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] |