Upper Airway Reflexes are Preserved During Dexmedetomidine Sedation in Children With Down Syndrome and Obstructive Sleep Apnea

Abstract

Study objectives: The assessment of pharyngeal collapsibility is difficult to perform in children under normal sleep. An alternative is to perform the assessment under an anesthetic, such as dexmedetomidine (DEX), that induces non-rapid eye movement (NREM) sleep. The objectives of this study were to compare critical closing airway pressure (Pcrit) obtained during natural sleep to that obtained under DEX in patients with Down syndrome (DS) and persistent obstructive sleep apnea (OSA) and determine whether Pcrit measured under sedation predicts the severity of OSA.

Methods: The passive and active Pcrit, which represent airway passive mechanical properties and active dynamic responses to airway obstruction, respectively, were measured. Upper airway reflex activity was estimated by calculating the difference between active and passive Pcrit. Subjects underwent overnight polysomnography during which Pcrit was measured during normal sleep. Pcrit was also measured during DEX sedation at a dose of 2 μg/kg/h.

Results: The study included 50 patients with median age of 11.4 years (interquartile range: 7.0-13.9) and median body mass index of 23.0 kg/m2 (interquartile range: 18.4-29.1), 66% male and 80% Caucasian. Passive Pcrit was significantly higher than active Pcrit when measured during normal sleep and DEX-induced sleep. There was a positive association between apnea-hypopnea index and passive Pcrit (Spearman r = 0.53, P = .0001) and active Pcrit (r = 0.55, P = .0002) under DEX-induced sleep. There were no significant differences between the Pcrit measurements during natural sleep and during DEX sedation.

Conclusion: Patients with OSA can compensate for airway obstruction under DEX-induced sleep. The close association between Pcrit and apnea-hypopnea index suggests that airway responses with DEX sedation parallel those seen during natural sleep.

Clinical trial registration: ClinicalTrials.gov identifier: NCT01902407.

Keywords: airway collapsibility; critical closing pressure; dexmedetomidine; sedation.

© 2017 American Academy of Sleep Medicine

Figures

Figure 1. Passive and active Pcrit measurements.

This figure shows how passive (measured with acute, transient, intermittent drops in nasal pressure) and active (measured with stepwise, decremental, steady state decreases in nasal pressure) Pcrit measurements were determined during natural sleep and during dexmedetomidine sedation. Pcrit = critical airway closing pressure.

Figure 2. Association between Pcrit under DEX sedation and OSA severity (all patients).

The association between Pcrit under DEX sedation and OSA severity as defined by the AHI for all patients. AHI = apnea-hypopnea index, DEX = dexmedetomidine, OSA = obstructive sleep apnea, Pcrit = critical airway closing pressure.

Figure 3. Association between Pcrit under DEX sedation and OSA severity (excluding outliers).

The association between Pcrit under DEX sedation and OSA severity as defined by the AHI after excluding the outliers. AHI = apnea-hypopnea index, DEX = dexmedetomidine, OSA = obstructive sleep apnea, Pcrit = critical airway closing pressure.