Nasal Resistance Is Elevated in People with Tetraplegia and Is Reduced by Topical Sympathomimetic Administration

Abstract

Study Objectives: Obstructive sleep apnea (OSA) is common in individuals with tetraplegia and associated with adverse health outcomes. The causes of the high prevalence of OSA in this population are unknown, but it is important to understand as standard treatments are poorly tolerated in tetraplegia. Nasal congestion is common in tetraplegia, possibly because of unopposed parasympathetic activity. Further, nasal obstruction can induce OSA in healthy individuals. We therefore aimed to compare nasal resistance before and after topical administration of a sympathomimetic between 10 individuals with tetraplegia (T) and 9 able-bodied (AB) controls matched for OSA severity, gender, and age. Methods: Nasal, pharyngeal, and total upper airway resistance were calculated before and every 2 minutes following delivery of ≈0.05 mL of 0.5% atomized phenylephrine to the nostrils and pharyngeal airway. The surface tension of the upper airway lining liquid was also assessed. Results: At baseline, individuals with tetraplegia had elevated nasal resistance (T = 7.0 ± 1.9, AB = 3.0 ± 0.6 cm H 2 O/L/s), that rapidly fell after phenylephrine (T = 2.3 ± 0.4, p = 0.03 at 2 min) whereas the able-bodied did not change (AB = 2.5 ± 0.5 cm H 2 O/L/s, p = 0.06 at 2 min). Pharyngeal resistance was non-significantly higher in individuals with tetraplegia than controls at baseline (T = 2.6 ± 0.9, AB = 1.2 ± 0.4 cm H 2 O/L/s) and was not altered by phenylephrine in either group. The surface tension of the upper airway lining liquid did not differ between groups (T = 64.3 ± 1.0, AB = 62.7 ± 0.6 mN/m). Conclusions: These data suggest that the unopposed parasympathetic activity in tetraplegia increases nasal resistance, potentially contributing to the high occurrence of OSA in this population.

Neuropsychological Function in Patients With Acute Tetraplegia and Sleep Disordered Breathing

“…5,6 Several mechanisms for SDB following tetraplegia have been proposed, such as increased upper airway resistance, 4 impaired respiratory feedback from the rib cage, 4 alterations in ventilatory control and plant gain, 7 and diminished activation of intercostal, abdominal, and diaphragm muscles. 4,8 In chronic tetraplegia, sleep onset hypoventilation, 9 obstructive, 7 and central apneas 7 have all been reported, 10 while in acute tetraplegia, obstructive and mixed events appear to predominate. 3,11,12 Reports, however, in both the acute and chronic, vary in methodology, scoring criteria, and participant characteristics, such that a clear pattern of the nature of SDB remains controversial.…”

Genioglossus reflex responses to negative upper airway pressure are altered in people with tetraplegia and obstructive sleep apnoea

“…; Gainche et al . ). One catheter was advanced to the level of the epiglottis with the tip positioned 1–2 cm below the base of the tongue.…”

“…However, while recent studies indicate a potential role for increased nasal resistance as a contributor to OSA for certain people with tetraplegia (Gainche et al . ; Wijesuriya et al . ), the specific pathophysiological factors that place people with tetraplegia at such a high risk of OSA are poorly understood.…”

Sleep-Disordered Breathing and Spinal Cord Injury: Challenges and Opportunities

“…However, similar increase in the inspiratory duty cycle was noted in chronic SCI and was independent of the level of injury. Furthermore, it was reported recently that nasal resistance is elevated in people with cervical SCI which is believed to be due to unopposed parasympathetic activity (37). But the mechanistic contribution of increased nasal resistance to UA collapsibility is unclear.…”