[Optimal use of the lumbar infusion test in patients with communicating hydrocephalus. Theoretical considerations in comparison to clinical observations].
OBJECTIVE
Lumbar infusion test (IT) is still one of the most important diagnostic tools in the communicating hydrocephalus. On one hand suitability of parameters achieved during tests is being highlighted, while on the other hand benefits are being questioned due to the test invasiveness. The aim of this paper is to assess the possibility of reducing the duration of IT. The study was based on a theoretical model and the analysis of selected IT performed in patients suffering from normal pressure hydrocephalus.


METHODS
Theoretical principles of the volume-pressure compensation in hydrocephalic patients are considered. Then, based on selected infusion test, an analysis of the data was carried out using the mathematical model. Finally the methods of IT optimization were proposed.


RESULTS
The analysis of IT should be performed in dynamic (not static) conditions. For the proper assessment of the IT the classical Marmarou's model is sufficient. This model interposed on the normal IT curve helps avoid too short and too long time of the IT. From a theoretical point of view it is impossible to minimize the duration of the IT by changing the infusion rate. This is due to the fact that formal relationships are characterized by curves with a single maximum, but not a minimum. The proposed algorithm for predicting the level of the steady state pressure, based on the initial course of the IT curve, allows for about 30% reduction of the IT time. The predictive error for the pressure value is less than 10%.
Cieślicki
Krzysztof
K
Pracownia Mechaniki Płynow, Instytut Automatyki i Robotyki, Politechnika Warszawska, ul. św. Andrzeja Boboli 8, 02-525 Warszawa. cieslick@mchtr.pw.edu.pl
Czepko
Ryszard
R
D000328:Adult; D000368:Aged; D015170:Cerebrospinal Fluid Pressure; D002557:Cerebrospinal Fluid Shunts / Q000379:methods*; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000175:diagnosis* / Q000503:physiopathology; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis; D007552:Isotonic Solutions; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D018709:Statistics, Nonparametric; D013997:Time Factors
D007552:Isotonic Solutions