Hazard Alert - Travel and the Risk of Deep Vein Thrombosis (DVT)

Recent media attention has identified long distance travel as a potential risk factor for developing Deep Venous Thrombosis (DVTs), however, there is currently no authoritative data to show any clear difference in the incidence of DVTs between those who have recently travelled and those who have not.

What is DVT?

DVT is where a small blood clot forms mainly in the deep veins of the legs. DVT is not dangerous in itself but complications arising from it may be life threatening. Complications occur when a clot breaks away from the wall of the vein to which it is attached and travels through the blood stream to the heart or lungs.

While there is no conclusive evidence that travel, particularly flying is a specific risk factor for developing DVT, medical research indicates that a number of factors increase the risk of the development of DVT in some groups within the population. Although the media attention has focused on air travel or the 'Economy Class Syndrome' the same risk factors may apply to all types of travel in excess of three hours. Risk factors for possible development of DVT include the following:

DVT Risk Factors

• increasing duration of travel
• cumulative effect of multiple trips
• prolonged immobility, which may be compounded by obesity or height, restricted leg room, and seated posture including when asleep
• wearing of tight undergarments or movement restricting clothing
• dehydration
• alcohol consumption.

Who is at Risk?

• increasing age over 40
• pregnancy
• former or current malignant diseases
• blood disorders leading to increased clotting tendency
• personal or family history of DVT
• recent major surgery or injury, especially to lower limbs or abdomen
• oestrogen hormone therapy, including oral contraceptives
• heart failure
• varicose veins
• for women who are pregnant or taking oral contraceptives, tobacco smoking is an additional risk factor.

If you meet any of the above criteria it is recommended you consult a medical officer. If you have any other concerns you should consider seeking medical advice prior to travelling in excess of three hours nonstop.

The Development of DVT may be avoided by

• drinking fluids such as water and juices frequently
• avoiding excess of alcohol and caffeine containing drinks both before and during travel
• avoiding smoking
• avoiding crossing legs when seated
• exercising by moving legs and feet for three to four minutes per hour while seated, occasionally moving around the cabin while in flight and walking around during stopovers
• wearing loose fitting comfortable clothing when travelling

The use of aspirin and support stockings is not recommended unless prescribed on a case by case basis by a medical officer.

DVTs may not cause symptoms until the blood supply is severely interrupted. If you experience any of the following symptoms following long distance travel you should seek medical advice without delay:

DVT Symptoms

• unexplained pain
• sudden swelling
• enlargement of the superficial veins
• reddish-blue discolouration
• skin that is warm to the touch

Pulmonary embolism is a relatively rare complication of DVT which can be life threatening. Medical assistance is to be sought immediately if any of the following symptoms are experienced following prolonged travel:

Seek help if any of the following occurs after long travel

• a feeling of apprehension
• shortness of breath
• sharp chest pain
• rapid pulse
• sweating
• cough with bloody sputum
• fainting

Reproduced with kind permission from the Department of Defence. This article appeared in The Key, Defence Personnel Executive, April 2001, p. 8,9. Web link: http://www.defence.gov.au/dpe/dpe_site/key/index.htm

Airline information for travellers (including on DVT)

QANTAS: http://www.qantas.com.au/info/flying/inTheAir/yourHealthInflight

For further information contact the UWA Safety and Health on 6488 3938 or 6488 7932.