Pre-operative distraction using electric ride-on cars for children undergoing elective ambulatory surgery: A randomised controlled trial : European Journal of Anaesthesiology | EJA

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Pre-operative distraction using electric ride-on cars for children undergoing elective ambulatory surgery

A randomised controlled trial

Pastene, Bruno; Piclet, Jules; Praud, Camille; Garcia, Karine; Louis, Katia; Schmidt, Claire; Boyadjiev, Ioanna; Boucekine, Mohamed; Baumstarck, Karine; Bezulier, Karine; Bouvet, Lionel; Zieleskiewicz, Laurent; Leone, Marc

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European Journal of Anaesthesiology 40(3):p 190-197, March 2023. | DOI: 10.1097/EJA.0000000000001758



  • Pre-operative anxiety is frequent in children and results in poor outcomes.
  • We assessed the effect of nonpharmacological distraction with ride-on electric cars on children's pre-operative anxiety in ambulatory surgery.
  • The ride-on e-cars were well accepted by both children and parents.
  • The use of ride-on e-cars did not reduce pre-operative anxiety.


Separation from parents and anaesthesia induction create fear and anxiety in children undergoing emergency or elective surgery. The incidence of anxiety in children ranges from 18 to 60% and results in adverse behavioural changes during the peri-operative period.1 Pharmaceutical anxiolysis has been widely used to prevent pre-operative anxiety in children.2 However, due to adverse events such as paradoxical reactions and prolonged sedation times, sedative drugs are not consistent with the principles of enhanced recovery after surgery.3 Nonpharmacological methods such as active distraction are promising interventions to alleviate peri-operative anxiety. A multitude of interventions are already associated with effective distraction, such as video games,4 virtual reality,5 music therapy6 among others.7–9

In 2018, a nonprofit organisation offered our department a set of three ride-on electric cars (ride-on e-cars) for children, which are routinely used by the children undergoing elective ambulatory surgery. Previous studies reported that transporting children on ride-on e-cars or a hand towed wagon was effective in reducing anxiety.10,11 The primary objective of our study was to assess the effect of pre-operative distraction with ride-on e-cars on children's pre-operative anxiety when undergoing elective ambulatory surgery. The secondary objectives were to assess the levels of child anxiety, pain and agitation as well as parental anxiety.

Materials and methods

Study design

This prospective, randomised, controlled and open-label study, with two parallel arms, was carried out from September 2019 to September 2021 in the ambulatory paediatric surgery unit of the Hospital Nord, a 650-bed teaching hospital, which is part of the Hôpitaux Universitaires de Marseille, Marseille, France.


Ethical approval for this study was provided by the Comité de Protection des Personnes – Île de France II, Hôpital Universitaire Necker Enfants Malades, Paris, France (Chairperson Dr S. Donnadieu) on 7 March 2019, under number 2019-A00531-56. The study protocol was registered with under number NCT03961581 on 26 May 2019. The study protocol was declared in accordance with the National Commission on Information Technology and Civil Liberties (Commission nationale de l’informatique et des libertés - CNIL) by our local data protection officer (agreement CNIL 2018172v0 from 20 December 2016). The patients were informed about the collection of their data, according to the French law and local ethical committee guidance.12 The methodology was based on the Consolidated Standards of Reporting Trials Statement (CONSORT).13

Selection criteria

Inclusion criteria were children of both sexes aged 2 to 10 years, weighing under 35 kg (as per the manufacturer's instructions for the ride-on e-cars) undergoing ambulatory elective surgery (ear-nose-throat and eye surgery). Exclusion criteria were cognitive or physical disabilities impeding the well tolerated use of the ride-on e-cars, emergency surgery and parental refusal. All included children were affiliated with a social security regimen. Informed written consent was obtained from the parents or legal guardians of all participating children. Patient selection and consent was obtained during the pre-anaesthesia consultation, at least 48 h before surgery. Parents and children had a minimum period of 48 h to decide on their consent to participate.


