Previous studies have shown that basing the cuff pressure on the LOP measured on each patient immediately prior to limb exsanguination and cuff inflation can lead to lower cuff pressures being used on many adult patients. This technique directly measures the cuff pressure required to occlude flow, thereby accounting for the individual patient's limb and vessel characteristics as well as the type and fit of the cuff. Unfortunately, the standard method of measuring limb occlusion pressure (monitoring a distal artery with a Doppler ultrasound probe while slowly increasing cuff pressure) is awkward and time consuming. A tourniquet device that allows automatic measurement of LOP at the start of each surgical procedure is now commercially available. This device has been shown to significantly reduce cuff inflation pressures necessary to occlude blood flow in adults; however, the magnitude of reduction in cuff pressure has not previously been determined in a paediatric population.