Intravenous isoproterenol as a marker for epidural test-dosing in children.
The purpose of this study was to determine if isoproterenol would be an effective marker of intravascular injection in anesthetized children. Forty-four ASA 1 children, aged 2 mo to 10 yr, were randomly assigned to two groups. Children in group 1 (n = 21) received 0.05 microgram/kg isoproterenol, and children in group 2 (n = 23) received 0.075 microgram/kg isoproterenol. A blinded observer continuously recorded heart rate and arterial blood pressure. Measurements were recorded before the surgical incision at steady-state halothane concentration of 1.2 minimum alveolar concentration adjusted for age. Isoproterenol produced a graded increase in heart rate with mean maximum increases of 16.5 +/- 8.7 beats/min in group 1 and 21.5 +/- 9.2 beats/min in group 2. No episodes of hypotension and arrhythmia were noted. Isoproterenol, 0.075 microgram/kg, is more sensitive but still is an imperfect marker of an intravascular injection. It produces a heart rate increase in 96% of children anesthetized with halothane and nitrous oxide in 50% oxygen. The application of isoproterenol as an epidural test dose appears promising, but cannot be recommended until its full reliability and neurotoxicity are evaluated.
Perillo
M
M
Children's Hospital, Boston, Massachusetts 02115.
Sethna
N F
NF
Berde
C B
CB
D000767:Anesthesia, Epidural; D001794:Blood Pressure / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D006221:Halothane; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007223:Infant; D007275:Injections, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage*
D007545:Isoproterenol; D006221:Halothane