Embolism Detected By Transoesophageal Echocardiography Druing Cemented Total Knee Replacement

Objective: To explore the incidence, timing, frequency, denseness,histological origin and its effects of the intraoperative ultrasound embolusin the right atrium on respiratory and circulatory system during cementedtotal knee replacement.Methods: We studied13patients undergoing cemented total kneereplacement under general anesthesia(GA)．All implants are posteriorcruciate ligament replacement cemented total knee prosthesis (RP or RPF,DePuy). In the surgery without an Esmarch bandage, the tourniquetpressure is350mmHg. All were entered through medial parapatellarcapsular approach, adopt tibia osteotomy in advance, and then distalfemoral osteotomy. After the drilling of the femur, immediately aspiratedmyeloid tissue with vacuum suction tube, then, inserted theintramedullary rod with a groove after a flushing with50ml saline and aclean aspiration, and make vacuum suction tube a clean aspiration afterthe insertion of tibia stem punch. All cases had no patellar resurfacing. Allthe surgeries were done within75minutes. Inserted the esophagus with multidimensional TEE adult probe(Vivid S6TEE), adjusted depth of theprobe in appropriate scanning angle and got the image of four chambersof heart at the following times: within1minutes before the tourniquetwas prepared to inflate, within3minutes after the tourniquet begins toinflate, within3minutes after the beginning of the drilling of femur,within5minutes after the beginning of implantation prosthesis, within15minutes after the tourniquet began to deflate. Record HR, SBP, DBPSpO2and ETCO2at the following times:5minutes before the tourniquetwas prepared to inflate,5minutes after its inflation, drilling of femur,5minutes after implanting prosthesis, the tourniquet prepared to deflate,and5minutes after the deflation. Collecting the blood from radial arteryfor arterial blood gas analysis in order to observe changes of oxygenationindex (PaO2/FiO2) and PCO2at the following times: before the tourniquetwas prepared to inflate,5minutes after the drilling of the femur,5minutes after the tourniquet began to deflate and at the end of operation.The haemodynamic and respiratory variables were processed by repeatedmeasures of analysis of variance. When differences were found, theLeast-Signifiant-Differenee test was performed for multicomparison. Thegrades of emboli detected by TEE were analysed by Friedman rank sumtest. When differences were found, Wilcoxon rank sum test wasperformed for multicomparison. Correlation analysis was analyzed usingthe spearman’s rank correlation. Results: All enrolled patients had successfully completed theanesthesia, surgery, and intraoperative monitoring indicators, and duringthe intraoperative TEE monitoring, all patients hadn’t been foundcongenital abnormalities of cardiac structure such as patent foramenovale. Emboli image hadn’t been found before the tourniquet inflated,either of the3minutes after the tourniquet inflated. There were2casesthat emboli were started to observed when inserting the intramedullaryrod and4cases during the implantation of prosthesis. Emboli weremonitored from all the patients after the tourniquet released, which form aslow peak with a gradual decline law. In the1minute of the tourniquetdeflated, emboli were the most obvious, and reaching a peak about40seconds, and then emboli basically disappeared within5minutes amongall cases. If knee flexion and extension, in some cases, small emboliwould appear again. After the tourniquet released monitoring, echogenicemboli of grade3was detected in3patients, approximately one in thesize of2.0×2.0cm2was like cotton wads. These “cotton wads” floatedand jiggled in the atria for a few seconds and then disappeared into thedownstream. HR、SpO2, ETCO2, DBP and PCO2varied little throughoutthe operation(P>0.05); However, SBP and PaO2/FiO2markedlydecreased after5minutes of the tourniquet deflated compared to the timebefore the tourniquet inflated (P <0.05). The grades of emboli SBP,PaO2/FiO2was negatively correlated. Most patients could tolerate the systolic blood pressure and oxygenation index changes, but2cases,which were detected with echogenic emboli of grade3needed to treatwith vasopressors and increasing the oxygen concentration.Conclusion:1. Emboli can be found in chambers of heart duringcemented total knee replacement (with a tourniquet). The large emboliwill appear in individual patients after the tourniquet deflated.2. Emboliare very obvious after a tourniquet deflated started within one minute3.After a tourniquet deflating, decreased blood pressure and oxygenationindex are often accompanied, and most patients may be able to withstandsuch changes.4. TEE can be used as a means for emboli monitoringduring TKR.