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Effect site concentrations of propofol producing hypnosis in children and adults: comparison using the bispectral index
Author(s) -
Muñoz H. R.,
Cortínez L. I.,
Ibacache M. E.,
León P. J.
Publication year - 2006
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.2006.01062.x
Subject(s) - bispectral index , propofol , medicine , anesthesia , sedation , confidence interval , hypnosis , surgery , alternative medicine , pathology
Background: No study has determined the concentration of propofol producing a degree of hypnosis compatible with anaesthesia in children. As a result, concentrations determined in adults are recommended for children. As this can result in an inadequate depth of anaesthesia, we determined the predicted effect site concentration ( C e ) of propofol necessary to obtain a bispectral index (BIS) of 50 in 50% ( EC e50 ) of children and adults. Methods: Twenty adults (aged 33–44 years) and 20 children (aged 3–11 years) undergoing surgery under general anaesthesia were studied. All were monitored with a BIS monitor, and a target controlled infusion of propofol aiming for a constant C e value was started. After 10 min, patients were evaluated using a sedation scale, and the last 5 min was used to determine the mean BIS for this C e value. The C e value of propofol was defined using the up‐and‐down method of Dixon and Massey. The first patient in each group received C e = 6 μg/ml; thereafter, it was modified in 0.5 μg/ml decrements/increments with positive or negative responses, respectively. A positive response was BIS < 50 and a negative response was BIS ≥ 50. The EC e50 value was compared using unpaired Student’s t ‐test. The prediction probability ( P K ) was used to study the association between BIS and the sedation score. Results: The mean EC e50 (95% confidence interval) values were 3.75 μg/ml (2.97–4.75 μg/ml) in adults and 3.65 μg/ml (3.36–3.96 μg/ml) in children (not significant). All patients with BIS < 50 were unarousable with tactile stimulation. The P K value was 0.99 in both groups. Conclusions: The predicted C e value of propofol resulting in BIS = 50 was similar in adults and children aged 3–11 years. The predicted C e value of propofol producing hypnosis in adults also seems to be useful in this paediatric population.