INTRODUCTION — Obstructive sleep apnea (OSA) is a disorder characterized by apneas and hypopneas due to repetitive collapse of the upper airway during sleep. For the majority of patients with OSA, positive airway pressure (PAP) is first-line therapy. The initiation of PAP therapy requires selection of a mode of PAP (eg, continuous or bilevel PAP) and titration of pressure to reduce and/or eliminate obstructive events to an acceptable level during sleep.
The titration methods for PAP in patients with OSA are reviewed here. The diagnosis and overall management of OSA, the indications for PAP therapy, and the initial mode selection for PAP titration are discussed separately. (See "Clinical presentation and diagnosis of obstructive sleep apnea in adults" and "Management of obstructive sleep apnea in adults" and "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea" and "Mode selection for positive airway pressure titration in adult patients with central sleep apnea syndromes".)
MODES OF POSITIVE AIRWAY PRESSURE — There are two major PAP modalities used to treat patients with OSA not complicated by central sleep apnea (CSA), other respiratory dysrhythmias, or hypoventilation (algorithm 1) [1,2]:
●Continuous PAP (CPAP)
●Bilevel PAP in spontaneous mode (BPAP-S)
Each of these modalities requires choosing between fixed or auto-titrating technology. Fixed-level CPAP and auto-titrating CPAP (APAP) are the most common modes used while BPAP-S is an acceptable alternative in select patients. The titration methods used to target the optimal level of PAP are discussed in this topic. Initial mode selection for OSA patients is discussed in detail separately. (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea".)
There are also more technologically advanced PAP devices designed for specific applications. It is uncommon to treat patients with uncomplicated OSA (ie, OSA which is not complicated by other respiratory and nonrespiratory disorders that could potentially affect respiration during sleep (table 1 and table 2)) with these more advanced (and more expensive) PAP modalities. These include the following:
●BPAP in spontaneous/timed mode or timed mode (BPAP-S/T and BPAP-T) for the treatment of CSA or chronic hypercapnic respiratory failure.
●Adaptive servo-ventilation (ASV), for the treatment of CSA or Biot/ataxic breathing (eg, for patients receiving opioids) or patients exhibiting combinations of CSA and OSA.
●Volume-assured pressure support (VAPS), for patients with chronic hypercapnic respiratory failure and neuromuscular disorders with or without concomitant OSA or CSA. (See "Noninvasive positive airway pressure therapy for the obesity hypoventilation syndrome", section on 'Average volume-assured pressure support'.)
Further details are provided separately. (See "Mode selection for positive airway pressure titration in adult patients with central sleep apnea syndromes" and "Noninvasive positive airway pressure therapy for the obesity hypoventilation syndrome", section on 'Average volume-assured pressure support'.)
Recall of Phillips PAP devices is discussed separately. (See "Management of obstructive sleep apnea in adults", section on 'Positive airway pressure therapy'.)
TITRATION GOALS — The goal of any titration is to determine the minimal pressure(s) required to resolve all apneas, hypopneas, snoring, and arousals related to obstructive events, in all stages of sleep and in all sleep positions. Assessing adequacy of the titration module for the selected mode of PAP is different for the mode selected and is discussed in the individual sections below. (See 'Adequacy assessment of CPAP titration' below and 'Assessment of APAP titration adequacy' below and 'Assessment of BPAP-S titration adequacy' below and 'Auto-titrating BPAP-S' below.)
IN-LABORATORY FIXED-LEVEL CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) — Fixed-level CPAP delivers PAP at a level that remains relatively constant (within 1 to 2 cm H2O) throughout the respiratory cycle. The PAP splints the upper airway open, preventing upper airway collapse or narrowing, during sleep. Patients must be able to initiate every breath while on CPAP. A fixed level of CPAP can be determined using either an in-laboratory polysomnographic (PSG) assessment, which is discussed in this section, or at home by using auto-titrating CPAP (APAP) technology, which is discussed below. (See 'Auto-titrating continuous positive airway pressure (APAP)' below.)
Indications — In-laboratory fixed-level CPAP titration is the gold standard for determining optimal fixed-level PAP for patients with OSA. While fixed-level CPAP was traditionally the first-line treatment for most patients with OSA based upon its efficacy and extensive clinical experience (algorithm 1), APAP is being increasingly used as an alternative in select patients with OSA, and has increased even more during the Coronavirus 2019 (COVID-19) pandemic. Details regarding the efficacy of CPAP and patient suitability for this mode selection are discussed separately (see "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Initial mode and setting options' and "Management of obstructive sleep apnea in adults"). Choosing between an attended in-laboratory PSG titration and in-home APAP titration is also discussed separately. (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Factors influencing the setting'.)
Initial settings and titration during polysomnography — The optimal level of CPAP can be determined in the sleep laboratory using a fixed-level CPAP device during full-night or split-night PSG. Fixed-level CPAP titrated during an attended in-laboratory PSG study is the gold standard method for PAP titration. Detailed protocols are available from the American Academy of Sleep Medicine (AASM) [1-3]. We suggest the following titration module:
●CPAP is started at a low level (eg, 4 cm H2O).
●The amount of CPAP is serially increased (usually in increments of 1 to 2 cm H2O) until evidence of upper airway obstruction is eliminated, allowing at least five minutes at each pressure.
●The minimal amount of CPAP that consistently prevents upper airway obstruction becomes the fixed CPAP setting.
●Engaging expiratory pressure relief and humidification may also be necessary during titration for improved tolerance. (See 'Intolerance of the sensation of pressure' below.)
●The recommended maximum level of CPAP is 20 cm H2O for adults. However, we and the AASM recommend considering transitioning to bilevel PAP in spontaneous mode (BPAP-S) at CPAP levels of approximately 15 cm H2O. (See 'Bilevel positive airway pressure, spontaneous mode (BPAP-S)' below.)
What constitutes an optimal titration during PSG is discussed separately. (See 'Adequacy assessment of CPAP titration' below and 'Intolerance of the sensation of pressure' below.)
While a full-night PSG is ideal and considered the gold standard [4], most patients can be successfully titrated using the same method during a split-night PSG. A split-night study involves an initial diagnostic study that is followed by PAP titration during the second half of the night. The titration is performed only if the diagnostic portion of the study conclusively identifies OSA. However, if more time is needed for OSA diagnosis or adequate CPAP titration is not achieved during the allocated time, or it is apparent that a patient may need BPAP-S instead of CPAP, the patient may need to be brought back on a separate night for another diagnostic study or PAP titration, respectively. Details regarding the diagnostic criteria for OSA during the diagnostic phase of a split-night study and factors that affect the choice between a full- or split-night study are discussed separately. (See "Clinical presentation and diagnosis of obstructive sleep apnea in adults", section on 'Polysomnography'.)
