Impact of adding opioids to paravertebral blocks in breast cancer surgery patients: A systematic review and meta-analysis

Table 1 Details of included studies

Ref.	Yr	Study location	Surgery type	Sample size		Age (yr)	Common protocol for PVB	Opioid added to PVB in intervention group)	Drug added to PVB in control group	Post-operative analgesics used
				Study	Control
Mostafa et al[21]	2018	Egypt	MRM or breast conservation surgery with axillary node dissection	20	20	18-78	Nalbuphine 10 mg	PVB at the level of T4 with bupivacaine 0.5% 0.3 mL/kg	No drug	Tramadol as PCA
Pushparajan et al[22]	2017	India	MRM	20	20	18-60	Fentanyl 2 μg/mL at 0.1 mL/kg/h for 24 h	Continuous PVB at the level of T4 with 0.2% ropivacaine for 24 h	No drug	Fentanyl as PCA. Paracetamol or tramadol or fentanyl for breakthrough pain
Morsy et al[23]	2017	Egypt	MRM	15	15	NR	Morphine 2 mg	PVB at the level of T3 with 20 mL of bupivacaine 0.25%	No drug	Meperidine for breakthrough pain
Bhuvaneshwari et al[24]	2012	India	Total mastectomy and axillary lymph node dissection	12	12	Study: 49.1 ± 7.1; Control: 50.7 ± 11	Fentanyl 2 μg/mL	PVB at the level of T3 with bupivacaine 0.25% and epinephrine 5 μg/mL	No drug	Morphine for breakthrough pain
Omar et al[25]	2011	Egypt	MRM	19	20	Study: 47.5 ± 9.3; Control: 49.3 ± 10.5	Tramadol 1.5 mg/kg (maximum of 150 mg)	PVB at the level of T1 (1/3rd of the dose) and T4 (2/3rd of the dose) with bupivacaine 0.5% 2 mg/kg	No drug	Fentanyl as PCA. Paracetamol 1 g thrice daily and ibuprofen 400-600 mg thrice daily
Burlacu et al[26]	2006	Ireland	Wide local excisions (at least one breast quadrant), mastectomies, and mastectomies with reconstruction	13	13	Study: 54 ± NR; Control: 51 ± NR	Fentanyl 50 μg with bolus followed by 4 μg/mL infusion	Continuous PVB at the level of T3 with initial bolus of 19 mL levobupivacaine 0.25% followed by continuous infusion of 0.1% solution for 24 h	Saline	Morphine as PCA

PVB: Paravertebral block; MRM: Modified radical mastectomy; PCA: Patient controlled analgesia; T: Thoracic vertebral level.

Table 2 Outcomes reported by included studies

Ref.	Outcome	Results
Mostafa et al[21]	Time to first analgesic request	Significantly longer in the opioid group
	Post-operative analgesic time	Significantly longer in the opioid group
	24 h total analgesic consumption	Significantly lower in the opioid group
	Pain scores up to 24 h	Significantly lower in the opioid group
	HR, SBP, DBP	No difference between the two groups
	Ramsay sedation scores	Patients in the control group were more agitated then opioid group in the first four hours after the operation. No difference between the two groups after four hours
Pushparajan et al[22]	Pain scores up to discharge	Significantly lower scores in the opioid group only at 24 h and not at other time periods
	24 h total analgesic consumption	No difference between the two groups
	PONV	No difference between the two groups
	Urinary retention, pruritis	No difference between the two groups
	Patient satisfaction	No difference between the two groups
Morsy et al[23]	24 h total analgesic consumption	No difference between the two groups
	Time to first analgesic request	No difference between the two groups
	Ramsay sedation scores	No difference between the two groups
	PONV	No difference between the two groups
	HR, SBP, DBP	No difference between the two groups
Bhuvaneshwari et al[24]	Time to first analgesic request	Significantly longer in the opioid group
	24 h total analgesic consumption	Significantly lower in the opioid group
	Cumulative pain scores at 24 h	Significantly lower in the opioid group
	PONV	No difference between the two groups
	Patient satisfaction	Significantly higher in the opioid group
Omar et al[25]	Time to first analgesic request	No difference between the two groups
	24 h total analgesic consumption	No difference between the two groups
	Pain scores up to 24 h	No difference between the two groups
	PONV	No difference between the two groups
Burlacu et al[26]	Total analgesic consumption	Significantly lower in the opioid group
	Pain scores up to 24 h	No difference between the two groups
	Nausea scores	Significantly higher in the opioid group
	SBP	No difference between the two groups
	Patient satisfaction	Significantly higher in the opioid group

PONV: Postoperative nausea and vomiting; HR: Heart rate; SBP: Systolic blood pressure; DBP: Diastolic blood pressure.

Table 3 Risk of bias in included studies

Ref.	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other bias
Mostafa et al[21]	Low risk	Low risk	Low risk	Low risk	Low risk	High risk	Low risk
Pushparajan et al[22]	Low risk	Unclear risk	Low risk	Low risk	Low risk	Low risk	Low risk
Morsy et al[23]	Unclear risk	Unclear risk	Unclear risk	Unclear risk	Low risk	Low risk	Low risk
Bhuvaneshwari et al[24]	Low risk	Unclear risk	Low risk	Low risk	Low risk	Low risk	Low risk
Omar et al[25]	Low risk	Unclear risk	Low risk	Low risk	Low risk	Low risk	Low risk
Burlacu et al[26]	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk