Animation-Based Caregiver-Patient Interaction Model for Postoperative Pain Management in Preschool Children with Congenital Heart Disease

Summary

This study aimed to explore the effect of an animation-based caregiver-patient interaction model on postoperative analgesia in children of preschool age with congenital heart disease, to evaluate its value in reducing postoperative pain and perioperative anxiety, and to provide evidence-based practical guidance for optimizing pain management for such children.

Abstract

This study aimed to evaluate an animation-based caregiver-patient interaction model for postoperative pain and anxiety management in preschool children with congenital heart disease (CHD). This randomized controlled trial included 70 preschoolers undergoing CHD surgery under general anesthesia, who were enrolled in the Cardiac Critical Care Unit at Beijing Children's Hospital (June-October 2024). Participants were stratified into intervention (n=35) and control (n=35) groups. The control group received standard postoperative care, while the intervention group additionally received a structured animation-based program involving preoperative personalized animation selection, post-extubation viewing (≤30 min/session, 3-6 times/day) with nurse-guided interaction, and parental involvement. Pain (WongBaker FACES scale) and anxiety (mYPAS) were assessed at 1 h/6 h postextubation, 24 h/48 h postsurgery, during OR transport, and 24 h postsurgery. Pain was assessed at four time points: 1 h/6 h post-extubation and 24 h/48 h post-surgery. At 1 h post-extubation, there was no significant difference in pain scores between the intervention and control groups (median 9 vs 8, p = 0.462). Pain scores were significantly lower in the intervention group than in controls at 6 h post-extubation (median 6 vs 9), 24 h post-operative (3 vs 6), and 48 h post-operative (2 vs 4); all p < 0.001. Anxiety scores (m-YPAS) were also significantly lower in the intervention group, both on transport to the OR (median 76 vs 80) and at 24 h after surgery (60 vs 80), p < 0.001. Friedman tests demonstrated significant within-group changes over time in anxiety levels (intervention p < 0.001), confirming that the intervention group experienced substantially reduced anxiety at these two key perioperative time points. The interactive animation model significantly reduces postoperative pain and perioperative anxiety in preschool patients with CHD, offering a safe non-pharmacological adjuvant for pain management.

Introduction

Congenital heart disease (CHD) is a common birth defect caused by abnormal development of the heart and large blood vessels during embryonic development^1,2 and is the leading cause of birth defects, seriously threatening the health of children³. Surgical treatment is the main method; however, pain management after surgery is still a key clinical challenge⁴. Postoperative pain not only brings significant discomfort but is also an important factor in inducing cardiovascular and pulmonary complications and poor prognosis, which has a dual impact on the child's physical and mental health in the short and long term^5,6. Therefore, scientific and effective postoperative pain management is crucial for the child's rehabilitation⁷.

At present, analgesic drugs are the main means of postoperative pain management; however, there is a risk of side effects, which has led to increasing attention to non-pharmacological interventions (NPIs) as an important complementary or alternative strategy⁸. Among many NPIs, audio-visual distraction therapy (e.g., animations, animated videos) has shown unique potential for preschool children (aged 3-7 years), whose developmental characteristics directly inform the design and effectiveness of such interventions⁹. This age group is in Piaget's preoperational stage, with distinct developmental traits that demand targeted intervention strategies, as follows: limited abstract reasoning and reliance on concrete visual cues - preschoolers cannot process abstract explanations of medical procedures or pain but respond strongly to vivid, image-based content¹⁰; short attention spans (10-15 min) - their ability to sustain focus is limited, requiring brief, frequent engagement to avoid fatigue¹¹; high emotional sensitivity and dependence on trusted adults - separation from parents, unfamiliar clinical environments and painful stimuli easily trigger intense fear and anxiety, which are amplified by their immature emotional regulation skills¹²; preference for active, playful participation - they learn and cope through play and interaction, rather than passive reception of information¹³. The results showed that after using personalized animation or films to distract the children, the preoperative anxiety level of the children was significantly reduced, the cooperation rate of anesthesia induction was improved to 94.2% and the incidence of agitation during the recovery period was reduced by 21.5% compared with the routine nursing group¹⁰.

