An investigation of the hammocking effect associated with interface pressure measurements using pneumatic tourniquet cuffs

A simple experimental arrangement is used to investigate the influence of sensor height on the pressure indicated by an inherently linear sensor sandwiched between a rigid curved surface and a pneumatic tourniquet cuff. The sensor-indicated pressure is monitored for sensor heights in the range 0–3 mm and for cuff inflation pressures of 0–40 kPa (∼0–300 mmHg). The sensor response is found to be non-linear with a saturation tendency at high applied pressures. A model which treats the cuff as an elastic membrane draped over the sensor is shown to be successful in accounting for the general form of the sensor characteristic particularly at cuff pressures greater than about 5 kPa. The model is of use in estimating the errors that are likely to arise in intrusive sensors used to measure interface pressures under tourniquets.