Artikel
Telemetric ICP measurements: Long-term performance over 2 years in an animal model
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Veröffentlicht: | 28. April 2011 |
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Objective: To study the long-term reliability of the new Raumedic telemetric intracranial pressure (ICP) sensor in a minipig model.
Methods: A subdural (STel) and an intraparenchymal (PTel)Raumedic telemetric ICP probe has been inserted in 9 adult minipigs. A Raumedic Neurovent P probe served as gold standard control. All data have been collected using a Raumedic data logger at a sampling rate of 1 Hz. Telemetric and control ICP measurements have been done in each animal after 3 ± 1 months regularly. During each control a new reference probe has been inserted via a frontal bore hole. To get data from a wider ICP range, the positioning of the animals has been changed according to protocol from prone position to 20° lowered and 20° raised head position. Each position has been maintained for 10 min. The data have been statistically analyzed using Bland-Altman-plots to compare the telemetric probes performance with its specifications. Further Chi2-tests and matched pair T-tests have been used at a significance level of p < 0.05.
Results: Overall 38 control measurements have been performed, 15 in STEL and 23 in PTEL probes. In each studied probe one to five controls have been performed throughout a maximal follow-up of 2 years. The zero-shift was –1.7 ± 7.6 mm Hg and –3.0 ± 6.0 mm Hg in subdural and parenchymal probes respectively. The ranges of the limits of agreement were 4.4 ± 1.9 mm Hg and 3.6 ± 2.6 mm Hg in STel and PTel respectively. Both measured variables differed not when comparing STel and PTel (p=0.1 for the zero-shift and p=0.82 for the range of the limits of agreement). The specification of ± 2 mm Hg drift was meted during 5 of 15 and 13 of 23 subdural and intraparenchymal controls respectively, but this difference achieved no significance (p=0.2).
Conclusions: With 1.7 and 3 mm Hg zero shift the new telemetric ICP probes provided reliable data throughout a maximum of 2 years follow-up. As the range of the limits of agreement was about 4 mm Hg in both probes they meet its specification perfectly. These data suggest that the Raumedic PTel and STel probes for telemetric ICP measurement might provide reliable data much longer than actually specified.