The Application Of Transcranial Doppler In The Evaluation Of Intracranial Pressure In Patients With Traumatic Brain Injury

Objective:The use of transcranial Doppler(TCD)detection of cerebral blood flow parameters to evaluate intracranial pressure(ICP)in craniocerebral trauma(TBI),explore the feasibility of using TCD parameter modeling formulas to evaluate ICP,and discuss the difference between decompressed patients and non-decompressed patients,as well as the difference between non-invasive evaluation of ICP using TCD under hydraulic and piezoelectric coupling technology,and provide a basis for noninvasive evaluation of intracranial disease changes at the bedside and guide clinical intervention.Date and Methods:Twenty patients who underwent ICP monitoring after traumatic brain injury from October 2018 to November 2019 were collected from the Department of Neurotrauma Surgery of the First Hospital of Jilin University,including 15 males and 5 females,aged 16-68 years old,with an average age of 53.35 ± 10.90 years old.Glasgow Coma Score(GCS)at admission: 15 patients with 3-8 points and 5 patients with 9-12 points,including 12 cases with deboned flap decompression,8 without deboned decompression,and piezoelectric-coupled ICP monitoring was used in 4 cases and hydraulic-coupled ICP monitoring was used in 16 cases.TCD was used to collect FVs,FVd,FVm,pulsatility index(PI)and RI data,and invasive monitoring collected ICP,CPP,and MAP values for a total of 200 times.The modeling formula was used to calculate the non-invasive ICP(n ICP),and the corresponding n ICP under the hydraulic and piezoelectric coupling techniques were calculated.And to calculate the n ICP of the decompressed and non-decompressed valve groups,using the bivariate Pearson correlation coefficient Analyze the correlation between the corresponding n ICP and ICP,draw the corresponding n ICP and ICP Bland-Altman test chart to compare the consistency,and use the ROC curve to predict the ability to diagnose increased intracranial pressure.Results:1.There is a high positive correlation between PI and ICP in the parameters of TCD detection(r=0.71,P<0.001).2.Among the three modeling formulas,formula 1(n ICP=4.47×PI+12.68)shows a high correlation between n ICP and ICP(r=0.71,P<0.001),and good consistency(average deviation : +1.8±2.1mm Hg,consistency range:-2.4 to 6.0mm Hg)and strong ability to predict ICP ≥ 20 mm Hg(AUC: 0.957,optimal cut-off value: 17.6mm Hg,sensitivity: 100%,specificity: 86.10%).Although with the extension of the monitoring time,the deviation of n ICP and ICP measured by formula 1 also increases correspondingly,but the deviation is between 1-3 mm Hg.3.Apply formula 1 to calculate the n ICP of the decompressed and undecompressed group,the decompressed group(r=0.69,P<0.001)and the undecompressed group(r=0.79,P<0.001),the correlation is slightly weaker,but there is a high correlation with ICP,and the two groups have a significant correlation between ICP from 16 to 21 mm Hg compared to other intervals.At the same time,the consistency of the two groups(average deviation: +1.5±2.1mm Hg vs +2.2±2.3 mm Hg,consistency range:-2.5-5.6 mm Hg vs-2.2-6.7 mm Hg)and the ability to predict ICP ≥ 20 mm Hg(AUC: 0.948 vs 0.970)Is basically the same.4.Three modeling formulas were used to calculate the n ICP of the hydraulic group and the piezoelectric group,and the correlation strength between the hydraulic group n ICP and ICP was consistent with the piezoelectric group(r: 0.72;0.43;0.71 vs 0.72;0.59;0.70).The Bland-Altman test showed that the results of the hydraulic group and the piezoelectric group were basically the same(very deviation: +1.7±2.1 mm Hg;-2.4±5.3 mm Hg;-6.0±1.9 mm Hg vs +1.9±2.2 mm Hg;-3.2 ±6.5 mm Hg;-6.0±2.0 mm Hg),the ROC curve shows that when ICP ≥ 20 mm Hg is used as the criterion for judging the increase in intracranial pressure,the ability of the hydraulic group to perform non-invasive evaluation of TCD to predict the increase in intracranial pressure is consistent with the piezoelectric group(AUC: 0.939;0.712;0.906 vs 0.982;0.796;0.982).Among them,formula 1(n ICP=4.47×PI+12.68)has good applicability under the two ICP monitoring technologies.Conclusion:1.There is a high positive correlation between PI and ICP in TCD parameters.2.In the TCD non-invasive evaluation ICP modeling formula,the formula n ICP=4.47×PI+12.68 has good applicability in correlation,consistency,and ability to predict ICP increase.3 In TBI,the use of TCD for noninvasive evaluation of ICP after decompressive bone decompression patients is still applicable,and there is a good correlation when ICP is in the range of 16-21 mm Hg.4.Under the two ICP monitoring technologies of hydraulic coupling and piezoelectric coupling,there is no obvious difference in the evaluation of ICP using TCD,and the formula n ICP=4.47×PI+12.68 has good applicability in both hydraulic and piezoelectric ICP monitoring technologies.5.In the treatment of clinical TBI patients,although TCD can’t replace the invasive ICP monitoring technology to accurately assess ICP,but TCD can help neurosurgeons to repeatedly,rapidly and dynamically monitor ICP changes in real time in some cases.