Nh. Badner et al., CONTINUOUS EPIDURAL INFUSION OF ROPIVACAINE FOR THE PREVENTION OF POSTOPERATIVE PAIN AFTER MAJOR ORTHOPEDIC-SURGERY - A DOSE-FINDING STUDY, Canadian journal of anaesthesia, 43(1), 1996, pp. 17-22
Purpose: A dose-finding study to investigate the use of epidural infus
ions of ropivacaine for postoperative analgesia following orthopaedic
surgery. Methods: This was a randomized, double-blind study. Surgery w
as performed using a combination of a lumbar epidural block utilizing
ropivacaine 0.5% and a standardized general anaesthetic. Postoperative
ly, an epidural infusion of the study solution (saline, ropivacaine 0.
1%, 0.2% or 0.3%) was started at the rate of 10 ml . hr(-1) and contin
ued for 21 hr after arrival in the PACU. Analgesia was supplemented wi
th PCA morphine (dose = 1.0 mg, lock-out = 5 min). Results: Forty-four
patients completed the study. The ropivacaine 0.1%, 0.2%, 0.3% groups
required less morphine over the 21 hr than the saline group (P < 0.01
). The VAS pain scores were also lower in the three ropivacaine groups
(P < 0.001). The ropivacaine groups maintained sensory anaesthesia to
pinprick when compared with saline (P < 0.05). The motor block in the
0.3% group was significantly higher than the saline group at all time
s (P < 0.05), and higher than the 0.1% group at eight hours (P < 0.01)
, while the 0.2% group had higher Bromage scores than saline at 4 and
21 hr (P < 0.05). Conclusions: The use of continuous epidural infusion
s of ropi vacaine 0.1%, 0.2% and 0.3% at 10 ml . hr(-1) improved posto
perative pain relief and decreased PCA morphine requirements in patien
ts undergoing major orthopaedic surgery. The 0.1% and 0.2% concentrati
ons produced similar sensory anaesthesia with less motor blockade than
the 0.3% concentration.