GB2260686A

GB2260686A - Stocking

Info

Publication number: GB2260686A
Application number: GB9120380A
Authority: GB
Inventors: Derek Walter Beavers
Original assignee: Brevet Hospital Products UK Ltd
Current assignee: Brevet Hospital Products UK Ltd
Priority date: 1991-09-25
Filing date: 1991-09-25
Publication date: 1993-04-28
Anticipated expiration: 2011-09-25
Also published as: GB9120380D0; GB2260686B

Abstract

A graduated compression stocking (1) provides improved blood flow in the leg of a patient. The stretchable material from which the stocking is made and the dimensions of the stocking in the relaxed state are each chosen such that, when the stocking is in use on the leg of a chosen patient, the compressive force exerted by the calf region (4) lies within the range of from 13-15 mm Hg and the compressive force exerted by the ankle region (3) lies within the range of from 15-17 mm Hg, there being a difference of from 1-3 mm Hg between the respective compressive forces exerted at the ankle and calf. <IMAGE>

Description

STOCKING This invention relates to a graduated compression stocking suitable for use by non-ambulant patients in a hospital environment. More particularly, the present invention relates to such a stocking which gives improved deep vein blood flow in a patient wearing the stocking. These stockings are sometimes referred to as "anti-embolism" stockings. A graduated compression stocking is one in which the pressure at the ankle exceeds that exerted at the calf which, in turn, exceeds that exerted at the thigh.

The main cause of thrombus formation in the legs of a previously active human adult is sudden and prolonged bed confinement since the volume flow of blood and the linear velocity are greatly reduced without leg exercise. Graduated compression stockings formed from a stretchable material are known which increase the velocity of linear flow of blood in the leg of a patient fitted with such a stocking. These stockings are effective as a prophylactic deterrent against deep vein thromboses and pulmonary emboli. The stockings provide an increased blood flow, and there is a resultant substantial reduction in venous stasis.

Presently, a size of graduated compression stocking is chosen such that the compressive force exerted at the ankle and calf regions of a wearer is of the order of 18 mm Hg and 12 mm Hg respectively. In practice, this is achieved by providing a series of different sizes of stocking (for instance, small, medium, large and extra large) which are adapted for different sized legs. Each size stocking is produced such that it exerts the desired pressure at the ankle and calf regions of a patient wearing that size of stocking.

It has now been found that the blood flow may be even further improved by the use of a stocking which exerts different pressures, falling within narrowly defined ranges, at the ankle and calf regions of the wearer. These results have been found after extensive tests conducted using a gamma-ray camera to monitor an injected radio-isotope in the muscle of a patient wearing a range of graduated compression stockings.

Thus, in accordance with the present invention, there is provided a graduated compression stocking of the type which is formed of a stretchable material and which comprises respective foot, ankle and calf regions, said calf region being enlarged relative to the adjacent ankle region of the stocking and each of the ankle and cafe regions being capable of exerting a compressive force at the ankle and calf respectively of a wearer, characterised in that said stretchable material from which the stocking is made and the dimensions of the stocking in the relaxed state are each chosen such that, when the stocking is in use on the leg of a chosen patient, the compressive forces exerted by the ankle region of the stocking of the ankle of the wearer and by the calf region of the stocking on the calf of the wearer lie within the range of from 15 to 17 mm Hg and from 13 to 15 mm Hg respectively, there being a difference of at least 1 mm Hg and no greater than 3 mm Hg between the said respective compressive forces.

It is preferred that the difference between the respectively ankle and calf compressive forces is about 2 mm Hg.

Most preferably, the compressive force exerted by the calf region of the stocking on the calf of the patient is about 14 mm Hg. The preferred compressive force exerted by the ankle region of the stocking on the ankle of a patient is about 16 mm Hg.

Stockings of the present invention may be of the so-called "knee length", "thigh length" or "full-leg length". "Knee length" stockings terminate at the knee, "thigh length" at the top of the thigh, and "full-leg length" at the top of the leg of the wearer.

For thigh length and full-leg length stockings, the compressive force exerted by the thigh region of the stocking on the thigh of the patient will be considerably reduced from that exerted at the calf region. The precise figure, which may for example be about 6 mm Hg is not important as it does not affect deep vein blood flow to any extent.

The graduated compression stocking of the present invention may have a reduced control-opening provided in the toe region thereof and an enlarged circumference at the instep. The heel region may be reinforced by the knitting-in of an additional thread, similar to the other threads.

