Relations Between Paramaters Of TCD Ultrasonography And Intracranial Pressure And Cerebral Perfusion Pressure And The Value Of Estimating Prognosis In Patients With Severe Brain Injury

Objectives: To investigate the dependability between Transcranial Doppler(TCD) parameter and intracranial pressure (ICP), cerebral perfusion pressure (CPP) while incracanial pressure is increased by studying dynamic changing rules of TCD frequency spectrum in severe craniocerebral injury patients who are suffering from increased intracranial pressure, and set up regression equation of ICP, CPP and TCD parameter.To investigate the correlation between parameter and prognosis.We want to provide some experimental data for clinical application of TCD.Methods: 40 severe craniocerebral injury patients(GCS≤8 score) have beendetected by TCD (ALT-3000,GE USA 2mHZ) through temple window. The peak systolic velocity (Vs), end diastolic velocity (Vd), mean velocity (Vm), pulsatility index(PI) and resistance index(RI) of middle cerebral altery(MCA) have been monitored on consecutive 7 days after admission to the hospitial or after surgfery.At the same time ,the mean arterial pressure(MAP), ICP, CPP are monitored through electrocardiogram monitor and cerebral ventricle vessel.GOS has been recorded within 6 months (slight mayhem and good recovery belong to eusemia; death vegetative state and severe disability to prognosis mala).we have analysed the correlation between TCD parameter and ICP, CPP, found the best dependable parameters, set up equation of linear regression or exponential curve. T-test for pairing sample has been used to analyse the estimated value and really monitored value of ICP, CPP. We have used Single-factor regression analysis to look for useful clinical index.Results: To severe craniocerebral injury patients, CPP level dropps as the ICPlevel increases. There are intimate correlations between ICP, CPP and TCD parameter. The correlations between ICP and Vs, Vd, Vm are nagetively linear-regressioned,but it is positive between ICP and RI, the correlation between ICP and PI is positively exponential-regressioned. It is just on the contrary to CPP. The PI's is the biggest within these coefficient correlations (r_ICP=0.809 r_CPP =-0.828 p<0.001), Not only the correlations between PI and ICP, CPP are linear-regressioned when the ICP level and the CPP level are respectively between 20～50 mmHg and 40～70 mmHg, but also the correlations are more intimate (r_ICP * =0.864 r_CPP* =-0.887 p<0.001).There are no significant deviation between really monitored value and the value estimated from the PI's regression equation of ICP, CPP (p>0. 05) .According to Logistical regression analysis results, incipient CPP, incipient ICP , Vm and PI are useful clinical index for us to judge prognosis.The patients' prognosis mostly are bad if their incipient CPP levels are below 60 mmHg; incipient ICP over 30 mmHg; Vm below 40cm/s; PI>1.2.Conclusions: We can judge ICP and CPP from TCD frequency spectrum andparameter variations,then use it for our clinical treatment. Incipient CPP, incipient ICP, Vm and PI can be useful for us to judge prognosis.The usage of TCD can be a new direction to monitor ICP and CPP without wounds.