"Long haul" flight and deep vein thrombosis: a model to help investigate the benefit of aspirin and below-knee compression stockings.
OBJECTIVE
to develop a model simulating factors of "long haul" flight to investigate the relationship with DVT.


METHODS
volunteers (19 males: 20 females) sat for 6 h in a warm (>25 degrees C), dry environment, limited in movement, consuming alcohol (40 ml of 40% alcohol/hour) and salted foods (300 g). Half of the subjects received 150 mg aspirin and wore especially designed below-knee, compression stockings (Class 1 profile). Changes in full blood counts were recorded, and as an indication of DVT formation, plasma was analysed for D-dimer. Limb swelling was assessed from leg measurements.


RESULTS
after 6 h, in controls, there were significant rises in platelet packing (Pct p<0.04), total platelet numbers (p<0.003) and total numbers of white blood cells (WBC's p<0.001). With aspirin plus stockings, there were similar significant rises in total platelet numbers (p<0.002) and total WBC's (p<0.001). In both groups, significant rises were seen in all WBC types (except basophils). Wearing compression stockings prevented calf swelling seen in controls after 6 h (p<0.002). No subject developed a DVT, or a change in levels of D-dimer.


CONCLUSIONS
changes in the cellular components of blood, particularly WBC's, combined with vaso-compression and reduced flow could predispose towards DVT. Aspirin, combined with compression stockings, may provide prophylaxis.
Hollingsworth
S J
SJ
The Academic Vascular Unit, Department of Surgery, The Royal Free and University College London Medical School, Mortimer Street, London, W1N 8AA, U.K.
Dialysis
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Barker
S G
SG
D000328:Adult; D000337:Aerospace Medicine; D001241:Aspirin / Q000627:therapeutic use*; D001458:Bandages; D004487:Edema / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D012307:Risk Factors; D018709:Statistics, Nonparametric; D020246:Venous Thrombosis / Q000209:etiology* / Q000517:prevention & control*
D010975:Platelet Aggregation Inhibitors; D001241:Aspirin