The heel of the stocking may be provided with a distinguishable marker, for instance a coloured region which is knitted into the stocking. This may be between 5 and 40 courses in length and, for example, 1 to 2cm in width. This may provide a size identification.

For knee length and thigh length stockings, the open end of the stocking may be provided with a nonslip band. For full-leg length stockings, a waist band may be provided.

Also contemplated by the present invention is a prophylactic method for reducing the incidence of thrombus formation in the leg of a previously active human in which a graduated compression stocking is fitted to the leg of a wearer, the stocking being chosen such that the compressive forces exerted at the ankle region and the calf region of the patient are in the ranges of from 15-17 mm Hg and 13-15 mm Hg respectively, with the proviso that there is a difference of at least 1 mm Hg and no greater than 3 mm Hg in the respective compressive forces exerted.

Stretchable materials from which the anti-embolism stocking of the present invention may be made will be known to those skilled in the art of graduated compression hosiery. Preferably, however, the material is a composite synthetic material knitted from, for example, a textured nylon or polyester thread, together with an elastomeric poXymeric thread such as that known (sswHJ as Elastane (LycraXlis a branded Elastane).

The compressive forces specified herein are in millimetres of mercury (mm Hg) and are as measured by the standard HATRA test method as referred to in British Standard 6612:1985 and which is specifically described in Appendix A2 of BS 6612:1985.

The compressive forces exerted at the ankle and calf regions and referred to herein are those which are exerted at the ankle girth" and "calf girth" respectively. The "ankle girth" is defined as the horizontal girth of a human leg just above the medial malleous, measured with the subject standing and with the weight of the body equally distributed on both feet. The calf girth" is the girth of a human calf measured at its maximum circumference, the upper edge of the tape measure passing horizontally through the point of maximum circumference measured with the subject standing and with the weight of the body equally distributed on both feet.

Also contemplated within the scope of the present invention is a hosiery knitting machine whenever set up and intended to produce graduated compression stockings in accordance with the first aspect of the present invention.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made by way of example only, to the accompanying drawing which shows a graduated compression stocking in accordance with the present invention.

Graduated compression stocking 1 comprises the following four general regions: a foot region 2, an ankle region 3, a calf region 4, and a thigh region 5.

The embodiments shown is, therefore, a "thigh-length" stocking.

The top of the stocking 1 has an opening 10 for insertion of a leg/foot of a patient. In addition, the stocking includes a heel region 12 and there is provided a reduced control opening 14 at the toe end of the stocking. The heel region 12 is provided with a distinguishable marker 16.

The opening end region 10 of the stocking 1 is provided with a non-slip band 13 to support the stocking on the leg of a patient.

In accordance with the present invention, the stocking 1 is adapted to exert a desired compressive force at the calf region of the leg of a chosen wearer.

Thus, the calf region 4 of the stocking 1 should exert a compressive-force of from 13 to 15 mm Hg. In addition, the compressive force exerted by the ankle region 3 of the stocking on the ankle of the patient is in the range of 15-17 mm Hg. There should also be a difference of 1-3 mm Hg between these figures.

It has been found that these specific compressive forces provide remarkably improved venus blood flow and thereby reduce the likelihood of deep vein thrombus formation in the leg of a non-ambulant patient.

Claims

1. A graduated compression stocking of the type which is formed of a stretchable material and which comprises respective foot, ankle and calf regions, said calf region being enlarged relative to the adjacent ankle region of the stocking and each of the ankle and cafe regions being capable of exerting a compressive force at the ankle and calf respectively of a wearer, characterised in that said stretchable material from which the stocking is made and the dimensions of the stocking in the relaxed state are each chosen such that, when the stocking is in use on the leg of a chosen patient, the compressive forces exerted by the ankle region of the stocking of the ankle of the wearer and by the calf region of the stocking on the calf of the wearer lie within the range of from 15 to 17 mm Hg and 13 to 15 mm Hg respectively, there being a difference of at least 1 mm Hg and no greater than 3 mm Hg between the said respectively compressive forces.

2. A stocking according to any preceding claim, wherein the difference between the respective ankle and calf compressive forces is about 2 mm Hg.

3. A stocking according to claim 1 or 2, wherein the compressive force exerted by the calf region of the stocking is about 14 mm Hg.

4. A stocking according to claim 1, 2 or 3, wherein the compressive force exerted by the ankle region of the stocking on the ankle of the patient is about 16 mm Hg.

5. A stocking according to any one of the preceding claims, further comprising a thigh region adjacent the calf region.

6. A stocking substantially as hereinbefore described, with reference to the accompanying drawing.