Wasicek Philip J, Teeter William A, Yang Shiming, Hu Peter, Gamble William B, Galvagno Samuel M, Hoehn Melanie R, Scalea Thomas M, Morrison Jonathan J
R Adams Cowley Shock Trauma Center, 22 S. Greene Street, Baltimore, MD, 21201, USA.
Shock Trauma and Anesthesiology Research Center, University of Maryland, School of Medicine, Baltimore, MD, USA.
Eur J Trauma Emerg Surg. 2021 Apr;47(2):325-332. doi: 10.1007/s00068-019-01140-2. Epub 2019 Apr 23.
The arterial pressure waveform is a composite of multiple interactions, and there may be more sensitive and specific features associated with hemorrhagic shock and intravascular volume depletion than systolic and/or diastolic blood pressure (BP) alone. The aim of this study was to characterize the arterial pressure waveform in differing grades of hemorrhage.
Ten anesthetized swine (70-90 kg) underwent a 40% controlled exponential hemorrhage. High-fidelity arterial waveform data were collected (500 Hz) and signal-processing techniques were used to extract key features. Regression modeling was used to assess the trend over time. Short-time Fourier transform (STFT) was utilized to assess waveform frequency and power spectrum density variance.
All animals tolerated instrumentation and hemorrhage. The primary antegrade wave (P1) was relatively preserved while the renal (P2) and iliac (P3) reflection waves became noticeably attenuated during progressive hemorrhage. Several features mirrored changes in systolic and diastolic BP and plateaued at approximately 20% hemorrhage, and were best fit with non-linear sigmoidal regression modeling. The P1:P3 ratio continued to change during progressive hemorrhage (R = 0.51). Analysis of the first three harmonics during progressive hemorrhage via STFT demonstrated increasing variance with high coefficients of determination using linear regression in frequency (R = 0.70, 0.93, and 0.76, respectively) and power spectrum density (R = 0.90, 0.90, and 0.59, respectively).
In this swine model of volume-controlled hemorrhage, hypotension was a predominating early feature. While most waveform features mirrored those of BP, specific features such as the variance may be able to distinguish differing magnitudes of hemorrhage despite little change in conventional measures.
动脉压力波形是多种相互作用的综合体现，与失血性休克和血管内容量减少相关的特征可能比单纯的收缩压和/或舒张压更敏感、更具特异性。本研究旨在描述不同程度出血时的动脉压力波形特征。
十只麻醉的猪（70 - 90千克）经历了40%的控制性指数出血。收集高保真动脉波形数据（500赫兹），并使用信号处理技术提取关键特征。回归建模用于评估随时间的趋势。短时傅里叶变换（STFT）用于评估波形频率和功率谱密度方差。
所有动物均耐受仪器植入和出血过程。在逐渐出血过程中，初级前向波（P1）相对保持，而肾（P2）和髂（P3）反射波明显衰减。几个特征反映了收缩压和舒张压的变化，并在大约20%出血时趋于平稳，最适合用非线性S形回归建模。在逐渐出血过程中，P1:P3比值持续变化（R = 0.51）。通过STFT分析逐渐出血过程中的前三个谐波，结果表明，对于频率（分别为R = 0.70、0.93和0.76）和功率谱密度（分别为R = 0.90、0.90和0.59），使用线性回归时，方差随着较高的决定系数而增加。
在这个容量控制性出血的猪模型中，低血压是主要的早期特征。虽然大多数波形特征反映了血压特征，但尽管传统测量变化不大，特定特征如方差可能能够区分不同程度的出血。
