Uysal Sanem Pinar, Williams Hayley G, Huerta Mina, Thompson Nicolas R, Hassett Catherine E
Department of Neurology, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
Case Western Reserve University School of Medicine, Cleveland, OH, USA.
Neurocrit Care. 2025 Apr;42(2):465-473. doi: 10.1007/s12028-024-02102-2. Epub 2024 Sep 18.
Intracranial compliance refers to the relationship between changes in volume and the resultant changes in intracranial pressure (ICP). This study aimed to assess the agreement of a noninvasive ICP waveform device for the estimation of compliance compared with invasive ICP monitoring employing three distinct methods.
We conducted a retrospective analysis of ICP waveform morphology recorded through both invasive (external ventricular drain) and noninvasive (mechanical extensometer) methods in adult patients with acute brain injury admitted to a neurointensive care unit between August 2021 and August 2022. Compliance was calculated as the amplitude of the fundamental component of cerebral arterial blood volume (estimated with concurrent Transcranial Doppler [TCD] recordings), divided by the amplitude of the fundamental component of the invasive and noninvasive ICP waveforms. Subsequently, we assessed the agreement between invasive and noninvasive intracranial compliance by repeated measures correlation coefficient analysis using three methods: TCD-derived, P2/P1 ratio, and time-to-peak (TTP). A linear mixed-effects model was used to compute the concordance correlation coefficient, total deviation index, and coefficient of individual agreement. Coverage probability plot was calculated to estimate the percent of observations within different cut points for each of the three methods.
A total of 21 patients were identified for this study. Repeated measures correlation analysis showed a strong correlation (R = 0.982, 95% confidence interval [0.980-0.984], p < 0.0001) between log-transformed noninvasive and invasive compliance. Agreement statistics for TCD, P2/P1 ratio, and TTP indicated that although the concordance correlation coefficient was highest for log(TCD) values, TTP and P2:P1 ratio measures had better agreement with total deviation index and coverage probability plot analyses.
Repeated measures correlations suggest that ICP waveform analyses may offer a more accurate estimate of compliance than TCD-derived methods for noninvasive ICP monitoring. Further validations studies are warranted to confidently establish this method as an indicator of intracranial compliance.
颅内顺应性是指容积变化与颅内压（ICP）相应变化之间的关系。本研究旨在评估一种非侵入性ICP波形装置与采用三种不同方法的侵入性ICP监测相比，在估计顺应性方面的一致性。
我们对2021年8月至2022年8月入住神经重症监护病房的成年急性脑损伤患者通过侵入性（脑室外引流）和非侵入性（机械伸长计）方法记录的ICP波形形态进行了回顾性分析。顺应性计算为脑动脉血容量基本成分的振幅（通过同步经颅多普勒[TCD]记录估计）除以侵入性和非侵入性ICP波形基本成分的振幅。随后，我们使用三种方法通过重复测量相关系数分析评估侵入性和非侵入性颅内顺应性之间的一致性：TCD衍生法、P2/P1比值法和峰值时间（TTP）法。使用线性混合效应模型计算一致性相关系数、总偏差指数和个体一致性系数。计算覆盖概率图以估计三种方法中每个方法在不同切点内的观察值百分比。
本研究共纳入21例患者。重复测量相关分析显示，对数转换后的非侵入性和侵入性顺应性之间存在强相关性（R = 0.982，95%置信区间[0.980 - 0.984]，p < 0.0001）。TCD、P2/P1比值和TTP的一致性统计表明，尽管对数（TCD）值的一致性相关系数最高，但TTP和P2:P1比值测量在总偏差指数和覆盖概率图分析方面具有更好的一致性。
重复测量相关性表明，对于非侵入性ICP监测，ICP波形分析可能比TCD衍生方法提供更准确的顺应性估计。需要进一步的验证研究，以可靠地将该方法确立为颅内顺应性的指标。
