Limb Blood Flow in the Presence of a Tourniquet

There is little accurate data on the blood flow to a limb distal to the site of application of a tourniquet. This has been studied in Rhesus monkeys with 50 μ diameter microspheres labelled with ⁵¹Cr and by the washout of ²²Na injected into the tissues. One limb was exsanguinated and the circulation occluded with a pneumatic tourniquet and the opposite limb used as a control. The results show that blood flow to the occluded limb is less than 1 per cent of the flow to the control limb. It is unlikely that this relieves the ischaemia in any way as has been suggested.