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

Abstract

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.