Department of Anesthesiology, Heidelberg University Hospital, Heidelberg, Germany.
Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany.
Microvasc Res. 2021 Jul;136:104164. doi: 10.1016/j.mvr.2021.104164. Epub 2021 Apr 6.
Microcirculatory alterations are key mechanisms in sepsis pathophysiology leading to tissue hypoxia, edema formation, and organ dysfunction. Hyperspectral imaging (HSI) is an emerging imaging technology that uses tissue-light interactions to evaluate biochemical tissue characteristics including tissue oxygenation, hemoglobin content and water content. Currently, clinical data for HSI technologies in critical ill patients are still limited.
TIVITA® Tissue System was used to measure Tissue oxygenation (StO2), Tissue Hemoglobin Index (THI), Near Infrared Perfusion Index (NPI) and Tissue Water Index (TWI) in 25 healthy volunteers and 25 septic patients. HSI measurement sites were the palm, the fingertip, and a suprapatellar knee area. Septic patients were evaluated on admission to the ICU (E), 6 h afterwards (E+6) and three times a day (t3-t9) within a total observation period of 72 h. Primary outcome was the correlation of HSI results with daily SOFA-scores.
Serial HSI at the three measurement sites in healthy volunteers showed a low mean variance expressing high retest reliability. HSI at E demonstrated significantly lower StO2 and NPI as well as higher TWI at the palm and fingertip in septic patients compared to healthy volunteers. StO2 and TWI showed corresponding results at the suprapatellar knee area. In septic patients, palm and fingertip THI identified survivors (E-t4) and revealed predictivity for 28-day mortality (E). Fingertip StO2 and THI correlated to SOFA-score on day 2. TWI was consistently increased in relation to the TWI range of healthy controls during the observation time. Palm TWI correlated positively with SOFA scores on day 3.
HSI results in septic patients point to a distinctive microcirculatory pattern indicative of reduced skin oxygenation and perfusion quality combined with increased blood pooling and tissue water content. THI might possess risk-stratification properties and TWI could allow tissue edema evaluation in critically ill patients.
HSI technologies could open new perspectives in microcirculatory monitoring by visualizing oxygenation and perfusion quality combined with tissue water content in critically ill patients - a prerequisite for future tissue perfusion guided therapy concepts in intensive care medicine.
微循环改变是导致组织缺氧、水肿形成和器官功能障碍的脓毒症病理生理学的关键机制。高光谱成像（HSI）是一种新兴的成像技术，它利用组织-光相互作用来评估包括组织氧合、血红蛋白含量和含水量在内的组织生化特性。目前，关于危重患者 HSI 技术的临床数据仍然有限。
使用 TIVITA® Tissue System 在 25 名健康志愿者和 25 名脓毒症患者中测量组织氧饱和度（StO2）、组织血红蛋白指数（THI）、近红外灌注指数（NPI）和组织水指数（TWI）。HSI 测量部位为手掌、指尖和髌上膝部。脓毒症患者在 ICU 入院时（E）、6 小时后（E+6）以及 72 小时的观察期内每天测量 3 次（t3-t9）。主要结局是 HSI 结果与每日 SOFA 评分的相关性。
健康志愿者在三个测量部位的连续 HSI 显示出较低的平均值方差，表明具有较高的复测可靠性。与健康志愿者相比，脓毒症患者的 E 时手掌和指尖的 StO2 和 NPI 以及 TWI 明显较低。髌上膝部的 StO2 和 TWI 也有相应的结果。在脓毒症患者中，手掌和指尖 THI 可以区分存活者（E-t4），并预测 28 天死亡率（E）。指尖 StO2 和 THI 与第 2 天的 SOFA 评分相关。TWI 在观察期间始终与健康对照组的 TWI 范围一致增加。手掌 TWI 与第 3 天的 SOFA 评分呈正相关。
脓毒症患者的 HSI 结果表明，皮肤氧合和灌注质量降低，伴有血液淤积和组织含水量增加，这表明存在独特的微循环模式。THI 可能具有风险分层特性，TWI 可用于评估危重症患者的组织水肿。
HSI 技术可以通过可视化危重患者的氧合和灌注质量以及组织含水量来提供微循环监测的新视角，这是重症监护医学中组织灌注导向治疗概念的前提。
