Immersive Virtual Reality Exposure for Reducing Preoperative Anxiety in Children
Phase: NA
Conditions: Anxiety State, Satisfaction, Compliance
Sponsor: Hong Kong Children's Hospital

 
 
 
  
Study Title: Immersive virtual reality exposure for reducing preoperative 
anxiety in children – a randomized controlled trial 
Central IRB Ref. No: HKCH-REC-2021-026 
NCT No: NCT07018999 
Document Title: Study Protocol 
Current Version: 10.0 
Current protocol date: 14 August 2025 
Approved by: Hospital Authority Central Institutional Review Board 
(Central IRB), Hong Kong 
Initial approval version: 31 Aug 2021 
Latest amendment approval: 9 Sept 2025 
Note: Study title is amended from ‘Immersive virtual reality exposure for 
reducing perioperative anxiety in children – a randomized controlled trial’ 
to  Immersive virtual reality exposure for reducing preoperative anxiety in 
children – a randomized controlled trial’ in year 2025 upon final submission of 
project and approved by Hospital Authority Central Institutional Review Board 
(Central IRB), Hong Kong 

Study Protocol  
Version 10 14082025 
 
Lead Principal Investigators:  
Dr. Chen Richard LI, Research Assistant Professor, The Department of Computing & Department of 
Applied Social Sciences, The Hong Kong Polytechnic University 
Dr. Vansie KWOK, Associate Consultant, Department of Anaesthesiology & Perioperative Medicine, 
Hong Kong Children’s Hospital 
 
Co-Investigators:  
Dr. Jacqueline Cheuk Kwun TSE, Anaesthesiology Specialist, Union Hospital 
Dr. Rebecca Ling-Hay YIM, Associate Consultant, Department of Anaesthesiology and Perioperative 
Medicine, Hong Kong Children’s Hospital 
Prof. Horace IP, Lee Shau Kee Professor of e-Learning, Chair Professor of Computer Science, 
Department of Computer Science, City University of Hong Kong 
Ms. Natalie Pui Fan HO, Advanced Practice Nurse, Operating Theatre, Hong Kong Children’s 
Hospital 
Ms. Ka Yan LEE, Hospital Play Specialist, Playright Children’s Play Association 
Mr. CHEN Guang, Research Assistant, Department of Computing, The Hong Kong Polytechnic 
University 
Ms. DAI Yixin, PhD student, Department of Computing, The Hong Kong Polytechnic University 
 
Title 
Immersive virtual reality exposure for reducing preoperative anxiety in children – a randomized 
controlled trial 
  
Introduction 
Undergoing an operation is a major stress for both children and their families, with up to 50% of the 
children reported to have significant perioperative anxiety (1). High levels of perioperative anxiety in 
children manifest as tension, irritability and increased autonomic nervous system activity (2,3); and 
are associated with a multitude of adverse clinical outcomes, including increased postoperative 
analgesia requirement, increased postoperative emergence delirium, increased postoperative 
behavioural changes (e.g. nightmares, postoperative separation and general anxiety, eating problems 
that can persist up to 2 weeks after surgery). (1) Furthermore, it impacts patient and parental 
satisfaction, creating an overall negative experience for families and staff.  
 
The multifaceted risk factors of perioperative anxiety in children warrant a multi-modal array of tools 
up anaesthesiologists’ sleeves to tailor for different children’s needs based on age, understanding of 
instructions, and temperament (3). While pharmacological anxiolytics, e.g. Dexmedetomidine and 
Midazolam, are commonly deployed and effective, it has its limitations, such as time to effect, 
patient’s age, as well as paradoxical agitation reported up to 10% for Midazolam, as well as taking 
away a learning opportunity for children to cope with stress. (4) Common non-pharmacological 
approaches include parental presence during induction of anaesthesia, distraction techniques, and 
educational approaches.   
 
Traditional educational approaches often involve providing information to children and parents/legal 
guardians by written pamphlets, either physical or video tour of the operating room, recovery area, 
and orientation of medical equipment. With the advance of technology, children are often familiar and 
easily engaged with technological devices, including smart phones, tablets, video games, and even 
immersive virtual reality (VR). VR is increasingly utilized in clinical setting, providing a fun and 
engaging educational experience for children.  
 
