Perioperative changes in the microcirculation in feet after foot and ankle surgery.

The senior author (N.P.G.) observed that if the foot became dependent in the first 48 hours after foot surgery, the patient had swelling and pain. This effect seemed less after about 48 hours. The authors set out to see if there was a scientific basis for this. Laser Doppler was used to assess blood flow in 14 patients. Flow was recorded in the big toe, at heart level, and on dependency, preoperatively and postoperatively. Postural vasoconstriction was calculated, and time for blood flow to normalize was recorded. Mean postural vasoconstriction preoperatively was 51.31%; postoperative mean at 24 hours was 23.05%, at 48 hours 36.62%, and at 72 hours 44.24%. There was a difference between the preoperative levels and the 24-, 48-, and 72-hour postoperative levels (P < .05). Results showed that it takes longer than 72 hours rather than 48 hours for microcirculation to return to normal. The results emphasized the importance of postoperative foot elevation for at least 48 hours because of this phenomenon.