Venous stasis, deep venous thrombosis and airline flight: can the seat be fixed?

Deep venous thrombosis (DVT) and pulmonary embolization (PE) associated with air travel are directly related to the duration of flight and seating in non-aisle seats. In this study, we assessed a modification of a standard airline seat (NewSit) designed to decrease the incidence of DVT on long flights. This seat raises the feet from the floor, facilitates mobility, and permits intermittent calf compression. Air plethysmography (APG) was used to measure the ejected venous volume of the calves of 25 volunteers before and after sitting for 5 hours on the conventional and modified seats. The mean percent (+/- standard deviation [SD]) increase in venous volume for the conventional seat after 5 hours of continuous sitting was significantly greater than that for the modified seat (26.6 +/- 18.5% vs 3.5 +/- 13.1%, P < 0.0001 by paired, two-tailed t-test). Improvement (any) was seen in 23 of 25 patients, with 15 of the 23 (65%) being better than 1 SD of the mean (P < 0.0001 by Chi-square analysis). This study suggests that the leg movement and calf compression associated with the modified airline seat (NewSit) may decrease the probability of DVT due to prolonged periods of sitting by reducing venous stasis as measured by APG. Further studies involving a larger randomized patient cohort, as well as analysis of the effect of this modification on specific coagulation markers such as tissue plasminogen activator and fibrin D-dimer, are planned.