Background: Sleep-disordered breathing and hypoxemia frequently underlie many common medical conditions for which patients require hospitalization. Sleep apnea is associated with adverse cardiovascular, neurovascular, inflammatory, and metabolic consequences, many of which can be reversed with nasal continuous positive airway pressure. Although polysomnography is the gold standard for outpatient evaluation of sleep apnea, it has not been used for establishing the diagnosis or as a means to intervene with evidence-based therapy in the hospital setting.
Setting: A 468-bed tertiary-care facility for adults in which an 801.11b wireless network supplements a typical hardwired local area network.
Methodology: We developed a technique to perform 16-channel polysomnography on any patient in any location in the hospital without interfering with routine nursing care. Qualified sleep technicians are able to remotely adjust electrophysiologic and respiratory parameters, as well as control continuous positive airway pressure titration. The study can also be monitored from any location with Internet access using a HIPAA-compliant virtual private network.
Results: Polysomnography was performed on 51 inpatients (age 26 to 89 years; 31 men). Mean (SD) body mass index measured 34.1 kg/m(2) (12.4). Cardiac disease (47%) and neurologic disease (27%) were the most frequent primary indications for admission. Data acquisition was not disrupted due to connectivity problems. The most frequent deficiencies were reduced sleep time (range 0.8-6.5 hours; mean [SD] 3.3 hours [1.6]) and reduced or absent rapid eye movement sleep. Mean (SD) apnea-hypopnea index measured 35.9 events per hour of sleep (SD 26.3) and 19.4 events per hour of total recording time (SD 17.5).
Conclusions: Polysomnography measurements transmitted across a wireless wide area network increases the capacity of the traditional hospital-based sleep laboratory. This technique can facilitate early implementation of appropriate therapy and may reverse underlying factors associated with the primary cause of hospitalization. Indications and standards of practice need to be specifically established for inpatient polysomnography.