WARNING DEVICE IN THE USE OF VENOUS DRIP FEEDS
The invention concerns auxiliary equipment for venous drip feeds .
The technique used in medical treatment known as the ve- nous drip feed is well known and consists in the adminis¬ tration of medicinal solutions into a patient's circulatory system, drop by drop, through a vein.
The liquids so introduced are contained in glass bottles hung in a position above the patient's bed. It is also known that the flow from bottle to vein must be cut off before the bottle is completely empty to avoid en¬ try of air into the vein.
This means constant supervision of the patient by the nurse who must await the exact time when the liquid is practically exhausted in order to shut off communication between the bottle and the needle inserted in the vein, and remove the needle. It is clear that this necessity creates serious problems and difficulties bearing in mind the dangers there may be for the patient if the nurse is late, the need for the nurse to be constantly nearby as well as the possibility of action being premature or delayed.
Such problems become even more serious where there are great numbers of patients requiring attention. The above invention prevents these problems from arising as will be explained below.
Subject of the invention is a warning devic for v nous drip feeds that comprises an oblong structure with a means for hanging it on the top. Inside the structure there is a slider able to slide freely in the axial direction, pushed upward by an elastic means.
Fixed to the lower end of said slider and projecting outside
the device is a means on which to hang the drip feed bottle.
Above said slider is a switch for the electric circuit of a visual or acoustic warning, or one of some other kind. The part operating said switch lies in the trajectory of a thrusting means fixed to the slider.
As the weight of the bottle is reduced by transfer of the liquid into the patient's vein, the slider will steadily rise, and consequently the thrusting means fixed to it as well, until the switch functions closing the circuit and setting off a warning of one kind or another.
The position of the switch in relation to the thrusting means is fixed so that the alarm is given when the quanti¬ ty of liquid remaining in the bottle has fallen to the level at which the nurse must intervene to cut off the connection between bottle and needle in the vein and to pull the needle out.
The position of the part operating the switch, on the tra¬ jectory made by the thrusting means, can be adjusted as required according to the weight of the type of bottle used for the venous drip.
The switch can be connected to the electric circuit of one of the numbers, marked on an indicator board, corres¬ ponding to the bed or room number of the patient having the drip. In one type of execution the switch is connected to the electric circuit of the bell, or some other warning means for the patient's bed, by fitting a suitable socket into said electric circuit.
In another type of execution the acoustic, visual or other kind of warning is supplied independently by electric bat¬ teries or the like. The warning device and the batteries
are placed inside the apparatus itself.
In another type of execution the acoustic, visual or other kind of warning device is placed together wi h its electric batteries in a special structure for the purpose and is connected to a plug outside said structure.
Said plug can be inserted in a socket, placed in the appa¬ ratus, connected to the contacts of the switch. Said socket can receive either the plug of said warning structure or a plug with a wire for connection to visual, acoustic or some other warning signals, to numerical signal indicator boards or other similar means
The elastic means is preferably a helical compression spring In one type of execution the slider is discoid in shape, is guided by the sides of the oblong structure and has a rod passing through a central hole in the slider disc, said rod having a headpiece at its top that connects to an upper surface of said slider disc.
The lower end of said rod has a threaded tip, said tip pas¬ sing through a hole in the bottom of the oblong structure of the apparatus and screwing into the lower hook of the ap¬ paratus from which the venous drip bottle hangs. In one type of execution the position of the part, opera¬ ting the switch on the trajectory of the means that thrusts the slider, can be adjusted as desired by moving a terminal , fixed to the switch, along a slit in the outwer wall of the apparatus, parallel to the trajectory of the slider, and tightening it at the desired level in relatio to th base of the apparatus. In another type of execution the position of the part,opera- ting the switch on the trajectory followed by the means thrusting the slider, can be adjusted as desired by using
a knob to rotate a threaded pin, supported by the struc¬ ture of the apparatus, to a position parallel to the tra¬ jectory of the slider, inside a threaded bushing fixed to the support of the switch. The position of said switch can be seen from the outside of the apparatus by means of pointers fixed to said swi¬ tch's support and by means of graded scales marked on the outside of the apparatus down the edges of a longitudi¬ nal slit through which the pointers pass. The advantages of the apparatus are clear.
Nurses no longer have to keep a constant watch on the le¬ vel of liquid in the bottle while the venous drips of a number of patients are in progress, thus leaving them free to attend to other patients. The time which nurses have to spend on these observations is greatly reduced as they will be informed by some kind of warning when the moment arrives to stop the flow of li¬ quid and put in a fresh bottle or to remove the needle from the vein. The risks caused by carelessness and delays are thus avoid¬ ed, as well as those due to nurses being overburdened with work.
Since the apparatus is easy to adjust, safety and speedy installation are assured. Characteristics and purposes of the invention will become even clearer by the following examples of its execution illustrated by diagrammatic drawings. Fig. 1: Side view of the apparatus. Fig. 2: Front view of the apparatus. Fig. 3: Side view of the apparatus cut through longitudinally. Fig. 4: Side view of the apparatus associated to a warning device with independent feed.
The apparatus 10 comprises a cylindrical body 11 and a cap 20 with collar 21 fixed to said apparatus by laterally placed screws 22.
By means of screw 25 the upper hook 23 is mounted on said cap 20 so that the apparatus can be hung up.
A discoid slider moves inside the cylindrical body 11, a rod 35 with head 36 passing through said slider in a cen¬ tral hole 31.
Passing through the hole 14 in the bottom 12 of the cylin- drical body 11, said rod is screwed by its thread 38 into the lower hook 24 onto which the venous drip bottle hangs.
