title: Evaluating hemodynamic and T wave criteria of simulated intravascular test doses using bupivacaine or isoproterenol in anesthetized children.
abstract: An increase in T wave amplitude > or =25% is a reliable indicator for detecting intravascular injection of lidocaine-epinephrine test dose in anesthetized children. We examined whether a simulated IV test dose containing bupivacaine instead of lidocaine, and isoproterenol instead of epinephrine, produces reliable changes in heart rate (HR) and T wave morphology. One hundred healthy infants and children (6-72 mo) were randomized to one of five groups (n = 20 each) during 1.0 minimum alveolar anesthetic concentration sevoflurane and 67% nitrous oxide in oxygen: atropine pretreatment (0.01 mg/kg IV) followed by 0.25% bupivacaine containing epinephrine 0.5 microg/kg IV, atropine followed by normal saline, atropine followed by 1% lidocaine containing isoproterenol 0.1 microg/kg, saline pretreatment followed by the lidocaine-isoproterenol test dose, and saline followed by saline. HR was recorded every 20 s and T wave amplitude of lead II was continuously recorded. All patients receiving the bupivacaine-epinephrine test dose and none receiving saline met the HR (positive if > or =10 bpm increase) and T wave criteria (positive if > or =25% increase in amplitude). The isoproterenol-containing test dose produced positive responses based only on the HR criterion with or without atropine pretreatment. Our results indicate that HR and T wave changes are useful if a bupivacaine-epinephrine test dose is used and that HR is the only useful indicator if an isoproterenol-containing test dose is used in sevoflurane-anesthetized children.
  
  
  CONCLUSIONS
  To determine if an epidurally administered local anesthetic has been unintentionally injected into a blood vessel, a small dose of epinephrine or isoproterenol may be added to a local anesthetic. We found that an increase in heart rate > or =10 bpm and an increase in T wave amplitude of lead II >or =25% are useful indicators for detecting accidental intravascular injection of an epinephrine-containing test dose in sevoflurane-anesthetized children, whereas only a heart rate change is a reliable diagnostic tool if an isoproterenol-containing test dose is used.
authors.affiliation: Department of Anesthesia, Akita University School of Medicine, Akita, Japan. mtanaka@med.akita-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Kimura
authors.forename: T
authors.initials: T
authors.lastname: Goyagi
authors.forename: K
authors.initials: K
authors.lastname: Ogasawara
authors.forename: R
authors.initials: R
authors.lastname: Nitta
authors.forename: T
authors.initials: T
authors.lastname: Nishikawa
mesh_terms: D000318:Adrenergic beta-Agonists / Q000097:blood; D000758:Anesthesia; D000779:Anesthetics, Local / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000097:blood; D002675:Child, Preschool; D004562:Electrocardiography / Q000187:drug effects*; D004837:Epinephrine; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007223:Infant; D007545:Isoproterenol / Q000097:blood; D008297:Male
chemical_list: D000318:Adrenergic beta-Agonists; D000779:Anesthetics, Local; D007545:Isoproterenol; D002045:Bupivacaine; D004837:Epinephrine