ICP MONITORING WITH A REUSABLE TRANSDUCER - EXPERIMENTAL AND CLINICAL-EVALUATION OF THE GAELTEC ICT B PRESSURE PROBE/

Intracranial pressure monitoring requires reliable transducers at a ju stifiable price. At present, transducers for single or repeated use ar e available. We examined the Gaeltec model ITC/b solid state miniature transducer experimentally and clinically. Measurement accuracy was as sessed in vitro at increasing steps of 5 mmHg from 0 to 80 mmHg. While new and recently serviced probes revealed minimal deviations from the preset values, frequently used transducers differed up to 7 mmHg. Thi s occured especially in the high pressure range above 50 mmHg. Additio nally the drift was investigated at different pressure levels. After 2 4 hours we already found drifts of 2 mmHg with new and serviced probes and up to 4 mmHg with used ones. In clinical practice we implanted 15 0 transducers in 121 patients from 1983 until 1995. The probes were re -used up to twelve times, the average time being 7 times. 32.7% of all measurements were regarded as not reliable. Dislocation (16.7%), inab ility to calibrate (3.3%) and defect pressure probes (3.3%) were the m ost common complications. Repeated use of the Gaeltec ICT/b probe also seemed to result in an additional decay of measurement quality. The s train of frequent cleaning and sterilizing may have caused changes of the physical properties of the probes with time. Whether these results also apply to other types of ICP probes for repeated use needs furthe r evaluation.