Table 2.

Parameters and levels used in the orthogonal design

Parameters	Levels
A: Stimulating time	1: 15 min before operation to immediate postoperative
	2: 20 min before operation to immediate postoperative
	3: 25 min before operation to immediate postoperative
B: Acupoints	1: Sanyinjiao27 (SP 6) (anode) + Zusanli28 (ST 36) (cathode)
	2: Sanyinjiao (SP 6) (anode) + Taichong29 (LR 3) (cathode)
	3: Sanyinjiao (SP 6) (anode) + Diji30 (SP 8) (cathode)
C: Age	1: ≤25 years
	2: ≥25 years and ≤ 30 years
	3: >30 years
D: Parity	1: G1P0A0
	2: G≥2P0A≥1
	3: GxP≥1Ax