US3551641A - Refrigerated intravenous liquid warming device - Google Patents

Description

United States Patent 1111 3,551,641

72] Invento And Truhan 2,000,478 /1935 Conte 219/303 M 392T.S9merset,N-J-08873 2,524,522 10/1950 Gilmore etal... 138/111 [21] AppLNO- 726. 3,336,463 8/1967 Johnson 219/304x 221 Filed May 3,19 3,370,153 2/1968 219/302 451 Patented Dec- 2 1 0 3,443,060 5/1969 219/302 3,475,590 10/1969 219/302 54 REFRIGERATED INTRAVENOUS LIQUID FORHGN PATENTS WARMING DEVICE 952,962 5/1949 France 219/302 mm mm n 8 1,376,352 9/1964 France 165/46 a a 17,621 9/1898 Switzerland 165/46 521 u.s.c1 219/303,

Przmary Examiner-A. Barns 128/214. 138/111, 165/46. 219/302, 219/305, Attorneksmwen & Stowe A6lf7/00 ABSTRACT: An intravenous liquid-warming device for ther- Field ofscalch 219/296- n conditioning Stored bloodthe components thereofetQ prior to transfusion into a subject comprises a preformed, disposable, plastic multiturn coil slidably superimposed over and in contact with the outer surface of a base complementary in size and shape to the coil. The base carries electric-heating means for uniformly heating the portion thereof contacted by the coil. An inlet for the fluid to be heated communicates with the uppermost turn of the coil and the lowermost turn is provided with a heated fluid outlet. A temperature sensing device in thermal contact with the lowermost turn of the coil adjacent the outlet regulates the heating means through a control unit.

1' MPERATU'R s usme DEVIECE THERMOSTAT CONTROL DEVICE PATENTEU UEC29 [97B SHEET 2 SF 2 TO PATIENT INVENTOQ ANDREW TRUHAN V .-,/Z;Mz y

ATTORNEYS REFRIGERATED INTRAVENOUS LIQUID WARMING DEVICE This invention relates to a device for warming blood or components thereof, such as plasma, which has been stored at depressed or refrigerated temperatures. The invention exhibits particular utility in operating and recovery rooms in hospitals. It is often required during the course of an operation or immediately after an operation to supply a subject with a fresh quantity of blood plasma. Very often the blood plasma is maintained or stored at refrigerated temperatures which are significantly lower than the average body temperature of approximately 98 to 99 F. In the event that blood plasma is required, the plasma bottle is often hung from a suspended support and a tube run from the bottle to appropriate injection apparatus for transmission into the body of the subject. In some cases, it has been observed that when the blood plasma has been refrigerated and not allowed to warm up sufficiently, a certain state of thermal shock has been observed in the subject and has been traced to the fact that the blood plasma was significantly lower in temperature than the normal body temperature. From such observations, it may be readily postulated that the transmission of relatively cold blood plasma into the body is a thing which is to be avoided if at all possible.

The prior art is aware of devices in this general field, as for example US. Pat. Nos. 2,876,769 to Cordova, 3,140,716 to Harrison, and 3,315,681 to Poppendiek. However such devices are not suitable for the specific purpose to which the subject invention is addressed for reasons which will become apparent.

It has become the mode in contemporary medical arts to employ, whenever possible, disposable instruments of either direct or indirect therapy. For example, inexpensive thermometers have been proposed which may be discarded after a single use. Inexpensive culture growing devices have been proposed which involve the taking of certain body fluids from a subject and the subsequent growth of a culture. Because of the cost of sterilizing therapeutic apparatus after use it is desirable to employ low-cost materials which will permit discarding. I

In general, the invention relates to a coil for the passage of blood plasma in the general form of a truncated cone. By virtue of this configuration the coil is readily placed upon and lifted off of a thermostatdevice for controlling the temperature of blood plasma passing therethrough. The coil is preferably formed from plastic or other inexpensive material, thus allowing for inexpensive discarding.

1n the drawings: FIG. 1 is an elevational view, partially in cross section;

FIG. 2 is a view taken along 2-2 of FIG. 1;

FIG. 3 is an elevational view which indicates the device in use as it cooperates with a storage receptacle for blood plasma;

FIGS. 4, 5 and 6 are cross-sectional views similar to the upper portion of FIG. 1 and disclosing several embodiments of the cross section of the coil.

Referring now to FIGS. 1, 2 and 3 of the drawings, the numeral l0 denotes generally an apparatus defined -in accordance with this invention and comprises in general two parts, the first being a coil through which blood plasma is adapted to pass and the second being a thermostat device for regulating the temperature of the coiland hence the temperature of fluid passing through the coil. The numeral 12 denotes generally a coil of this invention defined by a continuous and generally circular in cross section plastic tube. As illustrated at FIG. 4 of the drawings, the individual and adjacent whorls 42 may be formed, in a manner well-known to' workers in the plastic art, so that adjacent wall sections are common. The general shape of the coil 12 is that of a truncated right cylindrical cone whose upper or input end 14 is adjacent the uppermost turn and whose output 16 is adjacent the lower or last turn or convolution.

