Despite the high efficacy of continuous positive airway pressure (CPAP) to reverse upper airway obstruction in sleep apnea, treatment effectiveness is limited by variable adherence to prescribed therapy. When adherence is defined as greater than 4 hours of nightly use, 46 to 83% of patients with obstructive sleep apnea have been reported to be nonadherent to treatment. Evidence suggests that use of CPAP for longer than 6 hours decreases sleepiness, improves daily functioning, and restores memory to normal levels. The decision to embrace CPAP occurs during the first few days of treatment. Although many strategies in patient interface with CPAP or machine modality are marketed to improve CPAP usage, there are few data to support this. No single factor has been consistently identified as predictive of adherence. Patient perception of symptoms and improvement in sleepiness and daily functioning may be more important in determining patterns of use than physiologic aspects of disease severity. Emerging data suggest that various behavioral interventions may be effective in improving CPAP adherence.

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Adherence to continuous positive airway pressure therapy: the challenge to effective treatment.

CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) CURRENTLY IS CONSIDERED THE MOST EFFECTIVE TREATMENT FOR OBSTRUCTIVE SLEEP APNEA (OSA) THIS device provides a pneumatic splint to prevent nocturnal airway collapse In randomized clinical trials that included use of sham CPAP as a placebo, treatment with this device has been shown to produce improvements in symptoms, quality of life, sleepiness, neuropsychological performance, and hypertension1 It has also been established that optimal effectiveness depends on consistent use Skipping even 1 night of treatment reverses improvements in daytime sleepiness, response performance, and the physiologic measure of disease severity, the apnea-hypopnea index (AHI)2–4

Although these benefits have been shown in randomized clinical trials, there is considerable variation in use of CPAP by patients in routine clinical practice,5–8 with approximately half using it consistently every night on average 6 hours per night and the other half skipping from 1 to 7 nights per week using it on average 35 hours per night5 It is not known, however, what the impact of differential use of CPAP is on effectiveness of therapy in routine clinical practice It may be that individuals with shorter hours of use are, in general, less well treated with respect to improvements in outcomes such as sleepiness, than are those with longer durations of use Alternatively, there might be individual variation in need for CPAP so that, even though some individuals have shorter hours of CPAP use, they are effectively treated with respect to sleepiness This individual variation might be mediated by biologic mechanisms similar to those of the recently described individual variation in response to sleep deprivation9

To address this question, we conducted a multisite effectiveness study in which we evaluated clinical status outcomes before and after 3 months of routine clinical care that included measurement of CPAP adherence during the entire follow-up period This multisite international study capitalized on patient heterogeneity with regard to average nightly use of CPAP, in order to estimate relationships between the likelihood of achieving a “normal” value on salient clinical measures of sleepiness and functional status and the “dose” of CPAP treatment received (ie, hours of CPAP use per night) Because there is no consensus regarding which outcomes are primary with regard to the assessment of CPAP treatment response, we chose those deemed most applicable to the clinical management of OSA—subjective sleepiness (Epworth Sleepiness Scale [ESS]10), physiologic sleepiness (Multiple Sleep Latency Test [MSLT]11), and disease-specific functional status (Functional Outcomes of Sleep Questionnaire [FOSQ]12) By evaluating the nightly duration of CPAP relative to obtaining normal values in those impaired on each of these measures, we provide data that the clinician can employ in determining optimal treatment response within the context of treatment goals, eg, to reduce daytime sleepiness, improve daily functioning, or both

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Relationship between hours of CPAP use and achieving normal levels of sleepiness and daily functioning.

Obstructive sleep apnea (OSA) is accompanied by significant daytime cognitive and behavioral deficits that extend beyond the effects of sleepiness. This article outlines a causal model by which to understand these psychological effects among OSA patients. The model proposes that sleep disruption and blood gas abnormalities prevent sleep-related restorative processes, and further induce chemical and structural central nervous system cellular injury. This, in turn, leads to dysfunction of prefrontal regions of the brain cortex (PFC), manifested behaviorally in what neuropsychologists have termed 'executive dysfunction'. Executive dysfunction is proposed to markedly affect the functional application of cognitive abilities, resulting in maladaptive daytime behaviors. The proposed model (1) accounts for the specific psychological phenotype associated with OSA, (2) accommodates developmental components in this phenotype, (3) bridges between physical and psychological phenomena, (4) suggests mechanisms by which the nocturnal disorder might have effects on daytime functioning, (5) is empirically testable, (6) generates unique research hypotheses, and (7) has practical implications. The model is intended to act as a catalyst for future research and as a preliminary guide for clinicians.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2869.2002.00289.x

Obstructive sleep apnea and the prefrontal cortex: towards a comprehensive model linking nocturnal upper airway obstruction to daytime cognitive and behavioral deficits.