The primary objective was to assess the effect of transport on a ride-on e-car on pre-operative anxiety for children undergoing elective ambulatory surgery before they entered the operating room, as compared with standard transport on a trolley. Anxiety was assessed using the modified Yale Preoperative Anxiety Score Short Form (mYPAS-SF score).14 This score, which ranges from 23 to 100, is composed of 18 items distributed over four categories (activity, arousal, vocalisation and emotional status). A mYPAS-SF score less than 24 defined a nonanxious child, a score from 24 to 30 defined anxiety, and a score more than 30 defined severe anxiety.

Secondary objectives were to assess pre-operative anxiety in children by comparing the incidence of nonanxious, anxious and severely anxious children with the mYPAS-SF score at three different times: upon admission to the ambulatory surgical ward, on arrival in the waiting area at the entrance to operating suite and just before entering the operating room.

We also used the following scores: to evaluate the child's compliance with anaesthesia induction, we used the Induction Compliance Checklist (ICC)15 (range 0 to 9, zero being a perfect induction without signs of anxiety); for pain and agitation in the postanaesthesia care unit (PACU), we used the Face Legs Activity Cry Consolability (FLACC)16 (range 0 to 10; a score ≥3 calls for treatment); and for postanaesthesia delirium, we used the Paediatric Anaesthesia Emergence Delirium (PAED)17 (range 0 to 20; a score ≥10 calls for treatment). To minimise the risk of bias, before randomisation, the pre-operative anxiety profile of children under 7 years of age was assessed by the parent using the Preschool Anxiety Scale Revised (PAS-R)18 (range from 0 to 112, with higher score indicating higher anxiety) and parental anxiety was assessed using the State-Trait Anxiety Inventory (STAI)19 (range 20 to 80, higher score indicates higher anxiety). All the scores and scales used in this study are presented under Supplemental Material 1, (Supplemental data,

General procedure

To enhance protocol compliance, avoid frustration and a contamination bias, the randomisation was not performed at an individual level, but rather on the inclusion periods. Randomisation was set up as follows: ride-on e-cars or standard trolleys were used on alternate weeks for all children admitted for elective ambulatory surgery. The surgery was scheduled by the surgical teams, which were blinded to the use or not of the ride-on e-cars.

In the control group, the children were transported from the operating room waiting area to the operating room on a paediatric trolley. In the intervention group, the children were transported on a ride-on e-car that could be driven by the children themselves or by the medical team using a remote control. The distance from the waiting area to the operating room was approximately 100 m.

The anaesthesia protocol was similar in the two groups, except for the mode of transport from the waiting area of the theatre suite to the operating room. In our institution, parents accompany their child to the waiting area of the theatre suite, where they meet the medical team. No parents are allowed within the theatre suite and the children were accompanied by the anaesthesiologist and/or nurse anaesthetist to the operating room. The ride-on e-car was presented to the child and parents when it was time to transport the child to the operating room. No pharmacological premedication was used. Pre-operative fasting and management of recent or ongoing upper respiratory tract infections were in compliance with standard set guidelines.20 In the operating room, standard monitoring consisted of noninvasive blood pressure, oximetry and electrocardiography. Induction was performed via a facemask using sevoflurane, without use of nitrous oxide. Anaesthesia was maintained with sevoflurane with a minimal alveolar concentration (MAC) targeted at 1.0 (±0.2). An initial 50 : 50 mixture of oxygen:air was adjusted according to pulse oximetry measurements of oxygen haemoglobin saturation. Pain was controlled using sufentanil 0.2 μg kg−1. Airway management was left to the discretion of the anaesthesiologist in charge. To prevent postoperative pain and nausea, paracetamol, NSAIDs, droperidol and dexamethasone were administered unless contraindicated. After surgery, the children were transferred to the paediatric PACU where they met their parents. Clear fluids were authorised as soon as children requested them. Hospital discharge was allowed when the Post Anaesthetic Discharge Scoring System (PADS-S) was at least 8. In our institution, for children below 10 years of age, the anaesthetic team consisted of one senior anaesthesiologist and one nurse anaesthetist. Occasionally, a junior anaesthesiologist or junior nurse anaesthetist can complement this team.