The study further shows that audio-visual interventions can effectively divert children's attention from medical procedures through immersive narrative experiences, thereby improving perioperative behavioral responses. However, there are still obvious limitations in current research. First, there is relatively little research on audio-visual interventions for the specific vulnerable group of children with CHD before school age, especially for pain management after complex heart surgery¹¹. Second, most studies regard audio-visual materials as passive tools to distract attention, fail to effectively integrate the core element of caregiver-patient interaction, ignore the nurse's active role in guiding children to participate in content, emotional communication, and parental collaboration, and limit the depth and breadth of intervention effects. The absence of interactive design elements results in a one-dimensional intervention model, which significantly impairs the ability to unlock the full psychological support potential of audiovisual media tools. In addition, in terms of how to personalize the animation content according to the individual preferences of the children (such as age, interest), research on the communication skills and operating procedures of standardized nurses in interactions (such as playing time, frequency, and interaction methods) is still insufficient, which hinders the standardization and clinical promotion of this model. Therefore, there is an urgent need to develop and validate a systematic intervention model based on animation that focuses on the child, strengthens the interaction between caregivers and patients, covers the key stages of the perioperative period, and combines parental support. Such a model would fill the gap of efficient and feasible non-pharmacological strategies in postoperative pain management of preschool children with CHD.

The proposed interactive animation model of this research differs from standard passive audio-visual distraction by incorporating structured nurse-child interaction, personalized content selection, and family involvement. Compared with conventional distraction alone, which shows limited and inconsistent efficacy in patients with CHD (pain relief rates 15%-28%)¹⁴, the interactive model is designed to enhance engagement, sustain attention, and provide emotional co-regulation, thereby potentially offering superior and more consistent outcomes.

This model is intended for use in pediatric cardiac intensive care or surgical wards with dedicated nursing staff. The minimum requirements include at least one nurse per shift trained in child-communication and interactive animation techniques, access to portable electronic devices (tablets/smartphones) with preloaded, age-appropriate animated content, and a quiet, child-friendly environment to minimize distractions. Feasibility may be limited in settings with high nurse-to-patient ratios, a lack of devices, or insufficient training time. The approach may not be suitable for children with severe visual/hearing impairments, cognitive delays, or requiring immediate emergent care.

The purpose of this study is to explore the effect of an animation-based caregiver-patient interaction model on postoperative analgesia of children with CHD before school age, to evaluate its value in reducing postoperative pain and perioperative anxiety, and to provide evidence-based practical guidance for optimizing pain management for such children.

Protocol

This study employs a prospective, randomized, controlled trial design. A total of 70 children who underwent surgery for CHD under general anesthesia in the Pediatric Cardiac Critical Care Unit (CCU) of Beijing Children's Hospital Affiliated to Capital Medical University between June 2024 and October 2024 were selected as the research participants. This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Beijing Children's Hospital, Capital Medical University (Approval Number: 2024-Y-199-D, Approval Date: 20 Aug 2024). The trial was retrospectively registered at ClinicalTrials.gov on January 6, 2026 (Registration Number: NCT07319260). Prespecified outcomes and time points were documented in the registration protocol and are consistent with the study design reported herein. Written informed consent was obtained from the parents or legal guardians of all participating children prior to their enrolment in the study.

