title: Quantitative comparison of leakage under the tourniquet in forearm versus conventional intravenous regional anesthesia.
abstract: We compared the quantitative leakage between forearm and conventional IV regional anesthesia (IVRA). Forearm IVRA remains unpopular because of the theoretical risk of local anesthetic leakage through the interosseous vessels. IVRA was simulated on the forearm or arm during two separate, randomized sessions using a double tourniquet in 14 volunteers. A radiolabeled substance, DISIDA (99m Tc-disofenin) with a structure similar to lidocaine, was injected instead of local anesthetic. Volumes of 0.4 mL/kg (maximum 25 mL), were used for forearm IVRA and 0.6 mL/kg (maximum 45 mL) for conventional IVRA. A gamma camera recorded radioactivity levels in the limb distal to the tourniquet every 30 s while the tourniquet was inflated (25 min) and for 20 min postdeflation. The leakage of radiolabeled substance during inflation was similar in both groups, 6%+/-12% (mean +/- SD) from the forearm and 10%+/-20% from the upper arm. After deflation, mean loss of radioactivity was higher in conventional IVRA, 70%+/-7% vs 57%+/-11% and 82%+/-5% vs 69%+/-11% at 3 and 20 min, respectively (P < 0.001). We conclude that forearm IVRA results in tourniquet leakage comparable to conventional IVRA and is potentially safer because the required dose of local anesthetic is smaller.
  
  
  CONCLUSIONS
  Using a tourniquet on the forearm for IV regional anesthesia does not increase the risk of drug leakage. This is potentially a safer technique compared with conventional IV regional anesthesia because a much smaller dose of local anesthetic is required.
authors.affiliation: Department of Anesthesia, University of Toronto, The Toronto Hospital, Canada.
authors.forename: M M
authors.initials: MM
authors.lastname: Coleman
authors.forename: P W
authors.initials: PW
authors.lastname: Peng
authors.forename: J M
authors.initials: JM
authors.lastname: Regan
authors.forename: V W
authors.initials: VW
authors.lastname: Chan
authors.forename: A L
authors.initials: AL
authors.lastname: Hendler
mesh_terms: D000328:Adult; D000765:Anesthesia, Conduction / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D001132:Arm / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005260:Female; D005542:Forearm / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D019785:Technetium Tc 99m Disofenin; D014111:Tourniquets
chemical_list: D019275:Radiopharmaceuticals; D019785:Technetium Tc 99m Disofenin