Association between body mass index z-score and hypoxemia during pediatric dental sedation: a retrospective cohort study.

PURPOSE: Evidence regarding the effect of body habitus on respiratory safety during pediatric dental sedation remains limited. This study investigated the association between age- and sex-standardized body mass index (BMI) z-score and new-onset intraoperative hypoxemia in children undergoing dental treatment under deep sedation. METHODS: We retrospectively reviewed children aged 2-10 years who underwent comprehensive dental treatment under propofol-ketamine-based deep sedation at a single dental hospital between July 2024 and February 2026. The primary outcome was new-onset intraoperative hypoxemia, defined as a sustained decrease in SpO₂ to <95% for ≥10 s. Multivariable logistic regression was used to evaluate the association between BMI z-score category and hypoxemia. RESULTS: The final analysis included 512 children; 273 (53.3%) developed new-onset intraoperative hypoxemia. Compared with normal-weight children, overweight/obese children had higher odds of hypoxemia in the multivariable model (odds ratio [OR] 3.393, 95% confidence interval [CI] 1.596-7.213; p = 0.002). Underweight status was not associated with hypoxemia. Longer procedure duration was also associated with higher odds of hypoxemia (OR 1.116, 95% CI 1.083-1.150; p < 0.001). Ketamine and total propofol doses were not associated with the primary outcome. A post hoc sensitivity analysis using a more stringent definition of hypoxemia (SpO₂ <90%) yielded consistent results. CONCLUSION: Overweight/obese status was independently associated with new-onset intraoperative hypoxemia during pediatric dental sedation. Longer procedure duration also emerged as an associated procedural factor. These findings may support individualized respiratory vigilance in children with increased body mass during shared-airway dental sedation.