1. Participant selection and grouping

1. Inclusion criteria
   1. Include children diagnosed with CHD who underwent surgical treatment according to the Guidelines for the Diagnosis and Treatment of CHD in Children¹² and cardiac ultrasound imaging.
   2. Ensure they are aged between 3 to 7 years, both limits inclusive.
   3. Select participants where the surgical method was an open-chest operation.
   4. Include children with a diagnosis of ventricular septal defect, atrial septal defect, or atrial septal defect combined with ventricular septal defect and patent ductus arteriosus, tetralogy of Fallot, vascular ring, or partial atrioventricular septal defect.
2. Exclusion criteria
   1. Exclude patients with other chronic diseases, neuropsychiatric diseases, or malignant tumors. Also, exclude patients with CHD and other organ malformations.
   2. Exclude persons with intellectual disabilities, developmental delays, or behavioral disorders.
   3. Exclude children with hearing or communication disabilities and whose parents are mentally retarded or suffer from mental illness.
3. Participant discontinuation
   1. Discontinue intervention if the participant cannot pull out the tube after the operation or has a non-scheduled reoperation within 48 h after surgery.
   2. Exclude if, after the operation, there is a consciousness disorder or a change in the condition that makes it impossible to communicate normally.
   3. Remove if the patient stops the treatment due to other reasons, such as transfer to another hospital, transfer to another department, or death in the middle of treatment.
   4. Remove children and their families who choose to withdraw from study for various reasons.
4. Sample calculation
   1. For this study, use the sample size calculation formula for comparing the means of two independent samples for estimation:
      N1 = N2 = 2 × (Zα + Zβ)2σ²/δ²
   2. For the main outcome measure, use the Wong-Baker FACES pain score (0-10 points) as the main efficacy index.
   3. For source of parameters, refer to recent research data on pain management in children after surgery for CHD (for example, the Wong-Baker score in similar populations), assuming the standard deviation of the pain score σ = 1.2 and the expected score difference between the intervention group and the control group δ = 1.0 (i.e. the smallest clinically meaningful difference).
   4. For assessing the significance level and degree of confidence, set up a two-sided test significance level α = 0.05(Zα/2 =1.96), certainty 1 − β = 0.90(Zβ = 1.282). Calculate the n value as
      N1 = N2 = 2 × (Zα + Zβ)2σ² / δ² ≈ 32,
      i.e., each group needs ≥32 participants.
   5. Assuming approximately 10% dropouts or missing data may occur during the research process, expand the sample size by 10%; therefore, a total of 70 participants were included in this study, with 35 participants in the intervention group and 35 participants in the control group.
5. Subject grouping
   1. Perform grouping and allocation using the hierarchical block randomization method. First, determine the following stratification factors based on the known prognostic influencing factors: age group (3-5 years vs 6-7 years); disease complexity (simple type vs complex CHD); surgical type (thoracotomy vs minimally invasive surgery).
   2. Generate random sequences using computers by statisticians who were not involved in the implementation of the study and assign participants to the intervention group and the control group in a 1:1 ratio.
   3. Keep the random allocation plan in a sealed, opaque envelope and perform grouping by an independent research coordinator after the patients are enrolled. Make grouping information available to the nursing team responsible for implementing the intervention but keep the outcome assessors blinded.
   4. In the control group, there were 17 boys and 18 girls, with a median age of 5 years (4 years, 6 years) and a weight of 19 kg (16.6 kg, 22 kg). In the intervention group, there were 14 boys and 21 girls, with a median age of 4 years (3 years, 5 years) and a weight of 16.8 kg (13.4 kg, 20.9 kg). Ensure there is no statistically significant difference in the basic data between the two groups, and that they are comparable.

