The Effect of Different Doses of Intravenous Dexmedetomidine on the Properties of Subarachnoid Blockade: A Systematic Review and Meta-Analysis

Figures & data

Table 2 Group Characteristics of the RCTs

Articles: Author/Year	Groups	Dex Arms	Bolus	Timing	Maintenance
Agrawal 2016^Citation31	2	Dex 0.25	0.25 mcg/kg over 15 min	After spinal	0.3 mcg/kg/hr
Park 2014^Citation23	3	Dex 0.5	0.5 mcg/kg over 10 min	After spinal	N
		Dex 1	1 mcg/kg over 10 min	After spinal	N
Al-Mustafa 2009^Citation10	2	Dex 1	1 mcg/kg over 10 min	After spinal	0.5 mcg/kg/hr
Reddy 2014^Citation11	3	Dex 0.5	0.5 mcg/kg over 10 min	Before spinal	N
Kaya 2010^Citation12	3	Dex 0.5	0.5 mcg/kg over 10 min	Before spinal	N
Lee 2014^Citation21	3	Dex 0.5	0.5 mcg/kg over 10 min	Before spinal	N
		Dex 1	1 mcg/kg over 10 min	Before spinal	N
Elcicek 2010^Citation13	2	Dex 1	1 mcg/kg over 10 min	After spinal	0.4 mcg/kg/hr for 60 min
Jung 2013^Citation14	3	Dex 0.25	0.25 mcg/kg over 10 min	After spinal	N
		Dex 0.5	0.5 mcg/kg over 10 min	After spinal	N
Chan 2016^Citation32	2	Dex 0.5	0.5 mcg/kg over 10 min	Before spinal	0.5 mcg/kg/hr
Tekin 2007^Citation15	2	Dex 1	1 mcg/kg over 10 min	After spinal	0.4 mcg/kg/hr for 50 min
Harsoor 2013^Citation16	2	Dex 0.5	0.5 mcg/kg over 10 min	Before spinal	0.5 mcg/kg/hr
Hong 2012^Citation17	2	Dex 1	1 mcg/kg over 5 min	Before spinal	N
Dinesh 2014^Citation18	2	Dex 1	1 mcg/kg over 10 min	After spinal	0.5 mcg/kg/hr
Kumari 2017^Citation19	2	Dex 1	1 mcg/kg over 10 min	Before spinal	0.6 mcg/kg/hr
Rekhi 2017^Citation20	2	Dex 1	1 mcg/kg over 10 min	After spinal	0.5 mcg/kg/hr
Kavya 2018^Citation22	3	Dex 0.5	0.5 mcg/kg over 10 min	Before spinal	0.5 mcg/kg over 60 min
		Dex 1	1 mcg/kg over 10 min	Before spinal	N

Abbreviations: Dex 0.5, arm with IV dexmedetomidine loading dose of 0.5mcg/kg; Dex1, arm with IV dexmedetomidine loading dose of 1mcg/kg.

Table 1 Demographic Characteristics of the RCTs

Articles: Author/Year	Country	JADAD Score	Surgery	Number of Pts	Local Anesthetic
Agrawal 2016^Citation32	India	3	Lower extremity	80	12.5 mg bupivacaine + 10 mcg fentanyl
Park 2014^Citation23	South Korea	4	TURP + TURBT	42	6 mg bupivacaine
Al-Mustafa 2009^Citation10	Jordan	5	TURP + TURBT + TVT	48	12.5 mg bupivacaine
Reddy 2014^Citation11	India	5	Lower extremity	75	15 mg of bupivacaine
Kaya 2010^Citation12	Turkey	5	TURP	75	15 mg of bupivacaine
Lee 2014^Citation21	South Korea	5	Lower extremity	60	12 mg of bupivacaine
Elcicek 2010^Citation13	Turkey	5	Not mentioned	60	22.5 mg ropivacaine
Jung 2013^Citation14	South Korea	5	Lower extremity	60	12 mg of bupivacaine
Chan 2016^Citation32	Canada	5	Total knee arthroplasty	40	12.75 mg bupivacaine + 10 mcg fentanyl
Tekin 2007^Citation15	Turkey	4	Lower extremity + lower abdominal	60	80 mg prilocaine
Harsoor 2013^Citation16	India	5	Infraumbilical surgery	50	12.5 mg bupivacaine
Hong 2012^Citation17	South Korea	5	TURB	51	7.5 mg bupivacaine
Dinesh 2014^Citation18	India	5	Inguinal hernia, hysterectomy, arthroscopy ACL tear repair	100	15 mg of bupivacaine
Kumari 2017^Citation19	India	5	Lower abdominal surgery	60	15 mg of bupivacaine
Rekhi 2017^Citation20	India	3	Lower extremity	60	15 mg ropivacaine
Kavya 2018^Citation22	India	5	Infra-umbilical surgery	75	12.5 mg bupivacaine

