Stimulating catheters for continuous femoral nerve blockade after total knee arthroplasty: a randomized, controlled, double-blinded trial.

BACKGROUND: Continuous femoral nerve blockade (CFNB) is often used for postoperative analgesia after total knee arthroplasty (TKA). CFNB can be instituted using a variety of techniques. Stimulating catheters (SC) have the advantage of confirming placement of the catheter close to the nerve during advancement. METHODS: In this randomized, controlled, double-blind trial, we compared a SC with a nonstimulating catheter (NSC) technique for institution of CFNB and its effects on quality of analgesia after TKA performed under general anesthesia in 82 patients. Patients were randomized to have CFNB instituted using either a NSC or a SC technique. Sensory blockade was assessed 10 and 20 min after injection of lidocaine via femoral catheter and on postoperative days 1 (POD 1) and 2 (POD 2). A standardized multimodal analgesic technique, including a single injection sciatic block (preoperative), i.v. morphine (patient-controlled analgesia), celecoxib, and paracetamol, was administered to all patients. Outcome variables included morphine requirements, pain scores, and markers of early recovery. RESULTS: The proportion of patients with sensory blockade in the femoral nerve distribution was between 90% and 95% at all measurement times with no difference between groups. In the first 24 h, the NSC group required 19.5 (1-67) [median (10th-90th centiles)] mg morphine compared with the SC Group 18 (2-51) mg (P = 0.69). At 24 h, the 95% confidence interval for difference in morphine consumption between groups was -8 to 5 mg. There was no difference between groups in visual analog scale scores at rest on POD 1 and POD 2, during active and passive physiotherapy; and in markers of early recovery after surgery. CONCLUSIONS: In this study, blind catheter advancement was as reliable as a SC technique for establishing and maintaining CFNB for postoperative analgesia as a part of multimodal analgesia technique after TKA.

Epsilon-aminocaproic acid in coronary artery bypass graft surgery: preincision or postheparin?

BACKGROUND: Epsilon-aminocaproic acid (epsilon-ACA), an antifibrinolytic agent, is used in cardiac surgery to decrease postoperative bleeding. Theoretical concerns exist about the potential for epsilon-ACA to contribute to thrombotic complications. For this reason epsilon-ACA administration is sometimes delayed until after heparinization. This study investigated the impact of the timing of epsilon-ACA administration on its efficacy. METHODS: In this double-blind study, 90 patients undergoing primary coronary artery bypass graft surgery were prospectively randomized to receive either epsilon-ACA commencing prior to skin incision (bolus 150 mg/kg, followed by an infusion at 15 mg x kg(-1) x hr(-1), epsilon-ACA commencing after heparin (same doses), or placebo. All infusions were terminated at the end of cardiopulmonary bypass. Criteria for the transfusion of blood products were standardized. Postoperative chest tube drainage (at 6 h, 12 h, and at chest tube removal) and blood transfusion requirements of the three groups were compared. RESULTS: At all time intervals, the placebo group had significantly greater chest tube drainage than either of the two epsilon-ACA groups (P < 0.005). At no time did a significant difference exist between the two epsilon-ACA groups. A trend existed for the placebo group to require more blood products than either epsilon-ACA group. CONCLUSIONS: Epsilon-ACA produces a reduction in chest tube drainage in patients undergoing primary coronary artery bypass graft surgery. This effect is similar whether the drug is given prior to incision or following anticoagulation. Given the similar hemostatic efficacy and the theoretical potential for thrombotic complications, it may be prudent to administer epsilon-ACA following anticoagulation.