Application value of transcranial Doppler in intracranial pressure and cerebral perfusion pressure of the patients with aneurysmal subarachnoid hemorrhage

Liu Shuai; Wang Shuya; Xu Shanshan; Tian Ying; Chen Xiaolin; Zhang Linlin; Shi Guangzhi; Zhou Jianxin

doi:10.3969/j.issn.1002-1949.2024.09.017

Abstract：Objective To evaluate the correlation and agreement of transcranial Doppler(TCD)-related/derived parameters with intracranial pressure(ICP)and cerebral perfusion pressure(CPP)in the patients with aneurysmal subarachnoid hemorrhage(aSAH).Methods This was a single-center retrospective observational study.All the patients were diagnosed with aSAH and received TCD examination and ICP monitoring after microsurgery clipping.Systolic flow velocity(FVs),diastolic flow velocity(FVd)in middle cerebral artery(MCA)were collected,and mean flow velocity(FVm),pulsatility index(PI)were calculated.Mean arterial pressure(MAP)and ICP values were recorded,and noninvasive intracranial pressure(nICP),noninvasive cerebral perfusion pressure(nCPP)were calculated by formula based on FVd.Spearman correlation coefficients were used to evaluate the correlation of TCD-related/derived parameters with the ICP as well as CPP.According to the TCD results,the patients were divided into normal blood flow velocity group,mild TCD vasospasm(TCD-VS)group,and moderate to severe TCD-VS group,and subgroup analysis was conducted.The agreement between nICP and ICP,between nCPP and CPP were assessed by Bland-Altman plots.Finally,the area under the receiver operating characteristic(AUC)curve was used to determine the ability of nICP to predict ICP＞22 mmHg and nCPP to predict CPP＜60 mmHg.Results A total of 95 patients were included,201 data of TCD-related/derived parameters and ICP were recorded.The nICP showed a significantly positive correlation with ICP(r=0.240,P＜0.001),FVd and FVm showed a significantly negative correlation with ICP(r=-0.154 and-0.142,respectively,P＜0.05).PI showed a significantly negative correlation with CPP(r=-0.161,P＜0.05),nCPP and cerebral blood flow index(CBFi)showed a significantly positive correlation with CPP(r=0.695 and 0.734,respectively,P＜0.001).In subgroup analysis,the nICP had a significantly positive correlation with ICP in normal group and mild TCD-VS group(r=0.238 and 0.539,respectively,P＜0.05),and there was no significantly correlation between nICP and ICP in moderate and severe TCD-VS group(P＞0.05).There was no significant correlation of FVs,FVd,FVm,PI,CBFi with ICP in any TCD-VS group(P＞0.05).The nCPP showed a significantly positive correlation with CPP in any groups(r=0.659,0.828 and 0.781,respectively,P＜0.001),CBFi also showed a significantly positive correlation with CPP in any groups(r=0.709,0.856 and 0.795,respectively,P＜0.001).In Bland-Altman plot analysis,the mean differences between ICP and nICP in the overall population were(-2.35±9.22)mmHg,the mean differences between CPP and nCPP in the overall population were(2.38±9.23)mmHg.The AUC of nICP was 70.1％(95％CI 60.0％-80.3％,P＜0.001),the cutoff point for the prediction of ICP＞22 mmHg was 21.5 mmHg,the sensitivity was 80.6％,and the specificity was 53.9％.In normal group,the AUC of nICP was 71.4％(95％CI 59.5％-83.2％,P＜0.01),the cutoff point for the prediction of ICP＞22 mmHg was 23.5 mmHg,the sensitivity was 84.6％,and the specificity was 55.0％.The AUC of nCPP was 92.8％(95％CI 86.1％-99.6％,P＜0.001),the cutoff point for the prediction of CPP＜60 mmHg was 65.6 mmHg,the sensitivity was 94.4％,and the specificity was 83.3％.In normal group,the AUC of nCPP was 90.0％(95％CI 82.1％-97.9％,P＜0.01),the cutoff point for the prediction of CPP＜60 mmHg was 58.5 mmHg,the sensitivity was 97.2％,and the specificity was 80.0％.Conclusions TCD monitoring can be used to assess ICP in patients with aSAH,but its value is limited in moderate to severe TCD-VS.TCD monitoring in combination with MAP can be used to assess CPP in the patients with aSAH.