Case Report: Sedation crisis caused by drug-induced sleep endoscopy in a pediatric patient with symptomatic multilevel airway obstruction.

Background: Unexplained life-threatening events during pediatric sedation examinations are a major clinical challenge. Drug-induced sleep endoscopy (DISE) enables dynamic assessment of the site, severity, and pattern of airway collapse by simulating sleep through pharmacologically induced sedation. However, limited studies have utilized DISE as a diagnostic approach for elucidating the etiology of sedation-related events. Case presentation: A male patient aged 10 years was admitted with a cough for >30 days and a history of cardiopulmonary resuscitation (CPR) 2 days earlier. The patient was diagnosed with severe pneumonia at another hospital. Intravenous midazolam sedation administered during bronchoscopy preparation resulted in the development of sudden cardiorespiratory arrest. After successful CPR, the patient was transferred to Quanzhou Maternity and Children's Hospital(Quanzhou Children's Hospital). The patient experienced recurrent severe hypoxemia during sleep despite pulmonary infection control. Chest computed tomography (CT), cardiac CT angiography, echocardiography, video electroencephalography, polysomnography, and genetic testing did not reveal the underlying cause. Subsequently, the patient underwent DISE. DISE with midazolam revealed grade II tonsillar hypertrophy with posterior displacement of the tongue base restricting epiglottic elevation, which was consistent with partial upper airway obstruction. Mandibular advancement and head-and-shoulder elevation improved the obstruction. Additionally, a widened membranous portion was noted in the middle-lower segment of the trachea. The membranous portion protruded into the lumen during expiration, resulting in lumen narrowing and a reduction in lumen area by >90%, which was accompanied by blood oxygen desaturation. The final diagnosis was symptomatic multilevel airway obstruction with sedation-induced upper airway obstruction and severe dynamic tracheomalacia complicated by severe pneumonia. Home non-invasive ventilation maintained nocturnal oxygen saturation at >95% without cyanosis, bradycardia, or apnea. Conclusions: This case highlights that multilevel airway obstruction is a critical mechanism of pediatric sedation crisis. The upper airway anatomical narrowing and central airway dynamic collapse synergistically worsened under sedation. Occult tracheomalacia should be considered for sedation-related events of unclear etiology. DISE can aid in systematic airway assessment to achieve precise diagnosis, risk stratification, and safe pediatric sedation management.