Methods: Between February 2014 and July 2014, 32 nurses (30 females, 2 males; mean age 31.3±5.1 years; range 23 to 46 years) with a total of 64 lower extremities were evaluated prospectively using the Duplex ultrasonography before and after 12 hour nightshifts. Ultrasonographic examinations were performed by a single radiologist under similar conditions. Duration of working of the nurses was noted and examined prior to nightshifts and immediately following the nightshifts. Reflux was provoked by manual compression and Valsalva maneuver. Pretibial edema noted. Spectral data were obtained from deep and superficial vein segments.

Results: Prior to nightshifts, there was edema in only one nurse; however, bilateral edema developed in five additional nurses after nightshifts (p=0.002). Working duration of nurses with pretibial edema was significantly longer. In all vein segments, we found no significant differences in measurements before and after nightshifts using either technique (p>0.05). Manual compression and Valsalva maneuver showed either “no” or “poor” agreement in deep veins, while they showed either “fair” or “good” agreement in superficial veins.

Conclusion: Our study results show that both reflux provocation techniques yield similar outcomes before and after nightshifts with significantly increased pretibial edema after nightshifts.