RT Journal Article SR Electronic T1 Hyperosmolarity Does Not Contribute to Transient Radicular Irritation After Spinal Anesthesia With Hyperbaric 5% Lidocaine JF Regional Anesthesia: The Journal of Neural Blockade in Obstetrics, Surgery, & Pain Control JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 363 OP 368 DO 10.1136/rapm-00115550-199520050-00001 VO 20 IS 5 A1 Hampl, Karl F. A1 Schneider, Markus C. A1 Thorin, Dominique A1 Ummenhofer, Wolfgang A1 Drewe, Jürgen YR 1995 UL http://rapm.bmj.com/content/20/5/363.abstract AB Background and Objectives In addition to major neurologic injury, local anesthesia toxicity may also include less severe but more common neurologic side effects. The authors recently observed symptoms suggestive of transient radicular irritation in one third of patients after spinal anesthesia with hyperbaric 5% lidocaine, whereas evidence of neurologic symptoms was lacking with hyperbaric 0.5% bupivacaine. The purpose of this prospective double-blinded study was to evaluate if the high osmolarity of hyperbaric 5% lidocaine solution might contribute to the development of transient radicular irritation.Methods Forty-four patients undergoing brief gynecologic procedures under spinal anesthesia were randomly allocated to receive 1.5 mL of one of three study drugs: 5% lidocaine in 7.5% dextrose (drug A), 0.5% bupivacaine in 8.25% dextrose (drug B), or 5% lidocaine in 2.7% dextrose (drug C). Drug C was prepared by the pharmacy (University Hospital, Basel, Switzerland) with an osmolarity similar to that of drug B. Drugs A and B were commercially available. Patients were evaluated on postoperative day 1 for symptoms of transient radicular irritation by an anesthesiologist who was unaware of the drug given or details of the anesthetic technique.Results Symptoms suggestive of transient radicular irritation were observed with a similar high incidence in patients receiving both lidocaine preparations, but in no patient receiving hyperbaric 0.5% bupivacaine (P < .01).Conclusions The results suggest that transient radicular irritation did not result from the marked hyperosmolarity of the hyperbaric 5% lidocaine. However, because lidocaine and bupivacaine were not administered at equipotent dosages, the relative potential for both drugs to induce transient radicular irritation remains to be determined.