The child's age, sex and postoperative analgesia required were recorded, along with information on any previous anaesthesia. The scales and scores at each point were recorded by either the senior anaesthesiologist or the nurse anaesthetist, both of whom had received training before taking part in the study. The mYPAS-SF score was evaluated in the reception area of the ambulatory surgery ward, in the waiting area of the operating suite and just before entering the operating room (at the end of the transport). The PAS-R for the children under-sevens and the parents STAI scores were recorded in the reception area of the ambulatory surgery ward. The ICC was recorded just before anaesthesia induction. The FLACC and PAED scores were recorded during anaesthesia recovery in the PACU. A timeline of the study is presented in Fig. 1.

Fig. 1:
Timeline of the study.

Statistical analysis

Sample size calculation was based on a hypothesis formulated on the primary outcome, according to previously published data.21,22 To detect a significant difference of 10 ± 15 points between the groups on the mYPAS-SF score prior going into the operating room, with a power of 90% and an alpha risk of 5%, the sample size was 98 patients. To allow for 10% of missing data for the primary outcome, the final sample size was increased to 110 patients. The statistical analysis was carried out with SPSS statistics software (IBM Corp, Armonk, NY, USA) and was based on intention-to-treat. The level of significance was set at 5%. The scores of the different standardised questionnaires were calculated according to the algorithms provided by the scale developers.15–19,23 Descriptive analysis of the baseline characteristics was presented per group (age, sex, history of previous anaesthesia, use of postoperative analgesia). The means of the mYPAS-SF score prior to going into the operating room (primary outcome) were compared between the groups using Student's t-test. Secondary outcomes were compared between the groups according to the nature of the variable (χ2 test or Fisher exact test for qualitative variables, Student's t-test or Mann--Whitney test for quantitative variables). The evolution of the mYPAS-SF score over time was compared between the groups using a generalised linear model for repeated measures.


One hundred and fifteen children were included, 56 in the control group and 59 in the intervention group. The baseline characteristics are presented in Table 1.

Table 1 - Patient characteristics, anaesthesia and postoperative analgesia
Control group
n = 56
Intervention group
n = 58
Age (years) 5 [4 to 6] 5 [4 to 6]
Male 31 (55) 34 (59)
Female 25 (45) 24 (41)
History of previous anaesthesia 26 (47) 20 (35)
Use of postoperative analgesia in PACU 6 (11) 13 (23)
Data are median [IQR] and n (%).PACU, postanaesthesia care unit.

One child in the intervention group was under 2 years of age and was excluded from the intention-to-treat analysis. The final sample was 56 in the control group and 58 in the intervention group. The flowchart is presented in Fig. 2.

Fig. 2:
Flowchart of the study.

Regarding the primary outcome, the mean mYPAS-SF anxiety scores did not differ between the control group and the intervention group (39 ± 19 vs. 37 ± 21; P = 0.574) (Table 2). In the under-sevens, pre-operative anxiety and parental anxiety did not differ between the control group (n = 48) and the intervention group (n = 48), respectively: PAS-R score, 37 ± 20 vs. 43 ± 17; P = 0.362; STAI score, 39 ± 13 vs. 41 ± 12; P = 0.654 (Table 2).

