Ambulatory Versus Conventional Approach Diagnosing OSA
Ambulatory Versus Conventional Approach Diagnosing OSA
Very few studies have examined different models of care involving initial ambulatory
 home-based diagnosis in diagnosing obstructive sleep apnea (OSA), identifying patients who
 benefit from continuous positive airway pressure (CPAP), and reducing the need for
 polysomnography (PSG). This study aims to assess the role of an ambulatory approach with home
 diagnostic sleep study. We hypothesize that the ambulatory approach is as good as the
 conventional approach in managing OSA in terms of improvement of clinical outcome but the
 former approach will lead to substantial cost savings.
We conducted a prospective, randomized, controlled continuous positive airway pressure (CPAP)
 parallel study on new referrals to the Respiratory Clinic, Prince of Wales Hospital, with
 suspected obstructive sleep apnea (OSAS). OSAS was defined by apnea-hypopnea index(AHI) 5/hr
 or more of sleep plus excessive daytime sleepiness or two of the following symptoms: choking
 or gasping during sleep, recurrent awakenings from sleep, unrefreshed sleep, daytime fatigue,
 and impaired concentration. All patients with suspected OSAS underwent assessment at the
 clinic with the Epworth sleepiness score(ESS) and symptoms evaluation. Patients who had ESS
 score>9 or at least two OSAS symptoms as described above were invited to join the study. They
 were randomized into either group A)home-based management approach or group B)hospital-based
 management approach by a random table by a third party not involved in the trial.
Inclusion Criteria:

 -  symptoms of OSA with home sleep study AHI >= 15/hr.

 Exclusion Criteria:

 -  unstable cardiovascular diseases (e.g. recent unstable angina, myocardial infarction,
 stroke or transient ischemic attack within the previous 6 months or severe left
 ventricular failure)

 -  neuromuscular disease affecting or potentially affecting respiratory muscles

 -  moderate to severe respiratory disease (i.e. breathlessness affecting activities of
 daily living) or documented hypoxemia or awake oxygen saturation of <92%

 -  psychiatric disease that limits the ability to give informed consent or complete the
 study