Department of Anesthesiology and Critical Care, Karadeniz Technical University, Faculty of Medicine, Trabzon, Turkey,
Department of Anesthesiology and Critical Care, Karadeniz Technical University, Faculty of Medicine, Trabzon, Turkey.
Med Princ Pract. 2019;28(1):16-22. doi: 10.1159/000495110. Epub 2018 Nov 5.
The aim of this study was to determine whether an early increase in intracranial pressure (ICP) following the deflation of a tourniquet is related to the tourniquet time (TT) or tourniquet pressure (TP) and to identify a safe cut-off value for TT or TP.
Patients who underwent elective orthopedic lower-extremity surgery under general anesthesia were randomized into 2 groups: group A (inflation with a pneumatic TP of systolic blood pressure + 100 mm Hg; n = 30) and group B (inflation using the arterial occlusion pressure formula; n = 30). The initial and maximum TPs, TT, and sonographic measurements of optic-nerve sheath diameter (ONSD) and end-tidal CO2 values were taken at specific time points (15 min before the induction of anesthesia, just before, and 5, 10, and 15 min after the tourniquet was deflated).
The initial and maximum TPs were found to be significantly higher in group A than in group B. At 5 min after the tourniquet deflation, there was a significant positive correlation between TT and ONSD (r = 0.57, p = 0.0001). When ONSD ≥5 mm was taken as a standard criterion, the safe cut-off value for the optimal TT was found to be < 67.5 min (sensitivity 87% and specificity 59.5%).
The ICP increase in the early period after tourniquet deflation was well correlated with TT but not with TP. TT of ≥67.5 min was found to be the cut-off value and is considered the starting point of the increase in ICP after tourniquet deflation.
本研究旨在确定止血带放气后颅内压（ICP）的早期升高是否与止血带时间（TT）或止血带压力（TP）有关，并确定 TT 或 TP 的安全截止值。
接受全身麻醉下择期骨科下肢手术的患者随机分为 2 组：A 组（充气时使用收缩压+100mmHg 的气动 TP；n=30）和 B 组（使用动脉闭塞压公式充气；n=30）。在特定时间点（麻醉诱导前 15 分钟、止血带充气前、放气后 5、10 和 15 分钟）测量初始和最大 TPs、TT 以及视神经鞘直径（ONSD）和呼气末 CO2 值的超声测量值。
发现 A 组的初始和最大 TPs 明显高于 B 组。止血带放气后 5 分钟时，TT 与 ONSD 呈显著正相关（r=0.57，p=0.0001）。当 ONSD≥5mm 作为标准标准时，发现最佳 TT 的安全截止值<67.5min（灵敏度 87%，特异性 59.5%）。
止血带放气后早期 ICP 升高与 TT 密切相关，但与 TP 无关。TT≥67.5min 被认为是 ICP 升高的起始点。
