WARMING INFUSION FLUIDSThe present invention relates to the warming of infusion fluids intended for intravenous (I.V.) fluid administration and, more particularly, to the warming and insulation of infusion bottles, bags or other containers and giving sets.
The chances of recovery of a severely traumatised patient are considerably improved by stabilising the traumatised patient using I.V. fluid replacement before removal of the patient from an accident site to hospital. In many cases, prehospital patient stabilisation has a direct effect on patient condition on arrival at the hospital and this effect continues to benefit the patient during later treatment. Whilst it is important to attempt such prehospital stabilisation, difficulties can be experienced in cold environments owing to the fact that the temperature may affect the viscosity of some infusion fluids. In cold temperatures, usually below +30C, some infusion fluids begin to gel and consequently do not flow.Furthermore, hypothermia is common in severely traumatised patients so that, depending on the patient's level of trauma, it may also be important to infuse the replacement fluid at a temperature which is close to normal body temperature, otherwise infusion risks exacerbating the patient's condition.
With a view to alleviating the ove-mentioned difficulties and risks, it is therefore an object of the present invention to provide an arrangement for warming and insulating an infusion container and giving set, particularly, in an outdoor or outside hospital environment.
To this end, the invention consists in a set of parts for use in warming and insulating an infusion container and giving set, comprising an insulating bag for housing the infusion container, a self-contained heating means located in the bag so as to be adjacent the infusion container housed within the bag, and an insulating sleeve for receiving the giving set and surrounding at least a major portion of the length of the delivery tube of the giving set. Preferably, the set also includes an insulating cover for securing to a patient's arm over the puncture site and infusion cannula, and a self-contained heating means located within the cover so as to be adjacent the patient's arm and cannula.
Conveniently, the insulating bag fully encases the infusion container, except for a small opening in its bottom end via which the giving set is connected to the container, and has a closable opening providing access to the interior of the bag for insertion and removal of the container. This access opening may be closed by a zip fastening device. A suitable handle may be located at or adjacent the upper end of the bag to permit holding or hanging of the bag, and the enclosed infusion container, at a desired height for an infusion procedure.
The insulating sleeve for the giving set may be arranged to enclose the whole of the delivery tube of the giving set except for a short length adjoining the drip chamber or the cannula sufficient to accommodate the control clamp or pinch valve attached to the delivery tube to control the flow of infusion fluid.
The self-contained heating means used in the insulating bag and the patient's arm cover may each comprise a reusable heat pack of the type described in European PatentApplication No. 83304501.6. Such a heat pack basically comprises a plastic envelope containing a solution whose main ingredient is sodium acetate trihydrate to which is added a microbial polysaccharide, known as xantham gum.
The pack, is charged by heating it to about 650C, whereupon the ingredients change from a crystallised solid to a gel form, absorbing latent heat as a result. The gel is slowly cooled and remains stable down to and below normal room temperature. The pack is activated to release its stored latent heat by physically pressing an activator button contained within the pack, and this results in the pack heating to a temperature of about 580C over a period of 1 to 2 hours depending on the size and thickness of the pack and the insulation characteristics of the insulating bag and patient arm cover. Except in extreme low temperature conditions, this should be sufficient to raise and maintain the temperature of the infusion fluid to a value avoiding gelling of the infusion fluid and risk of exacerbating any hypothermia being suffered by the traumatised patient.
The present invention also consists in an infusion container and giving set when insulated by the set of parts described above.
In order that the present invention may be more readily understood, reference will now be made to the accompanying drawing which schematically illustrates one embodiment of the invention.
Referring to the drawing, 1 is an infusion bottle and 2 is a giving set comprising a drip chamber 3 and delivery tube 4. The drip chamber is connected to the infusion bottle 1 by a lance 5 at the upper end of the drip chamber inserted through the sealing plug in the bottom of the bottle, whilst at the opposite end of the giving set, the delivery tube, is connected to a patient's arm 7 by a cannula 8 which is inserted into the patient's arm at the required puncture site and through which fluid may be infused into the patient's arm. Flow of infusion fluid through the delivery tube 4 of the giving set is controlled by a conventional clamp device 9 engaged with the delivery tube adjacent the cannula. This is a conventional layout for I.V. fluid administration set.
In accordance with the present invention, the infusion bottle 1 is contained within an insulating bag 10 having an opening 11 extending from top to bottom of the bag and through which the infusion bottle 1 is inserted into and removed from the bag. This opening is closable by a zip fastener device 12. At its bottom end, the bag has a small opening 13 via which the lance 5 of the giving set may be inserted into the bottle 1 so as to connect the giving set to the latter. At the upper end, the bag has a handle 14 so as to enable it to be held or hung, together with the infusion bottle, at a desired height for an infusion procedure.
Contained in a pocket formed in the inside lining of the insulating bag 10 is a reusable heat pack 16 of the type described above with its ingredients in a gel form ready for use.
Below the drip chamber 3, the delivery tube 4 is surrounded by an insulating sleeve 17 which extends from a position adjoining the drip chamber to a position immediately above the control clamp 9. The sleeve 17 is a tight fit on the delivery tube so that it tends to remain in the required position and does not slip down the tube.
At the puncture site on the patient's arm 7, an insulating cover 18 is secured about the patient'# arm and over the puncture site and infusion cannula 8. On its inside, this cover 18 has a pocket containing a reusable heat pack 19 of a similar type to that used in the insulating bag 10 and having its ingredients in a gel form ready for use.
Preparatory to an infusion procedure under cold conditions, the reusable heat pack 16 in the insulating bag 10 is activated by pressing the activator button inside the pack and the bottle 1 is placed in the bag through the opening 11 which is then closed by actuation of the zip fastener 12. The infusion fluid is thereby warmed, whereafter the giving set 2 is connected to the bottle by inserting the lance 5 at the upper end of the drip chamber 3 through the sealing plug in the bottom of the bottle, via the opening 13 in the bottom of the bag. The giving set may then be primed and the infusion procedure commenced.
Prior to application of the insulating cover 18 to the patient's arm, the heat pack 19 on the inside of the cover is activated by pressing the starter button inside the pack and, as the warmed infusion fluid is dispensed from the infusion bottle 1 through the giving set 2, it is firstly insulated against heat loss during flow through the delivery tube 4 by the insulating sleeve 17 and then rewarmed by the action of the activated heat pack 19 within the arm cover 18.
After an infusion procedure, the heat packs 16,17 can be readily removed from the bag and arm cover, respectively, and be replaced with other packs whilst the spent packs are recharged by heating, as above described.
Whilst a particular embodiment has been described, it will be understood that modifications can be made without departing from the scope of the invention. For example, the insulating bag 10 may be of any suitable shape for containing an infusion bottle, bag or other container and the heat pack 16 used within the iiisulating bag may be shaped so as to embrace the infusion container about a major part of its periphery. The control clamp 9 may be located adjacent the drip chamber 3, in which event the insulating sleeve 17 is arranged to insulate the delivery tube 4 from a position just below the clamp to a position closely adjacent or adjoining the cannula 8.