VR utilizes a head-mounted display with visual, auditory and tactile stimuli to simulate a fully 
immersive 3-dimensional environment. Its application in the paediatric perioperative setting can be 
either as distraction during painful procedures or during induction of anaesthesia, or as an exposure 

tool in preoperative education. A meta-analysis of the effect of VR on preoperative anxiety shows a 
significant reduction of preoperative anxiety in paediatric patients (5). Ryu et al. utilized a famous 
cartoon character in the VR preoperative educational video and showed significant reduction in 
preoperative anxiety when compared to children receiving information through conventional means. 
(6,7) This benefit of VR exposure in reducing preoperative anxiety is not only evident in numerous 
studies (8-10) measuring anxiety score, but also demonstrated in studies measuring salivary cortisol 
concentration. (11, 12) 
 
In a joint project involving the Department of Computing of Hong Kong Polytechnic University, the 
Department of Computer science Center for Innovative Applications of Internet and Multimedia 
Technologies of the City University of Hong Kong and the Hong Kong Children’s Hospital (HKCH), 
an immersive VR operating theatre tour will be designed as part of preoperative education for 
children. A simulation of the perioperative journey in HKCH operating theatre will be created to help 
children form realistic expectations of their perioperative journey, and virtual exposure of different 
medical equipment helps children cope with their worries for the anticipated procedures. Parents/legal 
guardians will be able to monitor the VR experience on tablets via the monitoring software, which 
displays what the children see in VR. Given the fact that the capacity of conventional approaches, e.g. 
child-play involvement by child-life specialists are hugely limited now due to COVID pandemic, such 
a VR-enabled approach may help to alleviate patient's anxiety. 
 
 
Aims and objectives 
This study hopes to demonstrate the clinical effectiveness of virtual reality exposure in reducing 
children’s perioperative anxiety in Hong Kong Children’s Hospital.  
 
 
Design and setting 
This is a prospective and randomized controlled trial. 
 
Children who are planned to undergo elective surgeries in Hong Kong Children’s Hospital will be 
recruited in the study upon pre-anaesthetic assessment at clinic where written parental informed 
consent and paediatric assent (for patients >/= 7 years old) will be obtained. For patients aged 5-6, 
assent would be carried out by the study team through verbal communication. Everyone will receive 
standard medical care and provided with information regarding the perioperative journey as per usual 
practice, including watching an introductory video in the waiting room area with accompanying 
adults, receiving perioperative education by a pre-anaesthetic nurse, as well as having an opportunity 
to have any questions answered by an anaesthesiologist in the pre-anaesthetic assessment clinic. 
 
On the day of surgery where they are admitted for pre-surgery preparation, participants will complete 
a baseline anxiety assessment using the modified Yale Perioperative Anxiety Scale (mYPAS) (T0) 
(14) by a blinded researcher, after which they will be randomly assigned to intervention group (VR 
group) and conventional group (Non-VR group). Children assigned to the VR group will watch the 
designed VR immersive experience with headset, whereas children assigned to the non-VR group will 
receive standard medical care without any additional intervention. (Figure 1)  
 
 
 

 
 
Figure 1. The overall hardware setup and connections. 
 
 
All children will receive local anaesthetic cream to their dorsum of hands (EMLA or Ametop for 
those with contraindications to EMLA). Parents/legal guardians will accompany their children into the 
operating theatre until children are induced and unconscious unless parental refusal to do so. Patients 
will be allowed to lie down on the operating table, or sit up if preferred, when monitors including 
SpO2 probe, Blood pressure cuff, and 3-lead ECG are applied. Anaesthesiologists, who are blinded by 
the allocation, will conduct induction using either intravenous induction or inhalation induction. 
Inhalation induction would be used for those who refuse intravenous cannula placement or those who 
have received >1 failed attempt of intravenous cannula placement. Another set of mYPAS (T1), 
Induction compliance checklist and Procedure behaviour rating scale will be performed by a blinded 
researcher (either research assistant or anaesthesiologist involved) on the patient when they are on the 
operating table right before induction of anaesthesia.  Parents/legal guardians will be asked to fill in 
the State-Trait Anxiety Inventory (STAI) after accompanying their child during induction and while 
waiting outside. 
 
