Sleep Apnea. — Sleep Apnea is a respiratory dysfunction resulting in cessation or near cessation of respiration during sleep. These cessations of breathing may be due to either an occlusion of the airway (obstructive sleep apnea), absence of respiratory effort (central sleep apnea), or a combination of these factors (mixed sleep apnea). Central sleep apnea is a relatively rare entity. Obstructive sleep apnea (OSA) is caused by one of the following: (1) reduced upper airway caliber due to obesity, adenotonsillar hypertrophy, mandibular deficiency, macroglossia, or upper airway tumor; (2) excessive pressure across the collapsible segment of the upper airway; or (3) activity of the muscles of the upper airway insufficient to maintain patency.
The diagnosis of sleep apnea may be made using the following modalities:
- Polysomnography (PSG) performed in a sleep laboratory; or
- unattended home sleep monitoring device of type II; or
- unattended home sleep monitoring device of type III; or
- unattended home sleep monitoring device of type IV, measuring at least 3 channels (CAG-00093R2)
A positive test for obstructive sleep apnea (OSA) is established if either of the following criteria using the Apnea-Hypopnea Index (AHI) or Respiratory Distress Index (RDI) are met:
- AHI or RDI greater than or equal to 15 events per hour, or
- AHI or RDI greater than or equal to 5 and less than or equal to 14 events per hour with documented symptoms of excessive daytime sleepiness, impaired cognition; mood disorders or insomnia, or documented hypertension, ischemic heart disease, or history of stroke.
The AHI is equal to the average number of episodes of apnea and hypopnea per hour. The RDI is equal to the average number of respiratory disturbances per hour.
If the AHI or RDI is calculated based on less than 2 hours of continuous recorded sleep, the total number of recorded events to calculate the AHI or RDI during sleep testing is at least the number of events that would have been required in a 2 hour period (CAG-00093R2).
CPAP is a non-invasive technique for providing single levels of air pressure from a flow generator, via a nose mask. The purpose is to prevent the collapse of the oropharyngeal walls and the obstruction of airflow during sleep, which occurs in OSA.
For patients with severe and unambiguous obstructive sleep apnea, the initiation of treatment with nasal CPAP may be incorporated into the diagnostic study night. A “split-night” study (initial diagnostic PSG followed by CPAP Titration during PSG on the same night) may be an alternative to one full night of diagnostic PSG followed by a second night of Titration as long as:
- CPAP Titration is carried out for more than 3 hrs, and
- PSG documents that CPAP significantly improves patient respiration during sleep.
The use of CPAP devices is covered under Medicare when ordered and prescribed by the licensed treating physician to be used in adult patients with OSA if either of the criteria noted above are met.
Documentation supporting a diagnosis of OSA must be available upon request by Medicare.
Repeat PSG for diagnosing sleep apnea requires documentation justifying the medical necessity for the repeat test.
Repeat PSG may be indicated:
- If the first study is technically inadequate due to equipment failure;
- If the patient could not sleep or slept for an insufficient amount of time to determine a clinical diagnosis;
- If initiation of therapy or confirmation of the efficacy of prescribed therapy is clinically needed; or
- If the results were inconclusive.
The supplier of CPAP must conduct education of the beneficiary prior to the use of the CPAP device to ensure that the beneficiary has been educated in the proper use of the device. A caregiver, for example a family member, may be compensatory, if consistently available in the beneficiary’s home and willing and able to safely operate the CPAP device.
Follow up polysomnography is indicated for any of the following:
- to evaluate the response to treatment (CPAP, oral appliances, surgical intervention);
- after substantial weight loss has occurred in patients on CPAP for treatment of sleep-related breathing disorders to ascertain whether CPAP is still needed at the previously titrated pressure;
- after substantial weight gain has occurred in patients previously treated with CPAP successfully, who are again symptomatic despite the continued use of CPAP, to ascertain whether pressure adjustments are needed;
- when clinical response is insufficient or when symptoms return despite a documented good initial response to treatment with CPAP; or
- when there has been a significant change in cardiorespiratory status, such as the development or worsening of CHF or LV dysfunction.