Clinical observations suggested that children long recovered from buRN injury required larger doses of thiopental for a smooth anesthetic induction. A prospective randomized study examined children 6–16 yr old, with greater than 15% buRN, and more than 1 year after injury, for loss of lid reflex (LR), coRNeal reflex (CR), and acceptance of the anesthesia mask (AM) 60 sec after administration of thiopental. Children were unpremedicated, received the thiopental (2.5%) through a rapidly running peripheral intravenous line, and received either 2, 3, 4, 5, 6, 7, or 8 mg/kg. LR, CR, and AM were examined at 30, 60, and 90 sec. Blood pressure and heart rate were recorded for those patients receiving 7 or 8 mg/kg thiopental. The mean age was 12.0 ± 0.5 yr, weight 43.9 ± 2.9 kg, % buRN 44.7 ± 2.9, time since buRN 68.4 ± 7.7 months, and time since previous thiopental 25.1 ± 6.6 months. The estimated ED50 (95% confidence limits) for loss of LR was 4.78 (3.95–5.78) mg/kg; for loss of CR was 7.04 (4.87–10.10) mg/kg; and for AM was 6.74 (4.68–9.71) mg/kg. These doses of thiopental were significantly greater for LR and AM (P < 0.001) but not CR (P = 0.15) compared to non-thermally injured children. There were no clinically important or statistically significant decreases in blood pressure while heart rate did increase 11 beats/min (P < 0.05) in children who received 7 or 8 mg/kg. These data strongly suggest that thiopental requirements to ablate LR and AM in previously thermally injured children aged 6–16 yr are significantly greater than in non-thermally injured children. Logistic regression found no relationship with age, weight, % buRN, time since injury, thiopental exposureosures, previous anesthetics, or time since last thiopental exposure.
Address correspondence to Dr. Coté, Department of Anesthesia, Massachusetts General Hospital, Boston, MA 02114.
© 1985 International Anesthesia Research Society