As primary outcome is measured at the start of induction and anaesthesiologists are blinded from the 
allocation, the conduct of anaesthesia, including drugs of choice for induction and maintenance, 
analgesia, and airway intervention, will be performed as per usual practice which is not standardized. 
Intravenous induction will comprise of an opioid (either Remifentanil 0.1-0.2mcg/kg/min or 1-
2mcg/kg Fentanyl), Propofol (either 2-4mg/kg bolus or TCI Paedfusor starting with Cp 5mcg/mL 
titrated until patient is unconscious) with 1mL of 0.5% Lignocaine to alleviate sting caused by 
propofol, +/- muscle relaxant of choice as required. Inhalational induction will comprise of using a 
mask smeared with artificial flavouring of choice, administering O2/N2O/ Sevoflurane mixture. After 
securing airway with either laryngeal mask or endotracheal tube, patients will be maintained on total 
intravenous anaesthesia with Propofol under Paedfusor Cp model or Sevoflurane/O2/Air. Patients will 
be given adequate multi-modal analgesia and anti-emetic as per usual practice, and will be extubated 
in operating theatre after the surgery. Parents/legal guardians will accompany the patients again in the 
recovery room as soon as possible. Lastly, parents/legal guardians will provide feedback by 
completing a parental satisfactory score. 
 

 
 
 
 
Hypothesis 
We hypothesize that virtual reality preparation can significantly reduce anxiety in children, defined as 
20% reduction in mYPAS score at induction compared to control group. 
 
Inclusion and exclusion criteria  
Inclusion criteria: 
• Age 5-12years old 
• American Society of Anaesthesiologist (ASA) physical status I or II 
• Undergo elective surgical procedures which requires general anaesthesia 
• No previous experience of anaesthesia or surgery 
 
Exclusion criteria: 
• Patients who are undergoing ultra-major surgery requiring postoperative intensive care unit care. 
• Patients who are blind, or with hearing impairment 
• Patients with significant developmental or cognitive delays, ADHD or autism 
• Patients with history or current symptoms of vertigo 
• Patients with history of epilepsy or seizures  
• Patients who require anxiolytic premedication 
• Patients who have physical conditions that prohibit use of headsets e.g. head / facial injuries, open 
skin or infectious condition on head/face, head/ facial malformation that precludes proper fitting of 
the VR headset 
• Non-Cantonese speaking patients (due to limited resources of having Cantonese speaking VR 
design)  
• Patients and/or parents/legal guardians who refuse to participate in study 
 
Sample size and statistical analysis 
A previous study (17) measuring perioperative anxiety in children at induction reported a mean mYPAS 
of 30.1 with a SD of 8.4. Using this data, a sample size of 30.1 for each arm is at least required to detect 
a 20% reduction in mYPAS score to achieve an alpha of 0.5 and power of 80%.  We aim to recruit 96 
children-parent pairs in order to account for 37.5% dropout rate due to change of surgery or anaesthesia 
plan, or loss to follow-up, as well as to increase the power for studying secondary outcomes.  
 
Preanaesthesia 
clinic
•Recruitment of 
patients based 
on inclusion and 
exclusion criteria
•All will receive 
conventional 
perioperative 
information 
including a 
perioperative 
video
Before surgery 
•Baseline 
assessment of 
mYPAS for all 
recruited patients 
(T0)
•Randomization by 
blinded 
researcher
•VR group receives 
VR tour
•Non-VR group:
no video
At induction of 
surgery
•The following 
scores will be 
assessed during 
anaesthesia 
induction:
•1. mYPAS (T1)
•2. Induction 
compliance 
checklist
•3. Procedure 
behaviour rating 
scale
•Parents fill in the 
state-trait 
anxiety 
inventory
In recovery 
room
•Parental 
satisfactory score 
by parents
Figure 2: Flowchart of assessments and interventions for recruited patients 

Mann-Whitney U test will be applied to compare non-parametric data such as mYPAS score, induction 
compliance checklist, procedural behaviour rating scale and parental satisfactory score. Statistical 
significance will be accepted for p < 0.05. Baseline categorical variables will be analyzed using the X2 
test or the Fisher exact test. 
 
