Quantification and comparison of pulmonary emboli formation after pneumatic tourniquet release in patients undergoing reconstruction of anterior cruciate ligament and total knee arthroplasty.

UNLABELLED: The amount of emboli formed (percentage of total emboli area to the right atrial area [%Ae]) after tourniquet release in invasive procedures of the medullary cavity is empirically much larger than that in noninvasive procedures, even if the tourniquet duration is similar. Thus, we compared %Ae between arthroscopic reconstruction of the anterior cruciate ligament (ACL, n = 20) and total knee arthroplasty (TKA, n = 20). The right atrium was continuously monitored by transesophageal echocardiography to assess %Ae. Peak %Ae +/- SD (ACL, 4.1% +/- 3.4%; TKA, 20.7% +/- 16.7%) appeared 30-40 s after tourniquet release in both groups. However, %Ae in the TKA group was always larger than the peak %Ae in the ACL group. In addition, although the ET(CO(2)) significantly increased after tourniquet release in both groups, increase of ET(CO(2)) (1.1% +/- 0.3%) in the ACL group was significantly larger than that in the TKA group (0.5% +/- 0.2%). An increase in ET(CO(2)) was inversely proportional to peak %Ae (P < 0.01; r = 0.703). Therefore, the present data suggest that the risk of acute pulmonary embolism after tourniquet release may be more frequent during TKA than ACL. IMPLICATIONS: We compared emboli formation after tourniquet release in patients undergoing arthroscopic reconstruction of the anterior cruciate ligament (ACL, n = 20) and total knee arthroplasty (TKA, n = 20) using transesophageal echocardiography. The present data suggest that the risk of acute pulmonary embolism after tourniquet release could be more frequent during TKA than ACL.