Randomized controlled trial comparing flexible and continuous positive airway pressure delivery: effects on compliance, objective and subjective sleepiness and vigilance

APAP, BPAP, CPAP, and New Modes of Positive Airway Pressure Therapy

Positive airway pressure (PAP) is the primary treatment of sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. Just as clinicians use pharmacological mechanism of action and pharmacokinetic data to optimize medication therapy for an individual, understanding how PAP works and choosing the right mode and device are critical to optimizing therapy in an individual patient. The first section of this chapter will describe the technology inside PAP devices that is essential for understanding the algorithms used to control the airflow and pressure. The second section will review how different comfort settings including ramp and expiratory pressure relief and modes of PAP therapy including continuous positive airway pressure (CPAP), autotitrating CPAP, bilevel positive airway pressure, adaptive servoventilation, and volume-assured pressure support control the airflow and pressure. Proprietary algorithms from several different manufacturers are described. This chapter derives its descriptions of algorithms from multiple sources including literature review, manufacture publications and websites, patents, and peer-reviewed device comparisons and from personal communication with manufacturer representatives. Clinical considerations related to the technological aspects of the different algorithms and features will be reviewed.

PAP Adherence and Nasal Resistance. A Randomized Controlled Trial of CPAPflex versus CPAP in World Trade Center Responders

Rationale: Continuous positive airway pressure (CPAP) adherence is often poor in obstructive sleep apnea (OSA) and may be influenced by nasal resistance. CPAP with a reduction of expiratory pressure (CPAPflex) may reduce discomfort in those with high nasal resistance and improve adherence in this subgroup.Objectives: To evaluate the association of positive airway pressure (PAP) treatment adherence to nasal resistance and examine if CPAPflex improves adherence over CPAP in subjects with high nasal resistance.Methods: A randomized double-blind crossover trial of 4 weeks each of CPAPflex versus CPAP in subjects exposed to World Trade Center dust with OSA stratified by nasal resistance, measured by 4-Phase Rhinomanometry.Results: Three hundred seventeen subjects with OSA (mean, apnea-hypopnea index with 4% O₂ desaturation for hypopnea = 17 ± 14/h) were randomized. Overall, PAP adherence was poor, but adherence to CPAP (n = 239; mean hours per night [95% confidence interval (CI)]), 1.97 h (1.68 to 2.26) was greater than adherence to CPAPflex (n = 249; 1.65 h [1.39 to 1.91]; difference of 0.31 h [0.03; 0.6]; P < 0.05). Contrary to our hypothesis there was no correlation between nasal resistance and adherence to CPAP (r = 0.098; P = not significant) or CPAPflex (r = 0.056; P = not significant). There was no difference in adherence between CPAP and CPAPflex (mean Δ hours [95% CI]) in subjects with low resistance (0.33 h [-0.10 to 0.76]) or high nasal resistance (0.26 h [-0.14 to 0.66]). No significant differences were observed in any of the secondary outcomes between PAP modes.Conclusions: Contrary to expectations, our data do not show better adherence to CPAPflex than to CPAP in subjects with high or low nasal resistance and do show clinically insignificant better adherence overall with CPAP.Clinical trial registered with www.clinicaltrials.gov (NCT01753999).

Factors affecting compliance with positive airway pressure therapy in obstructive sleep apnea

OBJECTIVE

To investigate the factors affecting compliance with positive airway pressure (PAP) therapy and establish the relationship between compliance and pulmonary function tests (PFT) in patients with OSA.

MATERIAL AND METHODS

In this prospective study, patients with OSA using PAP devices were questioned about the complaints related to the device. Depression and anxiety scales along with PFT parameters were also assessed.

RESULTS

Of 98 participants, 63% were men. The mean age was 52.0 ± 9.6 years. Sixty-seven percent of the patients were compliant with their devices. A significant difference was observed between the proportion of the participants compliant or non-compliant with the device, based on OSA severity (p < 0.05). Beck depression inventory (BDI) and Beck anxiety inventory (BAI) scores of the compliant patients were significantly lower than those of the non-compliant patients (p < 0.001, p = 0.044, respectively). No statistically significant difference was detected between the groups regarding individual pulmonary function tests (p > 0.05). The rates of nasal mask use, not having difficulty in tolerating CPAP, falling asleep, absence of abdominal distension, no facial sores, no air leakage, patients benefiting from the device, reduction in daytime sleepiness, and the belief that they are receiving appropriate therapy in participants compliant with the device were higher than those in non-compliant participants (p < 0.05). The rates of claustrophobia and discomfort due to pressure were significantly lower in patients compliant with the device than in the non-compliant patients (p < 0.05).

CONCLUSION

While no relationship was detected between PFT parameters and PAP therapy compliance, significant factors affecting the device compliance were detected.

Obstructive Sleep Apnea: Treatment with Positive Airway Pressure

As in other adults, continuous positive airway pressure treatment for obstructive sleep apnea should be the mainstay of treatment. Benefits include improvements in sleepiness and quality of life, as well as improvements in hypertension control, arrhythmias, cardiovascular risk, and mortality. This article discusses issues in prescribing this treatment, including those related specifically to elderly individuals.

