Parmet J L, Horrow J C, Berman A T, Miller F, Pharo G, Collins L
Department of Anesthesiology, Allegheny University of the Health Sciences, Hahnemann Division, Philadelphia, Pennsylvania, USA.
Anesth Analg. 1998 Aug;87(2):439-44. doi: 10.1097/00000539-199808000-00039.
Echogenic venous emboli accompany tourniquet deflation during total knee arthroplasty. Two types of echogenic emboli appear in the central circulation: small venous emboli (miliary emboli) and large venous emboli (masses of echogenic material superimposed on miliary emboli). Presumably, medullary cavity trespass releases small and large echogenic emboli. However, patients undergoing lower extremity procedures with a tourniquet have large echogenic emboli regardless of medullary cavity invasion. Avoiding tourniquet inflation may decrease the release of large venous emboli. Thirteen patients undergoing total knee arthroplasty without pneumatic tourniquet received intramedullary guides and 11 patients received tibial extramedullary guides. Recordings of hemodynamic variables, mixed venous oximetry, end-tidal CO2, and echocardiographic images were made after the induction of anesthesia and for 15 min after femoral prosthesis cementing. Mean arterial pressure did not change during the study, and mean pulmonary arterial pressure increased minimally. Large venous emboli appeared in eight patients, small venous emboli appeared in 12 patients, and no emboli appeared in four patients. Compared with previous investigations of large venous emboli during total knee arthroplasty with a pneumatic tourniquet, multiple logistic regression analysis discloses a 5.33-fold greater risk of large venous embolism accompanied the use of a tourniquet during total knee arthroplasty.
One third of knee replacements performed without a tourniquet demonstrated large emboli. Reducing marrow cavity invasion did not decrease the release of large emboli. Compared with knee replacement without tourniquet, tourniquet use places patients at a 5.33-fold greater risk of having a large emboli.
全膝关节置换术中止血带放气时会出现回声增强的静脉栓子。两种类型的回声增强栓子出现在体循环中：小静脉栓子（粟粒样栓子）和大静脉栓子（叠加在粟粒样栓子上的回声增强物质团块）。据推测，髓腔侵入会释放小的和大的回声增强栓子。然而，接受下肢止血带手术的患者无论是否有髓腔侵犯都会出现大的回声增强栓子。避免使用止血带充气可能会减少大静脉栓子的释放。13例接受全膝关节置换术且未使用气动止血带的患者接受了髓内导向器，11例患者接受了胫骨髓外导向器。在麻醉诱导后以及股骨假体骨水泥固定后15分钟记录血流动力学变量、混合静脉血氧饱和度、呼气末二氧化碳和超声心动图图像。研究期间平均动脉压未发生变化，平均肺动脉压略有升高。8例患者出现大静脉栓子，12例患者出现小静脉栓子，4例患者未出现栓子。与先前对使用气动止血带的全膝关节置换术中大静脉栓子的研究相比，多因素逻辑回归分析显示，全膝关节置换术中使用止血带伴随大静脉栓塞的风险高5.33倍。
三分之一未使用止血带进行的膝关节置换术出现了大栓子。减少髓腔侵入并未减少大栓子的释放。与未使用止血带的膝关节置换术相比，使用止血带使患者出现大栓子的风险高5.33倍。
