(ESP) Group

(PVB) Group

(SAPB) Group

P value

Time to first rescued dose (min)

416 ± 68

371± 67

343.5 ± 54.7

(P < 0.001)

Total dose of morphine (mg)

4 ± 2

6 ± 2

7 ± 2

(P < 0.05)