The Accuracy of Electrical Transducers for the Measurement of Pressure Applied to the Skin

The accuracies of five commercially available small flat pressure transducers (~5 mm X ~1 mm) were evaluated for their ability to measure pressures applied to the body surface. The diaphragms of the transducer were loaded with rubber and cloth surfaces in an in vitro test and under a blood pressure cuff over the gastrocnemius muscle, 2 cm on the medial and lateral sides of the tibia and on the tibial crest of the leg. These areas offer varying amounts of underlying tissue compliance. The cuff was pumped up to 200 mmHg in 20 mmHg increments. The average error obtained with the transducers zeroed in air before placement on the leg varied from 20.4 to 64.9 mmHg depending on the hardness of the underlying surface. The averaged error obtained with the transducer zeroed after placing on the leg ranged from 9.5 to 47.9 mmHg.