title: Physiologic correlates of sleep quality in severe emphysema.
abstract: BACKGROUND
  Sleep quality is poor in severe emphysema. We hypothesized that in addition to nocturnal oxygen desaturation, the severity of airflow obstruction and degree of thoracic hyperinflation are responsible.
  
  
  METHODS
  Twenty-five patients (14 males, 64 ± 6 [ ± SD] yrs, BMI 24.7 ± 4.2 kg/m(2)) with severe emphysema (FEV(1) = 28 ± 8% predicted, TLC = 125 ± 14% predicted) were studied. Measurements included spirometry, lung volumes, arterial blood gas, length of the diaphragm's zone of apposition (LZAP) and a polysomnogram.
  
  
  RESULTS
  Total sleep time (TST) was 227 ± 93 minutes with a sleep efficiency (SE) of 56 ± 21%. The mean SaO(2), lowest SaO(2), and% TST with a SaO(2) < 90% were 90 ± 5%, 83 ± 8% and 29 ± 40%, respectively. TST correlated with FEV(1)% (r = 0.5, p = 0.02), FVC% (r = 0.4, p = 0.03) and LZAP (r = 0.5, p = 0.01). SE correlated with FEV(1)% (r = 0.5, p = 0.02) and LZAP (r = 0.5, p = 0.01), but not with FVC% (r = 0.4, p = 0.07). Additionally, TST and SE correlated negatively with residual volume% (r = -0.4, p = 0.046, and r = -0.4, p = 0.03, respectively). There was no correlation between TST and SE and measures of nocturnal oxygenation. Multiple linear regression was used to predict TST, with 50% (r(2) = 0.49) explained by a combination of LZAP (27%), mean SaO(2) (23%), and the lowest SaO(2) (< 1%). To predict SE, 44% (r(2) = 0.43) was explained by a combination of LZAP (29%), mean SaO(2) (14%), and the lowest SaO(2) (1%).
  
  
  CONCLUSIONS
  Although parameters of respiratory function and mechanics correlate with sleep quality, both nocturnal oxygenation and measurements of respiratory function/mechanics predict sleep quality in severe emphysema.
authors.affiliation: Dept. of Pulmonary, Critical Care, and Sleep, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140, USA. samuel.krachman@tuhs.temple.edu
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Krachman
authors.forename: Wissam
authors.initials: W
authors.lastname: Chatila
authors.forename: Ubaldo J
authors.initials: UJ
authors.lastname: Martin
authors.forename: Irene
authors.initials: I
authors.lastname: Permut
authors.forename: Gilbert E
authors.initials: GE
authors.lastname: D'Alonzo
authors.forename: John P
authors.initials: JP
authors.lastname: Gaughan
authors.forename: Alice L
authors.initials: AL
authors.lastname: Sternberg
authors.forename: David
authors.initials: D
authors.lastname: Ciccolella
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Criner
mesh_terms: D000368:Aged; D001784:Blood Gas Analysis; D003964:Diaphragm / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D011656:Pulmonary Emphysema / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012893:Sleep Wake Disorders / Q000097:blood / Q000209:etiology*; D014463:Ultrasonography
chemical_list: D010100:Oxygen