title: Nasal Resistance Is Elevated in People with Tetraplegia and Is Reduced by Topical Sympathomimetic Administration.
abstract: 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.
  
  
  
  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.
  
  
  
  At baseline, individuals with tetraplegia had elevated nasal resistance (T = 7.0 ± 1.9, AB = 3.0 ± 0.6 cm H2O/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 H2O/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 H2O/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).
  
  
  
  These data suggest that the unopposed parasympathetic activity in tetraplegia increases nasal resistance, potentially contributing to the high occurrence of OSA in this population.
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.|The University of Melbourne, Parkville, VIC, Australia.
authors: Laura
authors: L
authors: Gainche
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.|The University of Melbourne, Parkville, VIC, Australia.
authors: David J
authors: DJ
authors: Berlowitz
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.
authors: Mariannick
authors: M
authors: LeGuen
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.|The University of Melbourne, Parkville, VIC, Australia.
authors: Warren R
authors: WR
authors: Ruehland
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.|The University of Melbourne, Parkville, VIC, Australia.
authors: Fergal J
authors: FJ
authors: O'Donoghue
authors: The University of Melbourne, Parkville, VIC, Australia.
authors: John
authors: J
authors: Trinder
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.
authors: Marnie
authors: M
authors: Graco
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.
authors: Rachel
authors: R
authors: Schembri
authors: Neuroscience Research Australia and the University of New South Wales, Randwick, NSW, Australia.
authors: Danny J
authors: DJ
authors: Eckert
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.
authors: Peter D
authors: PD
authors: Rochford
authors: The Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia.|The University of Melbourne, Parkville, VIC, Australia.
authors: Amy S
authors: AS
authors: Jordan
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009666:Nose; D010656:Phenylephrine / Q000008:administration & dosage / Q000627:therapeutic use*; D011782:Quadriplegia / Q000150:complications*; D013566:Sympathomimetics / Q000008:administration & dosage / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D013566:Sympathomimetics; D010656:Phenylephrine
keywords: nasal congestion; quadriplegia; sleep apnea; upper airway physiology