Figure 61-5 Pulmonary artery oxygen saturation (SVO₂ ) during total-hip replacement is recorded from an oximetric pulmonary artery catheter (American Edwards, Baxter Healthcare Corporation, Irvine, CA). Notice the acute fall in pulmonary artery oxygen saturation after relocation of the hip at minute 62 after trial reduction (T) with 8 minutes of potential venous occlusion and minute 74 after final reduction (F) with 12 minutes of potential venous occlusion. (Adapted from Sharrock NE, Go G, Harpel PC, et al: The John Charnley Award. Thrombogenesis during total hip arthroplasty. Clin Orthop 319:16–27, 1995.)