title: Prevalence of central sleep apnea during continous positive airway pressure (CPAP) titration in subjects with obstructive sleep apnea syndrome at an altitude of 2640 m.
abstract: BACKGROUND
  The occurrence of central apneas when applying positive pressure (CPAP) to patients with obstructive sleep apnea syndrome (OSAS) is called complex sleep apnea (CompSA). This causes poor adherence to CPAP and persistence of symptoms. In Bogota, a city located at an altitude of 2640 m above sea level, chronic hypoxemia can generate certain instability of the respiratory system during sleep which could increase the presence of central apnea. The aim was to establish the prevalence of central apnea (central apnea index >5/h) in adults with moderate or severe OSAS during CPAP titration, and the factors associated with this.
  
  
  METHODS
  Patients over 18 years old with OSAS were referred to the Fundacion Neumologica Colombiana Sleep Center, from January 2008 to June 2010. Polysomnogram (PSG) for CPAP titration was performed according to the American Academy of Sleep Medicine criteria. The prevalence was calculated and the clinical and baseline PSG factors associated with the CompSA were analyzed.
  
  
  RESULTS
  We included 988 patients, 58% men. CompSA prevalence was 11.6%. Factors associated with CompSA were: central apneas in the baseline PSG (OR: 5.34 [3.49-8.16]), history of heart failure (OR: 2.53 [1.58-4.07]), and male sex (OR: 1.68 [1.06-2.69]).
  
  
  CONCLUSIONS
  The prevalence of complex sleep apnea in Bogota (11.6%) was intermediate compared to the reported in lower altitudes. The factors associated with the development of CompSA were male sex, heart failure, and the presence of central apnea in the baseline PSG.
authors: Sleep Center, Fundacion Neumologica Colombiana, Bogota, Colombia; School of Medicine, Universidad de La Sabana, Bogota, Colombia. Electronic address: mbazurto@neumologica.org.
authors: Maria Angelica
authors: MA
authors: Bazurto Zapata
authors: Sleep Center, Fundacion Neumologica Colombiana, Bogota, Colombia; School of Medicine, Universidad de La Sabana, Bogota, Colombia.
authors: William
authors: W
authors: Martinez-Guzman
authors: Sleep Center, Fundacion Neumologica Colombiana, Bogota, Colombia; School of Medicine, Universidad de La Sabana, Bogota, Colombia.
authors: Leslie
authors: L
authors: Vargas-Ramirez
authors: Sleep Center, Fundacion Neumologica Colombiana, Bogota, Colombia.
authors: Karen
authors: K
authors: Herrera
authors: Sleep Center, Fundacion Neumologica Colombiana, Bogota, Colombia; Research Department, Fundacion Neumologica Colombiana, Bogota, Colombia.
authors: Mauricio
authors: M
authors: Gonzalez-Garcia
mesh_terms: D000368:Aged; D000531:Altitude; D015331:Cohort Studies; D003105:Colombia; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015995:Prevalence; D012307:Risk Factors; D020182:Sleep Apnea, Central / Q000175:diagnosis / Q000453:epidemiology*; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis / Q000628:therapy*
keywords: Altitude; Central sleep apnea; Complex sleep apnea; Positive airway pressure; Sleep disorder breathing