Congenital heart disease (CHD) is the most prevalent congenital malformation globally, with an incidence ranging from 8.60‰ to 10.25‰ (Liu et al., 2019). Postoperative paediatric patients with this condition must be transferred to ICU for advanced therapeutic intervention. During the ICU stay, children who have undergone surgery for CHD are prone to fluid overload, which increases the risk of adverse events such as death and acute kidney injury (Bellos et al., 2020). Thus, children with CHD are subject to strict restrictions on fluid intake and output and invariably experience enduring and profound thirst in the ICU (Bellos et al., 2020). The prevalence of thirst among these children reaches an alarming 93.5%, with a significant 88.2% exhibiting moderate to severe levels of thirst (Chen et al., 2025).

The ramifications of this relentless thirst are far-reaching. Moderate thirst lasting for more than 5 h can lead to an increase in pain intensity; severe thirst lasting for more than 24 h will raise the risk of delirium in patients (Geuter et al., 2016; Sato et al., 2019). In addition, enduring thirst not only diminishes children's overall comfort but also precipitates adverse emotional states such as anxiety while concurrently augmenting the risk of thrombosis (Balkaya et al., 2022; Huang et al., 2020; Ma et al., 2023). Thus, implementation of efficacious nursing strategies has become a priority to mitigate the relentless and intense thirst experienced by children with CHD after surgery.

Although a study has explored the incidence and influencing factors of postoperative thirst in children with CHD (Chen et al., 2025), approximately 90% of the subjects in this study were children with simple CHD (such as atrial septal defect and ventricular septal defect) (Chen et al., 2025). The sample composition has bias, which limits the extrapolation of the research results and makes it difficult to fully reflect the thirst status of all children with CHD after surgery. In addition, this study has omissions in the inclusion of influencing factors for thirst, failing to consider key postoperative clinical factors such as vasoactive drugs and fluid restriction (Chen et al., 2025). As a result, the research results showed that postoperative thirst was only related to preoperative and intraoperative factors (Chen et al., 2025). Therefore, it is necessary to conduct further studies to explore the occurrence of thirst and the complete spectrum of influencing factors in children with different types of CHD after surgery.

Additionally, as a subjective physiological sensation, thirst is characterized by dynamic changes, with its severity and influencing factors evolving alongside the postoperative recovery process (Henly et al., 2003; Zhao et al., 2025). However, there is currently only one cross-sectional study investigating thirst in children following CHD surgery (Chen et al., 2025). Such a study cannot reveal the dynamic evolution of thirst status or the mechanisms of key influencing factors, leading to an insufficient and unreliable theoretical basis for formulating clinical intervention protocols. Notably, the existing study has indicated that uniform intervention measures for patients with long-term thirst symptoms often fail to achieve optimal outcomes (Zhang et al., 2022). The core reason may be attributed to population heterogeneity in the pathogenesis of thirst across different patients. Therefore, it is necessary to conduct a longitudinal study to analyze the thirst trajectory of children after CHD surgery, as well as to identify potential classifications of thirst trajectories and the key influencing factors for each classification.

In conclusion, the pervasive and intense experience of postoperative thirst among children with CHD substantially affects their recovery journey. Despite the recognized impact, the comprehension of the thirst trajectory, its group heterogeneity and influencing factors remains superficial. Therefore, in this study, we will adopt a longitudinal study, and utilize a latent growth model to identify the potential categories of thirst trajectories and their influencing factors, laying a robust foundation for developing evidence-based, personalized intervention strategies.