title: A comparative study of hemodynamic and T-wave criteria for detecting intravascular injection of the test dose (epinephrine) in sevoflurane-anesthetized adults.
abstract: This study was designed to determine the efficacy of heart rate (HR), systolic blood pressure (SBP), and changes in T-wave morphology in detecting intravascular injection of 15 microg of epinephrine (test dose) in sevoflurane-anesthetized adults. In addition, the testing threshold using the T-wave amplitude was derived. Ninety-six healthy patients were randomized to receive end-tidal sevoflurane 0.5%, 1%, or 2% and nitrous oxide 67% in oxygen (n = 32 for each sevoflurane concentration). Each group of patients was further randomized to receive 3 mL of 1.5% lidocaine plus 15 microg of epinephrine IV or 3 mL of saline IV (n = 16 each). HR, SBP, and T-wave amplitude were continuously monitored for 5 min after the IV injection of the study drug. None receiving IV saline and 15,15, and 14 patients receiving the IV test dose developed HR increases > or =10 bpm during 0.5%, 1%, and 2% sevoflurane, respectively. No patient receiving saline and all patients receiving the test dose developed SBP increases > or =15 mm Hg. T-wave amplitude decreased by >0.1 mV and by >25% in all patients receiving the IV test dose, and its magnitude was similar regardless of the sevoflurane concentrations. When 0.1-mV and 25% decreases in T-wave amplitude were considered as testing thresholds, 100% sensitivities and specificities were obtained. We conclude that a peak SBP increase > or =15 mm Hg and a decrease in T-wave amplitude > or =0.1 mV and > or =25% are more reliable than a HR increase > or =10 bpm for detecting intravascular injection of epinephrine-containing test dose during sevoflurane anesthesia.
  
  
  CONCLUSIONS
  To determine whether an epidural catheter resides in a blood vessel, a standard test dose containing a local anesthetic and 15 microg of epinephrine is used. We found that, in sevoflurane-anesthetized adult patients, a systolic blood pressure increase > or =15 mm Hg and a decrease in T-wave amplitude > or =0.1 mV and > or =25% in lead II, but not a heart rate increase > or =10 bpm, are reliable indicators for detecting intravascular injection.
authors.affiliation: Department of Anesthesia, Akita University School of Medicine, Akita-ken, Japan. mtanaka@med.akita-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Nishikawa
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D002408:Catheters, Indwelling; D004562:Electrocardiography / Q000187:drug effects*; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007267:Injections; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D008875:Middle Aged; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D004837:Epinephrine