Pressure modification or humidification for improving usage of continuous positive airway pressure machines in adults with obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) is the repetitive closure of the upper airway during sleep. This results in disturbed sleep and excessive daytime sleepiness. It is a risk factor for long-term cardiovascular morbidity. Continuous positive airway pressure (CPAP) machines can be applied during sleep. They deliver air pressure by a nasal or oronasal mask to prevent the airway from closing, reducing sleep disturbance and improving sleep quality. Some people find them difficult to tolerate because of high pressure levels and other symptoms such as a dry mouth. Switching to machines that vary the level of air pressure required to reduce sleep disturbance could increase comfort and promote more regular use. Humidification devices humidify the air that is delivered to the upper airway through the CPAP circuit. Humidification may reduce dryness of the throat and mouth and thus improve CPAP tolerability. This updated Cochrane Review looks at modifying the delivery of positive pressure and humidification on machine usage and other clinical outcomes in OSA.

OBJECTIVES

To determine the effects of positive pressure modification or humidification on increasing CPAP machine usage in adults with OSA.

SEARCH METHODS

We searched Cochrane Airways Specialised Register and clinical trials registries on 15 October 2018.

SELECTION CRITERIA

Randomised parallel group or cross-over trials in adults with OSA. We included studies that compared automatically adjusting CPAP (auto-CPAP), bilevel positive airway pressure (bi-PAP), CPAP with expiratory pressure relief (CPAPexp), heated humidification plus fixed CPAP, automatically adjusting CPAP with expiratory pressure relief, Bi-PAP with expiratory pressure relief, auto bi-PAP and CPAPexp with wakefulness detection with fixed pressure setting.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane. We assessed the certainty of evidence using GRADE for the outcomes of machine usage, symptoms (measured by the Epworth Sleepiness Scale (ESS)), Apnoea Hypopnoea Index (AHI), quality of life measured by Functional Outcomes of Sleep Questionnaire (FOSQ), blood pressure, withdrawals and adverse events (e.g. nasal blockage or mask intolerance). The main comparison of interest in the review is auto-CPAP versus fixed CPAP.

MAIN RESULTS

We included 64 studies (3922 participants, 75% male). The main comparison of auto-CPAP with fixed CPAP is based on 36 studies with 2135 participants from Europe, USA, Hong Kong and Australia. The majority of studies recruited participants who were recently diagnosed with OSA and had not used CPAP previously. They had excessive sleepiness (ESS: 13), severe sleep disturbance (AHI ranged from 22 to 59), and average body mass index (BMI) of 35 kg/m2. Interventions were delivered at home and the duration of most studies was 12 weeks or less. We judged that studies at high or unclear risk of bias likely influenced the effect of auto-CPAP on machine usage, symptoms, quality of life and tolerability, but not for other outcomes. Primary outcome Compared with average usage of about five hours per night with fixed CPAP, people probably use auto-CPAP for 13 minutes longer per night at about six weeks (mean difference (MD) 0.21 hours/night, 95% confidence interval (CI) 0.11 to 0.31; 31 studies, 1452 participants; moderate-certainty evidence). We do not have enough data to determine whether auto-CPAP increases the number of people who use machines for more than four hours per night compared with fixed CPAP (odds ratio (OR) 1.16, 95% CI 0.75 to 1.81; 2 studies, 346 participants; low-certainty evidence). Secondary outcomes Auto-CPAP probably reduces daytime sleepiness compared with fixed CPAP at about six weeks by a small amount (MD -0.44 ESS units, 95% CI -0.72 to -0.16; 25 studies, 1285 participants; moderate-certainty evidence). AHI is slightly higher with auto-CPAP than with fixed CPAP (MD 0.48 events per hour, 95% CI 0.16 to 0.80; 26 studies, 1256 participants; high-certainty evidence), although it fell with both machine types from baseline values in the studies. Ten per cent of people in auto-CPAP and 11% in the fixed CPAP arms withdrew from the studies (OR 0.90, 95% CI 0.64 to 1.27; moderate-certainty evidence). Auto-CPAP and fixed CPAP may have similar effects on quality of life, as measured by the FOSQ but more evidence is needed to be confident in this result (MD 0.12, 95% CI -0.21 to 0.46; 3 studies, 352 participants; low-certainty evidence). Two studies (353 participants) provided data on clinic-measured blood pressure. Auto-CPAP may be slightly less effective at reducing diastolic blood pressure compared to fixed CPAP (MD 2.92 mmHg, 95% CI 1.06 to 4.77 mmHg; low-certainty evidence). The two modalities of CPAP probably do not differ in their effects on systolic blood pressure (MD 1.87 mmHg, 95% CI -1.08 to 4.82; moderate-certainty evidence). Nine studies (574 participants) provided information on adverse events such as nasal blockage, dry mouth, tolerance of treatment pressure and mask leak. They used different scales to capture these outcomes and due to variation in the direction and size of effect between the studies, the comparative effects on tolerability outcomes are uncertain (very low-certainty evidence).  The evidence base for other interventions is smaller, and does not provide sufficient information to determine whether there are important differences between pressure modification strategies and fixed CPAP on machine usage outcomes, symptoms and quality of life. As with the evidence for the auto-CPAP, adverse events are measured disparately.

