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Tesi etd-11172012-231515

Thesis type
Tesi di laurea specialistica
email address
Development of an integrated testing regime for he investigation of the cephalic fluid shift and changes in intraocular and intracranial pressures associated with microgravity
Corso di studi
correlatore Green, David Andrew
relatore Prof. De Rossi, Danilo
Parole chiave
  • cephalic
  • pressure
Data inizio appello
Data di rilascio
Riassunto analitico
Cephalic fluid shifts occur with exposure to microgravity and is associated with minor subjective discomfort resulting from tissue swelling (increased blood volume) including the nasal mucosa - precipitating ‘space sniffles’. However, recently a number of astronauts upon return from long duration ISS missions have been identified to have occular damage indicative of increased intra-occular pressure (IOP) and suggestive of intra-cranial pressure (ICP) elevation.
Chronic ICP and IOP elevation is associated with cognitive decline (dementia) and occular pathology (including glaucoma) respectively.
Whilst fluid shifts associated with re-orientation and/or microgravity have been modelled for various anatomical compartments, the head has been relatively neglected. This in part relates to the complexity of the tissues and their pressure-flow relationships which is compounded by the paucity of appropariate non-invasive measurement techniques.
The determinants of ICP and IOP are particular unclear. We seek to test the hypothesis that non-invasive (infrared) recording of nasal mucosa blood volume (Rhinolux, Rhinos, Germany) may act as a predictor of ICP and IOP.
Thus, we sought to model pressure-flow-volume relationships in various head compartments ultilizing multiple 5-element Windkessel models developed in MATLAB run and within Simulink (MathWorks, USA).
Having created a model that was consistent with published data we sought to test its validity in predicting nasal blood volume changes associated with rapid 60° head up tilt and 10° head down tilt from concurrent arterial blood pressure, stroke volume, cardiac output and total peripheral resistance (Finometer, FMS, Netherlands).
Thus, our aim is to validate non-invasive recording of nasal mucosa blood volume as a potential proxy of IOP and ICP within a constrained cephalic fluid shift model.