Scully Christopher G, Kramer George C, Strauss David G
*Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland; and †Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas.
Shock. 2015 May;43(5):463-9. doi: 10.1097/SHK.0000000000000340.
Individual responses to hemorrhage vary, with varying periods of compensation before the development of shock. We characterized heart rate and blood pressure variability measures during hemorrhage of 25 mL/kgBody Weight for 15 min in conscious sheep (N = 7, 14 total hemorrhages) as markers of the transition from compensated to decompensated shock using the continuous wavelet transform. Heart rate-low frequency (HR-LF) and systolic blood pressure-low frequency (SBP-LF) indices were developed to represent the change in spectral power during hemorrhage as low-frequency (0.06 - 0.15 Hz) power divided by the sum of high (0.15 - 1.0 Hz)- and very low (0.02 - 0.06 Hz) frequency power. Heart rate rose from 96.3 (22.2) beats/min (mean [SD] across all trials) to a peak of 176.0 (25.4) beats/min occurring at a minimum time of 5.3 min to a maximum of 22.1 min (11.7 [1.6] min), depending on the trial, after the start of hemorrhage. During the HR-compensated response to hemorrhage, there was elevated HR-LF and SBP-LF in five of the seven animals. In these animals, HR-LF and SBP-LF dropped to below baseline levels around the time of the peak HR. The results from this conscious-animal study suggest that HR and SBP low-frequency power rise during the compensation phase of the response to hemorrhage in conscious sheep. Use of variability monitoring could aid in describing an individual's current response to hemorrhage and anticipation of impending decompensation; however, individual differences in the response limit this potential.
个体对出血的反应各不相同，在休克发生前有不同的代偿期。我们利用连续小波变换，将清醒绵羊（N = 7，共14次出血）以25 mL/kg体重的量出血15分钟期间的心率和血压变异性测量值，作为从代偿性休克向失代偿性休克转变的标志物。开发了心率低频（HR-LF）和收缩压低频（SBP-LF）指数，以表示出血期间频谱功率的变化，即低频（0.06 - 0.15 Hz）功率除以高频（0.15 - 1.0 Hz）和极低频（0.02 - 0.06 Hz）功率之和。心率从所有试验的平均[标准差]96.3（22.2）次/分钟升至峰值176.0（25.4）次/分钟，出现在出血开始后的最短5.3分钟至最长22.1分钟（11.7 [1.6]分钟），具体取决于试验。在对出血的心率代偿反应期间，7只动物中有5只的HR-LF和SBP-LF升高。在这些动物中，HR-LF和SBP-LF在心率峰值前后降至基线水平以下。这项清醒动物研究的结果表明，在清醒绵羊对出血反应的代偿期，HR和SBP低频功率升高。使用变异性监测有助于描述个体当前对出血的反应以及预测即将发生的失代偿；然而，个体反应的差异限制了这种潜力。
