[Changes in venous hemodynamics of lower extremities in military personnel during evacuation by air].

Abstract

Background: According to the scientific medical literature, venous thromboembolic complications (VTEC) in the wounded occur in 2.2-28% of cases. VTEC-associated mortality after evacuation by air transport reaches 1.1%.

Objective: This study was undertaken to investigate speed characteristics of venous blood flow in the lower limbs of military personnel during evacuation by air.

Patients and methods: We analyzed the results of ultrasound examination of lower-limb veins in 40 servicemen (males) fit for military service for health reasons, who had neither chronic diseases of the cardiovascular system nor overweight. The average age was 29.3±1.5 years, the average weight was 79.5±1.1 kg. Ultrasound examination was carried out in the AN-26 aircraft and the MI-8 helicopter at altitudes from 100 to 2500 meters using portable ultrasound devices with linear sensors with a frequency of 3-11 and 4-15 MHz in the vascular mode and was performed 2 hours before departure, when climbing, at altitude, during descent and within 1 hour after landing. Blood flow velocity was measured in the common femoral vein (CFV), superficial femoral vein (SFV), popliteal vein (PV), posterior tibial veins (PTV), and sural veins.

Results: Analyzing the results of studying the velocity blood flow in the CFV, SFV, PV and PTV in the aircraft revealed significant differences in the values (р<0.01) 2 hours before departure compared with the results when climbing, at altitude and during descent. In the helicopter, a significant (р<0.05) increase in blood flow velocity was revealed in the CFV, SFV, and PTV during takeoff and at altitude as compared with values before the flight, and the values in the PV were at the border of statistical significance (p=0.058).

Conclusion: During evacuation by an aircraft, blood flow velocity in the veins of the lower extremities significantly decreases (p<0.01) throughout the flight, whereas during air evacuation by a helicopter, it significantly increases at takeoff and during the flight (p<0.05), decreasing to the initial values at landing. The determined changes in blood flow velocity in the veins of the lower extremities make it possible to consider air transport evacuation as a risk factor of VTEC development.The revealed hemodynamic patterns suggest the need for mandatory prevention of venous thrombosis during air evacuation.