ABSTRACT
Objective To establish the animal model of acute intracranial hypertension,investigate the changes of transeranial Doppler patterns in raised intraeranial pressure so that the necessary experimental evidence will be provided to clinical experience for monitoring intraeranial pressure (ICP) and cerebral perfusion pressure (CPP) using transeranial Doppler non-invasively. Methods Acute intraeranial hypertension was induced by inflating the balloon inserted into the epidural space. Blood flow velocity of basilar artery was measured with transcranial Doppler and intracranial pressure as well as cerebral perfusion pressure was measured. Results With progressive increase of intracranial pressure five characteristic flow patterns were observed, appearing in the following order: high resistance pattern, systolic flow, retrograde diastolic flow, very small systolic flow and zero flow. Conclusions Analysing patterns of TCD may be helpful for evaluating ICP and CPP qualitatively. The animal model is simple and strict so that it is worthy of being spreadcd.
ABSTRACT
BACKGROUND: Transcranial Doppler(TCD) spectrum analysis techniques cannot measure the diameters of blood vessels and therefore and not be used to calculate the changes of brain blood flow. A formula was designed for regional cerebral blood flow loss index(rCBFLI) following arteriostenosis when arteriostenosis index formula was deduced; the former may provide a reference to assess cerebral function.OBJECTIVE: To introduce the formula of cerebral blood flow loss ratio obtained basing on TCD results.DESIGN: Retrospective controlled study based on patients with cerebral middle arteriostenosis diagnosed with TCD and healthy people.SETTING: At the departments of neurology in a university hospital and in a military medical university affiliated hospital of Chinese PLA.PARTICIPANTS: Between October 1994 and December 2000,43 patients who were confirmed of arteriostenosis with TCD at outpatient or neurological ward of the First Affiliated Hospital of Fujian Medical University were enrolled into this study,and their TCD results were compared with 908 normal controls between March 1992 and September 2000.METHODS: Stenosis index (STI) formula was deduced from TCD results of 31unilateral and 12 bilateral stenoses at middle cerebral artery(MCA) . STI = 1- [ normal average blood velocity (Vm0) ÷ average blood velocity at stenosisSince(PI1 ÷PI0) may be equal to [post-stenosis blood flow(Q1) ÷ normal blood flow(Q0)],regional cerebral blood flow loss index is concluded as:MAIN OUTCOME MEASURES: rCBFLI,relationship between STI and Vm,as well as between rCBFLI and STI.RESULTS: rCBFLI formula was used to calculate the rCBFLI of 31 patients following unilateral MCA stenosis. rCBFLI of these 31 patients was obtained by Pearson statistical analysis. STI was found to be related to the average blood velocity at stenosis with relative coefficient(Vm) of(r) =0.76( P ＜ 0. 001 )and r = 0. 83 ( P ＜ 0. 001 ) . rCBFLI was proved to be correlated with Vm and STI with r = 0. 76( P ＜ 0. 01 ) and r = 0. 81 in 55 side MCA stenoses,and the difference was of statistical significance( P ＜ 0. 001 ).CONCLUSION: rCBFLI can be used to assess the decrement of regional brain blood flow due to the stenosis of supplying artery; also,it can be used to observe the changes of brain hemodynamics if combined with STI.