Skip to main content

Table 2 Analyses of each sampling stage

From: Effect of different surgical procedures on the accuracy of prediction of the plasma concentration of fentanyl: comparison between mastectomy and laparoscopic prostatectomy

Sampling stage

Stage 1

Stage 2

Stage 3

Stage 4

Sampling time

<1.5 h

1.5–3 h

3–4.5 h

>4.5 h

Mastectomy

 Number of samples

83

74

19

0

 Plasma fentanyl concentration (ng/mL)

2.08 ± 0.74

2.07 ± 0.70

1.88 ± 0.54

 

 Simulated fentanyl concentration (ng/mL)

1.81 ± 0.54

1.68 ± 0.52

1.50 ± 0.31

 

 The difference between plasma and predicted fentanyl

0.27 ± 0.48

0.38 ± 0.47

0.34 ± 0.44

 

 Range of difference

[−0.82, 1.52]

[−1.1, 1.68]

[−0.7, 1.1]

 

 Number of a difference more than +0.5 ng/mL

28/83 (38%)

27/74 (36%)

6/19 (32%)

 

 Number of a difference less than −0.5 ng/mL

6/83 (7%)

3/74 (4%)

1/19 (5%)

 

 Median absolute performance error (%)

21

25

35

 

 Fixed bias [95% confidence interval] (ng/mL)

0.27 [0.17 0.37]

0.38 [0.27 0.49]

0.38 [0.17 0.59]

 

Laparoscopic prostatectomy

 Number of samples

48

59

48

27

 Plasma fentanyl concentration (ng/mL)

2.27 ± 1.26

2.08 ± 0.63

1.68 ± 0.56

1.43 ± 0.43

 Simulated fentanyl concentration (ng/mL)

1.98 ± 1.04

1.90 ± 0.47

1.83 ± 0.55

1.76 ± 0.48

 The difference between plasma and predicted fentanyl

0.29 ± 0.54

0.19 ± 0.52

−0.15 ± 0.53

−0.34 ± 0.41

 Range of difference

[−0.92, 1.42]

[−1.08, 1.20]

[−1.52, 0.78]

[−0.98, 0.30]

 Number of a difference more than +0.5 ng/mL

13/48 (27%)

14/59 (26%)

2/48 (4%)

0/27 (0%)

 Number of a difference less than −0.5 ng/mL

2/48 (4%)

5/59 (8%)

10/48 (21%)

12/48 (25%)

 Median absolute performance error (%)

18

18

20

21

 Fixed bias [95% confidence interval] (ng/mL)

0.29 [0.14 0.44]

0.18 [0.03 0.33]

−0.15 [0 −0.30]

−0.34 [−0.17 −0.51]