AU2001100427B4 - Deep vein thrombosis control - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT DEEP VEIN THROMBOSIS (DVT) CONTROL DEVICE The following statement is a full description of this invention, including the best method of performing it known to me: Deep Vein Thrombosis Control Background This invention relates to improvements in passenger seating for the reduction of the incidence of deep vein thrombosis, commonly known as DVT.

The pooling of blood in the lower legs caused by inaction for long periods, typically during lengthy surgical operations, long haul travel etc., significantly increases the likelihood of people developing the medical condition known as Deep Vein Thrombosis (DVT). The risk of DVT can be reduced or eliminated during periods of unavoidable inaction by countering the inaction with some degree of movement.

For example, in lengthy theatre operations under anaesthetic, doctors customarily 'exercise' patients' legs by means of electric currents. These mild electric charges are sufficient to prevent the pooling of blood in the lower leg by increasing the circulation of the blood.

This patent describes suggested modifications to a range of seats currently designed and used to carry long distance passengers by methods of public transport such as aircraft, coach, train etc where passenger movement is restricted. The suggested modifications, if utilized by passengers on a regular and/or intermittent basis, would achieve a reduction in the incidence of DVT.

The concept of the function of a passenger seat has already been extended to accommodate not just the seating needs of the passenger in the seat but also the convenience needs of the passenger behind. The backs of seats commonly hold safety and evacuation instructions, magazines, drop down tables for meals, drinks or work etc. and are currently being further utilized to accommodate the entertainment, work and telecommunication needs of the passenger behind (eg screen facilities for television/film/ personal computer/telecommunications/internet etc).

So the 'passenger seat' now effectively refers to the cubic volume of space allocated to the passenger which comprises the seat s/he sits in, the amount of space in front of, above and below the seat for entry and exit and extension of the legs, and the back of the seat in front which houses utilities for the passenger behind.

This patent extends the concept of the 'passenger seat' just described to include a DVT Control device designed to meet the health needs of passengers by helping to reduce the incidence of DVT during long haul travel.

Description The DVT control device comprises a horizontal cylindrical crosspiece containing two axles, one in each end of the cylinder, each machined with a half gear, each supported by bearings, each with a crank and variety of pedal attached to the non-geared end of the axle so that both pedals are at the bottom of the cycle.

The two half gears being permanently engaged prevents a full rotary motion of the cranks and pedals but allows an opposing motion of the cranks and pedals through the lower half of the cycle up to a maximum of 180 degrees depending on the muscular pressure applied. The mechanism may be secured to a transportation carriage, either by a base or stand positioned on the floor under the seat immediately in front of the passenger, or suspended from the underside of the seat in front.

The pedals in any version of the DVT Control device may be in any form of foot peg or foot board suitable to the purpose and may be protected for hygienic purposes by a variety of disposable foot cover separately supplied; further, the DVT Control device in any version may be fitted with a type of cover similar in construction to a footrest.

To assist with understanding the invention, reference will now be made to the accompanying drawings.

Referring to Diagram 1 (Prior to Mounting) and Diagram 2 (View from Above; Prior to Mounting), it can be seen that the DVT Control Device comprises a horizontal cylindrical crosspiece 3 containing two axles 4 with roller bearings 5, with a crank 7 and pedal 8 attached to each end of the axle by means of a threaded bolt 6. Each axle 10 includes a half gear 14 (which means each axle has gear teeth cut into only half of the circumference or required surface area), which, when the two cranks 7 are fitted to hang vertically parallel (Diagram with the pedals 8 at the bottom of the cycle, allows an opposing motion of the cranks 7 and pedals 8 through the lower half of the cycle up to a maximum of 180 degrees (Diagram 2) depending on the muscular pressure applied.

The mechanism may be secured either by a base or stand positioned on the floor under the seat immediately in front of the passenger, or suspended from the underside of the seat in front as in Diagram 3 (Version: Mounted; Not in Use; Viewed through Seat from Above). Provision would be made for the device to be adjustably slid forward or rearward and locked into position when in use to accommodate the difference in passenger size. In this position it would be accessible to, ie within reach of, any able bodied passenger seated behind the seat to which the mechanism is attached.

Diagram 3 shows the cylindrical horizontal crosspiece 3 extended in order to mount the DVT Control device under the seat 1 in front of the passenger. The cylindrical horizontal crosspiece is bent 11 to accommodate the gearing arrangements. A suitable retaining hook 12 enables the mechanism to be held in a rest position when not in use. Diagram 4 (Mounted to Underside; Ready for Use) shows the cylindrical horizontal crosspiece 3 flattened 13 at each end to facilitate attachment to the control rails incorporated in the underside of the seat.

The DVT Control mechanism provides for a passenger seated behind the seat to which the mechanism is attached to place the right and left feet on the right 8 and left 8 pedals respectively, and, by exerting pressure from the right leg muscles initiate a forwards movement of the right pedal by a pushing action of the right foot on the right pedal in a forward then upward direction to a maximum of 90 degrees from its base position.

This movement of the right leg and foot on the right pedal causes the left foot on the left pedal to be moved in the opposite direction, ie backwards and upwards in a simultaneous opposing motion of the pedal 8 to a maximum of degrees from its base position.

This pushing action of the muscles of the right leg results in a straightening of the right leg, and therefore of the right artery, while the left leg is bent in an acute angle nearer the body.

The next movement to maintain the opposing motion requires the exertion of pressure from the left leg muscles to initiate a forwards and downwards movement of the left pedal 8 by a pushing action of the left foot on the left pedal 8 in a forward, downward then upward direction to a maximum of 180 degree half circle.

This movement of the left leg and foot on the left pedal causes the right foot on the right pedal to be moved backwards in a simultaneous opposing motion of the pedals 8.

This pushing action by the muscles of the left leg results in a straightening of the left leg, and therefore of the left artery, while the right leg is now bent in an acute angle nearer the body.

The maintenance of the opposing motion of the pedals by the passenger thus entails the initiating and maintaining of a backwards and forwards opposing motion with both feet simultaneously moving in opposite directions away from and towards the body, which involves regular and rhythmical straightening of the legs and bending of the knees, as experienced in walking or skating, which straightens the right and left leg arteries in turn from a 'permanently' bent or kinked position when seated normally for long distances a known factor in the pooling of blood in the lower leg and so helps to lessen the risk of passengers developing deep vein thrombosis (DVT).

By the use of the DVT Control device the exertion of the passenger's leg and feet muscles: a) straightens the leg arteries in turn or together from a 'permanently' bent or kinked position when seated normally for long distances a known factor in the pooling of blood in the lower leg b) causes significant movement in the hip, knee and ankle joints as well as some muscular flexing in the legs and feet, not normally achievable while in a sitting position, which results in increased circulation of the blood an essential factor in the pumping of blood back up from the lower leg through the rest of the body c) contributes to the reduction of the risks of deep vein thrombosis (DVT) and/or to the prevention of DVT when used in conjunction with other methods such as walking around, passenger education, and health advice appropriate to individual medical conditions etc.

4 The DVT Control device may be made out of any suitable material such as metal, durable plastic, polymer etc.

While opposing motion is in the public domain, what is new is its use to modify standard passenger seats so that passengers can utilize it on long journeys for the control of DVT; ie using existing mechanical principles (pedaling in an opposing motion) to modify seating in a new (travel) context with the objective of achieving significant health benefits for travellers (reduction in the incidence of DVT).