Failure to influence hypotension during spinal anaesthesia with a limb tourniquet.

Fourty patients undergoing total hip replacement under spinal anaesthesia were allocated randomly to have a thigh tourniquet inflated after exanguination of the leg not being operated on or to act as controls. Significant hypotension (systolic arterial pressure < 70 mm Hg) was treated with i.v. ephedrine in 6 mg boluses. There was no significant difference between the two groups with respect to systolic blood pressure or requirement of ephedrine, during the hour that the tourniquet was applied or the period immediately after the removal of the tourniquet.