AUTHORS' CONCLUSIONS

In adults with moderate to severe sleep apnoea starting positive airway pressure therapy, auto-CPAP probably increases machine usage by about 13 minutes per night. The effects on daytime sleepiness scores with auto-CPAP are not clinically meaningful. AHI values are slightly lower with fixed CPAP. Use of validated quality of life instruments in the studies to date has been limited, although where they have been used the effect sizes have not exceeded proposed clinically important differences. The adoption of a standardised approach to measuring tolerability would help decision-makers to balance benefits with harms from the different treatment options available. The evidence available for other pressure modification strategies does not provide a reliable basis on which to draw firm conclusions. Future studies should look at the effects of pressure modification devices and humidification in people who have already used CPAP but are unable to persist with treatment.

Facilitators and Barriers to Positive Airway Pressure Adherence for Adolescents. A Qualitative Study

RATIONALE

Low adherence to positive airway pressure (PAP) treatment for adolescents with obstructive sleep apnea (OSA) can have long-term cardiometabolic and developmental impact.

OBJECTIVES

To explore the facilitators and barriers to PAP use in adolescents with OSA.

METHODS

We conducted a qualitative study using a descriptive thematic analysis approach. A total of 21 interviews were conducted in the clinical setting with adolescents prescribed PAP to treat OSA within the previous 12 months. Interview audio recordings were transcribed verbatim for analysis. Transcripts were reviewed, and data were categorized using a coding framework developed by the research team. Codes were structured into themes related to the barriers and facilitators to using PAP.

RESULTS

Participants described numerous challenges with the physical design of the PAP machine, including the restriction of the tubing, the discomfort of the mask, and concerns with its size and weight. A period of adjustment to wearing and preparing the PAP machine was described whereby participants had to develop their own strategies to improve comfort. After initiating the therapy, the challenges experienced by participants were cited more often than the perceived benefits, particularly for those who were less adherent. Finally, the unique needs of adolescents were highlighted, which impacted the amount of family support desired in using PAP.

CONCLUSIONS

This study identifies factors affecting PAP adherence when prescribed in adolescence and highlights the need for ongoing dialogue between adolescents and their clinical team with respect to challenges encountered, troubleshooting, adherence strategies, and parental engagement.

Treatment of Adult Obstructive Sleep Apnea With Positive Airway Pressure: An American Academy of Sleep Medicine Systematic Review, Meta-Analysis, and GRADE Assessment

INTRODUCTION

The purpose of this systematic review is to provide supporting evidence for the clinical practice guideline for the treatment of obstructive sleep apnea (OSA) in adults using positive airway pressure (PAP).

METHODS

The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of PAP with no treatment as well as studies that compared different PAP modalities. Meta-analyses were performed to determine the clinical significance of using PAP in several modalities (ie, continuous PAP, auto-adjusting PAP, and bilevel PAP), to treat OSA in adults. In addition, meta-analyses were performed to determine the clinical significance of using an in-laboratory versus ambulatory strategy for the initiation of PAP, educational and behavioral interventions, telemonitoring, humidification, different mask interfaces, and flexible or modified pressure profile PAP in conjunction with PAP to treat OSA in adults. Finally, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence for making recommendations.

RESULTS

The literature search resulted in 336 studies that met inclusion criteria; 184 studies provided data suitable for meta-analyses. The data demonstrated that PAP compared to no treatment results in a clinically significant reduction in disease severity, sleepiness, blood pressure, and motor vehicle accidents, and improvement in sleep-related quality of life in adults with OSA. In addition, the initiation of PAP in the home demonstrated equivalent effects on patient outcomes when compared to an in-laboratory titration approach. The data also demonstrated that the use of auto-adjusting or bilevel PAP did not result in clinically significant differences in patient outcomes compared with standard continuous PAP. Furthermore, data demonstrated a clinically significant improvement in PAP adherence with the use of educational, behavioral, troubleshooting, and telemonitoring interventions. Systematic reviews for specific PAP delivery method were also performed and suggested that nasal interfaces compared to oronasal interfaces have improved adherence and slightly greater reductions in OSA severity, heated humidification compared to no humidification reduces some continuous PAP-related side effects, and pressure profile PAP did not result in clinically significant differences in patient outcomes compared with standard continuous PAP.

The importance of clinical monitoring for compliance with Continuous Positive Airway Pressure

Introduction

Objective

Methods

Results

Conclusion

Pressure-Relief Features of Fixed and Autotitrating Continuous Positive Airway Pressure May Impair Their Efficacy: Evaluation with a Respiratory Bench Model

STUDY OBJECTIVES

Pressure-relief features are aimed at improving the patient's comfort during continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea. The objective of this study was to determine the effect of these therapy features on fixed CPAP and autotitrating CPAP (APAP) treatment efficacy.

