Bariatric patients, men on testosterone therapy, people with mild OSA or positional OSA, and those with REM-related sleep apnea may benefit from autotitrating devices.

The American Academy of Sleep Medicine 2007 guidelines contraindicate autotitrating continuous positive airway pressure (APAP) treatment for people with central sleep apnea, stroke, chronic obstructive pulmonary disease, congestive heart failure, or hypoventilation syndrome since these conditions often involve impaired feedback between central (that is, brain) receptors and peripheral receptors (for example, receptors on the aorta) that control breathing, which can induce cessations in breathing, even when the blood oxygen level is normal.1 An APAP machine may erroneously detect the cessation in breathing as an obstructive event and increase the pressure. This impairment may induce prolonged central apneas in these patients.

However, the guidelines did not address specific groups of patients—other than patients with moderate to severe obstructive sleep apnea (OSA)—who could best benefit from APAP treatment. Four types of patients who may be candidates for APAP therapy but who may be overlooked for APAP therapy are bariatric patients, men who are on testosterone therapy, people who have mild OSA or positional OSA, and people who have rapid eye movement (REM) sleep apnea.

In OSA, the upper airway intermittently collapses as a person sleeps, and partially or fully blocks airflow. In positive airway pressure treatment, pressurized air is blown through the upper airway to prevent its collapse during sleep. Three forms of positive airway pressure treatment are continuous positive airway pressure (CPAP), bilevel positive airway pressure (BPAP), and APAP. In CPAP, a person inhales and exhales against one pressure; in BPAP treatment, the pressure on inhalation is slightly higher than the pressure on exhalation; in APAP, the pressure varies on a breath-by-breath basis in response to airflow, vibration (ie, snoring), and/or airflow impedance (ie, upper airway resistance).

An APAP machine titrates the pressure upward or downward within a certain range set by a sleep physician. The pressure delivered by the machine varies throughout sleep and may vary from night to night if for some reason a person’s OSA changes temporarily. CPAP and BPAP could be problematic in certain patient populations like the groups detailed in this article, and APAP a more effective therapy for the following reasons.

APAP May Be the Best Option for Certain Populations

Bariatric Surgery Candidates
People with OSA who undergo bariatric surgery lose weight rapidly, which may cause rapid reductions in the pressure needed to prevent apneas. A bariatric patient with OSA who is on CPAP or BPAP would need to repeatedly come to a sleep center to have the pressure adjusted during their weight loss, which would be expensive and inconvenient.2

Testosterone Replacement Therapy
Testosterone replacement therapy in men is used to treat hypogonadism (ie, reduced or absent hormone secretion by the testes). However, some research indicates that testosterone replacement therapy may temporarily worsen sleep apnea for at least several weeks.3,4 During the first few weeks of testosterone therapy, CPAP or BPAP therapy may insufficiently treat apnea.

Mild OSA or Positional OSA
Some people have mild OSA (5–14 events/hour) or only have OSA when sleeping on their backs but not when sleeping on their sides. In these patients, pressure needs may change throughout the night. For example, in patients with positional apnea, positive pressure would only be necessary when a person is supine. Delivering positive pressure only when necessary (in mild apnea) or only when a person is supine is not possible with CPAP or BPAP. When pressure needs are lower, a person may experience continuous or bilevel pressures as excessive, which may then disrupt sleep.

REM-related Sleep Apnea
Some people with OSA only have episodes during REM sleep. Delivering positive pressure only when a person is in REM sleep is not possible with CPAP or BPAP therapy since these machines deliver their set pressures throughout all stages of sleep. When pressure needs are lower during non-REM stages, a person may experience continuous or bilevel pressures as excessive, which may then disrupt sleep.

APAP Advantages

In each of these groups of patients, the autotitrating capability of an APAP machine can increase and decrease the pressure as needed from night to night. An APAP machine could ideally be used temporarily until the changes in pressure stabilize in bariatric patients with OSA or in men who have been on testosterone therapy for several weeks, at which point the person may undergo a study for a retitration of CPAP or BPAP.

For people with mild apnea, positional apnea, and REM-related sleep apnea, APAP treatment would ideally be less disruptive to sleep and potentially improve adherence to treatment. However, treatment adherence with APAP versus CPAP or BPAP in patients with these milder forms of OSA needs further investigation. Some research indicates treatment adherence is not improved,1,5 and some research indicates that patients with mild OSA prefer APAP treatment over other forms of positive airway pressure treatment.6 Whether to use APAP in these patients often becomes, as Steve Moore, general manager of PAP manufacturer Human Design Medical, says, “a treating physician’s decision. There are questions in the literature centered-around the effectiveness of CPAP with REM sleep apnea.” (personal communication)

Further research is needed to obtain data that can be used to improve APAP treatment in these four groups of patients. “It’s important,” says Teofilo L. Lee-Chiong, MD, chief medical liaison of PAP manufacturer Philips Respironics, “for both the clinician and the patient to familiarize themselves with the different ways to troubleshoot problems that may arise and enhance comfort, and to understand how APAP therapy can improve OSA treatment.” (personal communication) With better knowledge and treatment adherence, quality of life and other factors could be improved by APAP treatment in people experiencing a temporary change in OSA severity or who have mild forms of OSA.

Regina Patrick, RPSGT, RST, is a freelance medical editor/writer for the Regina Patrick Writing Service. She covers numerous sleep medicine topics for Sleep Review.


1. Morgenthaler TI, Aurora RN, Brown T, et al; Standards of Practice Committee of the American Academy of Sleep Medicine. Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: an update for 2007. An American Academy of Sleep Medicine report. Sleep. 2008;31:141-147.
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3. Killick R, Wang D, Hoyos CM, et al. The effects of testosterone on ventilatory responses in men with obstructive sleep apnea: a randomised, placebo-controlled trial. J Sleep Res. 2013;22:331-336.
4. Hoyos CM, Killick R, Yee BJ, et al. Effects of testosterone therapy on sleep and breathing in obese men with severe obstructive sleep apnoea: a randomized placebo-controlled trial. Clin Endocrinol. 2012;77:599-607.
5. Littner MR. Mild obstructive sleep apnea syndrome should not be treated. J Clin Sleep Med. 2007;3:263-264.
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