Compliance measurement

Abstract

A method for influencing cerebral perfusion in a patient by modifying a volume of a volume adaptor introduced into a cerebral ventricle of the patient, the method comprising identifying a timing of a cerebral blood inflow and/or outflow in a cardiac activity of the patient, modifying a volume of the volume adaptor in synchronization to the identified timing of the cerebral blood flow, to an amount sufficient to modify an intracranial pressure in the cerebral ventricle, such that a flow of the cerebral blood flow is enhanced. In some exemplary embodiments of the invention, the inflation duration of the volume adapter is short relative to the cardiac cycle.

What is claimed is: 
     
         1 . A method of diagnosis of a patient comprising:
 receiving measurement of a cardiac cycle of said patient;   identifying a selected portion said cardiac cycle of said patient;   changing an expandable compartment positioned within cerebrospinal fluid of said patient, by a volume, in synchronization with said selected portion of said cardiac cycle;   receiving intracranial pressure measurements and identifying an effect of said volume on intracranial pressure;   generating a volume pressure relationship to indicate intracranial compliance for said patient, from said effect.   
     
     
         2 . The method of diagnosis according to  claim 1 , wherein said portion of said cardiac cycle of said patient is a diastolic phase of said cardiac cycle. 
     
     
         3 . The method of diagnosis according to  claim 1 , comprising:
 receiving measurement of an additional cardiac cycle of said patient;   identifying a selected portion of said additional cardiac cycle;   changing said expandable compartment by a further volume in synchronization with said selected portion of said additional cardiac cycle; and   receiving intracranial pressure measurements, and identifying a further effect of said further volume of intracranial pressure; and   generating, said volume pressure relationship, from said effect and from said further effect.   
     
     
         4 . The method of diagnosis according to  claim 1 , wherein said measurement of said cardiac cycle includes electrocardiogram measurements. 
     
     
         5 . The method of diagnosis of  claim 1 , comprising treating a patient based on said intracranial compliance. 
     
     
         6 . The method according to  claim 1 , wherein said portion of said cardiac cycle of said patient is a systolic phase of said cardiac cycle. 
     
     
         7 . The method according to  claim 6 , wherein said portion of said cardiac cycle of said patient is a maximum of a systolic phase of said cardiac cycle. 
     
     
         8 . The method of diagnosis according to  claim 2 , comprising:
 identifying a systolic phase of said cardiac cycle of said patient;   changing said volume adaptor by a further volume, in synchronization with said systolic phase of said cardiac cycle of said patient;   receive intracranial pressure measurements;   identifying an effect of said further volume on intracranial pressure;   generate a volume pressure characteristic to indicate said intracranial compliance for said patient, from said effect of said change in volume and from said effect of said further volume.   
     
     
         9 . The method according to  claim 1 , wherein said measurement of said cardiac cycle includes intracranial pressure measurements. 
     
     
         10 . The method according to  claim 1 , comprising changing said expandable compartment, by a sequence of volume changes, said sequence of volume changes determined using said intracranial compliance for said patient. 
     
     
         11 . The method according to  claim 1 , wherein said volume is between 0.01 cc and 2 cc. 
     
     
         12 . The method according to  claim 1 , wherein said volume is between 0.05 and 0.5 cc. 
     
     
         13 . The method according to  claim 1 , wherein said volume is about 0.5 cc. 
     
     
         14 . The method according to  claim 12 , wherein said change in volume is implemented over 10-100 ms. 
     
     
         15 . A system for determining intracranial compliance in a patient, comprising:
 a volume adaptor having an expandable compartment;   at least one sensor for measuring intracranial pressure of said patient; and   a controller in operating communication with said volume adaptor, and configured to:
 receive measurement of a cardiac cycle of said patient; 
 identify a selected portion of said cardiac cycle of said patient; 
 instruct said volume adaptor to change said expandable compartment by a volume, in synchronization with said portion of said cardiac cycle; 
 receive intracranial pressure measurements from said at least one sensor and identify an effect of said change in volume on intracranial pressure; and 
 generate a volume pressure relationship to indicate said intracranial compliance for said patient, from said effect. 
   
     
     
         16 . The system according to  claim 15 , wherein said volume adaptor is sized and shaped to be introduced into a cerebral ventricle. 
     
     
         17 . The system according to  claim 15 , wherein said portion of said cardiac cycle of said patient is a systolic phase of said cardiac cycle. 
     
     
         18 . The system according to  claim 15 , wherein said controller is configured to:
 receive measurement of an additional cardiac cycle of said patient;   identify a selected portion of said additional cardiac cycle of said patient;   instruct said volume adaptor to change said expandable compartment by a further volume, in synchronization with said selected portion of said additional cardiac cycle of said patient;   receive intracranial pressure measurements from said at least one sensor and identify an effect of said further volume on intracranial pressure;   generate a volume pressure relationship to indicate said intracranial compliance for said patient, from said effect of said change in volume and from said effect of said further volume.   
     
     
         19 . The system according to  claim 15 , wherein said measurement of said cardiac cycle includes intracranial pressure measurements from said at least one sensor. 
     
     
         20 . The system according to  claim 15 , comprising a cardiac measurement sensor; and
 wherein said measurement of said cardiac cycle includes electrocardiogram measurements received from said cardiac measurement sensor.