[Patient controlled analgesia reduces the consumption of bupivacaine in femoral nerve block for the treatment of postoperative pain after reconstruction of anterior cruciate ligament of the knee].
OBJECTIVE
Continuous femoral nerve block (CFNB) is used in postoperative analgesia of hip and knee replacement surgeries with good results. The objective of this study was to evaluate the usefulness of CFNB, comparing 3 administration schedules of bupivacaine in the arthroscopic anterior cruciate ligament (ACL) repair of the knee.


METHODS
A prospective, controlled study with 90 stable patients, physical status ASA I and II was undertaken. Patients were divided in three groups: Group 1 (n = 30): continuous infusion (CI) at a rate of 10 mL.h-1 of 0.125% bupivacaine + clonidine 1 microg.ml-1 (B+C); Group 2 (n = 30): CI at a rate of 5 mL.h-1 + PCA with 2.5 ml of B+C every 30 minutes; Group 3 (n = 30): PCA with 5 mL.h-1 of B+C every 30 minutes. Patients underwent spinal anesthesia. Postoperative pain at 2, 4, 6, 24, and 48 hours, using the Visual Analogue Scale (VAS), and consumption of morphine and bupivacaine were recorded.


RESULTS
There were no statistically significant differences regarding the demographic data in both groups. The postoperative VAS between 2 and 48 hours did not show any differences. Morphine consumption between 4 and 48 hours was similar in all 3 groups (p = 0.07). The consumption of bupivacaine was significantly lower in the group that used only PCA (p < 0.001).


CONCLUSIONS
Continuous femoral nerve block is a useful technique to manage postoperative pain after ACL repair. A rate of 5 mL.h-1 in CI or PCA boluses assures excellent postoperative analgesia.
Contreras-Domínguez
Victor A
VA
Universidad de Concepción, Chile. viccontredom@yahoo.com
Carbonell-Bellolio
Paulina E
PE
Ojeda-Greciet
Alvaro C
AC
Sanzana
Edgardo S
ES