 
Outcome and measurements 
Primary outcome is whether there is a significant reduction of anxiety of children at induction, 
defined by a 20% reduction in the modified Yale Preoperative Anxiety Scale (mYPAS) between 
control group and intervention group at T1.  
mYPAS is considered the gold standard in assessing preoperative anxiety in children (14), consisting 
of 27 items divided into five domains: activity, emotional expressivity, state of arousal, vocalization 
and use of parents/legal guardians, ranging from 23.3 to 100. A cut-off of >/= 30 indicates a high 
anxiety level in children. 
This instrument has been considered as a gold standard instrument for measuring preoperative anxiety 
and had been administered in many previous studies. mYPAS will be assessed by a blinded researcher 
or anaesthesiologist, at induction in the operating theatre.  
 
Secondary outcomes include baseline preoperative anxiety score using mYPAS at T0 (conducted 
before randomization by a blinded researcher), Induction compliance checklist, procedural behaviour 
rating scale, parental anxiety is evaluated by State-trait anxiety inventory (STAI), and parental 
satisfactory score.  
 
Randomization and Blinding  
Block randomization with stratification of age groups (5-8 years old, 9-12 years old) will be 
performed in a 1:1 allocation ratio.  
The study will be single-blinded where the assessors and anaesthesiologists conducting the 
anaesthesia will be blinded by the following arrangement: The preoperative baseline mYPAS will be 
conducted before allocation, and the assessor at induction will not be involved in the allocation 
process. Anaesthesiologists and recovery nurses are blinded and encouraged not to actively discuss 
the use of VR with patients and parents/legal guardians.  
 
Data handling and record keeping 
To protect patient privacy, all research data would be handled in line with HA/Hospital's policy in 
handling/storage/destruction of patients' medical records.  They would be locked in cabinets where the 
department keep confidential information.  Electronic data should be saved in secured computer of the 
hospital with restricted access.  Data collected will be destroyed after 3 years of publication.  
 
Ethical Implication 
All patients will receive standard medical care including information regarding the perioperative 
journey. VR itself is a non-invasive intervention, and patients will be reassured that they can terminate 
the VR appliance any time if they experience any discomfort. Although concerns of the risk of false 
memory formation have been raised, as children of young age may not be able to differentiate actual 
experience and imaginary play, adverse events are rarely reported. Risks of physical injury through 
collision into nearby objects while using the VR headset can be minimized by monitoring children in 
a spacious empty room devoid of obstacles. 
Besides, the issue of confidentiality is the major ethical issue, and will be solved by recording the data 
in a manner that does not allow the participants to be identified (i.e. using a non-recognizable code for 
each participants).  
 
This study will be conducted in compliance with Declaration of Helsinki and ICH-GCP. 
 
 
 
Study significance 

VR is an innovative technology with extensive applications in procedural anxiety and pain alleviation. 
Showing its effect on perioperative anxiety in children in our locality will give us a sustainable, 
simple, and non-pharmacological option of improving children’s coping and the perioperative journey 
for children and parents/legal guardians. 
 
Appendix: 
 
