Aim of the study: To verify the model of CSF circulation for both the increasing and decreasing CSF pressure during and after the infusion test.
Material: Computerized infusion tests of 27 patients diagnosed for communicating hydrocephalus in the Department of Neurosurgery, Medical University of Warsaw were analyzed.
Method: Pressure-volume (P-V) curves were plotted separately for ascending and descending phases of the test for comparison purposes.
Results: The phenomenon of significant change of the P-V curve slope after the infusion was identified in 70% of tests. It was found that the elastance coefficient was significantly greater during the infusion than after the infusion. The pulsatile changes in cerebral blood volume were higher after the infusion in comparison to values during the infusion. The baseline pressure was higher than that before the infusion. There was a significant increase in mean arterial blood pressure after the infusion and it was not associated with any change in the heart rate.
Conclusions: We hypothesized that vasogenic component of intracranial pressure is responsible for the change of P-V curve slope. We also presume that the higher value of the pressure after the infusion can be due to by the excessive accumulation of cerebrospinal fluid in the intracranial space, including extra cellular parenchymal space. Both hypotheses require further studies to be evaluated.