title: Systemic effects of nocturnal hypoxemia in patients with chronic obstructive pulmonary disease without obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  To study the effects of nocturnal hypoxemia in patients with chronic obstructive pulmonary disease without obstructive sleep apnea syndrome.
  
  
  METHODS
  We studied 21 patients-10 desaturators and 11 nondesaturators-submitted to arterial blood gas analysis, polysomnography, spirometry, cardiopulmonary exercise testing (cycle ergometer), and hand-grip dynamometry, as well as measurements of maximal inspiratory pressure, maximal expiratory pressure, and C-reactive protein (CRP) levels. Patients with arterial oxygen tension > 60 mmHg were included; those with an apnea-hypopnea index > 5 events/hour of sleep were excluded. Maximal oxygen uptake, maximal power, systolic blood pressure, diastolic blood pressure (DBP), and maximal heart rate were measured during exercise in order to detect hemodynamic alterations. Patients presenting CRP levels above 3 mg/L were considered CRP-positive.
  
  
  RESULTS
  Minimal peripheral oxygen saturation during sleep was significantly higher among nondesaturators (p = 0.03). More desaturators presented CRP > 3 mg/L (p < 0.05). No differences were observed in terms of any variables, However, mean peripheral oxygen saturation during sleep correlated with DBP and maximal inspiratory pressure (p < 0.001 and p = 0.001, respectively).
  
  
  CONCLUSIONS
  Although nocturnal hypoxemia does not reduce exercise capacity or hand-grip strength in patients with mild/moderate COPD, its effect on maximal exercise DBP seems to depend on the degree of hypoxemia. In addition, there is a positive relationship between maximal inspiratory pressure and mean peripheral oxygen saturation during sleep, as well as evidence of pronounced inflammatory activation in patients with nocturnal hypoxemia.
authors.affiliation: Department of Pulmonology, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil. mpaulo@nin.ufms.br
authors.forename: Paulo de Tarso Guerrero
authors.initials: Pde T
authors.lastname: Mueller
authors.forename: Marcílio Delmondes
authors.initials: MD
authors.lastname: Gomes
authors.forename: Carlos Alberto de Assis
authors.initials: CA
authors.lastname: Viegas
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Neder
mesh_terms: D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D002097:C-Reactive Protein / Q000032:analysis*; D002940:Circadian Rhythm / Q000502:physiology; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D010092:Oximetry; D017286:Polysomnography; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000503:physiopathology*; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive; D013147:Spirometry
chemical_list: D002097:C-Reactive Protein