Children allocated to this group received nurse-led verbal instruction supplemented with demonstration before spirometry. In addition to the routine verbal explanation, the researcher demonstrated each step of the spirometry maneuver by performing it on herself. The demonstration included correct placement of the nose clip and mouthpiece, maximal inspiration, rapid and forceful expiration sustained for at least 6 seconds, and a final maximal inspiration. After the demonstration, children were encouraged to ask questions and subsequently performed the spirometry procedure under the guidance of the researcher. The intervention lasted approximately 2-3 minutes.

Children allocated to this group received animation-assisted preparation in addition to the routine verbal instruction. A Pediatric Incentive Fish Animation specifically designed to prepare children for pulmonary function testing was used as the intervention. Before spirometry, the researcher introduced the animation and explained that a forceful and continuous expiration would enable the animated fish to swim toward its home, whereas interrupting expiration would stop the fish before reaching its destination. The researcher then demonstrated the correct use of the animation while simultaneously performing the spirometry maneuver. During spirometry, children used the animation as real-time visual feedback while performing their first three acceptable maneuvers. The intervention lasted approximately 3-4 minutes.

Children assigned to the control group received the unit's standard pre-spirometry preparation, which consisted of routine verbal instruction delivered by the certified pediatric pulmonary function nurse. The explanation included the purpose of the test, the correct performance of the spirometry maneuver, and the behaviors expected during the procedure. Children were encouraged to ask questions before testing. No additional demonstration or animation-assisted preparation was provided. The intervention lasted approximately 2-3 minutes.