Table 2 - Primary and secondary outcomes
Control group
n = 56
Intervention group
n = 58
Primary outcome
 mYPAS-SF score prior to going to the OR 39 ± 19 37 ± 21 0.574
Secondary outcomes
Anxiety at the reception area of the ambulatory surgery ward 0.534
 Nonanxious (mYPAS-SF < 24) 23 (50) 22 (49)
 Anxious (mYPAS-SF 24 to 30) 6 (13) 3 (7)
 Severely anxious (mYPAS-SF >30) 17 (37) 20 (44)
Anxiety at the reception area of the surgical facility 0.53
 Nonanxious (mYPAS-SF <24) 26 (46) 30 (52)
 Anxious (mYPAS-SF 24 to 30) 6 (11) 3 (5)
 Severely anxious (mYPAS-SF > 30) 24 (43) 25 (43)
Anxiety prior going to the OR 0.334
 Nonanxious (mYPAS-SF < 24) 22 (39) 30 (53)
 Anxious (mYPAS-SF 24 to 30) 5 (9) 3 (5)
 Severely anxious (mYPAS-SF > 30) 29 (52) 24 (42)
PAS-R 37 ± 20 43 ± 17 0.078
ICC 1 ± 2 2 ± 3 0.907
FLACC 2 ± 3 2 ± 2 0.681
PAED 3 ± 4 3 ± 3 0.398
STAI 39 ± 13 41 ± 12 0.654
Data are mean ± SD and n (%).FLACC, Face Legs Activity Cry Consolability; ICC, Induction Compliance Checklist; mYPAS-SF, modified Yale Preoperative Anxiety Score Short Form; OR, operating room; PAED, Paediatric Anaesthesia Emergence Delirium; PAS-R, Preschool Anxiety Scale Revised (under sevens); STAI, State-Trait Anxiety Inventory (for adults).

Regarding the secondary outcomes, no significant differences were reported between the two groups. The incidence of nonanxious, anxious and severely anxious children did not differ at any time (Table 2). Likewise, no significant differences were found between the control group and the intervention group for the PAS-R, ICC, FLACC or PAED scores (Table 2).

The evolution of the mYPAS-SF score over the time did not differ between the groups (P = 0.507) (Fig. 3).

Fig. 3:
mYPAS-SF score evolution over time in both groups.


Our randomised controlled trial did not find a significant effect on the levels of pre-operative anxiety by using pre-operative distraction with ride-on e-cars in children undergoing elective ambulatory surgery. Despite the use of several scores, the intervention did not alter the outcome for children and did not significantly relieve parental anxiety. However, no harm was reported with the use of ride-on e-cars.

Peri-operative anxiety in children is a critical issue that needs to be addressed accordingly. Indeed, peri-operative anxiety is associated with adverse events such as the need for an increased sedative dose at anaesthesia induction, increased postoperative pain and cognitive dysfunction, eating and sleep disorders, regressive behaviour and even increased surgical site infection.24–27 Pre-operative administration of midazolam is the most widely used pharmacological anxiolysis in children, but this intervention was associated with paradoxical reactions, prolonged sedation times and delayed discharge.3 Wide inter-individual variability and increased nursing time to prepare, check and administer the drug were also described.28 In our study, no children received pre-operative pharmacological premedication.

Distraction is supposed to be an effective nonpharmacological strategy to alleviate peri-operative anxiety in children. Many interventions have been described and compared with the use of premedication with midazolam.4–9 The use of ride-on e-cars is a nonpharmacological intervention with potential advantages. Their use is easy without any learning curve for the children and the medical team. In addition, they need minimal maintenance.

Two previous randomised controlled trials evaluated the use of toy cars to reduce pre-operative anxiety in children, using the mYPAS-SF anxiety score and a similar procedure of parental presence before surgery. Liu et al.10 showed that transport on a ride-on car was an effective way to reduce pre-operative anxiety, as compared to transport on a trolley for children undergoing cardiac surgery for congenital heart disease: median [IQR], 58 [46 to 73] vs. 44 [27 to 47), P < 0.001). The use of midazolam did not affect these findings.10 Park et al.11 showed that transport on a hand-towed wagon was also effective in reducing pre-operative anxiety as compared to transport on a trolley in nonpremedicated children undergoing minor surgery: 52 [37 to 83] vs. 37 [27 to 52], P = 0.007).

