0.5% levobupivacaine versus 0.5% ropivacaine: Are they different in ultrasound-guided sciatic block?

CONTEXT AND AIMS: Little is known about onset and duration of sciatic block after 0.5% levobupivacaine (Levo) versus 0.5% ropivacaine (Ropi) for ultrasound-guided technique. We assessed these parameters in the ultrasound-guided block, to know for the practice. SETTING AND DESIGN: A comparative randomized double-blind study was conducted in the University Hospital. MATERIALS AND METHODS: Were included 35 adults of ASA I-II, scheduled for foot surgery, presenting clear imaging of their sciatic nerve at mid-thigh. A volume of 20 mL of either 0.5% Levo or 0.5% Ropi were injected around the sciatic nerve at mid-thigh using ultrasound guidance (out of the plane) followed by placement of a catheter to use, if necessary, for perioperative analgesia. A femoral single shot block was systematically performed to block the saphenous nerve. The onset times until complete foot block (primary outcome) and the sensory and motor block duration (secondary outcome) were assessed using Wilcoxon test. Values were expressed as medians (1(st)-3(rd) quartile). RESULTS: Except for two delayed sciatic blocks in each group, the onset time otherwise was 35 min (20-60) in Ropi versus 40 min (30-60) in Levo, P = 0.5. Sensory block lasted longer in Levo, 17 h (14-27) compared with 15 h (10-17) in Ropi, P = 0.04. No significant between-group difference was found with motor block durations, 15 h (12-18) in Levo and 15 h (12-16) in Ropi, P = 0.3. CONCLUSION: No difference of onset times was found in ultrasound-guided sciatic block whether using Levo or Ropi. Levo induced a longer-lasting sensory block.

Preoperative moderate renal impairment is an independent risk factor of transfusion in elderly patients undergoing hip fracture surgery and receiving low-molecular-weight heparin for thromboprophylaxis.

STUDY OBJECTIVE: To define the risk factors of allogeneic erythrocyte transfusion in patients older than 65 years of age who underwent hip fracture surgery. DESIGN: Retrospective, single-center study. SETTING: Orthopedic unit of a university hospital. MEASUREMENTS: The records of 413 consecutive patients undergoing hip fracture surgery over a 12-month period and receiving low-molecular-weight heparin (LMWH) for thromboprophylaxis were retrospectively reviewed. Preoperative independent predictors of transfusion were determined by multivariate analysis, from which a model of individual probability of transfusion was derived using creatinine clearance calculated by Cockroft-Gault (CG) and the Modification of Diet in Renal Disease (MDRD) formulas. MAIN RESULTS: Using the CG and MDRD formulas, 56.9% and 50.1% of patients had moderate renal impairment that was an independent factor associated with transfusion, with adjusted odds ratios of 2.44 (1.49 - 4.02) and 2.35 (1.32 - 4.18), respectively. Other factors were fracture with trochanteric extension, preoperative hemoglobin (Hb) < 12 g/dL, and weight. The observed transfusion rate and probability of transfusion calculated with the regression logistic model were well correlated: y = 0.9534x + 0.0287, P < 0.0001, Pearson coefficient 0.988, goodness of fit, χ(2), P = 1 with CG; y = 0.9197x + 0.0504, P < 0.0001, Pearson coefficient 0.956, goodness of fit, χ(2), P = 1 with MDRD). CONCLUSION: This predictive model may be useful to identify those elderly patients undergoing hip fracture repair who are at risk of blood transfusion.

Is there any need for expanding the perineural space before catheter placement in continuous femoral nerve blocks?

BACKGROUND AND OBJECTIVE: There is debate regarding the benefit of perineural space expansion before catheter placement in continuous femoral nerve block. This question is addressed in this prospective, comparative, and randomized study. METHODS: Sixty patients scheduled for total knee replacement were randomly assigned to receive continuous femoral nerve block with or without perineural space expansion using 10 mL dextrose 5% in water (D5W) flush before stimulation-guided catheter placement. Femoral block was initiated with a 5-mL bolus followed by an infusion of 5 mL/h ropivacaine 0.2% during the 2-hour surgery. The number of attempts before successful placement of the stimulating catheter and the resistance during its insertion were assessed. Patients also received obturator nerve blocks by using ropivacaine 0.75% (10 mL) and sciatic nerve blocks (20 mL). The number of boluses of ropivacaine 0.2% needed to achieve zero VAS scoring was recorded in the postanesthesia care unit during the 2-hour stay. Images of the contrast spread were also studied. RESULTS: There were 30 patients in each group. The number of successful catheter placements at the first attempt was higher with expansion than without (22 vs. 8, P = .007). The resistance felt during insertion was lower with than without expansion (P = .01). More boluses of ropivacaine were required postoperatively without expansion (P = .03). No difference between groups was found regarding the images of the contrast spread. CONCLUSION: Expansion of the perineural space with D5W is useful for catheter placement in continuous femoral nerve block.