Background and Goal of the Study
Emergence agitation (EA) is a frequent phenomenon in children recovering from general anaesthesia and increases the risk of self-injury. Previously, we reported that stimulating the heart 7 (HT7) acupuncture point bilaterally using two neuromuscular transmission monitoring devices (NTMs) decreased the incidence of EA; the risk ratio was 0.56 (95% confidence interval: 0.36–0.86). However, bilateral stimulation is a barrier to clinical use because two NTMs are needed for one patient. The objective of this study was to examine the efficacy of unilateral electrical stimulation of HT7 using an NTM to prevent EA in children.
Methods and Materials
This was a prospective, randomized, double-blind controlled study, that included children (ages 18–96 months) scheduled to undergo sevoflurane anaesthesia. The enrolled subjects were randomly assigned to one of the following two groups: (1) HT7 group: unilateral (right side) stimulation of the HT7 acupuncture point located on the ulnar side of the wrist by using a single-twitch electrical stimulus (1 Hz, 50 mA) throughout the surgery, and (2) control group: only electrodes were attached to the right side HT7 point; an electrical stimulus was not applied. A power analysis (α = 0.05, β = 0.20) indicated that 40 patients were required in each group. To allow for 20% dropout rate, we recruited 50 patients for each group.
 The primary outcome assessed was the incidence of EA. The incidence and severity of EA were evaluated using the paediatric anaesthesia emergence delirium (PAED) scale, and a score ≥ 10 demonstrated the presence of EA. Outcome assessors who were blinded to the group allocation recorded the PAED score in the recovery room. 
Results and Discussion
All 100 enrolled subjects completed the study. The patient’s characteristics were not different between the groups. There was no statistical difference between the incidence of EA in the HT7 and the control group (28.0% vs. 24.0%; P = 1.0). The risk ratio was 1.17 (95% confidence interval: 0.60-2.27). The wide range of the confidence interval precludes any definitive conclusions. 
Conclusion
In this study, we did not identify the effect of single-twitch electrical stimulation to the unilateral HT7 on the incidence of EA, contrary to findings with bilateral HT7 stimulation. The effect of other types of stimulation (e.g., train-of-four, or tetanus stimulation) to unilateral HT7 on the incidence of EA should be examined in the future.

Unilateral electrical stimulation of the heart 7 acupuncture point to prevent emergence agitation in children: a prospective double blind randomized controlled trial