title: Bilevel positive airway pressure worsens central apneas during sleep.
abstract: OBJECTIVE
  While most patients with sleep-disordered breathing are treated with continuous positive airway pressure (CPAP), bilevel positive airway pressure (BLPAP) is often used. Having observed that BLPAP therapy increased central apneas in some of our patients undergoing sleep studies, we conducted this study to evaluate the effects of BLPAP.
  
  
  METHODS
  Retrospective analysis of all sleep studies performed in an outpatient sleep center that used BLPAP over a 2-year period. We assessed the incidence and frequency of events during rapid eye movement (REM) sleep and non-REM sleep during baseline conditions, CPAP, and BLPAP. Desaturations, hypopneas, obstructive apneas, and central events, including periodic breathing (PB), Cheyne-Stokes respiration (CSR), and non-CSR central apneas were evaluated.
  
  
  METHODS
  Ninety-five of the 719 patients who underwent sleep studies met inclusion criteria. Eighty of the 95 patients treated with BLPAP were also treated with CPAP.
  
  
  RESULTS
  BLPAP was more likely to worsen than improve CSR (p = 0.002), non-CSR central apneas (p < 0.001), and CSR or PB (p < 0.001). CSR (p = 0.03) and non-CSR central apneas (p = 0.01) were more likely to worsen with BLPAP (24% and 23%, respectively) than with CPAP (11% and 8%). Central events (p = 0.04) and CSR (p = 0.009) were more likely to worsen during BLPAP in patients with baseline CSR or PB (62% and 48%, respectively) than develop in those without baseline CSR or PB (34% and 18%). Higher BLPAP differences worsened central events in 28% of patients, while 7% improved (p = 0.02). During REM sleep, central apneas improved, while hypopneas and obstructive apneas worsened (p < 0.001).
  
  
  CONCLUSIONS
  BLPAP often increases the frequency of CSR and non-CSR central apneas during sleep. Since CSR has adverse effects on cardiac function and sleep, it is important to consider this possible adverse effect of BLPAP.
authors.affiliation: Rhode Island Hospital, Providence, USA.
authors.forename: Karin G
authors.initials: KG
authors.lastname: Johnson
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Johnson
mesh_terms: D045422:Continuous Positive Airway Pressure; D018450:Disease Progression; D004569:Electroencephalography; D006801:Humans; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration / Q000009:adverse effects*; D012120:Respiration Disorders / Q000628:therapy; D012189:Retrospective Studies; D012891:Sleep Apnea Syndromes / Q000503:physiopathology*
chemical_list: D010100:Oxygen