Adequacy assessment of CPAP titration — In the sleep laboratory, during PAP titration (for either continuous PAP [CPAP] or BPAP-S), the goal is to determine the minimal pressure required to resolve all apneas, hypopneas, snoring, and arousals related to these events, in all stages of sleep and in all sleep positions. However, a minority of titrations achieve this goal. Variable levels of PAP titration adequacy are defined by AASM as the following [3]:
●Optimal, good, adequate – This is defined as the following:
•Optimal – Reduces the respiratory disturbance index (RDI), which includes the respiratory effort-related arousal (RERA) index plus the apnea-hypopnea index (AHI), to <5 events per hour for at least 15 minutes; supine rapid eye movement (REM) sleep should not be interrupted by spontaneous arousals or awakenings.
•Good – Reduces the RDI ≤10 events per hour or by 50 percent if the baseline RDI is <15 events per hour; supine REM sleep should not be interrupted by spontaneous arousals or awakenings.
•Adequate – Does not reduce the RDI ≤10 events per hour but reduces the RDI by 75 percent from baseline (especially in severe OSA patients), or one in which the titration grading criteria for optimal or good are met with the exception that supine REM sleep did not occur at the selected pressure.
For patients who achieve an "optimal," "good," or "adequate" rating, the patient should receive the fixed-level therapy identified during the titration. However, in practice, suboptimal (ie, good or adequate) titrations are commonly compensated for by using APAP rather than repeating a titration study. This strategy is gaining acceptance and transitions the patient to APAP using settings incorporating a pressure range that allows pressures higher than the previously determined fixed CPAP pressure [1]. In fact, many durable medical equipment suppliers are routinely delivering APAP devices set to the prescribed fixed CPAP pressure, presumably for issues of cost and convenience (eg, the supplier may only stock one type of device rather than two).
●Inadequate – An inadequate titration is one that does not meet adequate, good, or optimal criteria.
For most patients with an "inadequate" titration, an assessment for potential explanations should be performed (eg, mask leak, oronasal issues, intolerant of pressure, pressure >20 cm H2O required, complex sleep disorder is suspected). We typically repeat in-laboratory titration using the same PAP modality as in the initial titration when the reasons for inadequacy have been addressed. Alternatively, if the patient has uncomplicated OSA (eg, patients with an "inadequate" titration due to inadequate supine or REM duration), we trial APAP (see 'Factors that influence initial success' below). For patients in whom higher pressures are required, we sometimes repeat titration with BPAP-S. (See 'Bilevel positive airway pressure, spontaneous mode (BPAP-S)' below.)
Success or lack thereof of PAP can subsequently be judged by the clinical response and downloaded data from the treatment device, as measured by the respiratory event index (REI). If the REI indicates control of the patient's OSA but the clinical response is not concordant, we typically proceed with repeat in-laboratory PSG [5]. (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Follow-up after initial titration' and "Downloading data from positive airway pressure devices in adults", section on 'Assessing effectiveness'.)
Measurement of the REI is a ubiquitous feature of modern flow generators. The REI, which is an AHI "estimate," is calculated by device software (also sometimes known as known as AHIflow) that measures changes in airflow. Manufacturers label residual event frequencies as AHIs on data downloads from their PAP devices despite the fact that the correct metrics are REIs. It is important that the clinician understand the distinction between the REI derived from device downloads and the AHI obtained from PSG; the latter is computed not just from flow data but also from associated declines in oxyhemoglobin saturation and/or electroencephalographic evidence of arousal. By contrast, the REI is determined by proprietary algorithms and hardware platforms that differ between manufacturers. In the uncommon situation when REI values obtained on the same patient but derived from different manufacturer's devices are compared, the clinician should take into account this possible source of imprecision [6]. Data comparing the two are limited, but some studies suggest good correlation if the PSG AHI is either very high or lower than 10 events per hour [5,7,8]. (See "Downloading data from positive airway pressure devices in adults".)
Further details on assessment after the initial titration are provided separately. (See 'Factors that influence initial success' below and "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Follow-up after initial titration'.)
AUTO-TITRATING CONTINUOUS POSITIVE AIRWAY PRESSURE (APAP) — APAP devices deliver continuous PAP (CPAP) at varying levels; higher pressure for when more is needed and lower pressure for when less is needed. APAP devices utilize proprietary algorithms to detect (figure 1) and resolve obstructive events during sleep and can therefore be used not only to determine an optimal fixed level of CPAP (see 'Titration' below) but also to treat OSA (even if a fixed pressure is identified by fixed-level titration in the laboratory). APAP is not a diagnostic modality and is designed primarily for in-home use. Similar to CPAP, patients must be able to initiate every breath while on APAP.
When APAP is used to treat OSA, the average pressure delivered by the device is generally lower than that used during treatment with fixed-level CPAP, which may lead to better tolerance of treatment [9-11].
Event-detection software provides estimates of the respiratory event index (REI), hours of use, and presence or absence of an air leak. Based on this information, algorithm software varies the level of PAP to treat device-detected events and compensate for leaks. The REI is a device-calculated corollary of the apnea-hypopnea index (AHI), the latter of which is measured during polysomnography (PSG). Since algorithms are proprietary, treatment efficacy may vary among individual devices. Data that support APAP as a treatment modality are discussed separately. (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Uncomplicated obstructive sleep apnea'.)
Indications — APAP titration or treatment is suitable for patients in whom a diagnosis of moderate to severe uncomplicated OSA is made (ie, OSA which is not complicated by other respiratory and non-respiratory disorders that could potentially affect respiration during sleep (table 1 and table 2 and algorithm 1)). Data to support this strategy are discussed separately. (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Uncomplicated obstructive sleep apnea'.)
Other patients in whom APAP titration is considered an option include patients with mild OSA, patients who are intolerant of the pressure associated with fixed-level CPAP (ie, APAP is used as a pressure-relief strategy), patients with known variable pressure requirements (eg, significantly higher pressures required when supine, intermittent use of alcoholic beverages near bedtime, exacerbations of allergic rhinitis), and patients in whom access to a sleep laboratory is not feasible (eg, during the COVID-19 pandemic, denied by insurance, or excessively inconvenient due to distance). (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Intolerance of pressure' and "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Variable pressure requirement'.)
APAP titration may not be suitable for patients who cannot be fit for an interface that adequately minimizes air leak, since leaks can affect the ability of the flow generator to detect abnormal breathing [11].
Titration — The optimal method of titration with an APAP device is unclear. Variations in APAP titration protocols include different durations of time (eg, 3 to 14 days) of APAP use, different minimum and maximum pressure ranges, and different definitions of trial success. We suggest the following as a general guide:
●We typically gather device-downloaded data from a 7- to 14-day period of in-home APAP titration and set a minimum and maximum pressure range of 5 to 20 cm H2O, respectively.
●The optimal fixed-level CPAP setting is typically the level of pressure at or below which obstructive events measured by the APAP device are eliminated for more than 90 or 95 percent of the time ("90th and 95th percentile pressure" or "P90 and P95 pressure") [12-14]. These data are provided by most APAP devices. Most modern APAP devices report P90 and/or P95 as well as an REI that can be used to confirm the efficacy of the chosen pressure.
