Effect of Fentanyl-Based Intravenous Patient-Controlled Analgesia with and without Basal Infusion on Postoperative Opioid Consumption and Opioid-Related Side Effects: A Retrospective Cohort Study

Figures & data

Figure 1 Flow diagram of the study.

Abbreviations: APS, acute pain service team; BMI, body mass index; IV-PCA, intravenous patient-controlled analgesia; POD, postoperative day; SORT, Surgical Outcome Risk Tool.

Table 1 Clinical Comparison Between Patients with and without Basal Infusion of Intravenous Patient-Controlled Analgesia Before and After Propensity Score Matching

	Before Matching				After Matching
	Basal Group (n=560)	No Basal Group (n=757)	P-value	Standardized Difference	Basal Group (n=539)	No Basal Group (n=539)	P-value	Standardized Difference
Female	243 (43.4)	316 (41.7)	0.588	0.033	233 (43.2)	231 (42.9)	0.951	0.007
Age, year	60 (51–67)	63 (53–72)	< 0.001	−0.255	60 (51–67)	61 (51–70)	0.283	−0.048
Height, cm	163.8 (157.2–169.6)	163.3 (157.2–168.9)	0.310	0.051	163.8 (157.2–169.4)	163.5 (157.1–169.0)	0.535	0.035
Weight, kg	63.4 (56.2–71.2)	63.2 (55.8–70.9)	0.459	0.070	63.1 (56.0–70.8)	64.0 (55.8–71.3)	0.831	0.021
BMI, kg/m^2	23.8 (21.5–26.0)	23.9 (21.8–25.9)	0.971	0.046	23.7 (21.5–25.9)	24.1 (21.7–26.1)	0.483	−0.002
ASA physical status, I/II/III/IV	115 (20.5)/364 (65.0)/81 (14.5)/0	128 (16.9)/532 (70.3)/96 (12.7)/1 (0.1)	0.129	0.037	108 (20.0)/352 (65.3)/79 (14.7)/0	100 (18.6)/374 (69.4)/64 (11.9)/1 (0.2)	0.277	0.016
Current smoker	85 (15.2)	106 (14.0)	0.549	0.033	77 (14.3)	80 (14.8)	0.796	0.016
Preoperative analgesic use	25 (4.5)	48 (6.3)	0.177	0.091	25 (4.6)	25 (4.6)	> 0.999	< 0.001
Preoperative strong opioid use	4 (0.7)	8 (1.1)	0.724	0.037	4 (0.7)	4 (0.7)	> 0.999	0
Preoperative antipsychotics use	12 (2.1)	21 (2.8)	0.585	0.041	12 (2.2)	12 (2.2)	> 0.999	0
Type of surgery			0.007	−0.191			0.484	0.006
General surgery	366 (65.4)	446 (58.9)			347 (64.4)	358 (66.4)
Thoracic surgery	61 (10.9)	72 (9.5)			60 (11.1)	46 (8.5)
Urologic surgery	105 (18.8)	171 (22.6)			104 (19.3)	102 (18.9)
Plastic surgery	28 (5.0)	68 (9.0)			28 (5.2)	33 (6.1)
SORT classification, II/III/IV	31(5.5)/140 (25.0)/389 (69.5)	51 (6.7)/179 (23.6)/527 (69.6)	0.609	0.018	31 (5.8)/134 (24.9)/374 (69.4)	36 (6.7)/119 (22.1)/384 (71.2)	0.498	−0.016
Type of anesthesia			0.337	0.053			0.682	0.025
Inhalation agent	404 (72.1)	564 (74.5)			388 (72.0)	394 (73.1)
TIVA	156 (27.9)	193 (25.5)			151 (28.0)	145 (26.9)
Surgical time, min	135 (91–199)	125 (85–191)	0.105	0.063	135.0 (91.0–198.0)	130.0 (83.0–199.0)	0.525	0.022
Continuous wound-infiltration analgesia use	12 (2.1)	28 (3.7)	0.143	−0.107	11 (2.0)	14 (2.6)	0.686	−0.038

Note: The values are presented as the median (interquartile range) or number (%).

Abbreviations: ASA, American society of anesthesiologists; SORT, Surgical Outcome Risk Tool; TIVA, total intravenous anesthesia.

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, mcg^a	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.

