farmdoc's blog post number 599

This month marks 40 years since I graduated as a doctor. Yet only in recent years have the medical journals, and thus the general media, mentioned the causal link between air travel and deep vein thrombosis/pulmonary embolism. More than likely there are multiple reasons for this recency. This review article in the December issue of Australian Prescriber mentions some of them: Aeroplane factors (longer flights, more cramped seating and aisles) and passenger factors (more people flying, more people flying frequently, more overweight people, more people with pre-existing health problems). The article also says four hours is the threshold flight duration; the effectiveness of the airlines’ currently recommended leg exercises is unproven; aspirin is useless in prevention; and the risk of significant thrombosis is greatest at flight’s end and doesn’t return to normal until 2-4 weeks later. Risk, and thus recommended prevention, is divided into low, moderate and high. It all a bit scary. The good news is that short flights (e.g. between Melbourne and Launceston) are risk free. And even on long flights, the incidence is one clinical episode per 4,500 flights – which is low given the number of passengers on 4,500 flights. But it pays to be careful, I think.