title: Low-flow oxygen and bilevel ventilatory support: effects on ventilation during sleep in cystic fibrosis.
abstract: We measured ventilation in all sleep stages in patients with cystic fibrosis (CF) and moderate to severe lung disease, and compared the effects of low-flow oxygen (LFO2) and bilevel ventilatory support (BVS) on ventilation and gas exchange during sleep. Thirteen subjects, age 26 +/- 5.9 yr (mean +/- 1 SD), body mass index (BMI) 20 +/- 3 kg/m2, FEV1 32 +/- 11% predicted, underwent three sleep studies breathing, in random order, room air (RA), LFO2, and BVS +/- O2 with recording of oxyhemoglobin saturation (SpO2) (%) and transcutaneous carbon dioxide (TcCO2) (mm Hg). During RA and LFO2 studies, patients wore a nasal mask with a baseline continuous positive airway pressure (CPAP) of 4 to 5 cm H2O. Minute ventilation (V I) was measured using a pneumotachograph in the circuit and was not different between wake and non-rapid eye movement (NREM) sleep on any night. However, V I was reduced on the RA and LFO2 nights from awake to rapid eye movement (REM) (p < 0.01) and from NREM to REM (p < 0.01). On the BVS night there was no significant difference in V I between NREM and REM sleep. Both BVS and LFO2 improved nocturnal SpO2, especially during REM sleep (p < 0.05). The rise in TcCO2 seen with REM sleep with both RA and LFO2 was attenuated with BVS (p < 0.05). We conclude that BVS leads to improvements in alveolar ventilation during sleep in this patient group.
authors.affiliation: Royal Prince Alfred Hospital, Camperdown, Sydney, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Milross
authors.forename: A J
authors.initials: AJ
authors.lastname: Piper
authors.forename: M
authors.initials: M
authors.lastname: Norman
authors.forename: H F
authors.initials: HF
authors.lastname: Becker
authors.forename: G N
authors.initials: GN
authors.lastname: Willson
authors.forename: R R
authors.initials: RR
authors.lastname: Grunstein
authors.forename: C E
authors.initials: CE
authors.lastname: Sullivan
authors.forename: P T
authors.initials: PT
authors.lastname: Bye
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis; D003550:Cystic Fibrosis / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D010100:Oxygen / Q000008:administration & dosage; D011659:Pulmonary Gas Exchange; D012119:Respiration; D012121:Respiration, Artificial / Q000379:methods*; D012720:Severity of Illness Index; D012890:Sleep
chemical_list: D010100:Oxygen