Between the above mentioned bottom 12 and the slider 30, a helical compression spring 37 is placed axially round the rod 35, said spring being guided by cylindrical extension 32 of the slider 30 and by cylindrical extension 13 of the bottom 12.
Inside the cylindrical body 11, above the slider 30, a cup 40 is supported by the inner face of the cylindrical body, at the level of the longitudinal slit 15, by means of the screw 43 and head 44 that passes through the hole 41 in the side of the cup 40 thereby enabling the knob 45 to be screwed on .
The cylindrical bushing 46, wider than the slit 15, is moun¬ ted on said screw 43 between the knob and the side of the cylindrical body.
Said bushing 46 has two sharp diametral projections, one at each side, forming two pointers 47 and 48 pointing in op¬ posite directions, and has also a raised parallelepiped part 49 whose width is slightly less than that of the slit 15.
Penetrating inside slit 15, said raised part holds the two
0
pointers 47 48 crosswise to said slit.
Collar 56 of switch 54 is inserted inside the central hole
50 in cup 40, said switch being fixed by a ring nut 57 that screws into said collar 56. The switch 54 has a push button 53 aligned w th the head
36 of rod 35.
On one face of the cylindrical body I I the two-pole socket
65 is fixed by screws 66 at the point of hole 16 made in said face to allow introduction of the plug 70 with 2-pole wire 71 connected to a visual, acoustic or other kind of warning.
Contacts 58 59 of the switches are connected to contacts
60 61 of the 2-pole socket by wires 62 63.
On both sides of the slit 15 in the cylindrical body 11 are graded scales 18 19 having a total of twenty notches.
By moving knob 45 the cup 40 can obviously be moved up or down and fixed in a certain position by tightening the knob on screw 43.
When so tightened the bushing 46 and opposite side of the cup 40 will press respectively against the outer and inner faces of the cylindrical body 11 at the edges of slit 15.
The position of the cup 40 and therefore the axial position of the push button 53 for switch 54, fixed to said cup 40, will be indicated by the positions of each of the pointers 47 48 respectively on one graded scale 18 and on the other 19.
The wire 71 of plug 70 is connected to a visual or acoustic warning or to one of both types.
When a drip feed is required the bottle containing it is hung onto the lower hook 24 of the apparatus, itself in turn hung by its upper hook 23 to the structure generally used for this purpose.
The weight of the full bottle will obviously induce par¬ tial compression of the helical spring 37 due to the force transmitted through the hook 24, by means of the rod 35, to the discoid slider 30 and therefore the head 36 of said rod 35 will lie at a certain level in relation to the bottom 12 of the apparatus, according to the weight of the bottle.
As the liquid gradually leaves the bottle and enters the patient's vein, said head 36 will also gradually rise. Before starting the venous feed, the cup 40 will be fixed, by means of knob 45, in a position enabling the push button 53 of the switch to act on the head 36 of rod 35 when the bottle becomes nearly empty. This will cause the switch to close the electric circuit of the warning device of whatever kind it may be.
To make the alarm go off at the noment when the drip feed is considered as finished, it being then necessary for the nurse immediately to close the connection between bot¬ tle and needle and remove the needle, the position of the cup 40 must be previously adjusted, for example by hanging an empty bottle to the apparatus, or by checking the final level of the first feed bottle, or by some other means.
Clearly, after checking the number that shows when a cer¬ tain type of feed bottle is empty and noting the position of the pointers on the graded scale, if a bottle of the same kind is hung on the apparatus the knob can be moved so that the pointers indicate which number is reached when that particular bottle is empty. The numbers for the empty position of each type of bottle will then be listed on a sheet to be consulted at he be¬ ginning of each drip feed.
The wire 71 can of course be connected either direct to the warning system or to one of the symbols on the board indicating the patient's bed or room number; in this way the nurse can see which feed is needing instant attention as soon as the warning is given.
The warning means could also be the one provided for the various hospital beds. In that case the wire 71 for plug 70 must be connected to the electric circuit of said warn¬ ing meansι which can therefore be made to operate either independently or by the patient in the usual way, or else by the warning apparatus subject of the present, invention.
Fig. 4 shows an independent warning device 75 comprising a container 76 to hold the feed batteries 77 and the buzzer 78. Said device can be connected to apparatus 10 by the two-pole plug 79 fitting into the two-pole socket 65.
As Fig 4 illustrates, the apparatus 10 can operate in a completely independent way without any need for electrical connections . The apparatus described above can include another electric switch connected to the alarm circuit together with a pilot light that can be operated from outside.
By means of this switch the apparatus can be activated, a condition which is indicated by the pilot light coming on; it can also be turned off after use or to prevent the warn- being given while the drip feed bottles are being exchanged
The movements of cup 40 supporting switch 56 can naturally be made by other means than the knob 45 described above. Said movements can be advantageously made by mounting a threaded bushing, or the like, on the support to switch 54 and into which bushing a threaded pin can be screwed paral¬ lel to the axis of the apparatus, with a head at the upper
end of said pin emerging from the cap 20 on the apparatus. Said pin can be free to rotate but not to make axial move¬ ments .
By rotating said head the switch 54 would be raised or low- ered in relation to the bottom of the apparatus, according to the direction of rotation.
The position of the switch will similarly be indicated by the pointers, sliding up and down the graded scale, fixed to the support of the switch and passing through the slit 15.
By this system switch movements could be very finely gra¬ duated and therefore the warning device could be tuned to a very high level of precision.