The P90 and P95 are typically starting points for the determination of a fixed-level CPAP setting since they can be affected by several factors including nightly adherence to therapy, pressure range settings, and extent of mask leak. Thus, we typically further adjust the pressure range and then reassess clinical symptoms and downloaded data in two to four weeks of use. Empiric adjustments in settings may also be required during follow-up (eg, morbidly obese patients may typically require both a higher minimum and maximum pressure range or weight loss may require the opposite). (See 'Assessment of APAP titration adequacy' below.)
Assessment of APAP titration adequacy — In the absence of published guidelines and assuming that auto-titrating CPAP (APAP) titration was performed at home, we use a common definition of a successful APAP trial, which consists of a combination of mean nightly use of at least six hours per night, a device-calculated REI ≤10 events per hour, and an acceptable leak profile (which is dependent on the individual device manufacturer, mask type, and proprietary algorithms). Symptoms must also be considered in assessment of titration adequacy.
If residual symptoms of daytime sleepiness and/or snoring persist despite adequate nightly APAP use, the clinician should assess for adequate mask fit, excessive leak, and proper pressure range settings:
●For those patients who have residual symptoms and/or snoring, a residual REI >10 events per hour, a normal leak profile, and data to suggest they frequently reach the maximum of the APAP pressure range, we typically empirically increase the top of the pressure range by 2 cm H2O or up to a maximum of 20 cm H2O (eg, initial pressure range of minimum of 8 to maximum of 14 cm H2O would change to maintaining the minimum pressure of 8 cm H2O but increasing the maximum pressure to 16, 18, or 20 cm H2O) and re-evaluate the patient's symptoms and adherence data in two to four weeks.
●For patients with persistent symptoms and/or snoring, an REI >10 events per hour and/or high levels of leak despite empiric changes in pressure and attention to mask fit, a formal attended in-laboratory titration with CPAP or, if indicated, bilevel PAP in spontaneous mode (BPAP-S) therapy is recommended with PSG monitoring. As with all auto-titrating devices, if the clinical response diverges from the device-reported REI, we also typically perform in-laboratory monitoring with the patient's own device at its usual settings. Although uncommon, when APAP devices are used in the laboratory setting, assessment of adequacy is similar to that described for CPAP. (See 'Adequacy assessment of CPAP titration' above.)
BILEVEL POSITIVE AIRWAY PRESSURE, SPONTANEOUS MODE (BPAP-S) — BPAP-S delivers PAP at different levels during inspiration and expiration. The level during inspiration is called the inspiratory PAP (IPAP) and the level during expiration is called the expiratory PAP (EPAP). IPAP is typically at least 4 cm H2O higher than the EPAP.
Although unclear, it is generally thought that BPAP-S splints the upper airway open in a manner similar to continuous PAP (CPAP), with the exception that the EPAP component is thought to be effective in suppressing frank obstructive apneas, while IPAP primarily acts to prevent obstructive hypopneas, respiratory effort-related arousals (RERAs), and snoring. This is an important concept when BPAP-S is titrated by technical personnel in the sleep laboratory. (See 'Initial settings and titration' below.)
BPAP-S has the additional feature of providing ventilatory support through the application of pressure support (PS), which is determined by the difference between IPAP and EPAP settings. As an example, greater ventilatory support is provided by BPAP-S (which translates into a greater tidal volume) when the IPAP is set at 15 cm H2O and the EPAP at 5 cm H2O (ie, PS of 10 cm H2O) compared with an IPAP set at 10 cm H2O and EPAP at 5 cm H2O (PS of 5 cm H2O). This function makes it useful for more complex varieties of sleep-disordered breathing (eg, patients with both OSA and a comorbidity producing hypoventilation, such as a neuromuscular disease).
Indications — BPAP-S is a second-line therapy for patients with OSA (algorithm 1). It is typically used in patients with uncomplicated OSA who fail or do not tolerate CPAP or auto-titrating CPAP (APAP).
BPAP may also be used in patients with coexisting OSA and the following hypoventilation syndromes, although the spontaneous/timed (S/T) mode is preferable in those who cannot reliably trigger spontaneous breaths (see "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Complicated OSA' and "Mode selection for positive airway pressure titration in adult patients with central sleep apnea syndromes"):
●Patients with obesity hypoventilation syndrome whose alveolar hypoventilation fails to improve despite CPAP or APAP therapy (BPAP-S). (See "Noninvasive positive airway pressure therapy for the obesity hypoventilation syndrome".)
●Patients with sleep-related hypoventilation due to opioid medication including those on buprenorphine with naloxone or a coadministered gabapentinoid who can reliably trigger spontaneous breaths may be candidates for BPAP-S. Those with Biot or ataxic breathing may respond better to adaptive servo-ventilation.
●Patients with ventilatory failure from neuromuscular disease who are reliably able to trigger spontaneous breaths (BPAP-S). For neuromuscular diseases where in-ventilatory failure is expected to be progressive, BPAP-S/T is more appropriate.
●Patients with idiopathic and central congenital alveolar hypoventilation (BPAP-S/T) [15].
●Patients with sleep-related hypoventilation from a medical disorder (eg, stroke, syringomyelia, multiple sclerosis, spinal cord injury, restrictive chest wall disease such as kyphoscoliosis) who can reliably trigger spontaneous breaths. For most of these patients, BPAP-S/T, average VPAPS, or a conventional home ventilator would be more suitable choices; however, hypoventilation due to these disorders is an uncommon occurrence.
BPAP-S is contraindicated in treatment-emergent central sleep apnea (TECSA or complex sleep apnea) or central sleep apnea (CSA) associated with heart failure. Although the pathogenesis of TECSA and CSA-associated congestive heart failure are unclear, most investigators believe that high loop gain and reduced carbon dioxide reserve are involved. BPAP-S augments loop gain, thereby leading to lower carbon dioxide reserve. (See "Treatment-emergent central sleep apnea", section on 'Treatment'.)
For patients who are intolerant of the pressure and fail fixed-level or auto-titrating CPAP with pressure relief engaged, we support a trial of BPAP-S as a "pressure-relief" measure. The premise upon which BPAP may work in this setting is based upon a lower-than-average airway pressure with BPAP-S when compared with CPAP. While randomized controlled trials have failed to prove benefit in this regard [16-18], trials may not have been designed to identify the relatively small subgroup of patients who might benefit from changing to BPAP-S [19]. (See 'Pressure relief' below.)
Initial settings and titration — BPAP-S titration should only occur in a laboratory setting with polysomnography (PSG), given the complexity of the underlying sleep disorders for which it is generally indicated and the poor validation of in-home auto-titrating BPAP devices. While a full-night attended in-laboratory titration is preferred, split-night titration studies may also be feasible [3].
●Titration module – We generally follow the American Academy of Sleep Medicine guidelines for manual titration in the sleep laboratory [3]. The titration of BPAP-S differs from CPAP because two levels of PAP need to be adjusted, IPAP and EPAP. It is important to remember that the level of EPAP determines whether frank obstructive apneas are suppressed, while the IPAP is used to eliminate other degrees of obstructed breathing (hypopneas, RERAs, snoring) [20].
