LABORATORY TESTING OF 3 INTRACRANIAL-PRESSURE MICROTRANSDUCERS - TECHNICAL REPORT

THREE COMPARATIVELY PRICED intracranial pressure (ICP) microtransducer s are now available, each characterized by the manufacturer as having very low zero drift over long periods, an excellent frequency response , and a low measurement error. The three microtransducers, coded Trans ducer A (Camino OLM ICP monitor; Camino Laboratories, San Diego, CA), Transducer B (Codman Microsensor ICP Transducer; Codman & Shurtlef Inc ., Randolph, MA), and Transducer C (ICP Monitoring Catheter Kit OPX-SD [4F]; InnerSpace Medical, Irvine, CA), were examined in a pressure-fl ow test rig designed for assessment of hydrocephalus shunts. All three microtransducers complied with the manufacturers' specifications and gave high-quality readings under test conditions. However, some differ ences were noted; Transducer C had the lowest 24-hour zero drift (drif ts in all transducers were <0.8 mm Hg). The temperature drift was very low in Transducers B and C, but Transducer A had a significantly high er drift (0.27 mm Hg/degrees C). Transducer A had a static error <0.3 mm Hg, Transducer B <2 mm Hg, and Transducer C <8 mm Hg. Frequency det ection in Transducers A and B were very good (bandwidth, >30 Hz), wher eas Transducer C had a limited bandwidth of 20 Hz. Transducer B scored the best overall, but all three scored satisfactorily during bench te sting.