Artikel
Intracranial pressure monitoring prior to and following probatory CSF drainage in patients with suspected normal pressure hydrocephalus – Preliminary results
Monitoring des intrakranialen Druckes vor und nach probatorischer Liquorentnahme bei Patienten mit Verdacht auf Normaldruckhydrocephalus - vorläufige Ergebnisse
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Veröffentlicht: | 23. April 2004 |
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Objective
The diagnostic evaluation of patients with suspected normal pressure hydrocephalus (NPH) often includes the continuous monitoring of intracranial pressure (ICP) and the assessment of clinical symptoms following probatory cerebrospinal fluid (CSF) drainage. However it has not yet been investigated whether probatory CSF drainage leads to a reduced duration and / or frequency of ICP waves. The aim of the present study was therefore to assess the duration and frequency of ICP waves prior to and following probatory CSF drainage in patients with suspected NPH.
Methods
In the ongoing study, up to now 15 patients with radiographic and clinical signs suggesting the presence of NPH underwent simultaneous video and ICP monitoring the night prior to and the night following drainage of 30 ml CSF. The video and the ICP signals were digitized by means of a video capture card and an analog-to-digital data acquisition card (50 Hz sampling rate) and stored on a personal computer for off-line evaluation. The duration and frequency of phases with characteristic pressure waves (ICP > 200 mmH2O, frequency 0.5 - 2 cycles / minute) were determined. Only artefact-free ICP measurement segments during sleep phases of the patient as assessed by simultaneous video-monitoring were included in the evaluation.
Results
Eleven out of 15 patients with suspected NPH showed recurrent ICP waves or prolonged periods of elevated ICP (ICP > 200 mmH2O, duration > 30 minutes) prior to CSF drainage. In all 5 patients with prolonged periods of elevated ICP prior to CSF drainage, similar ICP measurement characteristics with lasting periods of elevated ICP were observed in the night following CSF drainage. In 4 out of 6 patients with recurrent ICP pressure waves but no lasting ICP increase prior to CSF drainage, a reduction of the frequency and duration of ICP pressure waves of varying amounts could be observed, whereas no marked change of the ICP measurement characteristics was seen in the remaining 2 patients. As it could be expected, the 4 patients without ICP increases prior to CSF drainage showed no ICP increases following CSF drainage.
Conclusions
Our preliminary results suggest that ICP monitoring prior to and following probatory CSF drainage might become a helpful additional tool in making the diagnosis of NPH more reliable. However, only a study including more patients and a comparison with long-term outcomes following shunting will allow a more reliable judgment of the value of this new diagnostic approach.