•In a patient not previously titrated on PAP, initial IPAP and EPAP are usually started at 8 and 4 cm H2O, respectively. Both IPAP and EPAP are then serially increased by 1 to 2 cm H2O, allowing at least five minutes at each pressure, until frank obstructive apneas are eliminated. After that, IPAP alone is titrated in the same manner until obstructive hypopneas, RERAs, and snoring are eliminated. The maximum, recommended IPAP level is 30 cm H2O for adults. Sometimes this titration approach can result in a degree of PS that is too high (ie, the delta between IPAP and EPAP; see third bullet for management).
•In a patient previously titrated on CPAP, the starting EPAP can be set to the CPAP value that eliminated frank obstructive apneas during the previous study, and the IPAP is set to a level 4 cm H2O higher.
•The minimum recommended IPAP-EPAP differential is 4 cm H2O and the maximum is 10 cm H2O in uncomplicated OSA (ie, OSA which is not complicated by other respiratory and nonrespiratory disorders that could potentially affect respiration during sleep (table 1 and table 2)) [3]. Although contrary to these guidelines, we have observed the need for higher differentials to eradicate hypopneas, RERAs, and snoring after an EPAP level that suppresses obstructive apneas has been established. If TECSA emerges due to excessive ventilatory support, the differential can be reduced (by the technologist performing the titration) as necessary and both EPAP and IPAP simultaneously increased, maintaining a fixed differential, to accomplish the same goal. When OSA is complicated by hypoventilation (eg, ventilatory impairment from neuromuscular disease or chronic obstructive pulmonary disorder), a greater delta between EPAP and IPAP is often necessary to provide the degree of PS necessary to augment ventilation.
•Engaging expiratory pressure relief and humidification may also be necessary during titration. (See 'Intolerance of the sensation of pressure' below.)
•Other considerations, beyond the scope of this chapter, also apply with respect to neuromuscular ventilatory impairment; specifically, EPAP should not be set to a level that compromises the ability of the patient to exhale. (See "Noninvasive ventilation in adults with chronic respiratory failure from neuromuscular and chest wall diseases: Practical aspects of initiation".)
●Spontaneous-timed modes – When no back-up rate is set, the device is said to be in "spontaneous" (S) mode; when both patient-initiated and back-up breaths are possible, the device is in "spontaneous-timed" (S/T) mode; and when only back-up breaths are permitted, the device is in "timed" (T) mode.
•We typically start patients with uncomplicated OSA on a BPAP-S, which only provides breaths in response to patient inspiratory efforts without a back-up rate.
•We typically initiate BPAP in S/T mode in patients with OSA who exhibit central events (eg, a mixture of obstructive and central events is noted during the diagnostic study and persist during the titration, or patients with TECSA). (See "Treatment-emergent central sleep apnea", section on 'BPAP with a backup respiratory rate' and "Noninvasive ventilation in adults with chronic respiratory failure from neuromuscular and chest wall diseases: Patient selection and alternative modes of ventilatory support".)
•The T mode is almost never utilized since S/T mode essentially provides the same function. Utilizing BPAP in timed mode (BPAP-T) may result in patient/ventilator dyssynchrony if patient-initiated breaths are still present. (See "Noninvasive ventilation in adults with chronic respiratory failure from neuromuscular and chest wall diseases: Patient selection and alternative modes of ventilatory support" and "Central sleep apnea: Treatment", section on 'Bilevel positive airway pressure (BPAP) with back-up rate'.)
Newer BPAP-S flow generators commonly incorporate the ability to adjust various parameters other than IPAP and EPAP. These settings allow for tailoring trigger sensitivity and inspiratory (I)/expiratory (E) timing values to accommodate patient comfort, particularly those with various comorbidities. Such settings may include:
●Rise time (the time in seconds to transition from EPAP to IPAP)
●Ratio between inspiratory and expiratory time (I:E ratio)
●Trigger (transition from EPAP to IPAP) and cycle (transition from IPAP to EPAP) sensitivities
●Maximum time that the flow generator spends in IPAP (Ti Max)
●Minimum duration of IPAP (Ti Min)
Given the complexity of determining the proper settings for any given patient and the fact that they are largely determined by patient comfort with therapy, the values are most often empirically determined by the PSG technologist during the laboratory titration and then incorporated into the prescription by the clinician.
Assessment of BPAP-S titration adequacy — The same acceptability criteria recommended for a fixed-level CPAP titration to treat OSA are used for assessing the adequacy of titration with bilevel PAP in spontaneous mode (BPAP-S). (See 'Adequacy assessment of CPAP titration' above.)
However, there is one exception. The exception relates to situations in which BPAP-S is being used, in part, as a ventilatory support mode rather than treatment of obstructive episodes. When this is the case, the goal is to use noninvasive monitoring to achieve an acceptable arterial tension for carbon dioxide (PaCO2). In general, we prefer measurement of transcutaneous CO2 (PtCO2) since the airflow from BPAP-S dilutes the CO2 content of the exhaled breath, rendering end-tidal partial pressure of carbon dioxide (Pco2) monitoring less accurate. (See "Noninvasive ventilation in adults with chronic respiratory failure from neuromuscular and chest wall diseases: Practical aspects of initiation", section on 'Initial trial'.)
AUTO-TITRATING BPAP-S — Auto-titrating bilevel PAP in spontaneous mode (auto-titrating BPAP-S) delivers an amount of BPAP-S that varies during sleep. Common to all auto-titrating devices, auto-titrating BPAP-S devices use proprietary algorithms to determine optimal settings that reduce device-detected obstructive apneas, hypopneas, and more minor degrees of obstruction (eg, snoring) to an acceptable level.
Several BPAP-S flow generators are available in the United States and their algorithms differ with respect to how they deal with obstructive apneas and hypopneas. For example, one brand of flow generator operates with a fixed level of pressure support (PS; inspiratory PAP [IPAP] minus expiratory PAP [EPAP]) and titrates both IPAP and EPAP simultaneously to deal with the entire spectrum of obstructive events. By contrast, another brand of flow generator titrates both IPAP and EPAP separately: EPAP is titrated to eliminate frank obstructive apneas and IPAP to eliminate lesser degrees of obstructive events. Although EPAP and IPAP are auto-titrated independently, PS is constrained within limits set by the prescriber.
There remain limited efficacy data to help guide clinicians in the use of auto-titrating BPAP-S. Two small randomized trials of unselected patients using auto-titrating BPAP-S showed similar efficacy as measured by polysomnography (PSG) [21,22]. One employed the variable PS device but with a minimal PS range (maximum of 3 cm H2O) compared with continuous PAP (CPAP) [21]; the other used the competitor's flow generator set to a fixed PS of 4 cm H2O versus a comparison group using fixed BPAP-S [22]. Both studies demonstrated equal efficacy in terms of initial improvement of the apnea-hypopnea index (AHI) but one study suggested that it was not maintained [21]. It should be noted that the variable PS device used in the latter study appears to have employed expiratory pressure relief as well as auto-titration. Some studies have employed auto-titrating BPAP-S to treat a subgroup of patients with poor compliance with other PAP modalities or patients with no improvement in AHI on CPAP [17,23-25]. Results were mixed; compliance was better at 10 weeks in one study [23] and similar in two other trials after long-term follow-up [17,25].
