title: Predictors of nocturnal oxygen desaturation in chronic obstructive pulmonary disease in a South Indian population.
abstract: BACKGROUND
  Nocturnal Oxygen Desaturation (NOD) in patients with chronic obstructive pulmonary disease (COPD) is associated with a poor prognosis.
  
  
  OBJECTIVE
  To document the occurrence of NOD in COPD and to identify factors which might predict NOD in COPD patients with daytime arterial oxygen tension (PaO2) > or =60 mm Hg.
  
  
  METHODS
  This prospective study was conducted in patients attending the special respiratory clinics or admitted in JIPMER, Pondicherry.
  
  
  METHODS
  Thirty consecutive patients with COPD were divided into two groups, desaturators and non-desaturators on the basis of nocturnal oxygen saturation.
  
  
  METHODS
  Unpaired 't' test, Karl Pearson's correlation equation and stepwise multiple regression analysis was done.
  
  
  RESULTS
  Fourteen patients (46.6%) experienced NOD. Desaturators had lower awake oxygen saturation, PaO2, forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate. There was positive correlation between nocturnal O2 saturation and PaO2 (r=0.638 and P value =0.014) and awake SPO2 (r=0.901 and P value <0.001).
  
  
  CONCLUSIONS
  The rate of occurrence of NOD in COPD was 46.6%. Awake SPO2 is the only single predictor of nocturnal oxygen desaturation in these patients.
authors.affiliation: Department of Tuberculosis and Respiratory Diseases and Sleep Disorders Laboratory, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry - 605 006, India.
authors.forename: V D
authors.initials: VD
authors.lastname: Thomas
authors.forename: S
authors.initials: S
authors.lastname: Vinod Kumar
authors.forename: B
authors.initials: B
authors.lastname: Gitanjali
mesh_terms: D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis* / Q000453:epidemiology; D007194:India; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D017286:Polysomnography; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000503:physiopathology; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000097:blood / Q000453:epidemiology
chemical_list: D010100:Oxygen