Tourniquet pressure: the effect of limb circumference and systolic blood pressure.
Complications attributable to direct pressure may result from the use of pneumatic tourniquets during surgical procedures. Traditional estimates have determined the pressures employed rather than the minimal pressure necessary to produce a bloodless field. To determine this pressure, pre-operative and post-operative systolic blood pressures and the tourniquet pressure at which capillary bleeding occurred were measured in a group of patients undergoing elective surgery of the upper and lower limbs. From these results two equations were derived, one for each of the upper and lower limbs, which give the minimum tourniquet pressures to produce bloodless fields. In an average sized, normotensive patient, 200mm Hg was found to be adequate for the upper limb and 250mm Hg for the lower limb.