Children frequently encounter needle-related invasive medical procedures, such as venipuncture (Oschman & Rao, 2023). Needle pain can detrimentally affect children's physiological, psychological, and cognitive development (McMurtry et al., 2015): causing altered physiological indicators, hormonal changes, anxiety, resistant behaviors, and potentially complicating medical interventions. This may prolong care provision, augment the risk of secondary injury, and induce anxiety in family members, thereby straining healthcare relationships (Alsbrooks & Hoerauf, 2022; Sørensen et al., 2021). Furthermore, inadequate pain management may result in needle phobia (Healy et al., 2023), causing delays or refusal of vaccinations and reduced medical adherence (Hu & Shang, 2024).With the development of children's health care, pain management in children is increasingly valued.

Contemporary management of venipuncture pain encompasses pharmacological, physical, and psychological interventions (Friedrichsdorf & Goubert, 2020). Among the physical techniques, external cold and mechanical vibration are prevalent. The former elevates the pain threshold by decelerating nociceptive signal transmission (Movahedi et al., 2006); while the latter triggers the gate-control mechanism of pain signaling and stimulates β-endorphin release (Ahmad et al., 2021). Therefore, pain can be reflected not only through subjective descriptions but also through physiological indicators. In response to the need for child-specific pain alleviation, pediatric emergency specialists and pain researchers in the United States have introduced the Buzzy device (MMJ, Atlanta, Georgia, USA) (Baxter et al., 2009). This innovation marries the effects of vibratory stimulation (emulated by the body of the bee) with cryotherapy (achieved through detachable ice wings), encapsulated in the form of a bee. Nonetheless, a meta-analysis conducted by Merino-Lobato et al. indicates that the Buzzy device's efficacy diminishes in older pediatric cohorts (Merino-Lobato et al., 2023). The reason why the Buzzy device is less effective in older children—whether it is due to the device's own limitations or issues with pain assessment methods for older children—still warrants further discussion.

The suboptimal analgesic effect of the Buzzy device in older children may be attributable to the device's inherent characteristics. The prevailing perspective suggests that the analgesic efficacy of the Buzzy device arises from two primary mechanisms: the physiological effects of cold combined with vibration, and the distraction of the child's attention due to the device's design.(Cho et al., 2022; Yaz et al., 2024) However, Semerci et al. (2023) found that the application of cold spray alone was more effective in alleviating pain during venipunctures in children aged 5 to 12 compared to the Buzzy device. Furthermore, the distraction method using a bee shape is more effective in younger children (Loeffen et al., 2020).

Another potential reason for the suboptimal results may be reporting bias. The main issue with pain management in children is the difficulty involved in evaluating it, as children's age, perception, ability to express emotions and distress, and cognitive level are constantly changing during their development (Eccleston et al., 2021). The notion that “pain is always subjective” is widely accepted. Since children above the age of seven possess the ability to accurately describe pain, most studies rely on self-reported measures to assess pain in older children (Zieliński et al., 2020). In the brain, sensory information is integrated with various factors, including environmental influences, emotions, cognition, and both chemical and structural components (Tracey & Mantyh, 2007). Therefore, the International Association for the Study of Pain (IASP) recently considers pain to be “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”. Non-verbal expressions of pain should not be overlooked, as “ perceived pain” differs from “signs of pain”. However, the capacity to express pain accurately and the willingness to report it truthfully are two distinct issues. Due to their parents' education about pain, older children tend to hide their pain. Therefore, the subjective data from these children may lack accuracy (Ndengeyingoma et al., 2023). The IASP emphasizes that pain cannot be defined solely by nociception and must be considered alongside objective data (Raja et al., 2020). However, most studies have considered only the subjective experiences of children. Therefore, pain assessment tools should not be the sole method for evaluating pain; rather, pain scores should be integrated with physiological indicators and child behavior to provide a more accurate reflection of the situation. Whether the suboptimal analgesic efficacy of the Buzzy device in older children is attributable to the device's inherent limitations or to issues with pain assessment methods remains an open question worthy of further investigation. (Singh et al., 2024).

This study focused on children aged 7 and above as subjects because they possess certain cognitive abilities and can clearly express pain and anxiety (Pancekauskaitė & Jankauskaitė, 2018). Given that the distraction effect of the Buzzy device may be less effective in older children, this study focuses specifically on examining the efficacy of its cold and vibration components. Since children aged 7 and above may conceal pain, multidimensional assessments were employed: pulse changes served as an objective physiological measure; children self-reported pain using the Numerical Rating Scale (NRS) and anxiety with the Children's Anxiety Meter Scale (CAMS)); parental anxiety was assessed via NRS; and nurses rated the children's cooperation using a customized scale.