A Randomized Crossover Trial of a Pressure Relief Technology (SensAwake™) in Continuous Positive Airway Pressure to Treat Obstructive Sleep Apnea

Impact of CPAP Therapy on Cognition and Fatigue in Patients with Moderate to Severe Sleep Apnea: A Longitudinal Observational Study

Continued solicitation of cognitive resources eventually leads to cognitive fatigue (CF), i.e., a decrease in cognitive efficiency that develops during sustained cognitive demands in conditions of constrained processing time, independently of sleepiness. The expression of CF and its impact on cognition are partly contingent upon prior sleep quality and its restorative effects. Sleep in obstructive sleep apnea (OSA) may be largely restored through the use of continuous positive airway pressure (CPAP) treatment, contributing to a gradual improvement in sleep quality. In this longitudinal observational study, we investigated immediate and longer-term behavioral effects of CPAP treatment on cognitive functioning, evaluating outcomes after the initiation of treatment, and at three and six months, in compliant CPAP-treated OSA patients. Results indicate that CPAP therapy significantly enhances subjective sleep quality and cognitive functions, including episodic memory, inhibition, sustained attention, working memory, and executive control. Noticeable performance improvements were observed in CF-inducing tasks, particularly after six months of CPAP use. Participants also reported substantial gains in quality of life, reduced daytime sleepiness, and improved mood. These results confirm that CPAP therapy not only alleviates immediate physiological disturbances associated with OSA, but also supports cognitive recovery and enhanced overall daily functioning.

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.

Effects of Pressure Control Device (SensAwake™) on Obstructive Sleep Apnea (OSA) Patients Who Remove the Mask for Unknown Reasons during Automatic Continuous Positive Airway Pressure (Auto-CPAP) Therapy: A Prospective Randomized Crossover Trial

Backgroundand Objectives: Obstructive sleep apnea (OSA) patients may remove their mask unconsciously during automatic continuous positive airway pressure (Auto-CPAP) therapy and therefore cannot receive good treatment. The discomfort from the airflow of Auto-CPAP may be one reason for interrupted sleep. Sens Awake (SA) can detect the arousal and lower the pressure to prevent patients from fully awakening from sleep. Materials and Methods: To evaluate the effect of SA, we designed a prospective, randomized, crossover trial comparing Auto-CPAP with and without SA on Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Nasal Obstruction Symptom Evaluation (NOSE) Scale and recorded data from the auto-CPAP machine. Results: In the 25 patients who completed the study, the gender, age, body mass index, neck circumference, polysomnography data, and previous CPAP use were not significantly different between the two arms. The average and 90th percentile pressures were significantly lower during SA on (SA on vs. off: 6.9 ± 2.7 vs. 7.3 ± 2.6 [p = 0.032] and 8.6 ± 3.0 vs. 9.2 ± 2.9 [p = 0.002], respectively). The time used, days used, compliance, average and 90th percentile leaks, and the residual Apnea-Hypopnea Index (AHI) were not significantly changed between the SA on-and-off. Based on the subjective evaluation, PSQI, ESS, and NOSE were not significantly different between the SA on-and-off; however, based on additional analyses which were compared with baseline data, the ESS was significantly lower when the SA was on (SA on vs. baseline: 11.1 ± 6.1 vs. 13.2 ± 6.0 [p = 0.023]). Conclusions: CPAP therapy with or without two weeks of the SA had a similar effect on CPAP use, sleep quality, daytime sleepiness, and nasal obstruction. The SA may have a tendency to improve daytime sleepiness, but needs further study with a longer duration of treatment.

Telemedicine in Sleep-Disordered Breathing: Expanding the Horizons

Interest in telemedicine has increased exponentially. There is a growing body of published evidence on the use of telemedicine for patients using continuous positive airway pressure. Telemedicine-ready devices can support the transmission on use time, apnea-hypopnea index, and leakage. This approach enables early activation of troubleshooting. Automated, personalized feedback for patients and patient access to their own data provide unprecedented opportunities for integrating comanagement approaches, multiactor interactions, and patient empowerment. Telemedicine is likely cost effective, but requires better evidence. Notwithstanding barriers for implementation that remain, telemedicine has to be embraced, leaving the physician and patient to accept it or not.

The Impact of Device Modifications and Pressure Delivery on Adherence

This article reviews the evidence to date examining whether adherence to positive airway pressure (PAP) therapy is affected by any device modifications to pressure delivery. To date there is no robust evidence from systematic reviews and meta-analyses indicating that any modification to standard fixed-pressure PAP makes a clinically significant difference to patient adherence to therapy. The main modifications are reviewed in this article and whether improving pressure could drive adherence, in turn improving patient outcomes, is discussed.

Effect of Gender, Age, and Profound Disease on Upper Airway Stimulation Outcomes

OBJECTIVE

To evaluate treatment outcomes of upper airway stimulation (UAS) in obstructive sleep apnea (OSA) patients based on patient age, gender, and preoperative disease severity.