The numeral 20 denotes a base which may conveniently be formed of sheet metal also in the general form of a truncated cone. The top of the base may be apertured as indicated by the numeral 22 and the lowerportion may include an integral flange or skirt 24. The numeral 25 denotes in general resistance heating elements suitably mounted to the interior of the basemember 20. In general the heating elements are appropriately insulated from the metal, such insulation being well-known and hence not illustrated. The numeral 26 denotes electrical leads adapted to be coupled to an outlet, the coil leading into a thermostat control device shown in general by dashed lines at FIG. 1 and bearing the numeral 28. The thermostat control device 28 includes an on/off switch 30 and an operating-indicating light 32-adapted to become illuminated when the device is energized. The numeral 34 denotes generally a temperature sensing element coupled to the thermostat device 28. The sensor is located in contact with the lowermost convolution of the coil 12. The specific electrical circuitry employed in the thermostat device 28 may assume any one of a large number of configurations, well-known to workers in the temperature controlling art, and accordingly not here illustrated. Further, the specific construction details of the heating elements themselves, such as the elements 34 and 25 are so well-known as not to require description, particularly since these details form no part of the present invention.

FIG. 3 of the drawings indicates the mode of operation' of the device. In an operating or recovery room, a blood plasma storage vessel 40 is suitably suspended and a tube pendant therefrom is coupled to the upper or input portion 14 of the coil 12. In general, a rubber or'a plastic tube is attached to the output of the storage vessel 40, this tube being in turn coupled to input portion 14. The gravitationalforce acting on the liquid in the storage container 40 causes a flow of the liquid through the convolutions of the coil 12 and out exit portion 16 to the subject. By virtue of the rather snug contact between the coil 12 and the outer walls of the heated base 20 the individual turns or convolutions 42 become heated, with a consequent transfer of heat to the blood plasma flowing through the whorls. By suitable adjustment of the temperature, the temperature of the exiting blood plasma may be closely controlled and accordingly maintained at an optimum value.

After the transfusion or transfer process has been completed, couplings to portions 14 and 16 are broken and the entire coil 12 is discarded. It will readily be observed that the shape of the coil permits a simple lifting off of the base 20. This cooperation of configurations also permits a very rapid and foolproof insertion of the coil 12 on the base 20.

Referring now to FIG. 5 of the drawings, a modification of the shape of the individual turns is illustrated. Here, a square cross section 44 is indicated and is defined by outwardly extending portions 45 and parallel wall segments 46 and 48. Again, the material of construction is preferably plastic for purposes of ease in molding and it will be observed that the flat inner wall 48 provides surface-to-surface contact with the exterior wall of the support base 20. This promotes rapid and efiicient heat transfer.

Referring now to FIG. 6 of the drawings, a triangular cross section 50 is indicated for each of the individual turns of coil 12, an inner wall 52 rests against the outer surface of base 20.

Wall portions 54 and 56 define the triangular opening 50 and plastic is generally the material of construction. I claim: lQA blood warming device including: a. a disposable plastic conduit having a plurality of turns to thereby define a displaceable coil, an inlet for blood to be heated communicating with the upperturn of said coil,

and an outlet for heated blood communicating with the over the outer surface of said base with the inner surface of the turns thereof in thermal contact with the outer surface of said base;

(1. said base having a heating means for uniformly heating the portion thereof contacted by said'coil and a temperature sensitive element in thermalcontact with the lowermost whorl of said coil at a point immediately adjacent to said outlet;

e. said temperature sensitive element coupled to control means for regulating said heating means and thereby the temperature of the supporting base;

f. whereby the temperature of blood leaving the lower part of the coil may be set to a desired temperaturev 2. The device of claim 1 wherein the turns of said coil are rectangular in transverse cross section.

thereby define a displaceable coil, an inlet for blood to be heated communicating with the upper turn of said coil. and an outlet for heated blood communicating with the lowermost turn of said coil;

b. a base complimentary in size and shape to said coil, said coil slidably superimposed over the outer surface of said base with the inner surface of the turns thereof in thermal contact with the outer surface of said base; r

c. said base carrying a heating means for uniformly heating the portion thereof contacted by said coil and'means for directly sensing the temperature of a part of said coil;

d. said temperature sensing means coupled to control means for regulating said heating means and thereby the temperature of the base; and

e. whereby temperature of blood plasma exiting from said conduit may be set to a desired value.

6. The device of claim 5 wherein the turns of said coil are in tegrally sidewise connected to each other, to thereby enhance heat transfer from one turn to another and to minimize heat losses by radiation from individual turns.

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