摘自:Acta Neurochirurgica
作者:Frederick A. Zeiler & Marek Czosnyka & Peter Smielewski
摘要
2018年9月29日,劍橋大學Marek Czosnyka教授等人在最新一期的《Acta Neurochirurgica》發(fā)表最新研究:通過采用自動探頭,可以獲得危重TBI患者的長程腦血流記錄,從而獲得基于TCD腦血管反應指數(shù)的接近最優(yōu)的腦灌注壓。隨著自動探頭技術(shù)的不斷進步,更長的記錄成為可能,人員工時投入減少,TBI患者使用連續(xù)無間斷的TCD監(jiān)測將成為神經(jīng)多模態(tài)監(jiān)測的標準配置。
方法
本研究通過配備自動探頭監(jiān)護系統(tǒng)的經(jīng)顱多普勒系統(tǒng)DelicaEMS-9D(德力凱,中國深圳,http://stmarylebonefestival.com/html/en)進行MCACBFV的TCD評估。該系統(tǒng)允許使用1.6MHz自動TCD探頭連續(xù)長程記錄MCA CBFV,并具有糾正探頭移位的自動校正算法。
我們的目標是同時記錄來自所有設備的3~4h的連續(xù)數(shù)據(jù)。由于常規(guī)TCD監(jiān)測時間的限制,以前我們小組關(guān)于各設備參數(shù)關(guān)系的工作只能記錄到0.5~1小時的連續(xù)數(shù)據(jù)。
根據(jù)Delica自動探頭的技術(shù)規(guī)格,1.6MHz多普勒探頭的熱指數(shù)小于1.0,在大多數(shù)情況下熱指數(shù)小于0.5。因此,根據(jù)英國醫(yī)學超聲協(xié)會提供的成人TCD指南,該裝置的熱指數(shù)在可能“無限”的TCD連續(xù)監(jiān)測時間范圍內(nèi)是可接受的,同時遵守“ALARA”原則。因此,使用該系統(tǒng)進行長程監(jiān)護,不存在組織發(fā)熱的問題。
結(jié)論
隨著自動探頭監(jiān)護系統(tǒng)的應用,重癥外傷性腦損傷患者進行長程血流監(jiān)護成為可能,允許使用基于TCD的腦血管反應指數(shù)來近似獲得最佳腦灌注壓。隨著自動探頭技術(shù)的不斷發(fā)展,更長的血流監(jiān)測記錄成為可能,醫(yī)生投入工時大大減少,TBI患者使用連續(xù)無間斷的TCD監(jiān)測將成為神經(jīng)多模態(tài)監(jiān)測的標準配置。
Abstract
Individualized cerebral perfusion pressure (CPP) targets may be derived via assessing the minimum of the parabolic relationship between an index of cerebrovascular reactivity and CPP. This minimum is termed the optimal CPP (CPPopt), and literature suggests that the further away CPP is from CPPopt, the worse is clinical outcome in adult traumatic brain injury (TBI). Typically,CPPopt estimation is based on intracranial pressure (ICP)-derived cerebrovascular reactivity indices, given ICP is commonly measured and provides continuous long duration data streams. The goal of this study is to describe for the first time the application of robotic transcranial Doppler (TCD) and the feasibility of determining CPPopt based on TCD autoregulation indices.
Introduction
Continuous monitoring of cerebrovascular reactivity in traumatic brain injury (TBI) is becoming increasingly common in the multi-modal monitoring (MMM) of critically ill patients [10, 11, 16]. To date, support for such monitoring has arisen within international consensus statements [10, 16]. Such support is centered on what is considered the Bgold standard^continuous index, pressure reactivity index (PRx—correlation between intracranial pressure (ICP) and mean arterial pressure (MAP)) [11], given its association with global outcome in TBI and validation in experimental animal models against the lower limit of autoregulation [4, 23, 32]. Furthermore, literature supports the association of PRx-derived Bpersonalized^cerebral perfusion pressure (CPP) targets (referred to as CPP optimum or CPPopt) and global outcome[19].Numerous other continuous indices of cerebrovascular reactivity exist in the TBI literature [31, 32], derived from other invasive and non-invasive monitoring devices, including transcranial Doppler (TCD)-based measures. Indices based on TCD mean flow velocity (FVm) and systolic flow velocity (FVs) have been linked to global outcome in adult TBI [6, 22] and are known to be reasonably strongly associated with ICPderived indices, such as PRx [30, 33].
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Signal acquisition
Various signals were obtained through a combination of invasive and non-invasive methods. Arterial blood pressure (ABP) was obtained through either radial or femoral arterial lines connected to pressure transducers (Baxter Healthcare Corp.CardioVascular Group, Irvine, CA). ICP was acquired via an intra-parenchymal strain gauge probe (Codman ICP MicroSensor; Codman & Shurtleff Inc., Raynham, MA). Zeroing of the arterial line occurred at the level of the tragus during the course of this study.
Finally, TCD assessment of MCA CBFV was conducted via a robotic TCD system,the Delica EMS 9D (Delica, Shenzhen, China, http://stmarylebonefestival.com/html/en). This system allows for continuous extended duration recording of MCA CBFV, using 1.6 MHz robotically controlled TCD probes, with automated correction algorithms for probe shift.We aimed to record 3 to 4 h of continuous data from all devices simultaneously, given the previous work from our group on inter-index relationships focused on recording durations of only 0.5- to 1-h duration due to limitations of conventional TCD [22, 30]. Based on manufacturer specifications of the Delica robotic TCD system, the thermal index for the 1.6 MHz Doppler probes is less than 1.0, with the index less than 0.5 in most cases. As such, in keeping with the guidelines for adult TCD provided by the British Medical Ultrasound Society, the thermal index for the device is in the range acceptable for potentially Bunlimited^ TCD duration, while adhering to the principles of Bas low as reasonably achievable^(ALARA) [5, 12, 13]. Thus, there were no concerns with tissue heating as a result of the extended duration recordings using this system. Brain temperature, local or global, was not recorded in this patient cohort. Figure 1 displays the robotic TCD device and set up for recording in critical ill TBI patients.……
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