●Indications – We offer a trial of auto-titrating BPAP-S to OSA patients who do not tolerate or fail fixed- or auto-titrating CPAP (APAP) or fixed BPAP-S [26-28]. We also sometimes use auto-titrating BPAP-S devices as a form of "pressure-relief" (ie, reducing the uncomfortable sensation of breathing against high pressure from a fixed-level device). BPAP-S devices cannot be used to determine a fixed level of CPAP. It is also unlikely that auto-titrating BPAP-S devices can be used to identify fixed levels of BPAP-S as an alternative to a laboratory titration.
●Titration method – Titration for auto-titrating BPAP-S devices should preferably occur in an attended in-laboratory setting where efficacy can be demonstrated after an overnight PSG [29]. The optimal approach and empiric initial settings for auto-titrating BPAP-S devices are unclear, as there is a paucity of data and few validated algorithms to help guide clinicians with these devices. One reported approach, limited to the flow generator that allows for the setting of a PS range, arbitrarily sets the minimal EPAP at 4 cm H2O, maximal IPAP at 25 cm H2O, and maximal PS at 8 cm H2O, allowing the device's proprietary algorithms to titrate the pressures to resolve obstructive events [17]. We closely follow these patients and maintain a low threshold to perform a laboratory titration with PSG.
Adaptive servo-ventilation (ASV), used for patients with complex combinations of OSA and central sleep apnea, is substantively different from auto-titrating BPAP-S and consequently, an entirely different titration method is used. Further description of ASV and suggested titration methods are provided separately. (See "Central sleep apnea: Treatment", section on 'Adaptive servo-ventilation'.)
●Assessment of adequacy of titration – Similar to all auto-titrating devices, auto-titrating BPAP-S devices report 90th or 95th percentile and maximum pressures for both EPAP and IPAP as well as an average estimated residual respiratory event index (REI). This REI is based on continuous indirect monitoring of airflow and is not equivalent to the AHI derived from PSG, since it relies only on decreases in airflow to determine the presence of an event. Ideally, the settings for auto-titrating BPAP-S should be done in an attended in-laboratory setting, so that the response can be measured by PSG and an actual AHI obtained. In that way, adequacy can be measured in a manner similar to that described for fixed-level CPAP.
However, we have increasingly observed that auto-titrating BPAP-S is deployed using empiric settings without first confirming effectiveness in the sleep laboratory. When this is done, it is necessary to rely on the REI reported by the device to determine adequacy of treatment. Recently, the American Academy of Sleep Medicine (AASM) has issued a guideline approving the use of home sleep apnea testing (HSAT) for follow-up of some patients treated for OSA [30]. However, the guideline did not clearly state that HSAT should be done concurrently with the use of PAP. If HSAT using unmodified type 3 devices is used for this purpose, it might be necessary to rely on the chest and abdominal effort signals to identify respiratory events. We have not seen such use reported in the literature. However, we discovered that it is possible to fashion a cable that allows routing of the flow signal from a patient's PAP device to the flow channel on the type 3 HSAT device used in our laboratory. This allowed us to successfully score events based on actual PAP airflow while the patient used their PAP treatment at home. To our knowledge, this technique has not been previously reported but could possibly be employed depending on the particular HSAT device and PAP flow generator being used. Devices monitoring peripheral sympathetic tone to identify respiratory events could also be used for this purpose, and are supported by two studies [31,32]. There is no guidance from the AASM for this possible strategy. (See 'Adequacy assessment of CPAP titration' above.)
In the rare instance that titration is not performed in a sleep laboratory, the response is assessed on the presence or absence of symptoms and downloaded data from the device itself (REI, leak, and adherence, similar to APAP devices). (See 'Assessment of APAP titration adequacy' above and "Downloading data from positive airway pressure devices in adults", section on 'Autoadjusting device downloads'.)
PREDICTION FORMULA TITRATION — Published equations aimed at predicting the optimal setting for fixed-level continuous PAP (CPAP) therapy have been described [12,13,33-38]. However, they are not well validated. Given the ease of obtaining auto-titration PAP devices for patients, there does not appear to be any role for the use of prediction formulae, although they may be appropriate in patients who cannot afford or do not have access to a laboratory polysomnographic titration or an auto-titrating device. (See "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Follow-up after initial titration'.)
FACTORS THAT INFLUENCE INITIAL SUCCESS — Several factors influence success during (and following) titration to achieve adequate PAP settings. Addressing these factors optimizes efficacy and improves adherence.
Choosing the correct patient-device interface — We advocate for properly fitting interface between the patient and the device to optimize the adherence to and efficacy of PAP therapy.
Options include nasal masks, nasal pillows, oronasal masks, full facemasks, and oral interfaces (picture 1 and picture 2 and picture 3). Nasal and oronasal masks are the commonly used interfaces. In general, most patients do not tolerate nasal pillows if continuous PAP (CPAP) or inspiratory PAP (IPAP) is above 12 cm H2O due to the discomfort of excessive turbulent airflow directly impacting the nasal mucosa. Oral interfaces are rarely used but may be helpful in certain situations if nasal or oronasal interfaces cannot be tolerated. Full facemasks are rarely used.
A relatively new development is the availability of "minimal-contact" masks, which fit under the nose and over the mouth. They allow the patient to wear glasses, if necessary, and the patient can read, watch television, or use personal computing devices while in bed. Although these activities in bed are generally to be discouraged, it can be difficult to convince patients to follow these basic precepts of sleep hygiene. In our experience some patients fail to achieve adequate compliance with PAP treatment because they fall asleep, without their PAP, while engaging in these activities. The solution is to prescribe a minimal-contact mask and instruct them to wear their PAP, with the flow generator on, while engaging in these activities. In that way they are already using PAP when they do fall asleep. In addition, these interfaces are less bulky than conventional facemasks and seem to be better at staying in place with movement during sleep.
Patients should be encouraged to try several different interfaces during PAP titration. We typically prefer the interface that offers the best mix of comfort and efficacy is prescribed (ie, the most comfortable mask is not always the best fitting and the best-fitting mask is not always the most comfortable) [3]. However, trials of different interfaces may be necessary for the patient at home even after the seemingly best-fitting interface and optimal level of PAP have been determined in the laboratory or sleep clinic. In reality, the optimal interface varies from patient to patient and often is not the interface used during a laboratory titration. Many patients try a variety of interfaces before the optimal model and size are identified, leading most clinicians to conclude that the best interface is "the one the patient will use."
Pressure requirements may vary depending on the interface such that retitration may be needed when switching interfaces. For example, pressure requirements may be higher if an oronasal interface is used when compared with a nasal or nasal pillows interface [39-42]. In addition, for oronasal masks, pressure requirement varies depending on whether the patient preferentially breathes through the nose or mouth. While some evidence suggests that higher residual apnea-hypopnea index (AHI) and more leaks occur with the use of oronasal masks compared with nasal masks [40,43], one randomized controlled trial reported no difference in the residual AHI or compliance between these interfaces [44].
