WO2000024348A1

WO2000024348A1 - Pad for warming a patient

Info

Publication number: WO2000024348A1
Application number: PCT/US1999/023976
Authority: WO
Inventors: Brian Doherty
Original assignee: Medstat Financial, Inc. D/B/A Thermo-Tec
Priority date: 1998-10-23
Filing date: 1999-10-22
Publication date: 2000-05-04
Also published as: WO2000024348A9

Abstract

A patient pad (10) for regulating the core temperature of a patient undergoing medical treatment includes an outer covering (12) including a pocket (18), an arming pouch (20) for holding a phase change material having a melting/freezing temperature of greater than 93 F but less than 125 F that is received, and held within the pocket (18).

Description

PAD FOR WARMING A PAΗENT

This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/105,445 filed October 23, 1998.

Technical Field

The present invention relates generally to a portable and reuseable pad for warming a patient which functions to regulate patient core temperature before, during and after surgery and may also be utilized in the treatment of hypothermia.

Summary of the Invention

It is a primary object of the present invention to provide a portable, relatively inexpensive and reuseable pad for warming a patient.

Still another object of the present invention is to provide a patient warming pad particularly adapted to maintain a patient's body core at a normal temperature before, during and after surgery.

Still another object of the present invention is to provide a body warming pad which will maintain a patient's body core temperature at or near normal for extended periods of time thereby allowing for faster patient recovery from near hypothermic conditions during or after surgery. The pad is also useful in treating geriatric patients and hypothermic trauma. Additional objects, advantages and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as described herein, a patient pad is provided for regulating the core temperature of a patient undergoing medical treatment. The patient pad includes an outer covering including a pocket and a warming pouch of phase change material having a melting/freezing temperature of greater than 93 °F and less than 150°F that is received and held within that pocket.

The phase change material is at least 1 n-alkane. Preferably, the phase change material is selected from a group of n-alkanes consisting of eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane and any mixtures thereof.

In one embodiment, the patient pad also includes a heating element for heating the phase change material and a thermostat for controlling that heating within a desired temperature range. More specifically describing the invention, the warming pouch includes one or more sealed chambers. Where more than one sealed chamber is provided, each pair of adjacent sealed chambers is connected together by means of a live hinge. Additionally, each pouch includes a compartment adjacent the plurality of sealed chambers for receiving the heating element. In one embodiment, that heating element is a serpentine wire.

The patient pad of the present invention is relatively lightweight and thus, portable and easily manipulated to underlie a patient on a gurney, bed, operating table or the like. Advantageously, the patient pad is also reuseable. Further, the phase change material may be recharged quickly by means of the heating element so as to maintain a patient's body core temperature at or near normal for extended periods of time. This, advantageously, increases patient comfort and allows for faster patient recovery.

Still other objects of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

Brief Description of the Drawing

The accompany drawing incorporated in forming a part of the specification, illustrates several aspects of the present invention, an together with the description serves to explain the principals of the invention. In the drawing:

Figure 1 is a cross sectional view of the patient pad of the present invention; and

Figure 2 is a top plan schematical view illustrating one possible baffle arrangement. Reference will now be made in detail to the present preferred embodiment of the invention.

Detailed Description of the Invention The invention shown in the drawing figures is directed to an improved personal warming pad 10 which may be placed on a gurney, bed or operating table under a patient before, during and/or after surgery. The pad 10 may be affixed to the gurney, bed or operating table with straps, cooperating hook and loop fasteners such as Velcro, belts or other appropriate devices. Alternatively, the pad 10 may simple be left loose on the gurney, bed or operating table without the use of any means of attachment. Preferably, the pad 10 rests under the patient from the axis of the shoulder to the kidney region. The pad 10 is not affixed to the patient in any way. The personal warming pad 10 is constructed of a sewn outer shell generally designated by reference numeral 12. The outer shell incorporates a bottom layer 14 of insulating material such as antifungal/microbial neoprene 0.25 inches thick which reduces the thermal transfer of warmth (loss of energy) to the underlying gurney, bed, operating table or other structure supporting a patient. The bottom layer 14 may be covered top and bottom within fire retardant cotton.

The shell 12 also includes an top layer 16 constructed using a material such as 3000 denier Kevlar material (maximum of four layers) that is both impervious to needles, scalpels, knives, and other sharp instruments and provides good thorough thermal transfer between the pad 10 and the body of the patient. The top layer 16 may also be covered on both sides with fire retardant cotton material (not shown). The bottom and top layers 14, 16 are sewn together on three sides with the fourth side forming an opening communicating with a pocket 18 formed between the top and bottom layers. A pouch 20 containing a phase change material is inserted into the pocket 18 through this opening. One pouch 20 is shown in the drawing figure. It should be appreciated, however, that any number of pouches 20 may be provided.