2. Interventions

1. For all children, carry out standardized general anesthesia during the operation.
2. After extubation, for the control group, perform routine nursing care, whereas for the intervention group, perform the animation-based caregiver-patient interaction model treatment.
3. Carry out the nursing operations by two independent teams to avoid cross-interference, as follows: intervention group - 8 nurses who completed a standardized 6-h training program on animation-based interaction; control group - 8 nurses only receiving routine perioperative training (no exposure to the animation intervention protocol).
4. For the intervention group's training, cover three core competencies, with pre- and post-training assessments to verify proficiency: competency 1 - child-centered communication (e.g., age-appropriate language, open-ended questioning, emotional feedback techniques); competency 2 - intervention protocol fidelity (e.g., 15 min session duration, 3-4 min interaction checkpoints, parental coordination guidance); competency 3 - pain/anxiety scale administration (Wong-Baker FACES, m-YPAS) to ensure consistent assessment.
5. Evaluate inter-rater reliability among the 8 trained nurses using Cohen's kappa coefficient: kappa = 0.88 for protocol adherence (e.g., interaction frequency, session timing) and kappa = 0.91 for scale scoring. A kappa ≥ 0.85 was defined as excellent agreement, confirming uniform implementation of the intervention.
6. Prevent cross-contamination in the shared CCU environment by following the guidelines provided. Assign teams to separate daily shifts (no overlap in patient care hours); make each team responsible for a dedicated subset of beds (geographically separated within the CCU); provide nurses additional training on maintaining protocol blinding (e.g., no discussion of intervention details with the control team).
7. Monitor adherence to the assigned protocol via real-time checklists completed by nurses after each care episode (documenting intervention steps, session duration and interaction fidelity), weekly audits by the research coordinator (reviewing checklists, nursing records, and direct observation of 10% of sessions), and electronic logs on tablets (tracking animation viewing time and frequency) in the intervention group. Document and address any deviations immediately (e.g., retraining for nurses with low fidelity).
8. Control group
   NOTE: The nursing team in this study consisted of 30 nursing staff aged 23-40 years. All had received training in standardized peri-operative nursing but had not undergone special training on the animation intervention model.
   1. Post-operative routine nursing
      1. For the control group, carry out routine pain nursing. After transferring the children to the intensive care unit and removing the tracheal intubation during the post-operative period, perform post-operative management according to the routine nursing process.
      2. Follow the World Health Organization Guidelines on the Management of Chronic Pain in Children¹⁴ and the Practice Recommendations for the Management of Postoperative Pain in Children of the European Society for Paediatric Anaesthesiology¹⁵, including monitoring vital signs, maintaining water (electrolyte and acid) base balance, pulmonary and catheter nursing, oral administration of ibuprofen 5 (10 mg/kg as needed, single dose ≤400 mg) and routine soothing measures (hugging, caressing).
   2. Pain management
      1. Pain assessment: Use the Wong-Baker Pain Scale to assess the child's pain level every 4 h to adjust the corresponding nursing measures in time.
      2. Non-pharmacological intervention: When the child cries due to pain, ask the caregiver to use NPI methods, such as holding, soothing, and touching.
      3. Drug pain management: The peak period of pain occurs from 24 to 72 h after surgery. Ask nurses to administer oral or intravenous analgesics as prescribed by the doctor and according to the child's condition. Generally, it lasts for 3 consecutive days; some children need to extend the analgesic time.
9. Intervention group
   NOTE: The intervention group added an animation-based caregiver-patient interaction model to the routine care, which was developed by the research team based on distraction theory and the framework for alleviating medical fear in children. The specific content of the intervention group nurse training program and the detailed standards of the personalized animation library can be found in Supplementary Table 1, Supplementary Table 2, Supplementary Table 3, and Supplementary File 1.
   1. Preoperative preparation
      1. At 2-4 h before transfer to the operating room (OR), ask the trained nurse to spend 15-20 min with the child and parent, guide the child to choose three preferred animations from the personalized library, and engage in a brief (5-7 min) role-play discussion based on a chosen animation to establish rapport. Confirm engagement by observable indicators, such as the child maintaining eye contact, verbally responding to questions or actively participating in pretend play.
   2. Post-operative interactive session
      1. Initiation: Commence the first session within 30-60 min after successful extubation and confirmation of the child being awake and responsive (defined as a score of ≥9 on the Modified Aldrete Scale).
      2. Session structure: Play the child's selected animation on a tablet. Duration: Ensure each session lasts for a precisely timed 15 min period. Pause the session if the child shows signs of significant distress or fatigue or requests to stop. Frequency: Conduct sessions at 4 h intervals (approximately 3x in the first 12 h post-extubation), not exceeding three sessions per 24 h period. Interactive checkpoints: At 3-4 min intervals during viewing, ask the nurse to pose a simple, open-ended question related to the animation plot (e.g., What do you think will happen next?).
      3. Record active engagement if the child provides a relevant verbal or non-verbal (e.g., pointing, nodding) response. Emotional feedback: Immediately following the child's response or at natural story pauses, ask the nurse to provide specific, positive feedback (e.g., You remembered that detail so well!). Environmental control: Adjust the device's brightness and volume to a comfortable level (volume ≤ 50% of maximum, brightness adjusted to room light) prior to starting.
   3. Parental coordination
      1. Instruct the parents to engage in a 5 min post-session discussion with their child about the animation, offering a sticker as a reward for participation. Nurses verify this step through brief, informal parent feedback at the next scheduled contact.
   4. Protocol completion criterion
      1. Conclude the intervention protocol after the final data collection point at 48 h post-surgery. Administer no further structured animation sessions as part of the study protocol beyond this time point.

