Tujjar Omar, De Gaudio Angelo Raffaele, Tofani Lorenzo, Di Filippo Alessandro
Department of Health Sciences, Section of Anaesthesia, Intensive Care and Pain Therapy, Careggi University Hospital, University of Florence, Largo Brambilla 3, 50124, Florence, Italy.
Department of Neurosciences, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy.
J Clin Monit Comput. 2017 Jun;31(3):581-588. doi: 10.1007/s10877-016-9877-x. Epub 2016 Apr 12.
Near-infrared spectroscopy (NIRS) has been used to detect in vivo microvascular alterations by means of a vascular occlusion test. We sought to analyse by NIRS the microcirculatory profile of patients undergoing prolonged tourniquet-induced bloodless condition for extremity surgery, and compare the results with time of ischemia and comorbidities. We conducted a prospective observational study on 42 patients undergoing upper limb surgery. Regional anaesthesia was achieved and ischemia was induced by a tourniquet cuffed at 250 mmHg. The probe of a NIRS monitor (InSpectra 325, Hutchiston, USA) was placed on the brachial muscle, and muscle oxygen saturation (StO) was recorded continuously before anaesthesia, during and after surgery. The following variables were recorded: baseline StO, StO desaturation slope during occlusion (dSlope, units/s), resaturation rate following ischemia (RR, units/s), hyperaemic peak (peak, units), and duration of the hyperaemic period following ischemia (hyperaemic time, s). Values of dSlope were similar among all patients. RR and hyperaemic time were significantly correlated with the duration of ischemia, but not with comorbidities [p = 0.007 CI (-35.64 to -13.1), and p < 0.001 CI (0.049-0.159), respectively]. Grouping patients by duration of ischemia (30, 60, or 90 min), we found a significant decrease in RR after 60 and 90 min (p < 0.001 and p = 0.03, respectively). Hyperaemic peak was lower in the 90 min group (83.9 ± 6.8 vs. 91.2 ± 5.7 %, p = 0.02) whereas the hyperaemic time was significantly increased (595 ± 136 vs. 429 ± 107 min, p < 0.001). Alterations of skeletal muscle microcirculation were correlated with the duration of ischemia, but not with comorbidities. We observed an initial impairment of the microcirculatory recovery at 90 min of ischemia.
近红外光谱技术（NIRS）已被用于通过血管闭塞试验检测体内微血管变化。我们试图通过NIRS分析接受长时间止血带诱导的肢体无血状态以进行肢体手术的患者的微循环情况，并将结果与缺血时间和合并症进行比较。我们对42例接受上肢手术的患者进行了一项前瞻性观察研究。采用区域麻醉，通过充气至250 mmHg的止血带诱导缺血。将NIRS监测仪（美国哈钦斯顿的InSpectra 325）的探头置于肱二头肌上，在麻醉前、手术期间和手术后连续记录肌肉氧饱和度（StO）。记录以下变量：基线StO、闭塞期间的StO去饱和斜率（dSlope，单位/秒）、缺血后的再饱和率（RR，单位/秒）、充血峰值（peak，单位）以及缺血后充血期的持续时间（充血时间，秒）。所有患者的dSlope值相似。RR和充血时间与缺血持续时间显著相关，但与合并症无关[分别为p = 0.007，置信区间（-35.64至-13.1），以及p < 0.001，置信区间（0.049 - 0.159）]。根据缺血持续时间（30、60或90分钟）对患者进行分组，我们发现60分钟和90分钟后RR显著降低（分别为p < 0.001和p = 0.03）。90分钟组的充血峰值较低（83.9 ± 6.8%对91.2 ± 5.7%，p = 0.02），而充血时间显著延长（595 ± 136对429 ± 107分钟，p < 0.001）。骨骼肌微循环的改变与缺血持续时间相关，但与合并症无关。我们观察到在缺血90分钟时微循环恢复出现初始损害。
