Effect of Epidural Dexmedetomidine as an Adjuvant to Local Anesthetics for Labor Analgesia: A Meta-Analysis of Randomized Controlled Trials

Table 3

Subgroup analysis based on different controls (placebo and opioid).

Outcomes	DEX vs. placebo					DEX vs. opioids
	Studies	Participants	Effect estimate			Studies	Participants	Effect estimate
			MD (OR) and 95% CI	I^2 (%)				MD (OR) and 95% CI	I^2 (%)
VAS score (before block)	2	230	0.05 [−0.21, 0.31]	13	0.71	3	318	−0.12 [−0.40, 0.17]	17	0.41
VAS score (15 min after block)	1	80	Not applicable			1	160	Not applicable
VAS score (30 min after block)	2	230	−1.56 [−1.81, −1.31]	30	<0.00001	2	158	−0.20 [−0.58, 0.18]	0	0.31
VAS score (60 min after block)	1	80	Not applicable			2	158	−0.64 [−1.80, 0.52]	84	0.28
VAS score (120 min after block)	1	74	Not applicable			2	158	−0.74 [−1.65, 0.17]	79	0.11
VAS score (at the moment of disengagement)	2	219	−0.95 [−1.87, −0.02]	93	0.05	1	160	Not applicable
Time of first stage	5	1004	−12.44 [−34.08, 9.19]	78	0.26	3	301	−27.57 [−59.46, 4.33]	96	0.09
Time of second stage	5	999	−1.44 [−6.52, 3.64]	92	0.58	3	301	5.62 [−9.92, 21.16]	99	0.48
Mode of delivery	3	287	1.16 [0.44, 3.05]	0	0.77	4	276	1.13 [0.66, 1.93]	0	0.67
Onset of analgesia	1	60	Not applicable			3	228	0.25 [−2.89, 3.39]	95	0.87
MAP (before block)	2	230	1.89 [−0.83, 4.60]	0	0.17	2	247	−0.19 [−2.5, 2.11]	0	0.87
MAP (15 min after block)	1	80	Not applicable			2	247	1.49 [−7.43, 10.41]	93	0.74
MAP (30 min after block)	2	230	−1.16 [−6.35, 4.03]	75	0.66	1	87	Not applicable
HR (before the block)	2	230	−1.33 [−3.19, 0.54]	0	0.16	2	247	1.06 [−1.31, 3.43]	0	0.38
HR (15 min after block)	1	80	Not applicable			2	247	−0.89 [−10.80, 9.02]	95	0.86
HR (30 min after block)	2	230	−3.14 [−6.31, 0.04]	74	0.05	1	87	Not applicable
Blood loss	2	205	−6.55 [−13.81, 0.71]	0	0.08	1	70	Not applicable
Motor block (modified Bromage scale)	3	785	Not applicable			4	377	0.29 [−0.37, 0.96]	95	0.39
Apgar score (1 min)	2	207	0.01 [−0.08, 0.11]	0	0.79	2	230	Not applicable
Apgar score (5 min)	3	357	0.00 [−0.07, 0.08]	0	0.89	2	230	Not applicable
Umbilical artery pH	2	207	0.01 [−0.01, 0.03]	0	0.35	3	301	0.00 [−0.02, 0.02]	0	0.70
Umbilical artery PaO2	0		Not applicable			2	230	1.25 [−2.88, 5.37]	96	0.55
Incidence of maternal bradycardia	4	935	Not applicable			4	388	2.90 [1.04, 8.11]	0	0.04
Incidence of hypotension	3	785	1.59 [0.47, 5.36]	0	0.45	4	388	0.68 [0.06, 7.98]	70	0.76
Incidence of nausea/vomiting	5	1011	0.71 [0.37, 1.36]	0	0.30	4	388	0.27 [0.12, 0.61]	0	0.002
Incidence of itching	2	210	Not applicable			4	388	0.28 [0.07, 1.13]	2	0.07
Incidence of shivering	1	60	Not applicable			2	141	0.96 [0.26, 3.54]	0	0.95
Incidence of urinary retention	2	210	Not applicable			3	301	0.49 [0.20, 1.15]	0	0.10
Incidence of fetal heart rate abnormality	1	147	Not applicable			3	317	1.09 [0.44, 2.70]	0	0.86

DEX, dexmedetomidine; MD, mean difference; OR, odds ratio; CI, confidence interval; VAS, visual analog scale; MAP, mean arterial pressure; HR, heart rate.