Intolerance of the sensation of pressure — For patients with OSA who specifically complain of discomfort caused by exhaling against PAP, we suggest a trial of pressure relief and/or the application of a pressure ramp. Alternatively, switching to an auto-titrating device is also reasonable.
Pressure relief — Pressure relief involves lowering the delivered pressure during expiration in order to prevent the discomfort that some patients report when breathing out against PAP. This feature is available on CPAP, auto-titrating CPAP (APAP), bilevel PAP in spontaneous mode (BPAP-S), and auto-titrating BPAP-S (auto-BPAP-S) devices. However, it is important for the prescriber to understand how pressure relief is implemented by different manufacturers and in different models of flow generators by the same manufacturer. Options are as follows [45,46]:
●Brief reduction in CPAP or expiratory PAP (EPAP; BPAP-S flow generators) at the start of exhalation followed by a return to full pressure before the start of inspiration.
●Reduction in CPAP or EPAP during the entirety of expiration (alternatively described as adding a small degree of pressure support [PS] to IPAP, simulating a BPAP-S device).
●BPAP-S, with or without expiratory pressure relief.
●Auto-titrating BPAP-S, either with or without a fixed level of PS or PS that will auto-titrate within a small range of pressures.
However, all of these approaches are subject to change by the manufacturer, with little oversight by the US Food and Drug Administration (FDA) or notice to the medical community. PAP devices were designated in 2018 as class II devices by the FDA under rule 510(K), which means that if modifications are made, the flow generator must only be considered substantially equivalent to a legally marketed device (section 513[i][1][A] FD&C Act) [46].
The actual settings for any given device do not necessarily correspond to a fixed amount of pressure decrease, and therefore the selection can be somewhat arbitrary. For some devices, the mapping of a given setting to a given decrease in pressure is proprietary to the manufacturer, and may vary with the treatment pressure(s). For others, the degree of expiratory pressure relief may be chosen from values built into the flow generator.
In the case of laboratory titrations, the technologist usually determines whether to use pressure relief and at what setting; in our experience, the maximum setting is commonly (but not always) chosen since the goal is to perform a successful titration. This is best achieved when patient comfort with PAP is maximal.
In actual practice, there are few data to suggest that treatment efficacy varies with pressure relief setting regardless of which manufacturer's flow generator is prescribed.
One study examined the effects of various pressure relief strategies using a testing apparatus that used a Starling resistor to simulate sleep-disordered breathing [45]. This study examined a selection of flow generators from different manufacturers and identified the best setting(s) during an initial titration without pressure relief. They then instituted various pressure relief settings while maintaining the best titrated pressure(s). Instituting several of the pressure-relief mechanisms resulted in loss of control of the simulated sleep-disordered breathing. However, the Starling resistor is not a perfect model of the upper airway [47], and bench testing results may not be transferrable to the clinical arena. Nevertheless, we suggest that when in-laboratory titrations are used to determine treatment settings, the pressure relief setting determined during the laboratory titration should be replicated when treatment is prescribed. If pressure relief is initiated during the course of treatment, we are limited to using the respiratory event index (REI) reported by the PAP device to determine whether effectiveness is maintained. Similarly, if treatment is instituted with APAP at home, the REI must be closely monitored if pressure relief is later instituted or its setting changed.
A beneficial impact of routinely applying pressure relief on adherence has not been proven in randomized trials when compared with either conventional CPAP [48] or APAP [49] without pressure relief. This was best demonstrated by a meta-analysis of seven randomized trials (514 patients with OSA, mean AHI >30 events per hour of sleep) that compared CPAP with pressure relief with conventional CPAP [48]. The meta-analysis found no differences in adherence, sleepiness, or vigilance when pressure relief was used compared with patients who had PAP without pressure relief.
Pressure ramp — A pressure ramp initiates PAP delivery at a low level (usually 4 to 5 cm H2O) and then progressively increases the PAP to the prescribed level over a duration designated by the clinician (usually 5 to 45 minutes). This feature serves as a comfort measure, allowing the patient to fall asleep before reaching the higher pressures that might interfere with sleep onset. The pressure ramp can be restarted at any time and is available with CPAP and BPAP devices, whether fixed or auto-titrating. There are no published data indicating that a ramp feature augments acceptance or adherence with CPAP, although many clinicians routinely prescribe a pressure ramp. Noteworthy is that prescribing an APAP setting with a lower limit of 4 (or even 6) cm H2O basically provides the same feature since the device will start at the lower pressure limit and not increase the pressure until events are detected.
Ramp abuse refers to repeated activation of the ramp feature, usually at the beginning of the night, if the patient is still awake when the pressure ramps up to a level that is perceived as preventing sleep. This behavior, which can also occur during nighttime awakenings, can diminish the effectiveness of therapy [50]. We address ramp abuse by appropriate patient education or by any of the measures that improve patient comfort with PAP therapy. We sometimes repeat titration if there is suspicion that the ramp abuse is indicative of a therapeutic pressure target that is too high. We also sometimes change from a nasal mask to an oronasal mask when there is suspicion that the ramp abuse is the result of discomfort associated with the stronger force of flow from a nasal mask.
Auto-titratable or other device — In patients in whom pressure intolerance is an issue and in whom pressure relief or pressure ramping have not resolved the issue, we sometimes switch to an auto-titratable device (eg, APAP) on a trial basis. One meta-analysis of 64 studies reported that pressure modification by switching to APAP resulted in approximately 13 more minutes of usage per night at six weeks [51]. However, the AHI scores were lower in patients on fixed-level CPAP and the effects on daytime sleepiness scores were no different. (See 'Auto-titrating continuous positive airway pressure (APAP)' above.)
Rarely, switching to a bilevel device is needed, in which case we repeat an in-laboratory titration. (See 'Bilevel positive airway pressure, spontaneous mode (BPAP-S)' above.)
Troubleshooting common issues
Nasal dryness (heated humidification) — Although data are conflicting on the routine application of heated humidification, we agree with the American Academy of Sleep Medicine, which advocates heated humidification for all patients who receive PAP [1,2].
PAP airflow through the nose tends to dry and irritate the nasal mucosa and increase nasal resistance. [52,53]. This is especially true in the southwest of the United States due to a climate low in humidity, but also can occur in other locations during cold weather. Home heating invariably lowers indoor humidity unless a room humidifier is used or the heating system incorporates humidification.
Heated humidification decreases the nasal resistance by approximately 50 percent, whereas cold humidification has almost no impact on resistance because it does little to raise the relative humidity of the PAP airflow [53]. Heated humidification is particularly important in patients who have undergone uvulopalatopharyngoplasty, as PAP airflow tends to be more irritating due to the altered postoperative anatomy [54-56]. In theory, reduced nasal resistance from heated humidification may improve the comfort and effectiveness of PAP delivered via nasal mask or nasal pillows. However, clinical studies have not consistently found such benefits [54,55], and heated humidification may only improve adherence in those with nasal dryness [51,57,58].
