Reliability of intraventricular pressure measurement with fiberoptic or solid-state transducers: avoidance of a methodological error.
OBJECTIVE
The failure of intraventricular pressure measurement in cases of catheter blockage or dislodgement is thought to be eliminated by using intraventricular microtransducers. We report on an avoidable methodological error that may affect the reliability of intraventricular pressure measurement with these devices.


METHODS
Intraventricular fiberoptic or solid-state devices were implanted in 43 patients considered to be at risk for developing catheter occlusion. Two different types were used, i.e., devices in which the transducer is placed inside the ventriculostomy catheter (Type A) and devices in which the transducer is integrated in the external surface of the catheter (Type B). Type A devices were used in 15 patients and Type B devices in 28 patients. Pressure recordings were checked at bedside for the validity and reliability of the measurement.


RESULTS
Of the 15 patients treated with Type A devices, no reliable pressure recordings were able to be obtained in three patients in whom ventricular punctures were not successful. In 4 of the remaining 12 patients, periods of erroneous pressure readings were detected. After opening of cerebrospinal fluid drainage, all Type A devices failed to reflect real intraventricular pressure. In patients treated with Type B devices, no erroneous pressure recordings were able to be identified, irrespective of whether cerebrospinal fluid drainage was performed. Even when ventricular puncture failed, pressure measurement was correct each time.


CONCLUSIONS
Transducers that are simply placed inside the ventriculostomy catheter require fluid-coupling. They may fail, either during cerebrospinal fluid drainage or when the catheter is blocked or placed within the parenchyma.
Raabe
A
A
Department of Neurosurgery, Klinikum Chemnitz, Germany.
Stöckel
R
R
Hohrein
D
D
Schöche
J
J
D002408:Catheters, Indwelling; D002552:Cerebral Ventricles / Q000601:surgery; D015170:Cerebrospinal Fluid Pressure; D004322:Drainage / Q000379:methods; D004868:Equipment Failure; D005069:Evaluation Studies as Topic; D005336:Fiber Optic Technology; D006801:Humans; D008722:Methods; D011677:Punctures; D014159:Transducers