title: Clinical evaluation of a miniature strain-gauge transducer for monitoring intracranial pressure.
abstract: In 25 patients, we evaluated the accuracy of a new miniature strain-gauge transducer developed for the measurement of intracranial pressure (ICP). The ICP in each patient was measured with the intraventricular, miniature strain-gauge transducer, and that value was compared with the ICP measured with a ventriculostomy catheter coupled to an external strain-gauge transducer. From the two monitors, 2218 simultaneous measurements of ICP were obtained. The average ICP measured with the miniature strain-gauge transducer was 15.9 +/- 10.0 mm Hg (range, -3 to 104 mm Hg). The ICP measured with the ventriculostomy-catheter transducer averaged 15.4 +/- 10.1 mm Hg (range, -9 to 104 mm Hg). A highly significant correlation was found over the wide range of pressures observed (n = 2218, r = 0.97, P < 0.001). The average difference between the two measurements of the ICP was 0.5 +/- 2.6 mm Hg, and the differences were equally positive and negative, demonstrating no consistent bias. The two values for the ICP were within 2 mm Hg of each other on 63% of the measurements and within 4 mm Hg of each other on 89% of the measurements. The average zero drift of the miniature strain-gauge transducer, measured at ambient pressure after removal of the catheter, was 0.2 +/- 0.5 mm Hg. The results indicate that this miniature strain-gauge transducer is highly accurate and stable and that it is a reliable alternative to a ventriculostomy for monitoring the ICP.
authors.affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Gopinath
authors.forename: C S
authors.initials: CS
authors.lastname: Robertson
authors.forename: C F
authors.initials: CF
authors.lastname: Contant
authors.forename: R K
authors.initials: RK
authors.lastname: Narayan
authors.forename: R G
authors.initials: RG
authors.lastname: Grossman
mesh_terms: D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000503:physiopathology; D002408:Catheters, Indwelling; D005260:Female; D015600:Glasgow Coma Scale; D016489:Head Injuries, Closed / Q000503:physiopathology; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008904:Miniaturization / Q000295:instrumentation; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D015203:Reproducibility of Results; D013345:Subarachnoid Hemorrhage / Q000503:physiopathology; D014160:Transducers, Pressure; D014696:Ventriculostomy / Q000295:instrumentation*; D014948:Wounds, Gunshot / Q000503:physiopathology