The aim of this study was to determine the relationship between circadian preferences, regularity of sleep patterns, sleep problems, daytime sleepiness and daytime behaviour. As a part of an epidemiological survey on sleep in a representative sample of Italian high-school students, a total of 6631 adolescents, aged 14.1-18.6 years, completed the School Sleep Habits Survey, a comprehensive questionnaire including items regarding sleep, sleepiness, substance use, anxiety and depressed mood, use of sleeping pills, school attendance and a morningness/eveningness scale. The sample consisted of 742 evening-types (315 males and 427 females; mean age 17.1 years) and 1005 morning-types (451 males and 554 females; mean age 16.8 years). No significant sex differences were found for morningness/eveningness score. Eveningness was associated with later bedtime and wake-up time, especially on weekends, shorter time in bed during the week, longer weekend time in bed, irregular sleep-wake schedule, subjective poor sleep. Moreover, evening types used to nap more frequently during school days, complained of daytime sleepiness, referred more attention problems, poor school achievement, more injuries and were more emotionally upset than the other chronotype. They referred also greater caffeine-containing beverages and substances to promote sleep consumption. Our results suggest that circadian preference might be related not only to sleep pattern, but also to other adolescent behaviours.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2869.2002.00302.x

Circadian preference, sleep and daytime behaviour in adolescence

Positive airway pressure (PAP) devices are used to treat patients with sleep related breathing disorders (SRBDs), including obstructive sleep apnea (OSA). After a patient is diagnosed with OSA, the current standard of practice involves performing attended polysomnography (PSG), during which positive airway pressure is adjusted throughout the recording period to determine the optimal pressure for maintaining upper airway patency. Continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) represent the two forms of PAP that are manually titrated during PSG to determine the single fixed pressure of CPAP or the fixed inspiratory and expiratory positive airway pressures (IPAP and EPAP, respectively) of BPAP for subsequent nightly usage. A PAP Titration Task Force of the American Academy of Sleep Medicine reviewed the available literature. Based on this review, the Task Force developed these recommendations for conducting CPAP and BPAP titrations. Major recommendations are as follows: (1) All potential PAP titration candidates should receive adequate PAP education, hands-on demonstration, careful mask fitting, and acclimatization prior to titration. (2) CPAP (IPAP and/or EPAP for patients on BPAP) should be increased until the following obstructive respiratory events are eliminated (no specific order) or the recommended maximum CPAP (IPAP for patients on BPAP) is reached: apneas, hypopneas, respiratory effort-related arousals (RERAs), and snoring. (3) The recommended minimum starting CPAP should be 4 cm H2O for pediatric and adult patients, and the recommended minimum starting IPAP and EPAP should be 8 cm H2O and 4 cm H2O, respectively, for pediatric and adult patients on BPAP. (4) The recommended maximum CPAP should be 15 cm H2O (or recommended maximum IPAP of 20 cm H2O if on BPAP) for patients or = 12 years. (5) The recommended minimum IPAP-EPAP differential is 4 cm H2O and the recommended maximum IPAP-EPAP differential is 10 cm H2O (6) CPAP (IPAP and/or EPAP for patients on BPAP depending on the type of event) should be increased by at least 1 cm H2O with an interval no shorter than 5 min, with the goal of eliminating obstructive respiratory events. (7) CPAP (IPAP and EPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 1 obstructive apnea is observed for patients or = 12 years. (8) CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 1 hypopnea is observed for patients or = 12 years. (9) CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 3 RERAs are observed for patients or = 12 years. (10) CPAP (IPAP for patients on BPAP) may be increased from any CPAP (or IPAP) level if at least 1 min of loud or unambiguous snoring is observed for patients or = 12 years. (11) The titration algorithm for split-night CPAP or BPAP titration studies should be identical to that of full-night CPAP or BPAP titration studies, respectively. (12) If the patient is uncomfortable or intolerant of high pressures on CPAP, the patient may be tried on BPAP. If there are continued obstructive respiratory events at 15 cm H2O of CPAP during the titration study, the patient may be switched to BPAP. (13) The pressure of CPAP or BPAP selected for patient use following the titration study should reflect control of the patient's obstructive respiration by a low (preferably 3 hr).