In our study, distraction with the ride-on e-cars did not result in a significant diminution of pre-operative anxiety. However, our control group exhibited anxiety levels (39 ± 19) that were lower than those reported in the aforementioned studies.10,11 In a French randomised controlled trial comparing midazolam premedication to tablet distraction for children undergoing ambulatory surgery, Marechal et al.9 found no differences in the mYPAS-SF score between the two groups (41 ± 19 vs. 42 ± 21; P = 0.99). These levels of anxiety were comparable with those reported in our study (39 ± 19 vs. 37 ± 21).9 This variability in anxiety levels across studies might be explained by cultural and local factors such as the absence of the of parents for the final part of the journey, the experience of the medical team or unmeasured variables. For example, in our institution, many other nonpharmacological distractions are routinely used such as toys, songs, playing or a member of the team carrying the child in their arms. The type of surgery may also affect our findings, as we only included children undergoing elective ambulatory surgery, corresponding to minor procedures.

Our study has several limitations that we must acknowledge. The study may be underpowered to detect a difference in a population of children with lower anxiety scores than those expected, but the difference seems minimal after re-assessment. Although age as an inclusion criterion was wide, to match the manufacturer instruction for the use of ride-on e-cars, and could create a bias, the actual age spread observed in our population is narrow, reducing this confusion bias. Although statistically nonsignificant, we observed a difference in the previous anaesthesia history and in the use of postoperative analgesia in the PACU between groups. Of note, we did not collect the types of surgery in each group. However, only eye and ENT ambulatory procedures were performed during this study. We also observed that the subscale of the PAS-R scale assessing separation anxiety was higher in the intervention group (9 ± 5 vs. 7 ± 5; P = 0.023) (data not shown). These confounding factors may have had an impact on anxiety levels, but further evaluation will be required to assess them. Another limitation is the randomisation model, which was supposed to reduce the contamination bias. However, it could not eliminate it, as the same anaesthesia team managed children from both groups. In addition, we did not consider the colours and types of our three ride-on e-cars. Finally, our results may not be transferable in all healthcare settings, as our peri-operative pathway does not occur worldwide.

Nevertheless, the use of ride-on e-cars was feasible and well accepted by both children and parents. Although the differences between the two groups did not reach statistical significance, we observed a trend towards diminished anxiety for children in the intervention group, and feedback from children and parents regarding the ride-on e-cars was positive.

In conclusion, our randomised controlled trial showed that the use of ride-on e-cars neither improved nor worsened pre-operative anxiety or other outcomes, as compared with standard transport for children undergoing elective ambulatory surgery.

Acknowledgements relating to this article

Assistance with the study: the authors would like to acknowledge the nonprofit organisation ‘Les Cuistos du Cœur’ for offering our institution the children's ride-on electric cars used in the present study; the medical staff, nurse-anaesthetists and surgeons of Hôpital Nord (Marseille, France) who made this study possible; Pascal Auquier and Emilie Garrido (Medical Director and Administrative Director of the Clinical Research at Assistance Publique Hôpitaux de Marseille, Marseille, France) for supporting this project; and Alexandre Lopez for his help creating Fig. 1 using Biorender.

Financial support and sponsorship: this work was supported by a fund provided by Assistance Publique Hôpitaux de Marseille, Marseille, France (AORC 2019).

Conflicts of interests: ML reports personal fees from ASPEN, personal fees from AMOMED, personal fees from LFB, personal fees from AMBU, personal fees from GILEAD, outside the submitted work. LZ reports personal fees from GENERAL ELECTRIC HEALTHCARE, outside the submitted work. BP reports personal fees from EDWARDS LIFESCIENCES outside the submitted work. The remaining authors have nothing to disclose.

Presentation: the preliminary data for this study will be presented as an oral presentation at the upcoming Société Française d’Anesthésie et Réanimation (SFAR) meeting, 22 to 24 September 2022, Paris.

The data that support the findings of this study are available from the corresponding author, BP, upon reasonable request.

This manuscript was handled by Mona Momeni.


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