Table 3 Outcomes of the RCTs

Articles	Block Characteristics		Dexmedetomidine-Related Adverse Effects
Author/Year	Sensory Block Duration	Motor Block Duration	Hypotension	Bradycardia	Respiratory Depression	Postop Sedation
Agrawal 2016^Citation31	Y	Y	Y	Y	Y	N
Park 2014^Citation23	Y	Y	Y	Y	Y	Y
Al-Mustafa 2009^Citation10	Y	Y	Y	Y	N	N
Reddy 2014^Citation11	Y	Y	Y	Y	Y	Y
Kaya 2010^Citation12	Y	Y	Y	Y	Y	Y
Lee 2014^Citation21	Y	Y	Y	Y	Y	Y
Elcicek 2010^Citation13	Y	Y	Y	Y	Y	Y
Jung 2013^Citation14	Y	Y	Y	Y	Y	Y
Chan 2016^Citation32	N	N	Y	Y	Y	Y
Tekin 2007^Citation15	Y	Y	Y	Y	Y	Y
Harsoor 2013^Citation16	Y	Y	Y	Y	Y	N
Hong 2012^Citation17	Y	Y	Y	Y	Y	Y
Dinesh 2014^Citation18	Y	Y	Y	Y	Y	Y
Kumari 2017^Citation19	Y	Y	Y	Y	N	Y
Rekhi 2017^Citation20	Y	Y	Y	Y	Y	Y
Kavya 2018^Citation22	Y	Y	Y	Y	Y	Y

Figure 1 PRISMA flowchart.

Note: PRISMA figure adapted from Liberati A, Altman D, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. Journal of clinical epidemiology. 2009;62(10). Creative Commons.²⁴

Figure 2 Sensory block duration.

Table 4 Results for Sensory and Motor Block Duration

Outcome	N of Dex Arms	N of Patients	Mean Difference (95% Confidence Interval)	P value for Statistical Significance	I^2 Test for Heterogeneity
Sensory Block Duration overall	19	985	47.5 (33.13–62.03)	<0.001	95.7%
Dex 1mcg/kg	10	558	49.6 (24.7–74.5)	<0.001	97.3%
Dex 0.5mcg/kg	7	307	43.06 (27.8–58.2)	<0.001	83.9%
Dex 0.25mcg/kg	2	120	48.8 (12.6–85)	0.008	95.2%
Motor Block Duration overall	19	985	43.2 (23.6–62.7)	<0.001	97.5%
Dex 1mcg/kg	10	558	44.7 (23.2–66.3)	<0.001	97.03%
Dex 0.5mcg/kg	7	307	29.09 (9.3–48.7)	0.004	83.8%
Dex 0.25mcg/kg	2	120	83.6 (35.3–202.5)	0.168	99.03%

Figure 3 Motor block duration.

Table 5 Dexmedetomidine-Related Adverse Effects

Outcome	N of Dex Arms	N of Patients	Odds Ratio (95% Confidence Interval)	P value for Statistical Significance	I^2 Test for Heterogeneity
Bradycardia overall	20	1025	3.53 (2.48–5.02)	<0.001	98.6%
Dex 1mcg/kg	10	558	4.72 (2.72–6/7)	<0.001	85.4%
Dex 0.5mcg/kg	8	347	2.81 (1.53–5.15)	<0.001	99.4%
Dex 0.25mcg/kg	2	120	1.74 (0.39–7.69)	0.462	70.5%
Hypotension overall	20	1025	1.29 (0.98–1.69)	0.065	12.03%
Dex 1mcg/kg	10	558	1.3 (0.78–2.15)	0.301	28.29%
Dex 0.5mcg/kg	8	347	1.12 (0.71–1.77)	0.616	9.5%
Dex 0.25mcg/kg	2	120	1.5 (0.52–4.5)	0.438	0%

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