Table 5.

The grading of recommendations assessment, development and evaluation (GRADE) approach

No of studies	Design	Quality assessment					No of patients		Effects		Quality	Importance
		Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Analgesia	Control	Relative (95% CI)	Absolute
Duration of analgesia (Better indicated by lower values)
6	Randomised trials	Seriousa	Seriousb	No serious indirectness	No serious imprecision	None	178	176	–	MD 58.59 higher (66.13 lower to 183.31 higher)	⊕⊕ΟΟ Low	Critical
Sensory block onset (Better indicated by lower values)
4	Randomised trials	Seriousa	Very seriousc	No serious indirectness	No serious imprecision	None	132	133	–	MD 0.4 higher (1.24 lower to 2.04 higher)	⊕ΟΟΟ Very Low	Important
Sensory block duration (Better indicated by lower values)
4	Randomised trials	Seriousa	Very seriousc	No serious indirectness	No serious imprecision	None	128	126	–	MD 9.55 lower (186.07 lower to 166.98 higher)	⊕ΟΟΟ Very Low	Important
Motor block onset (Better indicated by lower values)
2	Randomised trials	No serious risk of bias	No serious inconsistency	No serious indirectness	No serious imprecision	None	55	56	–	MD 0.67 higher (0.03 to 1.32 higher)	⊕⊕⊕⊕ High	Important
Motor block duration (Better indicated by lower values)
2	Randomised trials	Seriousa	Very seriousc	No serious indirectness	No serious imprecision	None	81	79	–	MD 61.85 higher (178.16 lower to 301.86 higher)	⊕ΟΟΟ Very Low	Important
Analgesic consumption (Better indicated by lower values)
2	Randomised trials	Seriousa	No serious inconsistency	No serious indirectness	No serious imprecision	None	50	50	–	MD 29.12 lower (45.18 to 13.06 lower)	⊕⊕⊕Ο Moderate	Critical

No of studies	Design	Quality assessment					No of patients		Effect		Quality	Importance
		Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Adverse reaction	Control	Relative (95% CI)	Absolute
Postoperative nausea
2	Randomised trials	Seriousd	No serious inconsistency	No serious indirectness	No serious imprecision	None	7/50 (14%)	4/50 (8%)	RR 1.53 (0.28 to 8.39)	42 more per 1000 (from 58 fewer to 591 more)	⊕⊕⊕Ο Moderate	Important
							–	8.3%		44 more per 1000 (from 60 fewer to 613 more)
Postoperative vomiting
2	Randomised trials	Seriousd	No serious inconsistency	No serious indirectness	No serious imprecision	None	8/50 (16%)	2/50 (4%)	RR 3.33 (0.86 to 12.89)	93 more per 1000 (from 6 fewer to 476 more)	⊕⊕⊕Ο Moderate	Important
							–	3.3%		77 more per 1000 (from 5 fewer to 392 more)

^aSome authors did not provide sufficient details regarding blinding and concealment of sequence allocation and some outcome is incomplete.

^bI2 statistic was high without satisfactory explanation by subgroup analysis, but it can be reduced by sensitivity analysis

^cI2 statistic was high without satisfactory explanation by subgroup analysis

^dSome outcome is incomplete