Clinical guidelines for the manual titration of positive airway pressure in patients with obstructive sleep apnea.

STUDY OBJECTIVES Poor compliance with continuous positive airway pressure (CPAP) has been identified as a significant obstacle in the treatment of obstructive sleep apnea. While previous studies have focused on diagnostic screening variables, side effects, health beliefs, and measures of disease severity, investigators have generally ignored sleep parameters assessed during CPAP titration as predictors of compliance. As the titration night represents patients' initial exposure to nocturnal CPAP treatment, we hypothesized that nocturnal polysomnographic (PSG) variables, representing improved sleep at this time, would predict higher subsequent compliance. DESIGN Prospective analyses of a sequential case series were undertaken using nocturnal PSG variables during titration as early predictors of CPAP compliance. SETTING Accredited sleep center. PATIENTS Seventy-one patients with sleep apnea, aged 31-78 years, with a mean respiratory disturbance index of 62.0 +/- 32.2. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Compliance was calculated as mean hours per night of CPAP use over the initial follow-up period (mean 46.9 days). Standard PSG variables and subjective reports of sleep were used as predictive variables in multivariate analyses. Mean objective compliance was 5.04 hours per night +/- 2.59. Consistent with our hypothesis, the best predictor of compliance was change in sleep efficiency (SE) from diagnostic to titration night [F (1,66) = 17.31, p < .000 (r = .48)], indicating that patients whose sleep improved most on the titration night had the highest levels of compliance. This relationship was also significant after controlling for measures of disease severity obtained during the diagnostic testing night. Importantly, individuals whose sleep improved on the CPAP titration night had nightly compliance rates of approximately 2 hours greater than patients whose sleep did not improve during titration. CONCLUSIONS The findings suggest that patients' initial experience with CPAP treatment and, in particular, the degree of improvement in sleep during CPAP titration may be crucial factors in determining their subsequent use of this treatment modality.

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Sleep during titration predicts continuous positive airway pressure compliance.

CPAP therapy in patients with mild OSA: implementation and treatment outcome.

The behavioral morbidity of obstructive sleep apnea

Objectives: Uvulopalatopharyngoplasty (UPPP) is widely used as a first-step procedure for the surgical management of obstructive sleep apnea (OSA) syndrome but best manages obstruction occurring at the level of the oropharynx alone and not the hypopharynx. Previous publications have noted mediocre results with use of this procedure in unselected patients with OSA, but less clear is the effectiveness of this procedure in the unselected patient with mild OSA (respiratory event index [REI] 5–25). Using objective and subjective criteria, we retrospectively analyzed the results of UPPP in patients with mild OSA. Methods: We examined 37 patients with mild OSA (REI 13.5 ± 5.1, range 5.6–23.1) who had been operated on during 1996 with UPPP with or without tonsillectomy and/or septoplasty. Follow-up polysomnography was obtained in 25 (68%) an average of 40.5 weeks after surgery and compared with findings before surgery. Subjective assessment of sleepiness was performed with the Sleep-Wake Activity Inventory. Results: Ten patients (40%) had a postoperative reduction in the REI of more than 50%, comparable with the improvements reported in those with more severe apnea. Those who did not have a reduction in REI after surgery actually saw an increase in average REI from 16.6 ± 5 to 26.7 ± 18.4. Similarly, subjective assessment of sleepiness with the Sleep-Wake Activity Inventory showed no statistically significant improvement after surgery. Conclusion: Overall, these results indicate that UPPP alone in the unselected patient provides little benefit in the management of mild OSA, similar to findings for more severe OSA. Surgeons must use great care in discerning the level of obstruction in the patient with mild OSA to tailor the appropriate retropalatal and/or retrolingual procedures and thereby achieve excellent surgical outcomes. (Otolaryngol Head Neck Surg 2000;123:179–82.)

Ryan Day

Papers

Sleep during titration predicts continuous positive airway pressure compliance.

CPAP therapy in patients with mild OSA: implementation and treatment outcome.

The behavioral morbidity of obstructive sleep apnea

Efficacy of uvulopalatopharyngoplasty in unselected patients with mild obstructive sleep apnea

Sleepiness/alertness among healthy evening and morning type individuals.