Modified Yale Perioperative Anxiety Scale (14) 
Calculation of score: Highest score of the observed behaviour is the score of each category. A partial 
weighted score is calculated by dividing the score by the total items of that category. All categories 
used are added together, multiply by 100 and divided by the number of categories used.   
Activity 
1. Looking around, curious, playing with toys, reading (or other age-appropriate behavior); 
moves around holding area/treatment room to get toys or to go to parent; may move toward 
operating room equipment 
2. Not exploring or playing, may look down, fidget with hands, or suck thumb (blanket); may 
sit close to parent while waiting, or play has a definite manic quality 
3. Moving from toy to parent in unfocused manner, non-activity-derived movements; 
frenetic/frenzied movement or play; squirming, moving on table; may push mask away or 
cling to parent 
4. Actively trying to get away, pushes with feet and arms, may move whole body; in waiting 
room, running around unfocused, not looking at toys, will not separate from parent, 
desperate clinging 
Vocalizations 
1. Reading (nonvocalizing appropriate to activity), asking questions, making comments, 
babbling, laughing, readily answers questions but may be generally quiet; child too young 
to talk in social situations or too engrossed in play to respond 
2. Responding to adults but whispers, "baby talk," only head nodding 
3. Quiet, no sounds or responses to adults 
4. Whimpering, moaning, groaning, silently crying 
5. Crying or may be screaming "no" 
6. Crying, screaming loudly, sustained (audible through mask) 
Emotional expressivity 
1. Manifestly happy, smiling, or concentrating on play 
2. Neutral, no visible expression on face 
3. Worried (sad) to frightened, sad, worried, or tearful eyes 
4. Distressed, crying, extreme upset, may have wide eyes 
State of apparent arousal 
1. Alert, looks around occasionally, notices or watches what anesthesiologist does (could be 
relaxed) 
2. Withdrawn, sitting still and quiet, may be sucking on thumb or have face turned into adult 
3. Vigilant, looking quickly all around, may startle to sounds, eyes wide, body tense 
4. Panicked whimpering, may be crying or pushing others away, turns away 
Use of parents 

1. Busy playing, sitting idle, or engaged in age-appropriate behavior and doesn't need parent; 
may interact with parent if parent initiates the interaction 
2.  Reaches out to parent (approaches parent and speaks to otherwise silent parent), seeks and 
accepts comfort, may lean against parent 
3. Looks to parent quietly, apparently watches actions, doesn't seek contact or comfort, 
accepts it if offered or clings to parent 
4. Keeps parent at distance or may actively withdraw from parent, may push parent away or 
desperately clinging to parent and not let parent go 
 
Induction Compliance Checklist (16) 
Checklist 
Score (1 for each category) 
Crying, tears in eyes 
 
Turns head away from mask 
 
Verbal refusal, says “no” 
 
Verbalization indicating fear or worry, “where’s mommy?” or 
“will it hurt?” 
 
Pushes mask away with hands, pushes nurse/ anaesthetist with 
hands / feet 
 
Covers mouth/ nose with hands / arms or buries face 
 
Hysterical crying, may scream 
 
Kicks / flails legs / arms, arches back, and/or general struggling 
 
Requires physical restraint 
 
Complete passivity, either rigid or limp 
 
 
Procedure Behaviour Rating Scale (PBRS) 
 
Description 
Score 
Cry 
Tears in eyes or running down face 
 
Cling 
Physically holds on to parent, significant other, or nurse 
 
Fear verbal 
Says “I’m scared”, “I’m afraid” etc 
 
Pain verbal 
Says “Ow”, “Ouch," "It hurts," "You're hurting me," etc. 
 
Groan 
Nonverbal, vocal expresion of pain or discomfort 
 
Scream 
No tears, raises voice, verbal or nonverbal 
 
Laugh 
Smiling with a chuckling sound 
 
Stall 
Verbal expression of delay (“Wait a minute,” “I’m not ready yet”, etc 
or behavioural delay (ignores nurse’s instructions) 
 
Stoic silence 
Child does not respond to questions or remarks of others, may 
appear "trancelike" 
 
Carry 
Has to be physically carried into or out of room or placed on 
table, not because of physical inability to do so on his or her 
own 
 
Flail 
Random gross movements of arms or legs, without intention to make 
aggressive contact 
 
Nausea verbal 
Says "I'm sick," "I feel nauseous," "My stomach feels like I'm 
going to throw up" 
 
Vomit  
Includes retching, dry heaves 
 
Urinate/defecate Soils or wets self 
 
Kick 
Intentional movement of leg(s) to make aggressive physical 
contact 
 
Hit 
Intentional movement of arm(s) or hand(s) to make aggressive 
physical contact 
 

Bite 
Intentional closing of jaw to make aggressive physical contact 
 
Verbal hostility 
Says "I hate you," "You're mean," etc. 
 
