Abstract: We included 28 trials (2681 children) investigating 17 interventions of interest; all trials were conducted in high-income countries. Overall we judged the trials to be at high risk of bias. Except for parental acupuncture (graded low), all other GRADE assessments of the primary outcomes of comparisons were very low, indicating a high degree of uncertainty about the overall findings. Parental presence: In five trials (557 children), parental presence at induction of anaesthesia did not reduce child anxiety compared with not having a parent present (standardized mean difference (SMD) 0.03, 95% confidence interval (CI) -0.14 to 0.20). In a further three trials (267 children) where we were unable to pool results, we found no clear differences in child anxiety, whether a parent was present or not. In a single trial, child anxiety showed no significant difference whether one or two parents were present, although parental anxiety was significantly reduced when both parents were present at the induction. Parental presence was significantly less effective than sedative premedication in reducing children's anxiety at induction in three trials with 254 children (we could not pool results). Child interventions (passive): When a video of the child's choice was played during induction, children were significantly less anxious than controls (median difference modified Yale Preoperative Anxiety Scale (mYPAS) 31.2, 95% CI 27.1 to 33.3) in a trial of 91 children. In another trial of 120 children, co-operation at induction did not differ significantly when a video fairytale was played before induction. Children exposed to low sensory stimulation were significantly less anxious than control children on introduction of the anaesthesia mask and more likely to be co-operative during induction in one trial of 70 children. Music therapy did not show a significant effect on children's anxiety in another trial of 51 children. Child interventions (mask introduction): We found no significant differences between a mask exposure intervention and control in a single trial of 103 children for child anxiety (risk ratio (RR) 0.59, 95% CI 0.31 to 1.11) although children did demonstrate significantly better co-operation in the mask exposure group (RR 1.27, 95% CI 1.06 to 1.51). Child interventions (interactive): In a three-arm trial of 168 children, preparation with interactive computer packages (in addition to parental presence) was more effective than verbal preparation, although differences between computer and cartoon preparation were not significant, and neither was cartoon preparation when compared with verbal preparation. Children given video games before induction were significantly less anxious at induction than those in the control group (mYPAS mean difference (MD) -9.80, 95% CI -19.42 to -0.18) and also when compared with children who were sedated with midazolam (mYPAS MD -12.20, 95% CI -21.82 to -2.58) in a trial of 112 children. When compared with parental presence only, clowns or clown doctors significantly lessened children's anxiety in the operating/induction room (mYPAS MD -24.41, 95% CI -38.43 to -10.48; random-effects, I² 75%) in three trials with a total of 133 children. However, we saw no significant differences in child anxiety in the operating room between clowns/clown doctors and sedative premedication (mYPAS MD -9.67, 95% CI -21.14 to 1.80, random-effects, I² 66%; 2 trials of 93 children). In a trial of hypnotherapy versus sedative premedication in 50 children, there were no significant differences in children's anxiety at induction (RR 0.59, 95% CI 0.33 to 1.04). Parental interventions: Children of parents having acupuncture compared with parental sham acupuncture were less anxious during induction (mYPAS MD -17, 95% CI -30.51 to -3.49) and were more co-operative (RR 1.59, 95% CI 1.01 to 2.53) in a single trial of 67 children. Two trials with 191 parents assessed the effects of parental video viewing but did not report any of the review's prespecified primary outcomes. This review shows that the presence of parents during induction of general anaesthesia does not diminish their child's anxiety. Potentially promising non-pharmacological interventions such as parental acupuncture; clowns/clown doctors; playing videos of the child's choice during induction; low sensory stimulation; and hand-held video games need further investigation in larger studies.

Plain-language summary: We included 28 trials (2681 children under the age of 18 years and or their parents) with a large number of interventions (17) assessed. The presence of parents at induction of the child's anaesthesia has been the most commonly investigated intervention (eight trials), but has not been shown to reduce anxiety or distress in children, or increase their co-operation during induction of anaesthesia. Although parents should not be actively discouraged from being present if they prefer to do so, equally parents should not be encouraged to be present at their child's induction if they prefer not to do so. Most commonly other interventions are given to the child (e.g. video games or hypnosis) but sometimes the intervention is given to the parent. One study of acupuncture for parents found that the parent was less anxious, and the child was more co-operative, at induction of anaesthesia. Another study of giving parents information, in the form of pamphlets or videos, failed to show an effect. In other studies looking at interventions for children, clowns or clown doctors, a quiet environment, video games and computer packages (but not music therapy) each showed benefits such as improved co-operation in the children. Many of the studies were of poor quality and too small to provide clear answers to the study question. However potentially promising non-pharmacological interventions such as parental acupuncture; clowns/clown doctors; playing videos of the child's choice during induction, pre-operative hypnosis and hand-held video games require further testing in future studies. Non-drug interventions that might help parents relax need further study, as there is some evidence that more relaxed parents may improve their child's anaesthesia induction experience.