| Abstrakt: |
Instrumentation developed for the direct study of the human cerebrospinal fluid (c.s.f.) system is described. The configuration consists of a servo pressure regulator, two pressure transducers, a special function generator, an electronic pressure limiter, a strain-gauge balance, a volume and flow-rate meter, a c.s.f. conductance calculator, a 4-channel pen recorder, an x/y pen recorder and an ink-jet recorder. It is possible to regulate the c.s.f. pressure to any value between - 2·0 and 10.0 kPa or to regulate the flow rat of fluid into or out of the patient or to perform simple bolus injections/withdrawals. The c.s.f. model used allows indirect calculation of the pressure in the sagittal sinus and the pressure difference between the subarachnoid space and the sagittal sinus. The instrumentation is currently used for the study of c.s.f. pressure, c.s.f. formation rate, c.s.f. absorption rate, conductance of c.s.f outflow pathways, c.s.f. pressure/volume relationship and neurosurgical shunt systems. We have shown that the method of constant-pressure c.s.f infusion is faster than the method of constant-flow-rate c.s.f. infusion in obtaining reliable measuremnts of c.s.f. outflow conductance. [ABSTRACT FROM AUTHOR] |
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