Table 2.

Comparison Between Postoperative Pain Intensity, Fentanyl Consumption Using Intravenous Patient-Controlled Analgesia (IV-PCA), and Rescue Analgesic Use in Patients with and without Basal Infusion of Fentanyl in IV-PCA Before and After Propensity Score Matching

	Before Matching				After Matching
	Basal Group	No Basal Group	P-value	Median Difference (95% CI)	Basal Group	No Basal Group	P-value	Median Difference (95% CI)
At 24h postoperatively
Total numbers	560	757			539	539
NRS at resting, 0–10	4 (2–6)	4 (2–6)	0.044	0 (0–1)	4 (2–6)	4 (2–6)	0.032	0 (0–1)
Maximal NRS, 0–10	7 (5–8)	7 (5–8)	0.910	0 (0–0)	7 (5–8)	7 (5–8)	0.620	0 (0–0)
IV fentanyl PCA use, mcg	604 (480–742)	460 (120–740)	< 0.001	−126 (−180 – −90)	600 (480–743)	520 (160–760)	< 0.001	−80 (−112 – −45)
Rescue analgesics use during first 24 h postoperatively	333 (59.5)	456 (60.2)	0.821		319 (59.2)	316 (58.6)	0.901
Number of rescue analgesics during first 24 h postoperatively	1 (0–2)	1 (0–2)	0.456	0 (0–0)	1 (0–2)	1 (0–1)	0.971	0 (0–0)
At 48h postoperatively
Total numbers	352	419			338	300
NRS at resting, 0–10	3 (1–4)	3 (1–4)	0.152	0 (0–1)	3 (1–4)	3 (1–4)	0.146	0 (0–1)
Maximal NRS, 0–10	5 (4–7)	5 (3–7)	0.143	0 (−1 – 0)	5 (4–7)	5 (3–7)	0.347	0 (−1 – 0)
IV fentanyl PCA use, mcga	1080 (768–1340)	600 (230–1140)	< 0.001	−378 (−464 – −288)	1074 (757–1299)	720 (300–1200)	< 0.001	−286 (−380 – −190)
Rescue analgesics use during 24–48h postoperatively	57 (16.2)	92 (22.0)	0.054		87 (25.8)	86 (28.7)	0.420
Number of rescue analgesics during 24–48h postoperatively	0 (0–0)	0 (0–0)	0.043	0 (0–0)	0 (0–0)	0 (0–0)	0.068	0 (0–0)

Notes: The values are presented as the median (interquartile range). ^aThis included 367 patients without basal infusion and 314 patients with basal infusion before matching. This included 266 patients without basal infusion and 303 patients with basal infusion after matching.

Abbreviations: NRS, numeric rating scale; PCA, patient-controlled analgesia.