Continuous blockade of the lumbar plexus after knee surgery: a comparison of the plasma concentrations and analgesic effect of bupivacaine 0.250% and 0.125%.
In 20 patients a continuous block of the lumbar plexus was administered after knee-joint surgery, and the analgesic effect of two different concentrations of bupivacaine was compared. The same volume of bupivacaine was given to both groups of patients: a bolus dose of 0.4 ml/kg, 0.5% or 0.25%, followed by infusion of 0.14 ml/kg/h, 0.25% or 0.125%, respectively, via a catheter placed in the neurovascular fascial sheath of the femoral nerve according to the "3-in-1 block" technique. The median morphine consumption during the first 16 h postoperatively was 6.0 mg when bupivacaine 0.5/0.25% was used and 9.5 mg when 0.25/0.125% was used. This difference is not significant. The visual analogue pain scores were also similar in the two groups (P greater than 0.05). All plasma concentrations were below 4 micrograms/ml, the highest concentration measured being 3.6 micrograms/ml. It is concluded that when used for a continuous block of the lumbar plexus after knee-joint surgery, bupivacaine in a concentration of 0.125% offers the same pain relief as a concentration of 0.25%, and the risk of toxic reactions is reduced.
Anker-Møller
E
E
Department of Anesthesiology, Arhus Amtssygehus, University Hospital, Denmark.
Spangsberg
N
N
Dahl
J B
JB
Christensen
E F
EF
Schultz
P
P
Carlsson
P
P
D000328:Adult; D002045:Bupivacaine / Q000008:administration & dosage* / Q000097:blood; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008160:Lumbosacral Plexus / Q000187:drug effects*; D008297:Male; D009407:Nerve Block; D010149:Postoperative Pain / Q000517:prevention & control*; D013997:Time Factors
D002045:Bupivacaine