Czosnyka M, Czosnyka Z, Pickard J D
United Kingdom Shunt Evaluation Laboratory & Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, England.
Neurosurgery. 1996 Jan;38(1):219-24. doi: 10.1097/00006123-199601000-00053.
Three comparatively priced intracranial pressure (ICP) microtransducers 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 Transducer 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-flow test rig designed for assessment of hydrocephalus shunts. All three microtransducers compiled with the manufacturers' specifications and gave high-quality readings under test conditions. However, some differences were noted; Transducer C had the lowest 24-hour zero drift (drifts in all transducers were < 0.8 mm Hg). The temperature drift was very low in Transducer B and C, but Transducer A had a significantly higher 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 detection in Transducers A and B were very good (bandwidth, > 30 Hz), whereas Transducer C had a limited bandwidth of 20 Hz. Transducer B scored the best overall, but all three scored satisfactorily during bench testing.
