Population pharmacokinetic-pharmacodynamic model of propofol in adolescents undergoing scoliosis surgery with intraoperative wake-up test: a study using Bispectral index and composite auditory evoked potentials as pharmacodynamic endpoints

Table 3 Population pharmacodynamic parameters for the one-compartment effect model and two compartment effect model for propofol induced changes of the Bispectral index (BIS) and composite A-line ARX index (cAAI)

Parameter	BIS	Bs BIS	cAAI	Bs cAAI
Parameter	Mean (CV%)	Mean (%)	Mean (CV%)	Mean (%)
Fixed effects
E₀	100 Fixed	100 Fixed	63.4 (14.9)	63.3 (100)
E_max (value)	100 Fixed	100 Fixed
E_max (fraction of E₀)	100 Fixed	100 Fixed	0.786 (6.1)	0.787 (100)
EC₅₀ (mg/l)	3.51 (6.61)	3.53 (101)	2.14 (12.4)	2.10 (98)
γ	1.43 (10.1)	1.44 (100)	6.85 (46.4)	7.03 (103)
k_eo (min⁻¹)	0.102 (20.4)	0.103 (101)	0.067 (14.8)	0.079 (118)
k_e12	0.121 (49.3)	0.118 (98)
k_e21	0.172 (35.8)	0.160 (93)
Interindividual variability
ω _EC50²	0.059 (48.1)	0.056 (96)	0.159 (33.9)	0.165 (103)
ω γ ²	0.117 (41.0)	0.111 (95)	0.952 (39.3)	1.12 (118)
ω k_eo ²	0.192 (49.7)	0.195 (102)	0.498 (38.4)	0.522 (105)
Residual error
σ²	59.5 (11.1)	58.4 (98)	133 (18.9)	122 (92)
Performance measures
-2LL	6.984.424	6972.363 (100)	9354.40	9310.08 (100)

BIS Bispectral index, cAAI composite A-Line ARX index, Bs bootstrap validation (250 times), E0 baseline, Emax maximum possible effect expressed as absolute value or fraction of E0, EC50 propofol concentration at half maximum effect, γ Hill coefficient, ke0 first-order equilibration constant, ke12 rate constant from central to peripheral effect site, ke21 rate constant from peripheral to central effect site, ω2 variance, the square root of the exponential variance of η minus 1 is the percentage of interindividual variability in the pharmacodynamic parameters, σ2 additive intraindividual variance, values in parentheses are CV coefficient of variation of the parameter values, -2LL objective function

ISSN: 1471-2253