Pediatric Venipuncture Trial Puts Virtual Reality Against a Pinwheel Breathing Protocol
Venipuncture remains one of the most unsettling procedures in pediatric care, and the MOLIVeR trial was built around a very practical question: can a structured breathing-based distraction method work as well as immersive virtual reality, and better than conventional technique, when children need a peripheral venous catheter? The completed study, registered at ClinicalTrials.gov under NCT07878117, enrolled 201 children between 4 and 12 years of age in a tertiary university hospital in northern Spain and compared three approaches to procedural support during cannulation. Investigators set out to measure both pain and anxiety immediately after the procedure, using the Faces Pain Scale-Revised and the Groningen Distress Scale as primary endpoints.
The trial’s central idea is clinically grounded. Venipuncture is brief, but in a child it can trigger a disproportionate stress response, with anticipatory fear, muscle tension, and a heightened perception of pain all feeding into one another. A technique that slows expiration, redirects attention, and preserves the child’s sense of control may interrupt that loop at the bedside. Immersive virtual reality aims at the same endpoint through a different pathway, occupying attention with a competing sensory environment.
Three Arms, One Question, and a Tight Procedural Window
MOLIVeR used a single-center, parallel, three-arm randomized design with 1:1:1 allocation. The intervention arms were the MOLI technique, immersive VR using a Meta Quest 3 headset with Fruit Ninja VR in Classic mode, and a conventional venipuncture technique. All interventions were delivered by trained pediatric nurses after a preparatory session before trial start. Children, families, and clinical staff could not be blinded because the interventions were visibly different, but allocation was handled through sealed, opaque, sequentially numbered envelopes generated by an independent statistician, and the analysis was performed by an investigator who had not participated in allocation or intervention delivery.
A single sentence captures the physiologic logic behind the protocol.
The design matters because venipuncture pain unfolds in minutes, not hours, and the intervention must act immediately on attention, breathing pattern, and procedural fear.
The MOLI technique itself combines several bedside maneuvers that are easy to miss when they are not written down carefully. Children were positioned on a caregiver’s lap, with the caregiver and nurse working together in a standardized sequence. The procedure included playful reframing of the equipment, a forced slow-expiration exercise using a paper pinwheel held by the caregiver, and visual concealment of the venipuncture material by an assistant nurse. In effect, the protocol braided movement, observation, and active ludic engagement into a single distraction strategy, with immersion coming from the child’s focused breathing and visual attention.
Why the Comparator Choice Matters in Real Pediatric Care
Virtual reality has become one of the more visible nonpharmacologic tools for procedural distress, but pediatric teams rarely get to compare it directly with a low-cost breathing protocol that can be deployed without a headset. That direct comparison is the strength of this trial design. The conventional arm did not leave the child unsupported; it used standardized positioning, gentle limb restraint by an assistant nurse, and family emotional support, but no structured distraction method. In other words, the comparator reflects usual procedural care rather than a stripped-down control.
The trial was conducted in three pediatric settings within the same institution: the emergency department, the short-stay unit, and the inpatient ward. Eligibility was limited to children aged 4 to 12 years with a clinical indication for peripheral venous catheter insertion, triage priority III, IV, or V in the Andorran Model of Triage-Spanish Triage System pediatric version, and parental consent with age-appropriate child assent. Several exclusions protected the interpretability of the anxiety and pain assessments, including language barriers, severe respiratory distress, Glasgow Coma Scale of 14 or less, sensory conditions that could alter pain perception, seizure or recurrent syncope history, neurocognitive delay, and visual or hearing impairment incompatible with the headset or verbal communication.
Endpoint Selection Reflects Bedside Priorities
The study focused on outcomes that matter during a single procedure rather than delayed recovery. Pain intensity was captured immediately after catheter insertion with the Faces Pain Scale-Revised, a choice that fits the age range and keeps the measure accessible for young children. Anxiety was assessed with the Groningen Distress Scale, giving the trial a second primary endpoint that reflects the emotional burden of the procedure rather than pain alone. Secondary outcomes included pre- and post-procedure heart rate, first-attempt insertion success, procedure duration, successful blood sampling, and adverse events attributable to each intervention.
Those secondary measures are not cosmetic additions. Heart rate can reflect sympathetic arousal, first-pass success can reveal whether agitation interfered with the procedure, and procedure duration can matter in a crowded pediatric unit where repeated attempts can escalate distress for both child and staff. A distraction strategy that improves subjective pain but delays the procedure or complicates access would be less useful in actual practice.
Sample Size, Randomization, and Reporting Discipline
Investigators calculated the sample size with the GRANMO calculator, aiming to detect a between-group difference of at least 1 point on the Faces Pain Scale-Revised, with an expected standard deviation of 0.5 points, a two-sided alpha of 0.05, 80% power, a 5% anticipated dropout rate, and Bonferroni adjustment for multiple pairwise comparisons. That calculation yielded a target of 201 children, or 67 per arm. The final enrollment matched that target exactly.
Statistical methods were pre-specified and appropriately conservative for a three-arm pediatric trial. Continuous variables were summarized using mean and standard deviation or median and interquartile range, depending on distribution. Between-group comparisons used the Kruskal-Wallis test with epsilon squared as an effect-size measure, followed by Mann-Whitney U tests for pairwise comparisons with Bonferroni correction and r as the effect-size measure. Categorical variables were compared with the Chi-square test, and age subgroup analyses were planned for 4 to 6, 7 to 9, and 10 to 12 years. The trial was designed and reported in line with CONSORT 2025 guidelines for parallel-group randomized trials and the TIDieR checklist for intervention description.
What This Completed Trial Can and Cannot Yet Answer
The record shows a completed study with a clear procedural question, a well-defined pediatric population, and a three-way comparison that should help clarify whether a pinwheel-guided breathing method can compete with immersive VR for venipuncture support. What the registry entry does not yet provide are the results themselves, so no claims can be made about superiority, equivalence, or safety differences between arms. The study also remains single-center, which limits immediate generalization beyond the hospital setting in Santander, Cantabria.
Even so, the protocol speaks directly to the daily mechanics of pediatric care. A nurse can position the child, a caregiver can coach breathing, a headset can occupy visual attention, and a second nurse can shield the catheter materials from view. The remaining question is not whether these tools are plausible; it is how much pain, anxiety, and procedural friction each one actually reduces when tested head to head in children who need venous access.