METHODS

Seven pressure-relief features applied by three CPAP devices were included in our study (Remstar Auto: C-Flex 3, C-Flex+ 3, A-Flex 3, P-Flex; AirSense 10: EPR 3; Prisma 20A: SoftPAP 2 and 3). In fixed CPAP, the devices were subjected to a 10-min bench-simulated obstructive apnea sequence (initial apnea-hypopnea index, AHI = 60/h) with and without pressure-relief features. In APAP, the sequence was lengthened to 4.2 h (initial AHI = 58.6/h). The residual AHI and mean/median pressure were compared with and without pressure-relief features.

RESULTS

Compared to conventional CPAP, where pressure was adjusted to be just sufficient to control the simulated obstructive events, C-Flex+ 3, P-Flex, and EPR 3 failed to normalize the breathing flow and did not reduce the AHI. The mean pressures with the three features, respectively, were 1.8, 2.6, and 2.6 cmH2O lower than the conventional CPAP. Compared to conventional APAP, similar levels of control were observed with pressure-relief features, apart from P-Flex where the delivered mean pressure was lower and residual AHI greater. The device-reported mean/median pressures in APAP with A-Flex 3, P-Flex, EPR 3, and SoftPAP 3 were higher than that measured on the bench.

CONCLUSIONS

Pressure-relief features may attenuate CPAP efficacy if not adjusted for at the time of their introduction. In clinical practice, efficacy can be ensured by increasing the therapeutic pressure delivered by fixed CPAP or by enabling the pressure-relief features prior to initial pressure titration. Device-reported pressures in APAP devices with pressure relief activated may overstate delivered pressures.

Factors Contributing to Unintentional Leak During CPAP Treatment: A Systematic Review

CPAP is the first-line treatment for moderate to severe OSA syndrome. Up to 25% of patients with OSA syndrome discontinue CPAP treatment due to side effects. Unintentional leakage and its associated annoying consequences are the most frequently reported adverse effects of CPAP. Successive technological improvements have not succeeded in addressing this issue. A systematic review was conducted (1) to assess the impact of different technological advances on unintentional leaks and (2) to determine if any patient characteristics have already been identified as determinants of unintentional leakage. No CPAP modality was superior to another in reducing unintentional leaks and, surprisingly, oronasal masks were associated with higher unintentional leaks. Nasal obstruction, older age, higher BMI, central fat distribution, and male sex might be associated with an increased risk of unintentional leakage. Such leaks remain an important problem. Further studies are needed to improve the understanding of underlying clinical factors so that patients at risk of unintentional leaks may be identified and individualized solutions applied.

Trends in CPAP adherence over twenty years of data collection: a flattened curve

BACKGROUND

Obstructive sleep apnea (OSA) is a common disorder, and continuous airway positive pressure (CPAP) is considered to be the gold standard of therapy. CPAP however is known to have problems with adherence, with many patients eventually abandoning the device. The purpose of this paper is to assess secular trends in CPAP adherence over the long term to see if there have been meaningful improvements in adherence in light of the multiple interventions proposed to do so.

METHODS

A comprehensive systematic literature review was conducted using the Medline-Ovid, Embase, and Pubmed databases, searching for data regarding CPAP adherence over a twenty year timeframe (1994-2015). Data was assessed for quality and then extracted. The main outcome measure was reported CPAP non-adherence. Secondary outcomes included changes in CPAP non-adherence when comparing short versus long-term, and changes in terms of behavioral counseling.

RESULTS

Eighty-two papers met study inclusion/exclusion criteria. The overall CPAP non-adherence rate based on a 7-h/night sleep time that was reported in studies conducted over the twenty year time frame was 34.1 %. There was no significant improvement over the time frame. Behavioral intervention improved adherence rates by ~1 h per night on average.

CONCLUSIONS

The rate of CPAP adherence remains persistently low over twenty years worth of reported data. No clinically significant improvement in CPAP adherence was seen even in recent years despite efforts toward behavioral intervention and patient coaching. This low rate of adherence is problematic, and calls into question the concept of CPAP as gold-standard of therapy for OSA.

Sleep remains disturbed in patients with obstructive sleep apnea treated with positive airway pressure: a three-month cohort study using continuous actigraphy

OBJECTIVE

Some patients with obstructive sleep apnea (OSA) remain sleepy despite positive airway pressure (PAP) therapy. The mechanisms by which this occurs are unclear but could include persistently disturbed sleep. The goal of this study was to explore the relationships between subjective sleepiness and actigraphic measures of sleep during the first three months of PAP treatment.

METHODS

We enrolled 80 patients with OSA and 50 comparison subjects prior to treatment and observed them through three months of PAP therapy. PAP adherence and presence of residual respiratory events were determined from PAP machine downloads. Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), and actigraphic data were collected before and at monthly intervals after starting PAP.

