Abstract
Aim The senior author observed over 15 years that if the foot became dependant during the first 48 hours following foot surgery, the patient suffered marked swelling and pain. This effect seemed less after about 48 hours. Aware of the work of Tooke and Rayman (1986) with postural effects on laser Doppler skin flow, we set out to see if there was a demonstrable scientific basis for this practice.
Method Laser Doppler flow meter was used to assess blood flow in 14 patients (16 feet), peri-operatively. Flow was recorded in the big toe, at heart level and on dependency, pre-operatively, and at 24, 48, 72 and 96 hours post-operatively. Postural vasoconstriction (PV) was calculated using the formula:
Blood flow at heart level
Results PV was recorded for all 14 patients at 48 hours, for seven at 72 hours, and for two at 96 hours post-operatively. The mean PV pre-operatively was 51.31%; at 24 hours post-op. was 23.05%; at 48 hours post-op. was 36.62%; and at 72 hours post-op. was 44.24%. There was a significant difference between the pre-op. levels and the 24, 48 and 72 hours post-op. levels (p< 0.05).
Significance of work It takes longer than 72 hours for microcirculation to get back to normal rather than 48 hours, but the return towards normality was evident by that time. This emphasised the importance of postoperative foot elevation for at least 48 hours due of this phenomenon. We believe that this practice minimises post-operative complications, such as oedema, wound breakdown and pain on dependency.
Correspondence should be addressed to BOFSS, c/o Wrightington Wigan and Leigh NHS Trust, Hall Lane, Appley Bridge, Wigan, Lancashire WN7 9EP.
References
Rayman, G, Hassan, A, Tooke, JE et al. (1986) Blood flow in the skin of the foot related to posture in diabetes mellitus. BMJ292:86–90 Google Scholar
Rayman, G, Tooke, JE et al. (1986) Impaired microcircular hyperaemic response to minor skin trauma in type I diabetes. BMJ292:1295–1298 Google Scholar