Refusal position Does not follow instructions with regard to body placement on 
treatment table 
 
Restrain 
Has to be held down because of lack of cooperativeness 
 
Curse 
Verbally utters profanity 
 
Muscular 
rigidity 
Any of following behaviors: clenched fists, white knuckles, 
gritted teeth, clenched jaw, wrinkled brow, eyes clenched shut, 
contracted limbs, body stiffness 
 
Questions 
Nondelay, information-seeking verbal behavior ("What are you 
doing now?" Is it over yet? etc.) 
 
Emotional 
support 
Verbal or nonverbal solicitation of hugs, physical comfort, or 
expression of empathy from parent, significant other, or nurse 
 
Requests 
termination 
Verbally asks/pleads that procedure be stopped 
 
Total Score (25):  
 
一、 State Trait Anxiety Inventory for Adults   
二、 Read each statement and select the appropriate response to indicate how you feel right now, 
that is, at this very moment. There are no right or wrong answers. Do not spend too much 
time on any one statement but give the answer which seems to describe your present feelings 
best. 
State Anxiety Scale Items 
0 
Not at all 
1 
A little 
2 
Somewhat 
3 
Very much so 
1. I feel calm 
 
 
 
 
2. I feel secure 
 
 
 
 
3. I am tense 
 
 
 
 
4. I feel strained 
 
 
 
 
5. I feel at ease 
 
 
 
 
6. I feel upset 
 
 
 
 
7. I am presently worrying over possible 
misfortunes 
 
 
 
 
8. I feel satisfied 
 
 
 
 
9. I feel frightened 
 
 
 
 
10. I feel comfortable 
 
 
 
 
11. I feel self-confident 
 
 
 
 
12.  I feel nervous 
 
 
 
 
13.  I am jittery 
 
 
 
 
14.  I feel indecisive 
 
 
 
 
15.  I am relaxed 
 
 
 
 
16. I feel content 
 
 
 
 
17. I am worried 
 
 
 
 
18.  I feel confused 
 
 
 
 
19. I feel steady 
 
 
 
 
20.  I feel pleasant 
 
 
 
 
Trait Anxiety Scale Items 
0 
Almost 
never 
1 
Some-
times 
2 
Often 
3 
Almost  
always 

21. I feel pleasant 
 
 
 
 
22. I feel nervous and restless 
 
 
 
 
23.  I feel satisfied with myself 
 
 
 
 
24. I wish I could be as happy as others 
seem to be 
 
 
 
 
25. I feel like a failure 
 
 
 
 
26.  I feel rested 
 
 
 
 
27.  I am ‘calm, cool, and collected’ 
 
 
 
 
28. I feel that difficulties are piling up so 
that I cannot overcome them 
 
 
 
 
29. I worry too much over something that 
really doesn’t matter 
 
 
 
 
30. I am happy 
 
 
 
 
31. I have disturbing thoughts 
 
 
 
 
32. I lack self confidence 
 
 
 
 
33. I feel insecure 
 
 
 
 
34. I make decisions easily 
 
 
 
 
35. I feel inadequate 
 
 
 
 
36. I am content 
 
 
 
 
37. Some 
unimportant 
thought 
runs 
through my mind and bothers me 
 
 
 
 
38. I take disappointments so keenly that I 
can’t put them out of my mind 
 
 
 
 
39. I am a steady person 
 
 
 
 
40. I get in a state of tension or turmoil as I 
think about my recent concerns and 
interests 
 
 
 
 
 
Parental Satisfactory Score 
English version: Please tick the most appropriate box for each question. 
 
Very Unsatisfied (1) 
Not satisfied (2) 
Satisfied (3) 
Very satisfied (4) 
Are you satisfied with our preadmission service? (Pre-anaesthetic 
assessment/Pre-anaesthesia clinic) 
 
 
 
 
Are you satisfied with our preoperative instructions? 
 
 
 
 
Are you satisfied with the operating theatre service? 
 
 
 
 
Are you satisfied with postoperative service? 
 
 
 
 
 
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