RESULTS

Patients with OSA were sleepier and showed a greater degree of sleep disruption by actigraphy at the baseline. After three months of PAP, only ESS and number of awakenings (AWAKE#) normalized, while wake after sleep onset and sleep efficiency remained worse in patients with OSA. FOSQ was improved in patients with OSA but never reached the same level as that of comparison subjects. ESS and FOSQ improved slowly over the study period.

CONCLUSIONS

As a group, patients with OSA show actigraphic evidence of persistently disturbed sleep and sleepiness-related impairments in day-to-day function after three months of PAP therapy. Improvements in sleepiness evolve over months with more severely affected patients responding quicker. Persistent sleep disruption may partially explain residual sleepiness in some PAP-adherent OSA patients.

Reconsidering first-line treatment for obstructive sleep apnea: a systematic review of the literature

BACKGROUND

Continuous positive airway pressure (CPAP) is typically recommended as first line therapy for obstructive sleep apnea, but the adherence rate of CPAP is problematic. This study's objective was to systematically review the literature relating to CPAP as first line therapy for OSA and compare it to surgical literature on the same topic.

METHODS

A systematic review was conducted according to PRISMA guidelines, examining Medline-Ovid, Embase, and Pubmed databases. The primary search objective was to identify all papers reporting the results of (1) randomized clinical trials (RCT) of CPAP for the treatment of adults with OSA; and (2) both randomized and non-randomized clinical trials and case series on the surgical treatment of OSA in adults. A PhD-level biostatistician first screened papers, and then those that met study criteria were retrieved and analyzed using standardized forms for each author. The primary outcomes were adherence rates of CPAP.

RESULTS

A total of 82 controlled clinical trials for CPAP and 69 controlled and non-controlled surgery trials were identified for analysis. Variation in CPAP use within reported RCT trials were identified, and the majority of patients in the studies would eventually be considered non-adherent to CPAP.

CONCLUSIONS

When considering the numerous patient-related factors that come into play when CPAP is prescribed, the concept of CPAP as gold-standard therapy for OSA should be reconsidered. In many cases surgery can provide a better overall outcome. This study's results suggest that certain patients with OSA may be managed more effectively with surgery than CPAP, without confounding issues of treatment adherence.

Obstructive sleep apnoea in the general population: highly prevalent but minimal symptoms

The aim was to assess the prevalence of obstructive sleep apnoea (OSA) as defined by an apnoea-hypopnea index (AHI) ≥15 in the middle-aged general population, and the interrelationship between OSA, sleep-related symptoms, sleepiness and vigilance.A general population sample of 40-65-year-old Icelanders was invited to participate in a study protocol that included a type 3 sleep study, questionnaire and a psychomotor vigilance test (PVT).Among the 415 subjects included in the study, 56.9% had no OSA (AHI <5), 24.1% had mild OSA (AHI 5-14.9), 12.5% had moderate OSA (AHI 15-29.9), 2.9% had severe OSA (AHI ≥30) and 3.6% were already diagnosed and receiving OSA treatment. However, no significant relationship was found between AHI and subjective sleepiness or clinical symptoms. A relationship with objective vigilance assessed by PVT was only found for those with AHI ≥30. Subjects already on OSA treatment and those accepting OSA treatment after participating in the study were more symptomatic and sleepier than others with similar OSA severity, as assessed by the AHI.In a middle-aged general population, approximately one in five subjects had moderate-to-severe OSA, but the majority of them were neither symptomatic nor sleepy and did not have impaired vigilance.

Redefining the timing of surgery for obstructive sleep apnea in anatomically favorable patients

OBJECTIVES/HYPOTHESIS

Healthcare remunerating agencies in North America require patients with obstructive sleep apnea (OSA) to undergo a continuous positive airway pressure (CPAP) trial before funding surgical therapy. The adherence rate of CPAP is problematic. This study's objective was to determine the proportion of surgically favorable patients who failed CPAP who subsequently benefitted from surgical therapy, and to explore consideration of surgical therapy as first-line treatment in this specific OSA subpopulation.

STUDY DESIGN

This was a prospective cohort study.

METHODS

Patients with moderate-severe OSA who had failed a minimum 6-month trial of CPAP were recruited. All had optimal anatomy for surgery and underwent tonsillectomy with palatoplasty ± septoplasty. Outcome measures included apnea-hypopnea index (AHI), Epworth Sleepiness Scale (ESS), and Sleep Apnea Quality of Life Index (SAQLI-E), and blood pressure. Patients were followed for 1 year.

RESULTS

By AHI measurement, 85.7% of patients in the entire cohort were successfully treated by surgery. ESS while on CPAP was 13.7 ± 2.9, improving to 4.1 ± 2.5 after surgery. SAQLI-E scores on CPAP were 25.7 ± 5.8, improving to 10.2 ± 3.2 after surgery. Blood pressure remained elevated during CPAP but normalized after surgery. All changes were significant at P < .001.

CONCLUSIONS

Surgical intervention improved OSA severity as measured by the ESS, SAQLI-E, and blood pressure. These measures had not improved on CPAP. AHI improved as well. Our results suggest that certain patients with OSA may be managed more effectively with surgery than CPAP, without confounding issues of treatment adherence and with only minor surgical risk.

