Comparison of analgesia induced by continuous epidural infusion of plain 1% lidocaine and 1% lidocaine prepared by dilution of 2% lidocaine with the same volume of saline.
OBJECTIVE
To compare the extent of sensory block induced by continuous epidural infusion of plain 1% lidocaine and 2% lidocaine diluted with saline to 1% lidocaine.


METHODS
Prospective, randomized, blinded study.


METHODS
University hospital.


METHODS
40 ASA physical status I inpatients scheduled for lower extremity orthopedic surgery.


METHODS
After surgery with lumbar epidural anesthesia with 0.75% ropivacaine, patients were randomized to two postoperative epidural infusion groups to receive plain 1% lidocaine (plain group) or 2% lidocaine diluted with the same volume of normal saline (dilution group). Continuous epidural infusion was started at a rate of 6 mL/h.


RESULTS
Regression of sensory block was significantly prolonged in the plain group, resulting in a significant difference in the spread of sensory block between the two agents from 4 to 6 h postoperatively. There also was a significant difference from the two groups in the level of motor block (modified Bromage scale) between 3 and 5 h postoperatively.


CONCLUSIONS
Two percent lidocaine diluted with the same volume of saline is a less potent than the plain 1% lidocaine. The effect of saline as a diluent on epidurally administrated local anesthetics may be of clinical importance.
Kanai
Akifumi
A
Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Japan. kanaiakifumi@aol.com
Koiso
Shintaro
S
Hoka
Sumio
S
D000328:Adult; D015360:Analgesia, Epidural; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D035002:Lower Extremity / Q000601:surgery; D008297:Male; D009407:Nerve Block; D019637:Orthopedic Procedures; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000188:drug therapy*; D011446:Prospective Studies; D012965:Sodium Chloride
D000779:Anesthetics, Local; D012965:Sodium Chloride; D008012:Lidocaine