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Title: The measurement of the flow of cerebrospinal fluid in response to short duration pressure changes
Author: Prytherch, David Roger
ISNI:       0000 0001 3502 5767
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1982
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This thesis describes the theory, development and use of an electrochemical flow transducer for the measurement of the flow of cerebrospinal fluid. The flow sensitive part of the flow transducer is a gold sphere cathode at which oxygen is reduced to hydroxyl ions. The rate of reduction of oxygen is limited by the transport of oxygen to the cathode by convective-diffusion and so the current flowing through the cathode is a function of flow past the cathode. Theories are developed to describe the dependence of the output current on flow velocity, and other variables, for various cathode geometries. In all the cases considered the output current is proportional to the square root of the flow velocity magnitude and directly proportional to the oxygen concentration. The limiting time response of the transducer is that to a decrease in flow velocity and a theory to describe this is presented, for the cathode geometries considered. Experiments were performed to investigate the dependence of the output current, of the various cathode geometries, on the main variables involved in the response to a steady flow, and in the time response to a decrease in flow. Good agreement was found between the experimental results and the theoretical predictions. The development of the flow transducer used clinically is described, with the results of the final animal experiment performed to confirm the in-vivo operation of the flow transducer. In the form used clinically the flow transducer is small enough to enter the CSF pathways through an 18 gauge spinal needle whilst still allowing the simultaneous measurement of CSF pressure through the same needle. Typical results from the initial clinical trials are presented.
Supervisor: Not available Sponsor: Science Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics ; QP Physiology