GB2429647A

GB2429647A - Fluid or blood warmer

Info

Publication number: GB2429647A
Application number: GB0517595A
Authority: GB
Inventors: Ahmed Messahel; Farouk Messahel
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-08-30
Filing date: 2005-08-30
Publication date: 2007-03-07
Anticipated expiration: 2025-08-30
Also published as: GB2429647B; GB0517595D0

Abstract

Apparatus for warming fluid, blood and its derivatives when administered to patients comprising a transparent plastic container 1 with a cover 3 containing two holes on each side and one in the centre. Preferably the container is filled with soda lime granules 2. A stiff coiled medical tube 11 is embedded in the granules 2 with each end of the tube 12, 13 passing through two holes. Corrugated tubes 9, 10 are attached to two larger holes 4, 5 and a small central hole may receive a thermometer 14. Carbon dioxide from a cylinder or the patients expired air may enter the container via corrugated tube 9 and reacts with the soda lime 2 to give off heat which warms the fluid in the coiled tube 11. Carbon dioxide may be removed via the second corrugated tube 10. The coiled tube 11 may be attached to a transfusion set.

Description

FLUID/BLOOD WARMER This invention relates to an apparatus used in warming

fluids, blood and its derivatives when administered to patients or injured individuals, whether inside or outside hospitals or medical centres.

Lowering of body temperature (hypothermia) is an undesirable consequence of many factors. One such factor is intravenous administration of fluids and blood or its derivatives, to patients or injured individuals. Irrigation of the urinary bladder during urological surgical procedures may also lower the body temperature. One litre of intravenous fluid at room temperature when given to a patient lowers the body temperature by 0. 25 C. Blood is stored at 4 C, and when transfused to a patient, particularly if more than one unit of blood are transfused, body temperature falls to a level that harms the body and could result in a fatal outcome. Warming of fluids and blood or its derivatives, and fluids used in urinary bladder irrigation are essential component of patient care.

Fluid/blood warmers depend on electric power in their operation to generate heat whether in "water-bath' or dry-heat warmers. This means that they are used mainly in hospitals, while patients and victims in the field and at scene of incidents are denied such valuable care at a time they are in most need of it.

Added factors such as the bulk of warmers, lack of operational simplicity and cost may contribute to the fact that many resuscitators may refrain from using them.

Soda lime is a substance containing the hydroxides of sodium and calcium. It is chemically known that it absorbs carbon dioxide gas (C02) and one result of this reaction is heat: Carbon dioxide + water leads to carbonic acid Carbonic acid + sodium hydroxide leads to sodium carbonate + water + heat Calcium hydroxide + sodium carbonate leads to calcium carbonate + sodium hydroxide + heat.

By using chemical symbols, the reaction proceeds as follows: CO2+H2O -* HCO3 2H2C03 + 2NaOH - Na2CO3 +41120+ Heat 2Ca(OH)2 + Na2CO3 -* 2CaCO3 + 2NaOH + Heat The intensity of the heat liberated from this reaction is gradual and the temperature may reach 60 C. This process continues as long as CO2 is flowing or until the soda lime is exhausted. Signs of exhaustion include cessation of heat production or change in the colour of the soda lime to violet. At this stage the soda lime granules should be replaced with fresh ones.

Accordingly, this invention does not depend on electric power to warm up fluids or blood infused to patients or injured victims. Instead, it utilizes the heat produced from the reaction of soda lime when it absorbs CO2. It can be used in

I

closed breathing circuits when the patient is attached to it, and in this case expired CO2 of the patient is the source of the gas and there will be no need for CO2 supply from cylinders. This allows the warmer to operate anywhere and under wide range of circumstances.

A preferred embodiment of the invention will now be described with reference to the accompanying drawing in which: FIGURE 1 shows in perspective, the apparatus when assembled: FIGURE 2 shows a side view of the transparent plastic container when filled with soda lime granules; FIGURE 3 demonstrates a top view of the cover of the plastic container with its five openings; FIGURE 4 illustrates a side view of the apparatus when fully assembled and connected to different tubes; and FIGURE 5 shows the stiff plastic coil with its two ends.

As shown in Figure 1 the apparatus consists of a transparent plastic container I of different sizes, filled to near its rim with soda lime granules 2 (Fig 2). The container has a cover 3 (Fig 1,2 & 3) made of the same material which firmly fits on the container 1 (Fig 2). This cover 3 (Fig 3) contains five holes: two on each side, one is bigger 4 & 5 than the other 6 & 7, and the fifth hole 8 lies in the middle of the cover. The bigger opening on one side 4 is connected to a corrugated tube 9 delivering carbon dioxide gas (C02) from either a CO2 cylinder or through the expiratory limb of a closed breathing circuit, if the patient is already attached to one (Fig 4). Depending on where the warmer is used, a small CO2 cylinder is practical outside treatment centre set-up while big capacity cylinders can be used inside hospitals. Another corrugated tube 10 is connected to the bigger hole on the opposite side 5 for the removal of any unabsorbed CO2 gas or for the return of other gases back to the closed breathing circuit following removal of CO2 gas from them.

Embedded in the soda lime granules 2 in the container 1 is a coiled tube 11 made of stiff plastic, which is medically sterile, with two ends 12 & 13, each end emerges from the smaller openings on each of the cover 6 & 7. One end 12 is attached to the transfusion set of fluid or blood or its derivative to be warmed prior to administering it to patients. The other end 13 is connected to the tube which carries the warm solution to the patient.

Fitted in opening 8 in the centre of the cover 3 of the container I is a medical mercury thermometer 14 (due to its limited scale between 35 -42 C) to monitor the temperature generated from the reaction between CO2 gas and soda lime granules 2. To prevent overheating of the fluid or blood inside the coiled plastic tube 11, the flow of CO2 to the container 1 via the corrugated tube 9 should be interrupted, to be resumed again when the temperature starts to fall below 38 C.

The inability of soda lime to further absorb CO2 gas will be manifested by a change in its colour to violet. This can be easily observed through the transparent container 1. Another sign of soda lime exhaustion is cessation of heat production. At either stage soda lime granules should be replaced by fresh ones.

Claims

1. An apparatus for warming fluid, blood and its derivatives when administered to patients or injured individuals, composed of transparent plastic container of different sizes having cover of the same material which contains five holes: two on each side and the fifth in the middle.

2. An apparatus as claimed in Claim 1 filled to near its top with soda lime granules

3. An apparatus as claimed in Claim 2 embedded in the soda lime is a medically sterile coiled tube made of stiff plastic with two ends.

4. An apparatus as claimed in Claim I has a cover of same material containing four openings two on each side, one is bigger than the other.

5. An apparatus as claimed in Claim 4 has a small fifth hole in the middle of the cover.

6. An apparatus as claimed in Claim 4 where a corrugated plastic tube is attached to the bigger opening on each side.

7. An apparatus as claimed in Claim 4 where each end of the coiled plastic tube embedded in the soda lime passes through the smaller opening on each side of the cover of the plastic container.