The beneficial effect of chlorpromazine on dorsal skin flap survival.

A 3 x 10-cm dorsal rat skin flap contains a distal portion that is poorly perfused. The dorsal flap served as a useful model to test hemodynamic properties of the vasodilatory drug chlorpromazine. A control group of flaps were treated with saline and the test group with chlorpromazine (15 mg/kg intraperitoneally). Eight days postoperatively, the surface area of the flaps that necrosed was 27.3% for the treated group and 36.5% for the controls. Using Student's t-test this difference was significant (p less than 0.001). Nutrient blood flow determined by the penetration of fluorescein dye into the flap was consistently greater in the chlorpromazine-treated group compared with the control group in the first 24 hours postoperatively. The adenosine triphosphate (ATP) levels measured at 0 and 24 hours postoperatively were consistently lower in the distal parts of the flap, treated or control, compared with proximal parts of the flap (p less than 0.001, analysis of variance). However, there were no significant differences in ATP levels between treated and control biopsies at any one site on the flap. In conclusion, chlorpromazine had a beneficial effect on rat skin survival, and increased blood flow appears to be one of the major reasons.