Once the pouch 20 is inserted into the pocket 18, the opening is closed utilizing hook and loop fasteners 22 such as Velcro or any other type of fastener known in the art to be suitable for this purpose (e.g. buckles, snaps). Of course, the closing of the opening prevents accidental discharge of the pouch 20 from the pocket 18 as the pad 10 is, for example, manipulated to a proper position on a gurney, bed or operating table where it will underlie a patient.

The pouch 20 includes one or more sealed compartments 24 (two shown in the drawing figure 1). Each compartment 24 may be of the same or a unique shape so as to provide an overall configuration adapted to minimize bulkiness of the pad 10 and provide a volume of phase change material across the entire body of the pad sufficient for several hours of personal warming at a comfortable temperature. Of course, each of the sealed compartments 24 may include one or more baffles 28 to help reduce or prevent any rocking or waving motion in the phase change material when in its liquid or semi-liquid state.

The pouch 20 is constructed from a suitable flexible plastic material such as polyurethane, polyethylene, polyether or the like. The pouch 20 is formed by heat, radio frequency, infrared or ultraviolet sealing two separate sheets of plastic material at the periphery to form the desired overall shape and sealed chamber arrangement. At the same time, one or more small openings are left to allow filling of each compartment 24. The heat sealed seams 26 between each compartment 24 effectively form a live hinge. Baffles 28 are also heat sealed at various spaced and predetermined locations in the compartments 24. The baffles 28 extend partway across each compartment 24 (see Figure 2) leaving channels 30 which still allow fluid communication throughout each compartment. After the heat sealing formation of the flexible seam or line hinge 26 and the baffles 28, a desired volume of phase change material is added to each compartment 24 through the associated small opening. Those openings are then sealed. In use, the compartments 24 serve to prevent lumping and hold or maintain the phase change material across the entire body of the pouch 20 so as to provide consistent, even heating to all parts of a patient contacting the pad 10. This is true regardless of the position assumed by the patient. The baffles 28 prevent wave action from developing in the phase change material when in the liquid phase.

The phase change material held in the pouch 20 is at least one n- alkane. Preferably, the phase change material is selected from a group of n- alkanes consisting of eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane and any mixtures thereof. A volume of phase change material sufficient for several hours or more of personal warming at a comfortable temperature is utilized.

In one embodiment of the invention, a third layer 32 of plastic material is added to the pouch 20. This layer 32 is heat sealed to the pouch 20 on three sides with the fourth remaining open. A heating element 34 is inserted with the element facing and in direct thermal communication with the pouch 20 holding the phase change material. The element 34 is comprised of a substrate material, 16 gauge to 30 gauge insulated or uninsulated wire sewn into place forming a serpentine configuration which is contiguous, a thermal overload device or thermostat or thermocoupler 36 and a control cord 38 to connect to a machine controller 40. The heating element 34 will charge the phase change material within the pouch 20. The energy is collected and stored within the phase change material where the phase change material will make a phase change from a solid waxy state to a semi solid or liquid state. The machine controller 40 will monitor the temperature of the phase change material through the thermostat or thermocouple 36 and will control the electrical input (current) to the element 34. The machine controller 40 has 12 preset temperature options ranging from 96 °F to 120°F which are operator selectable. The machine controller 40 may be disconnected or stay connected throughout the intended use cycle. The pad 10 is generally to be utilized without any encumbrances during patient care, and is to be charged in an ancillary site. While attached to the machine controller 40, the temperature of the phase change will be regulated within ±1 °F. Upon attaining the present temperature, the element 34 will shut down (off) and will remain off until the phase change material cools and causes the contacts of the thermal regulating (thermocoupler) device 36 to close causing the machine controller 40 to electrify the element again, re-heating the pouch 20 of phase change material to the operator's predetermined temperature.

Claims

Tn the Claims

1. A patient pad for regulating the core temperature of a patient undergoing medical treatment, comprising: an outer covering including a pocket; a warming pouch of a phase change material having a melting/freezing temperature of greater than 93 °F and less than 125 °F that is received and held within said pocket.

2. The patient pad of Claim 1, wherein said phase change material is at least one n-alkane.

3. The patient pad of Claim 1 , wherein said phase change material is selected from a group consisting of eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, monacosane, triacontane and any mixtures thereof.

4. The patient pad of Claim 1 , further including a heating element for heating said phase change material and a thermostat for controlling said heating withing a desired temperature range.

5. The patient pad of Claim 4, wherein said pouch includes a plurality of sealed chambers, each pair of adjacent sealed chambers being connected together by means of a live hinge.

6. The patient pad of Claim 5, wherein said pouch includes a compartment adjacent said plurality of sealed chambers for receiving said heating element.

7. The patient pad of Claim 6, wherein said heating element is a serpentine wire.