Lowering surface tension (gamma) of upper airway lining liquid (UAL) reduces upper airway opening (anesthetized @entity1 ) and closing (anesthetized @entity95 ) pressures. We now hypothesize that in @entity27 ( @entity27 ) @entity1 lowering gamma of UAL will enhance upper airway stability and decrease the severity of @entity387 . Nine @entity27 @entity1 [respiratory disturbance index (RDI): 49 +/- 8 (SE) events/h, diagnostic night] participated in a two-part, one-night, polysomnography study. In the first part, upper airway closing pressures (during non-rapid eye @entity10522 , Pcrit) were measured and samples of UAL (awake) were obtained before and after 2.5 ml of surfactant (Exosurf, Glaxo Smith Kline) was instilled into the posterior pharynx. The gamma of UAL was determined with the use of the "pull-off" force technique. In the second part, subjects received a second application of 2.5 ml of surfactant and then slept the remainder of the night (205 +/- 30 min). Instillation of surfactant decreased the gamma of UAL from 60.9 +/- 3.1 mN/m (control) to 45.2 +/- 2.5 mN/m (surfactant group) (n = 9, P < 0.001). Pcrit decreased from 1.19 +/- 1.14 cm @entity2507 (control) to -0.56 +/- 1.15 cm @entity2507 (surfactant group) (n = 7, P < 0.02). Compared with the second half of diagnostic night, surfactant decreased RDI from 51 +/- 8 to 35 +/- 8 events/h (n = 9, P < 0.03). The fall in RDI (deltaRDI) correlated with the fall in gamma of UAL (deltagamma) (deltaRDI = 1.8 x deltagamma, r = 0.68, P = 0.04). @entity387 decreased approximately 50% from 42 +/- 8 to 20 +/- 5 events/h (n = 9, P < 0.03, paired t-test). The gamma of UAL measured the next morning remained low at 49.5 +/- 2.7 mN/m (n = 9, P < 0.001, ANOVA, compared with control). In conclusion, instillation of surfactant reduced the gamma of UAL in @entity27 @entity1 and decreased Pcrit and the occurrence of @entity387 . Therapeutic manipulation of gamma of UAL may be beneficial in reducing the severity of @entity387 in @entity27 @entity1 .

Relationship between surface tension of upper airway lining liquid and upper airway collapsibility during XXXX .

@entity1 :: ('9606', 'Species') :: ['humans', 'patients'] @entity387 :: ('MESH:D012891', 'Disease') :: ['sleep-disordered breathing', 'hypopneas', 'Hypopneas'] @entity10522 :: ('MESH:D020189', 'Disease') :: ['movement sleep'] @entity95 :: ('9986', 'Species') :: ['rabbits'] @entity27 :: ('MESH:D020181', 'Disease') :: ['sleeping obstructive sleep apnea hypopnea syndrome', 'OSAHS'] @entity2507 :: ('CHEBI:33813', 'Chemical') :: ['H2O']
@entity27 :: (MESH:D020181,Disease) :: ['sleep in obstructive sleep apnea hypopnea syndrome']
