GB2063071A

GB2063071A - Medical or surgical fluid feed arrangement

Info

Publication number: GB2063071A
Application number: GB7928038A
Authority: GB
Original assignee: GODRICH J
Current assignee: GODRICH J
Priority date: 1979-08-11
Filing date: 1979-08-11
Publication date: 1981-06-03

Abstract

A medical or surgical fluid feed arrangement such as a drip feed arrangement has sensing means for abnormality in the supply of fluid. A saline bag 13 for example can have a magnet 14 and reed switch 15 normally kept apart when the bag is full but which come together when the bag is emptying, or a fluid pressure sensitive diaphragm can trip a limit switch. <IMAGE>

Description

SPECIFICATION Medical or surgical drip feed arrangement This invention relates to medical or surgical fluid feed arrangements.

An example of such arrangements is the wellknown saline drip, which is normally a collapsible bag of solution suspended at a certain height above a a patient's bed and which feeds the solution via a drop sight and a flexible tube and through a hypodermic needle. Another arrangement is described in GB Patent Application No. 46696/78 where a drip feed arrangement has pressure means to apply a pressure other or in addition to that applied gravitationally, to urge the fluid through the drip tube. The pressure means comprise means for applying pressure to the flexible bag containing the solution, or a peristaltic pump acting on the feed tube. Powerforthe pressure means is produced by a pump driven by the chest expansion of the patient.

This latter arrangement enables the patient to walk about.

In either case, the treatment is continuous over a period of at least several hours and frequently for much longer periods. The arrangements are checked from time to time by nursing staff. However, it is not possible continuously to monitor the treatment and this means that the supply can sometimes run out and treatment be suspended unintentionally on that account for quite long periods of time.

Another possibility, particularly with the pump arrangement above referred to, is that a blockage in the system (or in the patient) can lead to an undesirable pressure build up.

The present invention provides improved drip feed arrangements to deal with these problems.

The invention comprises a medical or surgical fluid feed arrangement, characterised by having sensing means for an abnormality in the supply of fluid.

Said sensing means may detect a low or zero fluid content of the container. When the container comprises a flexible bag, the sensing means may detect collapse of the bag, and may comprise a magnet and a reed or other magnetically activated switch so positioned that liquid in the bag normally keeps them apart but that they come together when the bag is emptying.

The sensing means may detect fluid pressure. A change in fluid pressure may cause a diaphragm to move which in turn activates switch means.

In any event, the sensing means, on detecting an abnormality in the supply of fluid, may activate an alarm and/or stop the feeding or attempted feeding thereof automatically.

Embodiments of medical or surgical fluid feed arrangements will now be described with reference to the accompanying drawings in which: Figure l is a diagrammatic illustration of a flexible bag for a saline solution showing sensing means with the bag full, Figure2 is an illustration like Figure 1 showing the bag emptying, and Figure 3 is a diagrammatic illustration of sensing meansforfluid pressure.

The Figures show medical or surgical fluid feed arrangements, characterised by having sensing means 11 for an abnormality in the supply of fluid.

Figures 1 and 2 show a conventional drip feed arrangement in which saline solution 12 is fed from a collapsible bag 13 via the usual drop sight, flexible tube and hypodermic needle (not shown). Attached to the outer wall of the bag 13 are, on one side, a magnet 14 and, on the other side, a reed switch 15.

The reed switch is connected in an electrical circuit (powered, for safety reasons, by, for example, a low voltage dry cell) to activate an alarm 16. When the bag 13 is full, the magnet 14 and reed switch 15 are kept apart, but when the bag is emptying, as shown in Figure 2, the two come together so that the magnet 14 activates the reed switch 15 to set off the alarm 16. The alarm may comprise a buzzer and/or a light.

If the arrangement comprises a pump (like the one in the Patent Application referred to) the exhaustion of fluid from the bag may also interrupt the action of the pump or operate a valve or otherwise prevent air being drawn into the system.

Figure 3 shows a pressure sensitive diaphragm 31 in a feed line 32 from a pump 33 to a hypodermic needle 34. The diaphragm 31 is situated between the pump 33 and a filter and drop sight 35, and actuates a limit switch 36 which is connected into an alarm and/or automatic cut-off system (not shown) as before.

Claims

1. A medical or surgical fluid feed arrangement, characterised by having sensing means for an abnormality in the supply of fluid.

2. An arrangement according to claim 1, in which said fluid is fed from a container, characterised by sensing means detecting a low or zero fluid content of the container.

3. An arrangement according to Claim 2, in which said fluid container comprises a collapsible bag, characterised by sensing means detecting collapse of said bag.

4. An arrangement according to Claim 3, characterised in that said sensing means comprise a magnet and a reed or other magnetically activated switch so positioned that liquid in the bag normally keeps them apart, but that they come together when the bag is emptying.

5. An arrangement according to Claim 1, characterised in that said sensing means detect fluid pressure.

6. An arrangement according to Claim 5, characterised in that a change in fluid pressure causes a diaphragm to move which in turn activates switch means.

7. An arrangement according to Claim 1, characterised in that said sensing means, on detecting an abnormality in the supply of fluid, activates an alarm.

8. An arrangement according Claim 1, characterised in that said sensing means, on detecting an abnormality in the supply of fluid, stops the feeding or attempted feeding thereof automatically.

9. An arrangement according to Claim 1, characterised by being adapted for drip feed arrangements.

10. An arrangement according to Claim 9, characterised by being incorporated in drip feed arrangements according to British Patent Application No.

46696/78 aforesaid