Table 3 The time to first press PCA, the oxycodone consumed postoperatively, and times of PCA

First press time(min)

45.5(10.5–212)

201(66.5–414)

563(371–830)

 < 0.001^b

Consumption of oxycodone in PCIA (mg)

23.36 ± 6.30

20.17 ± 5.13

15.90 ± 5.40

 < 0.001^a

Effective compressions of PCA (time)

15(9.5–18.5)

9(4–14.5)

5.5(3–8)

 < 0.001^b

Total compressions of PCA (time)

17(10.5–20.5)

10.5(5–16)

6(4–9)

 < 0.001^b