METHODS

Retrospective chart review of patients undergoing UAS from 2014 to 2018 at a tertiary care center. Data collected included demographic information, implantation records, and pre- and postoperative polysomnography (PSG) results. Profound OSA was defined as AHI >65 and age ≥65 was considered advanced age. The primary outcome measured was initial treatment response, defined as a post-operative AHI <20 with a >50% reduction from baseline.

RESULTS

145 patients underwent UAS at our institution including 98 males and 47 females with a mean age of 61.7 ± 11.5 years, mean BMI of 29.1 ± 3.9 kg/m², and mean preoperative AHI of 34.1 ± 18.2 events/hour. After surgery, patients had a significantly lower mean AHI of 8.6 ± 15.0 events/hour (<0.001). Older patients had a lower initial treatment response rate (78%) when compared to their younger counterparts (94%) (P = 0.005). Male gender and profound disease status did not significantly impact treatment response rates; young age was the only variable found to predict early treatment response on multivariate analysis (P = 0.003).

CONCLUSION

Although the overall OSA population showed significant postoperative AHI reduction with UAS, patients age ≥65 years were less likely to have an initial response to treatment, when compared to their younger counterparts. A larger proportion of elderly patients and patients with profound OSA had residual moderate disease (AHI > 15) after UAS.

LEVEL OF EVIDENCE

4.

Elevated Central and Mixed Apnea Index after Upper Airway Stimulation

Objective

Upper airway stimulation (UAS) is used to treat patients with moderate to severe obstructive sleep apnea (OSA). The aim of this study is to report the incidence and potential predictors of elevated central and mixed apnea index (CMAI) after UAS.

Study Design

Retrospective chart review of patients undergoing UAS.

Setting

Tertiary care center.

Subjects and Methods

Included patients underwent UAS for OSA at our institution between 2014 and 2018. Data collected included demographic information, implantation records, and pre- and postoperative polysomnography (PSG) results. CMAI ≥5 was considered elevated. Post hoc univariate analysis was performed to evaluate factors associated with elevated CMAI.

Results

In total, 141 patients underwent UAS at our institution. This included 94 men and 47 women with a mean age of 61.2 ± 11.0 years and a mean body mass index of 29.1 ± 3.9 kg/m2. Five patients had an elevated CMAI after surgery during UAS titration. Demographics, comorbid conditions, and device settings were not associated with an elevated postoperative CMAI ( P > .05).

Conclusion

The occurrence of an elevated CMAI after surgery may represent treatment-emergent events. Demographics, comorbid conditions, and UAS device settings were not associated with central and mixed apneic events.

Level of Evidence

4

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.

A randomized, placebo-controlled trial using a novel PAP delivery platform to treat patients with OSA and comorbid PTSD

PURPOSE

Positive airway pressure (PAP) adherence is poor in comorbid OSA/PTSD. SensAwake™ (SA) is a wake-sensing PAP algorithm that lowers pressure when wake is detected. We compared auto-PAP (aPAP) with and without SA for comorbid OSA/PTSD.

METHODS

Prospective, randomized crossover study comparing aPAP to aPAP + SA. We enrolled patients with OSA/PTSD who were PAP naïve. Four weeks after randomization, the patients were crossed over to the alternate treatment group, with final follow-up at eight weeks. Sleep questionnaires (ESS, ISI, FSS, and FOSQ-10) were assessed at baseline and follow-up.

RESULTS

We enrolled 85 patients with OSA/PTSD. aPAP reduced AHI to < 5/h in both groups. Our primary endpoint, average hours of aPAP adherence (total) after 4 weeks, was significantly increased in the SA group in our intention-to-treat (ITT) analysis (ß = 1.13 (95% CI 0.16-2.1); p = 0.02), after adjustment for ESS differences at baseline. After adjustment for ESS, SA (ITT analysis) also showed significant improvement in percentage of nights used for ≥ 4 h (ß = 14.9 (95% CI 1.02-28.9); p = 0.04). There were trends toward an increase in percentage nights used total (ß = 17.4 (95% CI - 0.1 to 34.9); p = 0.05), average hours of aPAP adherence (nights used) (ß = 1.04 (95% CI - 0.07 to 2.1); p = 0.07), and regular use (OR = 7.5 (95% CI 0.9-64.7); p = 0.07) after adjustment for ESS at baseline. After adjustment for ESS and days to cross over, SA by actual assignment did not show any effect on adherence variables. The ESS, ISI, FSS, and FOSQ-10 all showed significant improvements with PAP, but there were no differences in the magnitude of improvement in any score between groups.

CONCLUSIONS

Adherence to aPAP may be improved with the addition of SA and deserves further study. SA is as effective as standard aPAP for normalizing the AHI and improving sleep-related symptoms.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT02549508 https://clinicaltrials.gov/ct2/show/NCT02549508?term=NCT02549508&rank=1 "Comparison Study Using APAP With and Without SensAwake in Patients With OSA and PTSD".