Fig. 1. Intervention synopsis. (A ) The intermittent pneumatic compression device is composed of a compressor and two cuffs that cover both legs. The cuffs are made out of 12 chambers that are consecutively inflated from toe to groin to a preset pressure of 60 mmHg in the first (distal) chamber and 38 mmHg in the last (proximal) chamber. (B ) Compression cycle schematic. The sequential inflation of all chambers to a pressure of 60 mmHg (first chamber/forefoot) to 38 mmHg (last chamber/groin) takes no more than 60 s. The pressure is then released. After a 4-s pause, the next cycle begins with inflation of the distal chamber. (C ) To maintain blinding, cuffs were placed next to the patient's legs (placebo compression) or attached correctly. In both cases, the patient's legs were covered with drapes placed on a frame. The compression device was activated and run continuously from induction of general anesthesia to wound closure.