Continuous epidural infusion of ropivacaine for the prevention of postoperative pain after major orthopaedic surgery : a dose-finding study

• Published in: Canadian journal of anesthesia Vol. 43; no. 1; pp. 17 - 22
• Main Authors: BADNER, N. H, REID, D, SULLIVAN, P, GANAPATHY, S, CROSBY, E. T, MCKENNA, J, LUI, A
• Format: Journal Article
• Language: English
• Published: Toronto, ON Canadian Anesthesiologists' Society 1996
• Subjects: Adult; Aged; Amides - administration & dosage; Analgesia, Epidural; Anesthetics, Local - administration & dosage; Anesthetics. Neuromuscular blocking agents; Biological and medical sciences; Dose-Response Relationship, Drug; Double-Blind Method; Female; Humans; Male; Medical sciences; Middle Aged; Neuropharmacology; Orthopedics; Pain, Postoperative - prevention & control; Pharmacology. Drug treatments; Local anesthetic; Postoperative; Analgesia; Regional anesthesia; Orthopedic surgery; Pain; Treatment; Perfusion; Extradural administration; Dose activity relation
• ISSN: 0832-610X; 1496-8975
• DOI: 10.1007/BF03015952

A dose-finding study to investigate the use of epidural infusions of ropivacaine for postoperative analgesia following orthopaedic surgery.
This was a randomized, double-blind study. Surgery was performed using a combination of a lumbar epidural block utilizing ropivacaine 0.5% and a standardized general anaesthetic. Postoperatively, 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 continued for 21 hr after arrival in the PACU. Analgesia was supplemented with PCA morphine (dose = 1.0 mg, lock-out = 5 min).
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 times (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).
The use of continuous epidural infusions of ropivacaine 0.1%, 0.2% and 0.3% at 10 ml.hr-1 improved postoperative pain relief and decreased PCA morphine requirements in patients undergoing major orthopaedic surgery. The 0.1% and 0.2% concentrations produced similar sensory anaesthesia with less motor blockade than the 0.3% concentration.