. New Eng J Med 334:1209-1215, 1996, reports that hypothermic colorectal surgical patients had three times more wound infections (19% vs. 6%) than those who were kept normothermic during surgery with a Bair Hugger® patient warming system described in commonly assigned U. S. Pat. Nos. 5,324,320, 5,300,102 and 5,350,417. Further, six weeks of warming therapy with the Bair Hugger® patient warming system has successfully healed chronic progressive ulcers which heretofore have been resistant to antibiotic therapies.
As stated hereinabove, enzymatic reactions are promoted by normothemia. Both platelet adhesion and the clotting cascade result from a series of enzymatic chemical reactions. Research efforts have been reported that show hypothermic patients bleeding more than normothermic patients. J Thorac Cardiovasc Surg 104:108-116, 1992, and Ann Surg 205:175-181, 1987, report that skin cooling produces a reversible platelet dysfunction and prolonged bleeding times. Lancet 347 (8997):289-292, 1995, reports that mildly hypothermic total hip arthroplasty patients lost an average of 500 ml more blood and had an 88% higher incidence of transfusion than patients who were kept normothermic with the aforementioned Bair Hugger® Patient Warming System. Anesthesiology 85: A66, 1996, reports that hypothermic liver transplant patients required twice as many units of blood (18.6 vs. 9.8) and 57% more units of all blood products (46.2 vs. 29.4) than patients who were kept normothermic with the Bair Hugger® Patient Warming System.
SUMMARY OF THE INVENTION
There is a need for a treatment apparatus to conveniently treat a tissue by raising the temperature of tissue toward normothermia, while allowing patient mobility. It is also important that the treatment apparatus be flexible and have a low profile for convenience of the patient. Such an apparatus should be thermally conductive for efficient heat transfer, be convenient to operate without adversely impacting the patient, and be capable of maintaining a moist wound environment.
Preferably, the operation of the treatment apparatus is referred to a “treatment area” that may include a wound, unwounded skin, or both.
One purpose of this invention is to raise the temperatures toward normothermia to promote a more optimal healing environment. The present invention is not a “heating therapy”, per se, where it is the intent of “heating therapy” to heat the tissue above normothermia to hyperthermic levels. Rather, the present invention is intended to bring the tissues towards normothermia, without exceeding normothermia.
This invention is also designed to elevate the temperature of the hypothermic skin and subcutaneous tissue of the selected treatment area to a temperature which is close to normothermia. The purpose of this is to create within the tissues of the selected treatment area a more normal physiologic condition, specifically a more normothermic condition, which is conducive to healing. This invention contemplates the use of an active heater to deliver heat to a treatment area, but the role of the heater can better be described as “guarding” against heat loss by providing a heat source to counteract the effects of heat loss.
The concept of a “guard heater” is straightforward. The guard heater is heated to approximately the same temperature as the adjacent heated body. Since heat must flow down a temperature gradient, it can only be lost to a cooler surface. The guard heater is not cooler than the adjacent body and, therefore, cannot accept heat from the adjacent body. The normal temperature gradient for tissue goes from about 37° C. deep in the body's core down to about 32° C. at the skin's surface. With a guard heater in place, heat loss directly from the tissue surfaces is markedly diminished. This decrease in local heat loss provides for the zone of 37° C. core temperature to move outward toward the skin, narrowing the gradient
Augustine Medical, Inc.
Gray Cary Ware & Freidenrich
Nasser Robert L.
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