LEVEL OF EVIDENCE

2 Laryngoscope 124:S1-S9, 2014.

The SomnuSeal Oral Mask Is Reasonably Tolerated by Otherwise CPAP Noncompliant Patients with OSA

Compliance with CPAP is the major limiting factor in treating patients with OSA. The novel SomnuSeal mask is an oral self-adaptable mask located between the teeth and the lips ensuring that there are no air leaks or skin abrasions. Fifty patients with AHI > 20, who failed previous CPAP trials, were asked to sleep with the mask for one month. In all patients, the mask was connected to an AutoPAP machine with a heated humidifier. Efficacy, convenience, and compliance (average usage for 4 or more hours per night) were monitored. Fifty patients (41 m and 9 f, mean age 57 ± 12 years, BMI 33.6 ± 4.9 kg/m(2), and AHI 47 ± 23/h) participated. Eleven were classified as compliant (average mask usage of 26 nights, 4.7 hours per night), five were only partially compliant (average usage of 13 nights, 2.9 hours per night), and 34 could not comply with it. In all patients who slept with it, the efficacy (assessed by residual AHI derived from the CPAP device) was good with an AHI of less than 8/hour. Interestingly, the required optimal pressure decreased from an average of 9.3 cmH2O to 4.6 cmH2O. The SomnuSeal oral interface is effective and may result in converting noncompliant untreated patients with OSA into well-treated ones.

Flexible positive airway pressure improves treatment adherence compared with auto-adjusting PAP

STUDY OBJECTIVES

There are no clinical data comparing adherence and quality of life between auto-adjusting positive airway pressure (APAP) and two different flex positive airway pressure (PAP) devices (A-Flex, C-Flex) in patients with obstructive sleep apnea (OSA).

DESIGN AND SETTING

Ninety-three patients in whom OSA was newly diagnosed were randomly assigned to receive 3 mo of APAP (n = 31), APAP with C-Flex (n = 31), or APAP with A-Flex (n = 31). Objective adherence was determined after 3 mo of CPAP treatment, and the Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Calgary Sleep Apnea Quality of Life Index (SAQLI) were examined at baseline and after 3 mo. After 3 mo, patients in the APAP with A-Flex group and those in the APAP with C-Flex group were crossed over and those in the APAP group were switched to A-Flex for an additional 3 mo.

MEASUREMENTS AND RESULTS

The groups were similar demographically. Treatment adherence during the first 3 mo was significantly greater in the APAP with C-Flex group (APAP with C-Flex: 5.19 ± 1.84 h/night versus APAP: 3.96 ± 1.66 h/night versus APAP with A-Flex: 4.27 ± 2.12 h/night, P = 0.04). There was a significant improvement in two of four of the SAQLI domain scores and in the ESS and PSQI in the APAP with C-Flex group. Adherence significantly improved among the poor compliers (< 4 h/night of use) in the APAP group after change to APAP with A-Flex (P = 0.01).

CONCLUSIONS

Of these three modes of PAP delivery, adherence was greatest with APAP with C-Flex.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00873977.

Sleep quality, short-term and long-term CPAP adherence

STUDY OBJECTIVES

Adherence to CPAP therapy is low in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). The purpose of the present study was to evaluate the utility of measures of sleep architecture and sleep continuity on the CPAP titration study as predictors of both short- and long-term CPAP adherence.

METHODS

93 patients with OSAHS (RDI 42.8 ± 34.3/h) underwent in-laboratory diagnostic polysomnography, CPAP titration, and follow-up polysomnography (NPSG) on CPAP. Adherence to CPAP was objectively monitored. Short-term (ST) CPAP adherence was averaged over 14 days immediately following the titration study. Long-term (LT) CPAP adherence was obtained in 56/93 patients after approximately 2 months of CPAP use. Patients were grouped into CPAP adherence groups for ST (< 2 h, 2-4 h, and > 4 h) and LT adherence (< 4 h, > 4 h). Sleep architecture, sleep disordered breathing (SDB) indices, and daytime outcome variables from the diagnostic and titration NPSGs were compared between CPAP adherence groups.

RESULTS

There was a significant relationship between ST and LT CPAP adherence (r = 0.81, p < 0.001). Neither ST nor LT adherence were related to demographic variables, baseline severity of untreated SDB, sleep architecture, or measures of daytime impairment. Good CPAP adherence groups had significantly lower %N2 and greater %REM on the titration NPSG. A model combining change in sleep efficiency and change in sleep continuity between the diagnostic and titration NPSGs predicted 17% of the variance in LT adherence (p = 0.006).

CONCLUSIONS

These findings demonstrate that characteristics of sleep architecture, even on the titration NPSG, may predict some of the variance in CPAP adherence. Better sleep quality on the titration night was related to better CPAP adherence, suggesting that interventions to improve sleep on/prior to the CPAP titration study might be used as a therapeutic intervention to improve CPAP adherence.