Many devices allow for the specification of heated humidification that may be fixed or adaptive. In the latter, the degree of heated humidification can be increased, reduced, or turned off at will by the patient or clinician. In addition, the tubing that connects the flow generator to the patient interface can be specified as either simple, unheated tubing or tubing that incorporates electrical heating wires (picture 4). Heated tubes reduce condensation or "rain out" of water that can occur when humidified PAP air flows through an unheated tube. Heated tubes can be set to a fixed temperature controlled by the patient, or can be set to adapt the temperature according to specific algorithms aimed at maintaining a warm flow of air through the tube. External insulation of PAP tubing with cloth or other material may also reduce "rain out," but the availability of heated tubing has for the most part replaced this strategy.
Ideally, the humidifier reservoir is full at bedtime and is almost empty in the morning. This means the maximum amount of humidification is being supplied. However, some patients aren't comfortable with this degree of humidity and prefer lower settings, or even turn the heat to zero.
Nasal congestion — Nasal congestion is a common problem that may pre-exist or be precipitated by PAP therapy [59]. Airflow resistance is higher when nasal congestion is present. This can impair comfortable breathing through the nose, thereby negatively impacting adherence. It may also impede PAP delivery to the upper airway and ameliorate upper airway collapse during sleep.
For nasal congestion, we typically administer a topical nasal glucocorticoid, antihistamine or ipratropium, or prescribe an oral antihistamine [60-62]. Switching from a nasal to an oronasal mask may also be helpful, allowing the positive pressure to be delivered through the mouth if nasal patency is compromised [63,64]. While some patients find oronasal masks less tolerable than nasal masks [65], in our experience most patients tolerate these well and benefit from the avoidance of mouth leaks and dependence on nasal patency. (See "Chronic nonallergic rhinitis" and "Pharmacotherapy of allergic rhinitis".)
Mouth breathing and air leaks — Patients who breathe through their mouths while asleep or who are unable to keep their mouth closed against the PAP are likely to develop a mouth leak when PAP therapy is initiated through a nasal interface. A mouth leak exists when the airflow delivered through the nose exits through the mouth instead of reaching the more distal oropharyngeal airway. Air leak through the mouth may present as oral dryness. We typically use a chin strap that holds the mouth closed to eliminate mouth leaks [66]. However, in patients who continue to have a mouth leak despite a chin strap, we typically switch to an oronasal mask [63-65].
Air leaks via the mask may be improved by switching to a better-fitting mask.
Claustrophobia — Claustrophobic patients may find nasal pillows less intimidating than other interfaces. Alternatively, we have patients undergo a trial of mask desensitization [67]. During desensitization, the patient wears the mask while awake, initially for a short period while relaxing (eg, reading or watching television). Once comfortable, we encourage the patient to wear the mask for progressively longer periods, with the goal of incrementally increasing the patient's tolerance of the mask and of positive pressure so that it can be worn at night during sleep.
Altitude compensation — Although pressure levels induced by earlier generations of PAP devices decrease significantly at higher altitudes and reduce efficacy [68], newer generations of PAP devices typically include an altitude compensation feature as standard. Thus, altitude compensation is not usually a consideration when choosing a device. However, should a patient insist on using an older flow generator, altitude compensation should be confirmed if the device pressure is set at an altitude lower than that at which the patient resides, or if the patient customarily sleeps in locations at different altitudes [59]. Some older flow generators are equipped with a manual control that the patient can set to compensate for changes in altitude, but this method is inconvenient and the accuracy of the compensation is questionable.
Others — Other factors that influence success include the following:
●Facial hair – Patients with a mustache or beard may experience excessive leakage with nasal masks or full facemasks, respectively, in which case nasal pillows can be employed, if shaving their facial hair is not an option. Given the wide range of interfaces now available (picture 5), it is usually possible to identify an interface that will work despite facial hair.
●Cosmetic issues – Some patients may complain that the interface headgear disturbs their hair style or leave imprints on the skin of their face. Manufacturers have addressed this by designing headgear less likely to have this effect (picture 5).
●Reading or watching television in bed – Although the latter practice especially is at odds with good sleep hygiene and not to be encouraged, many patients insist on these practices. Some interfaces are less likely to interfere with vision in these situations (eg, nasal pillows and other interfaces specifically designed not to impede vision (picture 6)).
●Headgear placement – Headgear may be difficult for some patients to put in place or adjust (eg, patients with arthritis or muscle weakness). In our experience, nasal pillows are often the easiest to take on and off. With any interface, the patient may experience difficulty replacing the interface when sleep is interrupted for bathroom breaks or other reasons. In this case we instruct patients to simply disconnect the distal end of the tubing from the PAP device rather than trying to remove and replace the interface itself.
●Aerophagia - A chin strap may reduce aerophagia. Aerophagia may also be improved by switching to an APAP device (or rarely BPAP) because it lowers the mean pressure, although this strategy may not improve compliance [69]. We have had success with the use of simethicone over-the-counter products taken at bedtime, and during the night during awakenings if necessary. Theoretically, asking the patient to sleep in the left lateral decubitus position, which places the gastroesophageal junction in a superior position to the stomach, may help also, although to our knowledge there are no studies supporting this strategy.
●Intimacy – We discuss in advance how to employ PAP therapy in a manner that has limited interference with intimacy or sexual activity (eg, engaging in sex prior to initiating CPAP treatment). The bed partner should be included in this discussion.
●Lack of perceived benefit or attitudinal resistance to CPAP use – In these patients, education, supportive intervention, behavioral intervention, or a combination of all three techniques have all been shown to improve compliance [70]. Educational interventions alone (eg, emphasizing the long-term benefits of treatment by eliminating OSA as a risk factor for hypertension, heart disease, diabetes type II, or stroke) are supported by relatively low levels of evidence but in our experience often improve motivation and therefore compliance. Assessing persistent sleepiness despite adequate CPAP therapy is discussed separately. (See "Evaluation and management of residual excessive sleepiness in adults with obstructive sleep apnea".)
Additional practical information regarding patient-device interface and troubleshooting problems for patients with acute or chronic respiratory failure is discussed separately. (See "Noninvasive ventilation in adults with chronic respiratory failure from neuromuscular and chest wall diseases: Adaptation and follow-up after initiation" and "Noninvasive ventilation in adults with acute respiratory failure: Practical aspects of initiation".)
INVESTIGATIONAL METHODS OF TITRATION (SELF-TITRATION) — Small randomized trials report that in patients with uncomplicated moderate to severe OSA, continuous PAP (CPAP) titration may be possible in the unattended home setting using a self-adjustment protocol targeted at resolving snoring and daytime symptoms [34,36]. However, this is not our practice, and more robust outcome data are needed before self-adjusted titration can become routine. Moreover, the availability of auto-titrating CPAP (APAP) has largely supplanted this methodology.
The use of home sleep apnea testing (HSAT) is not recommended for the titration of CPAP or other PAP therapies as there are few data evaluating the reliability of HSAT devices for this indication. (See "Home sleep apnea testing for obstructive sleep apnea in adults".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Sleep-related breathing disorders in adults".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Beyond the Basics topics (see "Patient education: Sleep apnea in adults (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Introduction – Positive airway pressure (PAP) is the mainstay therapy for obstructive sleep apnea (OSA), a disorder that is characterized by obstructive apneas and hypopneas due to repetitive collapse or narrowing of the upper airway during sleep. (See 'Introduction' above.)
