与对照组相比，干预组术后24小时内阿片类药物的使用剂量显著降低，中位吗啡当量为4.0 mg，而对照组为5.3 mg，效应量为0.36。干预组术后有121名（63％）患者需要阿片类药物，显著少于对照组（155名，80%）。为避免术后使用阿片类药物而需要治疗的有6人。干预组在手术后24小时内的疼痛评分始终且显著降低，平均降低25％。没有不良反应的报道。
Title: Effect of therapeutic suggestions during general anaesthesia on postoperative pain and opioid use: multicentre randomised controlled trial
Author: Hartmuth Nowak, Nina Zech, Sven Asmussen, Tim Rahmel, Michael Tryba, Guenther Oprea, Lisa Grause, Karin Schork, Manuela Moeller, Johannes Loeser, Katharina Gyarmati, Corinna Mittler, Thomas Saller, Alexandra Zagler, Katrin Lutz, Michael Adamzik, Ernil Hansen
Objective To investigate the effect of therapeutic suggestions played to patients through earphones during surgery on postoperative pain and opioid use.
Design Blinded randomised controlled study.
Setting Five tertiary care hospitals in Germany.
Participants 385 of 400 patients consecutively recruited from January to December 2018 who were to undergo surgery for 1-3 hours under general anaesthesia. In the per protocol analysis 191 patients were included in the intervention group and 194 patients in the control group.
Intervention The intervention comprised an audiotape of background music and positive suggestions based on hypnotherapeutic principles, which was played repeatedly for 20 minutes followed by 10 minutes of silence to patients through earphones during general anaesthesia. Patients in the control group were assigned to a blank tape.
Main outcome measures The main outcome was dose of opioid administered by patient controlled analgesia or nurse controlled analgesia within the first postoperative 24 hours, based on regular evaluation of pain intensity on a numerical rating scale (range 0-10, with higher scores representing more severe pain).
Results Compared with the control group, the intervention group required a significantly (P=0.002) lower opioid dose within 24 hours after surgery, with a median of 4.0 mg (interquartile range 0-8) morphine equivalents versus 5.3 (2-12), and an effect size (Cohen’s d) of 0.36 (95% confidence interval 0.16 to 0.56). The number of patients who needed opioids postoperatively was significantly (P=0.001) reduced in the intervention group: 121 of 191 (63%, 95% confidence interval 45% to 70%) patients in the intervention group versus 155 of 194 (80%, 74% to 85%) in the control group. The number needed to treat to avoid postoperative opioids was 6. Pain scores were consistently and significantly lower in the intervention group within 24 hours after surgery, with an average reduction of 25%. No adverse events were reported.
Conclusions Therapeutic suggestions played through earphones during general anaesthesia could provide a safe, feasible, inexpensive, and non-drug technique to reduce postoperative pain and opioid use, with the potential for more general use. Based on the finding of intraoperative perception by a considerable number of patients, surgeons and anaesthetists should be careful about background noise and conversations during surgery.