Table 3 Comparison Between the Opioid-Related Side Effects Between Patients with and without a Basal Infusion of Intravenous Patient-Controlled Analgesia Before and After Propensity Score Matching

	Before Matching				After Matching
	Basal Group	No Basal Group	P-value	Odds Ratio (95% CI)	Basal Group	No Basal Group	P-value	Odds Ratio (95% CI)
During the first 24h postoperatively
Total numbers	560	757			539	539
Overall opioid-related side effects	171 (30.5)	187 (24.7)	0.019	0.75 (0.58–0.95)	167 (31.0)	124 (23.0)	0.003	0.67 (0.51–0.87)
Nausea	121 (21.6)	135 (17.8)	0.088	0.79 (0.60–1.04)	119 (22.1)	85 (15.8)	0.008	0.66 (0.49–0.90)
Vomiting	15 (2.7)	11 (1.5)	0.120	0.54 (0.24–1.18)	15 (2.8)	7 (1.3)	0.092	0.46 (0.19–1.14)
Somnolence or dizziness	72 (12.9)	78 (10.3)	0.150	0.78 (0.55–1.09)	70 (13.0)	54 (10.0)	0.128	0.75 (0.51–1.09)
During the 24–48h postoperatively
Total numbers	353	419			300	338
Overall opioid-related side effects	67 (19.0)	49 (11.7)	0.005	0.57 (0.38–0.84)	64 (18.9)	33 (11.0)	< 0.001	0.48 (0.31–0.75)
Nausea	48 (13.6)	38 (9.1)	0.046	0.63 (0.40–1.00)	45 (13.3)	24 (8.0)	0.002	0.43 (0.26–0.73)
Vomiting	6 (1.7)	2 (0.5)	0.118	0.28 (0.06–1.38)	6 (1.8)	1 (0.3)	0.075	0.15 (0.02–1.21)
Somnolence or dizziness	21 (6.0)	15 (3.6)	0.124	0.59 (0.30–1.16)	21 (6.2)	13 (4.3)	0.081	0.53 (0.26–1.08)
O2 administration via nasal cannula in the ward during the first 48h postoperatively	26 (4.6)	32 (4.2)	0.890	1.04 (0.61–1.78)	26 (4.8)	22 (4.1)	0.304	0.73 (0.41–1.32)
Hypoxemia during the first 48h postoperatively	3 (0.5)	3 (0.4)	-		3 (0.6)	3 (0.6)	-

Note: The values are presented as the number (%) or the odds ratio (95% confidence interval [CI]).

Table 4 Comparison Between the Cessation of Intravenous Patient-Controlled Analgesia (IV-PCA) and Its Cause Between Patients with and without Basal Infusion of Fentanyl Before and After Propensity Score Matching

	Before Matching				After Matching
	Basal Group	No Basal Group	P-value	Odds Ratio (95% CI)	Basal Group	No Basal Group	P-value	Odds Ratio (95% CI)
During the first 24h postoperatively
Total numbers, n	560	757			539	539
IV-PCA cessation	66 (11.8)	43 (5.7)	< 0.001	0.45 (0.30–0.67)	65 (12.1)	31 (5.8)	< 0.001	0.45 (0.29–0.69)
Cause of IV-PCA cessation
Opioids related side effects	56 (10.0)	28 (3.7)	< 0.001	0.35 (0.22–0.55)	55 (10.2)	19 (3.5)	< 0.001	0.32 (0.19–0.55)
Other than side effects	10 (1.8)	15 (2.0)			10 (1.9)	12 (2.2)
Tolerable pain	4 (0.7)	10 (1.3)			4 (0.7)	8 (1.5)
Conversion to oral analgesics	5 (0.9)	4 (0.5)			5 (0.9)	3 (0.6)
Patient refusal	1 (0.2)	1 (0.1)			1 (0.3)	1 (0.3)
During the 24–48h postoperatively
Total numbers, n	352	419			338	300
IV-PCA cessation	74 (21.0)	60 (14.3)	0.015	0.63 (0.43–0.91)	70 (20.7)	42 (14.0)	0.027	0.62 (0.41–0.95)
Cause of IV-PCA cessation
Opioids related side effects	32 (9.1)	15 (3.6)	0.002	0.37 (0.20–0.70)	29 (8.6)	8 (2.7)	0.003	0.29 (0.13–0.65)
Other than side effects	42 (11.9)	45 (10.7)			51 (15.1)	34 (11.3)
Tolerable pain	19 (5.4)	15 (3.6)			18 (5.3)	10 (3.3)
Conversion to oral analgesics	22 (6.3)	32 (7.6)			32 (9.5)	24 (8.0)
Patient refusal	1 (0.3)	0			1 (0.3)	0

Note: The values are presented as the number (%) or the odds ratio (95% confidence interval [CI]).