AV Impulse

Foot Impulse Therapy

One of the problems that the wearers of fixation devices may experience is the swelling of the extremities. This is due to the reduced mobility of the limb concerned.
The swelling is often due to poor venous return (blood return). This can, in some cases lead to swelling, as mentioned, pain, slowed healing, thrombosis and other complications
In the leg, blood is returned to the heart by the normal motion of walking and from the hand by the normal clenching movement of the fist.
As a wearer of an Ilizarov, I was very aware of the degree to which my foot and leg could swell during a fairly short period of time. This then required me to try to get comfortable in a position where my foot was higher than my hip. This helped the blood to return but still meant a long period of immobility in this position.
Then, during one of my visits to clinic after my discharge in June 1999, Mr Groom was being shown a device called an AV Impulse equipment. This device simulates the effects normally produced by walking on patients who, for whatever reason are non-mobile. I was asked if I would like to try the equipment and of course the answer was yes!. We went into a seperate cubicle where the company representative attached the two foot cuffs or bootees to my feet. There was a degree of difficulty in attaching the right cuff as it needed to be threaded through my Ilizarov foot plate but this could be addressed by a change to the cuff and the velcro fittings.
The main unit is connected to the cuffs by two lengths of plastic pipe. When the machine is switched on, the cuffs alternately inflate and deflate. The preset, though adjustable settings were 130mm of Mercury (pressure) 1 second pulse (inflate/deflate) and every 20 seconds. This produces a pressure on each foot in turn and it is this pressure which pumps the blood back toward the heart.
As I had been on my feet (foot?) for some hours by the time the machine was switched on, I already exhibited a considerable swelling in the foot and leg. This is always visible by the tightness of the skin across the instep. After less than an hour on the machine, the swelling was obviously reduced as was the sensation of tightness.
It was then suggested that I should be allowed to borrow the machine for a week and try it at home to see the results. I had intended to use it during the night as the level of noise and physical effects are so minimal as to be ignorable. However due to the difficulty of feeding the cuff round the pins, there was a problem, after about 3 hours, with the sites becoming sore. So 3 hours was the longest period that I utilised the machine for. The amount of 'shrinkage' in the foot obtained in this time was almost identical to the amount that normally required me to sleep the whole night with the foot partially elevated, ie; about 8 hours
[See the pictures later] During my use of the unit I also noticed a few other effects.

Reddening of the skin of the left (good) leg, caused by the extra load being placed on it, was greatly reduced.
Aching of the left ankle caused by the extra loading was also noticably reduced as was pain in the left knee.
Muscular aches in the right leg, particularly around the upper 6 pin sites were also reduced such that I took less co-dydramol analgesics than previously.
The overall skin quality on the right leg showed a marked improvement.
Any tendency for pin site seepage was reduced in line with the reduced swelling.

The following are some pictures taken from the Novamedix catalogue of the AV6000 unit

Venous Plexus Full

With each step, the plantar arch is longitudinally flattened. This causes the venous plexus to empty, returning a column of blood to the heart.

Femoral vein pulse flow graph

This shows a typical pulse caused in the femoral vein by the application of the AV Impulse. This shows a surge of blood through the entire leg.

Venous Plexus empty

This shows the Venous Plexus empty after the AV Impulse has pumped the blood from this location.

Novamedix 6000 AV Impulse unit
This is a photograph of the unit showing the salient points.

This shows the foot cuffs or bootees with their connecting pipes.

Diagram of the foot showing the main veins affected by the pumping action of walkin

Puffy foot in foot cuff

Wrinkly old foot!

Another shot of the wrinkly old foot

Clockwise from bottom Left

Shot of my leg showing how wrinkled the skin becomes after the swelling has reduced. This normally requires a full nights rest or a period of about 3 hours on the AV Impulse unit.

Shot of my foot in the AV machine cuff. As can be seen it was a bit difficult feeding the cuff round the pins.

Another shot of the wrinkly thing after the Impulse machine had done it's bit.

Even the dog liked it!
And finally, the machine was so quiet that the dog fell asleep against it.
It's a hard life!

A quick note of possible interest. (December 2005)

Some of the satellite TV shopping programs have been pushing a system which is designed to relax and ease your legs after a hard day at work.

It is basically a cheap and cheerful version of the above.

It comes with two lower leg and foot cuffs, two thigh cuffs and the control box. Whilst this version may not be any easier to fit round a frame, I have found it of great help just to reduce the swelling I still occasionally suffer if I've been standing too long or tried over doing it walking-wise. Since I am missing a considerable amount of muscle tissue on the injured leg, it does tend to complain if over worked. I have found this unit to be of great help.

It's called the Air Press Massager (or similar other names)

At present (Dec 2005) they are available in the USA via This Company or via HERE and probably elsewhere on a search or two.

In the UK they can be bought through This Company

As per usual, the Americans are paying less than half what we poor suckers in the UK are getting ripped off. I'd suggest ordering from the states but by the time the USPS and our customs people have got their teeth into your order, just bite the bullet and pay the UK price.

Back to the contents page