MOLI Technique and Virtual Reality Versus Conventional Venipuncture for Pain and Anxiety in Children

Study design. Single-centre, parallel three-arm randomised controlled trial with 1:1:1 allocation, without blinding of participants or study personnel, and analysed under the intention-to-treat principle. Designed and reported in accordance with the CONSORT 2025 guidelines for parallel-group randomised trials and the TIDieR checklist for intervention description.

Setting and sample size. Conducted between 1 November 2024 and 31 August 2025 in the paediatric emergency department, paediatric short-stay unit and paediatric inpatient ward of a tertiary university hospital in northern Spain. Sample size was calculated using the GRANMO calculator to detect a between-group difference in pain intensity of at least 1 point (Faces Pain Scale-Revised) with an expected standard deviation of 0.5 points, accepting a two-sided alpha of 0.05, 80% power, an anticipated dropout rate of 5%, and Bonferroni adjustment for multiple pairwise comparisons. A total of 201 children (67 per arm) were required.

Randomisation. A statistician independent of the clinical team generated the randomisation sequence using Epidat 4.2 with permuted blocks of variable size (6 and 9). Group identifiers were placed in sealed, opaque, sequentially numbered envelopes. Because of the nature of the interventions, blinding of participants, families and staff was not possible. Statistical analysis was performed by an investigator who had not participated in allocation or intervention delivery.

Interventions. All interventions were delivered by paediatric nurses trained in a preparatory session before the trial start. The MOLI technique combined standardised positioning on the caregiver's lap, playful reframing of clinical devices, a forced slow-expiration exercise using a paper pinwheel held by the caregiver, and visual concealment of the venipuncture material by an assistant nurse. The virtual reality arm used a Meta Quest 3 headset with the Fruit Ninja VR application (Classic mode); positioning and family involvement were identical to the MOLI arm, replacing the pinwheel with the headset. The conventional arm consisted of standardised positioning, gentle limb restraint by an assistant nurse and family emotional support, without any structured distraction technique.

Outcomes. Primary outcomes were pain intensity (Faces Pain Scale-Revised, 0-10) and procedural anxiety (Groningen Distress Scale, 1-5) assessed immediately after peripheral venous catheter insertion. Secondary outcomes were pre and post-procedure heart rate (bpm), first-attempt insertion success, procedure duration, successful blood sampling and adverse events attributable to each intervention.

Statistical analysis. Continuous variables were summarised as mean and standard deviation or median and interquartile range depending on distribution. Between-group comparisons used the Kruskal-Wallis test with epsilon squared as the effect-size measure. Post-hoc pairwise comparisons were performed with Mann-Whitney U tests using Bonferroni adjustment for three comparisons, reporting r as the effect-size measure. Categorical variables were compared with the Chi-square test. A pre-specified age-subgroup analysis (4-6, 7-9, 10-12 years) was performed for the primary outcomes. All tests were two-sided at the 5% level.