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Intravenous isoproterenol as a marker for epidural test-dosing in children
M Perillo1, N F Sethna, C B Berde
1Children's Hospital, Boston, Massachusetts 02115.
Insights
Isoproterenol shows promise as an intravascular injection marker in children, with a higher dose (0.075 microgram/kg) proving more sensitive. However, further evaluation is needed before clinical recommendation.
Area of Science:
- Anesthesiology
- Pediatric Pharmacology
Background:
- Identifying intravascular injection during pediatric anesthesia is critical for patient safety.
- Current methods for detecting accidental intravascular injection in children can be unreliable.
Purpose of the Study:
- To evaluate isoproterenol as a potential marker for intravascular injection in anesthetized children.
- To determine the optimal dose of isoproterenol for this purpose.
Main Methods:
- Forty-four pediatric patients (2 months to 10 years) received either 0.05 or 0.075 microgram/kg of isoproterenol.
- Heart rate and blood pressure were continuously monitored by a blinded observer.
- Measurements were taken at a steady-state halothane concentration (1.2 MAC) prior to surgical incision.
Main Results:
- Isoproterenol administration resulted in a dose-dependent increase in heart rate.
- The 0.075 microgram/kg dose increased heart rate in 96% of patients, indicating higher sensitivity.
- No adverse events such as hypotension or arrhythmia were observed.
Conclusions:
- Isoproterenol, particularly at 0.075 microgram/kg, is a sensitive indicator of intravascular injection in anesthetized children.
- While promising, its reliability and potential neurotoxicity require further investigation before widespread use as an epidural test dose.
Abstract:
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.