Positive airway pressure: Making an impact on sleep apnea

Tubing

The tubing from the PAP device to the facial interface can be a source of irritation to patients due to rubbing against the skin or entanglement. Products to cover the tubing to reduce irritation and avoid entanglement are available. Extra-long tubing is also available.

Cleaning

Some people find cleaning CPAP equipment daunting. Cleaning devices are available and recommended to patients looking for reassurance about how to keep their CPAP equipment clean. There are also CPAP wipes to clean the mask of oils and creams from the skin to improve the mask seal and reduce leaks.

Pressure control

Advanced modalities are available to adjust how pressure is delivered by PAP devices, including ramp, APAP, pressure relief, and BiPAP. Ramp is a feature that delivers a lower pressure at the beginning of the sleep cycle and slowly increases pressure to therapeutic levels. The lower pressure makes it easier for the user to fall asleep and builds to therapeutic pressure once asleep. APAP adjusts the pressure automatically when needed and reduces the pressure when not needed. Pressure relief is a feature that allows the PAP pressure to decrease at the point of expiration. BiPAP gives a distinct pressure on inspiration and a distinctively different and lower pressure at the point of expiration.

Auto-PAP

Case scenario #3

A 52-year-old woman with hypertension and mild sleep apnea has a polysomnogram with an apnea–hypopnea index of 7 events per hour that increase to 32 events per hour in rapid eye movement (REM) sleep. She is on CPAP at 5 cm of water, but complains of waking every 2 hours with a sense of panic and hot flashes.

Which of the following is the most likely cause of her symptoms?

1. An underlying anxiety disorder
2. An underlying heart condition
3. Perimenopausal symptoms
4. Undertreated REM-related apnea
5. None of the above

Answer: While all of these choices can occur, the most likely cause is undertreated REM-related apnea.

Figure 3. Sleep study overview showing rapid eye movement sleep (arrow/black bar) associated with increased arousals and apneic events and decreased oxygen levels.

What would be the best next step in treatment for this patient?

1. Hormonal replacement therapy
2. Positional therapy in addition to CPAP
3. APAP
4. Anxiolytic medication
5. All of the above

Answer: APAP.

APAP incorporates an algorithm that detects and adjusts to airflow, pressure fluctuations, and airway resistance. The consensus from the American Academy of Sleep Medicine is that APAP is useful in the case of:

• Pressure intolerance
• REM apnea or positional apnea
• Inadequate in lab PAP titration
• Planned weight loss (bariatric surgery)
• Recurrent symptoms after long-term CPAP use.¹⁵

Pressure relief

Case scenario #4

A 45-year-old man with severe sleep apnea uses CPAP at 10 cm of water. He complains of the inability to exhale against the pressure from the device.

What would be the best next step?

1. Set the pressure relief to a maximum of 3
2. Lower the pressure of CPAP and check a download use at a lower pressure
3. BiPAP titration study in the laboratory
4. Switch to BiPAP if insurance allows
5. Change to a different mask

Answer: Set the pressure relief to a maximum of 3.

The CPAP device delivers pressure in conjunction with the patient’s inspiration and expiration. At the point of expiration, there is a decrease in the pressure delivered by the device to make it easier for the user to exhale. Three selectable settings provide flow-based pressure relief with a setting of 1 for the least degree of pressure reduction and a setting of 3 for the greatest degree of pressure reduction.¹⁶

In a study of the effect of PAP with pressure relief, 93 patients were assigned to use APAP without pressure relief, CPAP with pressure relief (C-Flex), or APAP with pressure relief (A-Flex).¹⁶ At 3 and 6 months, patients using A-Flex had the best adherence to therapy.

Quality of life was also examined in this same study.¹⁶ For patients using APAP alone, there was no statistically significant difference in the Epworth Sleepiness Scale measuring daytime sleepiness or the Pittsburgh Sleep Quality Index. However, in patients using A-Flex, daytime sleepiness improved, as did sleep quality, with statistically significant improvement at 3 months.

Bilevel PAP

Case scenario #5

A 62-year-old man with severe sleep apnea uses CPAP set at 17 cm of water and pressure relief set at 3. He stopped using CPAP due to abdominal pain, extreme belching, and pressure intolerance.

What would be the appropriate next step?

1. Use of simethicone
2. Elevate the head while using PAP therapy
3. BiPAP titration study in the laboratory
4. Switching directly to BiPAP if insurance allows
5. All of the above

Answer: All of the above.

BiPAP devices provide 2 distinct pressures, one for inhalation and one for exhalation. BiPAP also has the ability to deliver a higher overall pressure. A CPAP device typically has a maximum pressure of 20 cm of water, but BiPAP has a maximum pressure of 25 cm of water on inspiration. BiPAP may be helpful in patients with air aphasia and extreme belching. If a patient cannot tolerate CPAP because of the pressure, and if C-Flex has not alleviated the problem, BiPAP would be the next step.

The effectiveness and level of comfort of BiPAP compared with CPAP for the treatment of OSA was evaluated by the American Academy of Sleep Medicine.² The analysis of 7 randomized control trials reporting level I and II evidence found that BiPAP was as effective as CPAP in the treatment of OSA in patients with no comorbidities. For patients with OSA and comorbidities, a level III evidence study reported an increased level of comfort in patients using BiPAP.