Randomized, double-blind clinical trial of two different modes of positive airway pressure therapy on adherence and efficacy in children

STUDY OBJECTIVES

To determine the effects of bilevel positive airway pressure with pressure release technology (Bi-Flex) on adherence and efficacy in children and adolescents compared to standard continuous positive airway pressure (CPAP) therapy. We hypothesized that Bi-Flex would result in improved adherence but similar efficacy to CPAP.

METHODS

This was a randomized, double-blinded clinical trial. Patients with obstructive sleep apnea were randomized to CPAP or Bi-Flex. Repeat polysomnography was performed on pressure at 3 months. Objective adherence data were obtained at 1 and 3 months.

RESULTS

56 children and adolescents were evaluated. There were no significant differences in the number of nights the device was turned on, or the mean number of minutes used at pressure per night for CPAP vs Bi-Flex (24 ± 6 vs 22 ± 9 nights, and 201 ± 135 vs 185 ± 165 min, respectively, for Month 1). The apnea hypopnea index decreased significantly from 22 ± 21/h to 2 ± 3/h on CPAP (p = 0.005), and 18 ± 15/h to 2 ± 2/h on Bi-Flex (p < 0.0005), but there was no significant difference between groups (p = 0.82 for CPAP vs Bi-Flex). The Epworth Sleepiness Scale decreased from 8 ± 5 to 6 ± 3 on CPAP (p = 0.14), and 10 ± 6 to 5 ± 5 on Bi-Flex (p < 0.0005; p = 0.12 for CPAP vs Bi-Flex).

CONCLUSIONS

Both CPAP and Bi-Flex are efficacious in treating children and adolescents with OSAS. However, adherence is suboptimal with both methods. Further research is required to determine ways to improve adherence in the pediatric population.

The supraglottic effect of a reduction in expiratory mask pressure during continuous positive airway pressure

STUDY OBJECTIVES

Patients with obstructive sleep apnea may have difficulty exhaling against positive pressure, hence limiting their acceptance of continuous positive airway pressure (CPAP). C-Flex is designed to improve comfort by reducing pressure in the mask during expiration proportionally to expiratory airflow (3 settings correspond to increasing pressure changes). When patients use CPAP, nasal resistance determines how much higher supraglottic pressure is than mask pressure. We hypothesized that increased nasal resistance results in increased expiratory supraglottic pressure swings that could be mitigated by the effects of C-Flex on mask pressure.

DESIGN

Cohort study.

SETTING

Sleep center.

PARTICIPANTS

Seventeen patients with obstructive sleep apnea/hypopnea syndrome and a mechanical model of the upper airway.

INTERVENTIONS

In patients on fixed CPAP, CPAP with different C-Flex levels was applied multiple times during the night. In the model, 2 different respiratory patterns and resistances were tested.

MEASUREMENTS AND RESULTS

Airflow, expiratory mask, and supraglottic pressures were measured on CPAP and on C-Flex. Swings in pressure during expiration were determined. On CPAP, higher nasal resistance produced greater expiratory pressure swings in the supraglottis in the patients and in the model, as expected. C-Flex 3 produced expiratory drops in mask pressure (range -0.03 to -2.49 cm H(2)O) but mitigated the expiratory pressure rise in the supraglottis only during a sinusoidal respiratory pattern in the model.

CONCLUSIONS

Expiratory changes in mask pressure induced by C-Flex did not uniformly transmit to the supraglottis in either patients with obstructive sleep apnea on CPAP or in a mechanical model of the upper airway with fixed resistance. Data suggest that the observed lack of expiratory drop in supraglottic pressure swings is related to dynamics of the C-Flex algorithm.

Positive airway pressure initiation: a randomized controlled trial to assess the impact of therapy mode and titration process on efficacy, adherence, and outcomes

STUDY OBJECTIVES

(1) To determine the efficacy of automatically adjusted positive airway pressure (APAP) with a comfort feature (A-Flex) at reducing apneas and hypopneas in participants with moderate to severe OSA. (2) To determine the relative difference between A-Flex, continuous positive airway pressure (CPAP), and APAP-derived optimal pressure for CPAP (CPAP(APAP)) on adherence to treatment. (3) To determine the relative difference between APAP with A-Flex, CPAP, and CPAP(APAP) on long-term change in functional outcomes.

DESIGN

Randomized, double-blinded, 3-arm, multicenter trial.

SETTING

University and Veterans Affairs medical centers.

PATIENTS OR PARTICIPANTS

168 participants were randomized, and 140 completed the 180-day study.

INTERVENTIONS

(1) A-Flex; (2) CPAP; (3) APAP for 14 days and then switched to CPAP at a fixed pressure.

MEASUREMENTS AND RESULTS

Apnea-hypopnea indices, average and minimum oxygen saturation, time spent < 90% were significantly poorer for A-Flex vs. CPAP at the initiation of study treatment; with the exception of minimum oxygen saturation, these differences were absent at 180 days. A-Flex had lower average leak values at both 3 and 6 months. There were no significant differences between groups in major efficacy, adherence, and outcome (subjective sleepiness, objective vigilance, blood pressure, quality of life) measures. No differences between groups in attitudes toward use were observed at 3 or 6 months; participant ratings for CPAP were significantly higher than A-Flex on treatment satisfaction and benefit, but not different for sleep quality and mask comfort.

