Study On The Relationship Between FVEP Latent Period And Intracranial Pressure (ICP)

Background and Objective:Intracranial pressure (ICP) increasing is the critical illness of the department of never internal medicine. The elements is manifold factor leading compensation maladjustment in encephalic. Hydrocephalus must lead the ICP increased when it achieve a certain extent, so with the exception of encephaloma and water head leading ICP increased, hydrocephalus is equal to the ICP increased. It is major injury to the health of patient and cause death. So it is very important for doctor to know the tite of ICP. The tradition method of getting the tite of ICP is invasive method like lumbar puncture. It has numerous shortcomings. If do it with non-invasive technique, will decrease the shortcoming greatly. The fVEP technique is just direction of non-invasive technique to monitoring ICP. The energy metabolize impediment and electrolyte disorder that hydrocephalus caused are not only the substance base, but also theoretic base of the relativity of fVEP latent period and ICP. We study the relationship between flash visual evoked potentials (fVEP)and intracranial pressure (ICP)?to evaluate the usefulness of baseline fVEP testing in the diagnosis of increased ICP and instruction therapy tall intracranial pressure. Material and Method:22 normal individuals and 88 patients who were measured by Lumbar puncture were recorded with fVEP. We compared the latency of their waves. And other 40 patients were recorded by fVEP for three times in 10minutes We summarized the character, the variation and the latency of N2 waves.We compared the difference of 4 measurement in latency of N2 wave in the same pation for the same time. Measured 147increased intracranial pressure patients before mannitol and after mannitol(every 10min), choose 60min analysis. Results :A positive correlationship between elevated intracranial pressure and a latency shift of the P2 , N2 , P3, N3 wave of the flash-evoked potential isdemonstrated, we find the N2 wave is unconstant and it's amplitude is un -relative to ICP .additional we also find it is wider than N1 wave and has a deep P2 in the front of it and a deep P3 in the post of it .our reasurch implied that the peak lantcy of N2 is unstable .and the Intermedium latency have the minimum variation in all of 4 measurements A linear relationship between elevated intracranial pressure and the latency of P2, N2, P3, N 3 wave and fVEP is a reliable noninvasive method to Monitoring intracranial pressure.The N2 wave is mutable even though for the same people in the same time. Conclusion :(1) fVEP can exact and harmless monitoring ICP.(2) The wave of N2 is variation, it s latent period is 131.02 + 7. 10ms, it lengthen followed the increase of ICP. We suggest we should choose the Intermedium lantcy as parameters for monitoring ICP .(3) The effect is decrease when mannitol is used over 8, even useless while exceed 10-14.(4) It is no difference to monitoring ICP with fVEP when unilateral lesion in cerebum.(5) Although there are some shortcomings, we think fVEP has importance value to instruction therapy tall intracranial pressure in clinical.