Table 2.

Propofol and remifentanil effective concentration (Ce), bispectral index (BIS) values, heart rate (HR), and mean arterial pressure (MAP) during skull pin fixation.

	T0	T1	T2	T3	T4	P value
Ce of propofol (mcg/ml)	3.7 ± 1.1#	2.3 ± 0.7#	2.3 ± 0.7#	2.2 ± 0.6#	2.3 ± 1.2#	< 0.001
Ce of remifentanil Ce (ng/ml)	3.1 ± 0.9*!	4.1 ± 0.9%+	4.2 ± 0.7▼&	1.9 ± 0.5*▼+	1.1 ± 0.8%&!	< 0.001
BIS	92.7 ± 7.2#	49.6 ± 10.5#	46.0 ± 6.6#	44.6 ± 8.6#	47.0 ± 8.5#	< 0.001
HR (bpm)	75.3 ± 14.4*	72.2 ± 13.9+	70.2 ± 12.5	68.3 ± 14.1*+	68.5 ± 12.6	< 0.001
MAP (mmHg)	101.3 ± 12.4	92.2 ± 13.0$	102.3 ± 16.6$▼	84.9 ± 13.3▼	94.1 ± 15.7	< 0.001

Ce indicates effect-site concentration.

T0: baseline (at initial induction of general anesthesia before loss of consciousness); T1: 2 min before pin fixation; T2: during pin fixation; T3: 5 min after pin fixation; T4: 15 min after pin fixation.

^#P < 0.05 as T0 versus other time points.

^@P < 0.05 as T0 versus T2.

*P < 0.05 as T0 versus T3.

^!P < 0.05 as T0 versus T4.

^$P < 0.05 as T1 versus T2.

⁺P < 0.05 as T1 versus T3.

^%P < 0.05 as T1 versus T4.

^▼P < 0.05 as T2 versus T3.

^&P < 0.05 as T2 versus T4.