●Ventilatory modes and goals of titration – The initiation of PAP therapy requires choosing a mode of PAP and ascertaining the optimal device settings. Device settings have traditionally been identified during a laboratory polysomnography (PSG), but select patients are candidates for auto-titrating continuous PAP (APAP) or bilevel PAP in spontaneous mode (BPAP-S). The goal of any titration is to determine the minimal pressure(s) required to resolve all apneas, hypopneas, snoring, and arousals related to obstructive events, in all stages of sleep and in all sleep positions. (See 'Modes of positive airway pressure' above and "Mode selection for titration of positive airway pressure in adults with obstructive sleep apnea", section on 'Initial mode and setting options' and 'Titration goals' above.)
●In-laboratory fixed-level CPAP titration – In-laboratory fixed-level CPAP titration is the gold standard for determining optimal fixed-level PAP for patients with OSA. (See 'In-laboratory fixed-level continuous positive airway pressure (CPAP)' above.)
•Fixed-level CPAP delivers PAP at a level that remains relatively constant (within 1 to 2 cm H2O) throughout the respiratory cycle. The PAP splints the upper airway open, preventing upper airway collapse or narrowing during sleep.
•Titration is performed during a split- or full-night PSG study. During titration, CPAP is typically started at a low level (4 cm H2O) and incrementally increased (1 to 2 cm H2O increments) until there is no evidence of upper airway obstruction in all stages and sleeping positions. (See 'Initial settings and titration during polysomnography' above.)
•The optimal level of PAP is one that reduces the respiratory disturbance index to <5 events per hour for at least 15 minutes, including during supine rapid eye movement sleep, and ensures that sleep is not interrupted by spontaneous arousals or awakenings. Lesser degrees of success may be acceptable depending on the clinical situation. (See 'Adequacy assessment of CPAP titration' above.)
●At-home APAP titration – Select patients who are candidates for in-home titration (eg, patients with moderate to severe uncomplicated OSA) can have a fixed level of CPAP calculated using data derived from an in-home APAP device. APAP can also be used for ongoing treatment of OSA or may be of use as a strategy to attain compliance with therapy in patients who are intolerant of higher pressures. (See 'Auto-titrating continuous positive airway pressure (APAP)' above.)
•APAP delivers CPAP at a variable amount during sleep using proprietary algorithms to detect and resolve obstructive events during sleep.
•The optimal method of APAP titration is unclear. We typically gather device-downloaded data from a 7- to 14-day period of in-home APAP titration, employing a minimum and maximum pressure range of 5 to 20 cm H2O. The optimal fixed CPAP setting is typically the level of pressure at or below which obstructive events measured by the APAP device are eliminated for more than 90 or 95 percent of the time (reported as "90th and 95th percentile pressure" or "P90 and P95 pressure"). Modern APAP devices report a respiratory event index (REI) that can be used to confirm the efficacy of the chosen pressure. (See 'Titration' above.)
•In the absence of published guidelines, we define an adequate APAP trial when mean nightly use is ≥6 hours per night, a device-calculated REI is ≤10 events per hour, and interface leakage is within acceptable bounds. (See 'Assessment of APAP titration adequacy' above.)
●In-laboratory BPAP-S – BPAP-S is a second-line therapy for patients with OSA and is more commonly indicated in patients with OSA when CPAP or APAP fails. It can also be used in noncompliant patients as a pressure-reducing strategy, or in those with OSA who also have significant hypoventilation (eg, in patients with coexisting neuromuscular ventilatory failure). (See 'Bilevel positive airway pressure, spontaneous mode (BPAP-S)' above.)
•BPAP-S delivers PAP at different levels during inspiration (IPAP) and expiration (EPAP). BPAP-S splints the upper airway open in a manner similar to CPAP but can additionally provide ventilatory support through the application of pressure support (PS). When ventilatory support is needed, the patient must have sufficient inspiratory effort to trigger the device to transition from EPAP to IPAP, otherwise the timed function should be engaged.
•BPAP-S titration is typically performed during an attended in-laboratory PSG-based study, preferably during a full night of sleep. IPAP and EPAP are usually started at 8 and 4 cm H2O, respectively, and both are serially increased until frank obstructive apneas are eliminated, following which, IPAP is titrated until obstructive hypopneas, respiratory effort-related arousals, and snoring are eliminated. The minimum recommended IPAP-EPAP differential is 4 cm H2O and the maximum is 10 cm H2O. (See 'Initial settings and titration' above.)
•The same criteria as for assessing response to fixed-level CPAP in patients with OSA are used for assessing the adequacy of titration with BPAP-S. When there is coexisting hypoventilation, another titration goal requires attaining an acceptable level of transcutaneous CO2 (PtCO2). (See 'Bilevel positive airway pressure, spontaneous mode (BPAP-S)' above.)
●Auto-titrating BPAP – A trial of auto-titrating BPAP is reasonable in OSA patients who do not tolerate or fail CPAP, APAP, or BPAP-S. Similar to APAP, auto-titrating BPAP-S devices use proprietary algorithms to determine optimal settings to resolve device-detected sleep-related events. The optimal approach for auto-titrating BPAP devices is unclear and depends upon the capabilities of the flow generator. One approach arbitrarily sets the minimal EPAP to 4 cm H2O, maximal inspiratory pressure to 25 cm H2O, and maximal PS to 8 cm H2O. Close follow-up is necessary to make sure that patients are adequately treated using this approach. (See 'Auto-titrating BPAP-S' above.)
●Factors influencing success – Several factors influence success during (and following) titration to achieve adequate settings. (See 'Factors that influence initial success' above.)
•A properly fitting interface between the patient and the device optimizes efficacy and improves adherence. The optimal interface varies from patient to patient; options include nasal masks, nasal pillows, oronasal masks, and, rarely, oral-only interfaces. (See 'Choosing the correct patient-device interface' above.)
•For patients who experience discomfort exhaling against PAP, pressure relief and/or ramping may be attempted, although data suggest that adherence is not impacted by these maneuvers. Alternatively, an auto-titrating device may be tried. (See 'Intolerance of the sensation of pressure' above.)
•Nasal dryness may prompt the need for heated humidification of delivered PAP (although this feature is almost universally performed), and nasal congestion may require topical medications (glucocorticoids, antihistamines, anticholinergics). Mouth breathing can be addressed by a chin strap or change to an oronasal mask. Claustrophobia can be addressed by use of nasal pillows or mask desensitization. Altitude compensation may be needed for those who sleep in locations at different altitudes. (See 'Troubleshooting common issues' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Nilesh Dave, MD, MPH, Neil Freedman, MD, and Tomasz J Kuzniar, MD, PhD, FCCP, FAASM, who contributed to earlier versions of this topic review.
17 : A pilot study assessing adherence to auto-bilevel following a poor initial encounter with CPAP.
22 : Evaluation of auto bi-level algorithm to treat pressure intolerance in obstructive sleep apnea.