CONCLUSIONS

We found that A-Flex shows equivalency, but non-superiority (except for average leak values), in efficacy, adherence, and functional outcomes compared to CPAP after either 3 or 6 months.

CLINICAL TRIAL REGISTRY

Positive Pressure Treatment of Obstructive Sleep Apnea, http://www.clinicaltrials.gov, NCT00636181.

Driving simulator performance remains impaired in patients with severe OSA after CPAP treatment

STUDY OBJECTIVES

To assess the effectiveness of CPAP treatment in improving 90-minute driving simulator performance in severe OSA patients compared to age/gender matched controls.

DESIGN

Driving simulator performance was assessed at baseline and 3 months later, with OSA patients treated with CPAP during the interval.

SETTING

University Teaching Hospital.

PARTICIPANTS

Patients with severe OSA (n = 11) and control subjects without OSA (n = 9).

INTERVENTIONS

CPAP MEASUREMENTS AND RESULTS: Simulator driving parameters of steering deviation, braking reaction time and crashes were measured at baseline and ∼3 months follow-up. At baseline, OSA subjects demonstrated significantly greater steering deviation compared to controls (mean [95% CI], OSA group, 49.9 cm [43.7 to 56.0 cm] vs control group, 34.9 cm [28.1 to 41.7 cm], p = 0.003). Following ∼3 months of CPAP treatment (mean ± SD 6.0 ± 1.4 h/night), steering deviation in OSA subjects improved by an average of 3.1 cm (CI, 1.4 to 4.9), p < 0.001, while no significant steering changes were observed in the control group. Despite the improvement, steering deviation in the OSA group remained significantly higher than in controls (OSA group, 46.7 cm [CI, 40.6 to 52.8 cm] vs control group, 36.1 cm [CI, 29.3 to 42.9 cm], p = 0.025).

CONCLUSIONS

While driving simulator performance improved after ∼3 months of CPAP treatment with high adherence in patients with severe OSA, performance remained impaired compared to control subjects. These results add to the growing body of evidence that some neurobehavioral deficits in patients with severe OSA are not fully reversed by treatment. Further studies are needed to assess causes of residual driving simulator impairment and to determine whether this is associated with persistent elevated real-life accident risk.

TRIAL REGISTRATION

Data presented in this manuscript was collected as part of a clinical trial "Experimental Investigations of Driving Impairment in Obstructive Sleep Apnoea" ACTRN12610000009011, http://www.anzctr.org.au/trial_view.aspx?ID=334979

Flexible pressure delivery modification of continuous positive airway pressure for obstructive sleep apnea does not improve compliance with therapy: systematic review and meta-analysis

BACKGROUND

Continuous positive airway pressure (CPAP) is the first-line therapy for obstructive sleep apnea (OSA), but patient compliance is a major barrier to long-term effectiveness. Flexible pressure delivery of PAP reduces pressure during early exhalation with the aim of improving comfort and, therefore, compliance, leading to subsequent symptoms improvement.

METHODS

We undertook a systematic literature search of PubMed (January 1, 2000, to July 11, 2010) to identify all randomized trials comparing flexible and standard CPAP in adult patients with OSA with at least 1-week follow-up. Either we or the original trial investigators extracted means, SEs, and sample sizes for all relevant outcome measures. We then performed meta-analyses quantifying improvements in objective compliance and symptoms as measured by the Epworth Sleepiness Scale (ESS), the Maintenance of Wakefulness Test (MWT), and the Psychomotor Vigilance Task (PVT).

RESULTS

We found 10 relevant trials (599 patients). Meta-analysis of the seven trials where we could extract compliance data (514 patients) indicated that flexible pressure did not improve compliance compared with CPAP in either the parallel (0.16 h; 95% CI, -0.09-0.42; P = .21) or the crossover trials (0.20 h; 95% CI, -0.26-0.66; P = .39). Flexible pressure caused no improvement over CPAP in any secondary outcome (ESS, MWT, PVT, and residual OSA, all P > .05).

CONCLUSIONS

Flexible pressure modification neither significantly improves compliance with CPAP in patients with OSA nor significantly improves patient outcomes beyond the effects of CPAP. Unfortunately, we were unable to locate compliance data in the correct format for three out of the 10 suitable trials.

How treatment affects cognitive deficits in patients with sleep disorders: methodological issues and results

Sleep disorders are frequently associated with impaired performance although the type and extent of cognitive deficits varies widely between different types of sleep disorders. Treatment is expected to ameliorate these deficits. However, cognitive functioning and its change with treatment depend on numerous factors. In this chapter we discuss methodological issues, including test selection, and person-specific, task-specific and environmental factors that influence cognitive functioning. In addition, features of study design and sampling strategies are discussed. The chapter ends with a short overview of routes by which treatment may affect cognition in sleep-disordered patients.