Environmental Engineering Reference
In-Depth Information
carriers to inform travellers of the risk of DVT when travellers make their reserva-
tion. Airlines such as Qantas, Air New Zealand and Singapore Airlines now offer
advice on DVT on their main websites.
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Others such as Japan Airlines, Lufthansa
and KLM are also considering methods of informing travellers of the risks by updat-
ing passenger information material via in-flight magazines, audio and video pro-
gramming or health leaflets attached to tickets.
Meanwhile, doctors recommend a variety of practices to prevent thrombotic events
after airline travel, including leg exercises, walking around the cabin where possible
within safety constraints, avoidance of alcohol and smoking, and drinking plenty of
water. As a response to public attitudes, British Airways introduced an in-flight exer-
cise programme in 2001, which primarily comprises stretching exercises that are
designed to be carried out in the airline seat by passengers. Although not licensed for
preventing travel-related DVT, many experts now advocate taking aspirin pre-flight
for those passengers who have been determined to be at a moderate risk of thrombo-
embolic disease (House of Lords, 2000). For those passengers with a case history of
thrombotic disease, some experts have recommended wearing elasticated compres-
sion stockings (Scurr et al, 2001) or administering subcutaneous anti-coagulants,
such as low-molecular weight heparin (Kesteven, 2000).
Finally, some commentators are calling for airlines to re-evaluate seating arrange-
ments in some aircraft cabins that are not conducive to moving in and out of seats,
particularly for large individuals. The storage of luggage under seats and the seat
pitch (usually between 71-79cm or less) restricts leg room, and compression of the
popliteal vein can be caused by the edge of the seat when sitting in cramped condi-
tions for prolonged periods, which can lead to decreased venous blood flow (Hito-
sugi et al, 2000). However, any increase in economy passenger's room will be at a
cost, with the improvements passed onto the consumer as higher ticket prices; in the
absence of conclusive further medical study, there is no firm scientific foundation
for such cost.
Airborne disease and infection (tuberculosis)
The increase in international travel and migration has also seen an increase in the
spread of a number of infectious diseases such as AIDS and cholera; consequently,
there is great interest in the role and mode of travel in disease transmission. As a
result of the typical conditions associated with airline travel (ie a close and restricted
confinement for many hours, combined with a high proportion of recirculated air),
experts have expressed the concern that passengers are at an increased health risk from
fellow passengers, particularly with regard to bio-aerosols and airborne infection.
The bio-aerosol risk is believed to be primarily for contagious disease or for exacer-
bation of an existing asthma condition.
Studies on the concentration of micro-organisms in US airline cabin air found
numbers of micro-organisms to be lower than in ordinary city locations and unlikely
to be a contributor to the risk of transmission among passengers. The numbers found
were comparable to typical indoor environments, particularly when in flight and when
the aircraft environmental control systems are operating (Wick and Irvine, 1995).
One reason for this is the use of high-efficiency particulate air (HEPA) filters in the
