The effects of deliberate hypotension and foot down tilt on the incidence of deep vein thrombosis during plastic surgical operations: a pilot survey.

The incidence of postoperative deep vein thrombosis (DVT) has been investigated in a group of 88 patients undergoing plastic surgical operations on the head and neck, and upper limb. Fifty-two cases were operated upon in the foot-down tilt position and 36 were horizontal. With the effects of blood pressure ignored as a possible contributory factor, the incidence of thrombosis in the latter group was 8-3% and was slightly higher in the tilted group (11-5%). Of those who were hypotensive, 3 developed DVT out of 41 (7-3%) who were tilted; whilst in the 11 who were normotensive and tilted 3 developed DVT, an incidence of 27-3%. Of those who were normotensive and operated flat the incidence of deep vein thrombosis was 8-0%, while in those subjected to a foot-down tilt it was 27-3%. The hypothesis has been advanced that frequent inflation and deflation of the cuff used for monitoring blood pressure in the hypotensive patients may release fibrinolytic activity and explain these differences. Age, sex and operative duration were not found to have an effect. It is concluded that the incidence of postoperative deep vein thrombosis in patients undergoing plastic surgical operations is lower than that found in general surgery, and is not worsened by deliberate hypotension.