3. Observation indicators and data collection

1. In this study, assess the relevant indicators of pain assessment, perioperative anxiety assessment, and analgesic medication used in the two groups of children after surgery.
2. Pain assessment
   1. Assess pain using the Wong-Baker FACES Pain Rating Scale. Set the evaluation time points as 1 h post-extubation (approximately 6 h post-surgery), 1 h post-extubation (approximately 12 h post-surgery), 24 h post-surgery, and 48 h post-surgery. The total score of the scale is 10 points, and the scoring range is defined as 0-10 points: 0-3 points indicate no pain or mild pain, 4-7 points indicate moderate pain and 8-10 points indicate severe pain. The reliability and validity of the scale have been verified by Chinese groups (Cronbach's alpha = 0.89)¹⁶.
3. Anxiety assessment
   1. Use the m-YPAS to evaluate the anxiety of the patient on the day of admission, the 1^st day before surgery, on the way to the OR, on the 1^st day after surgery, and on the 2^nd day after surgery.
   2. The scale includes activities, vocalizations, emotional expression, obvious alertness, and dependence on parents (five dimensions, 22 items). The total score range is 21-100 points; the higher the score is, the higher the anxiety level of the patient. Confirm validity in preschool surgical patients with area under the receiver operating curve as 0.91¹⁷.
4. Analgesic medication used assessment
   1. Data collection content: Record the following information: the type of analgesic medications used (including oral ibuprofen and intravenous opioids, such as fentanyl), total dosage (calculated as mg/kg for weight-based medications), administration timing (including time of first dose and intervals between doses) and use of rescue analgesics (defined as additional analgesic administration due to pain score ≥ 7 points despite routine analgesia) for each child within 48 h after surgery.
   2. Data collection method: Ask nurses to record medication administration information in real time using a standardized analgesic medication log, including drug name, dosage, administration route, and time. Review the log and verify it by the research coordinator daily to ensure accuracy.

4. Statistical analysis

1. Use the SPSS 27.0 software package for analysis. Test measurement data first for normality using the Shapiro-Wilk test. Express non-normally distributed data as median (interquartile range [IQR]) and normally distributed data as mean ± standard deviation.
2. Apply consistent non-parametric tests for non-normally distributed data, the Mann-Whitney U test for between-group comparisons, and the Friedman test for within-group differences across multiple time points.
3. For analgesic consumption data (non-normally distributed), use the Mann-Whitney U test. Perform a covariance analysis (ANCOVA) to adjust for total analgesic dosage (ibuprofen equivalent) when comparing pain scores between groups (ANCOVA was deemed appropriate here as residuals met normality assumptions).
4. To reduce the risk of Type I errors from multiple comparisons across time points, apply the Holm-Bonferroni correction to all pairwise between-group comparisons (e.g., pain/anxiety scores at different time points) and within-group repeated measures. A two-sided P-value of <0.05 (after correction) was considered statistically significant.

Results

In the control group, there were 35 participants, comprising 17 boys and 18 girls. Among them, 2 participants were diagnosed with atrial septal defect and 33 with ventricular septal defect. In the intervention group, there were also 35 participants, comprising 14 boys and 21 girls. Among them, 1 participant was diagnosed with partial atrioventricular canal repair, 1 with partial pulmonary vein connection repair, 4 with atrial septal defect, and 29 with ventricular septal defect.

Person...

Discussion

This study confirmed through a control experiment that the caregiver-patient interaction model based on animations can significantly reduce the postoperative pain and perioperative anxiety level of children before school age with CHD and is associated with lower analgesic medication consumption. This finding provides new evidence-based support for non-pharmacological pain management in children after surgery, while revealing the unique advantages of interactive audio-visual interventions compared with traditional passive...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Cardiovascular ultrasound system		Siemens
SPSS		IBM