Effects of humidification on nasal symptoms and compliance in sleep apnea patients using continuous positive airway pressure

Impact of posture and CPAP on nasal airflow

Obstructive sleep apnea (OSA) patients who use continuous positive airway pressure (CPAP) often complain of nasal dryness and nasal obstruction as side effects of CPAP. The physiological mechanisms by which CPAP may cause nasal dryness and nasal obstruction remain poorly understood. It has been hypothesized that CPAP interferes with the nasal cycle, abolishing the resting phase of the cycle and leading to nasal dryness. We performed rhinomanometry measurements in 31 OSA patients sitting, laid supine, and supine after 10 min of CPAP at 10 cmH2O. A posture change from sitting to supine led to more symmetric airflow partitioning between the left and right nostrils in the supine position. CPAP did not have a significant impact on nasal resistance, unilateral airflows, or airflow partitioning. Our results suggest that airflow partitioning becomes more symmetric immediately after changing to a supine position, while CPAP had no effect on nasal airflow, thus preserving the nearly symmetric airflow partitioning achieved after the posture change.

Assessment and management of continuous positive airway pressure therapy in patient with obstructive sleep apnea

Obstructive sleep apnea (OSA) causes excessive daytime sleepiness, impaired daytime functioning, and an increased risk of cardiovascular diseases. Continuous positive airway pressure (CPAP) is a highly effective therapy for moderate to severe OSA. Although CPAP adherence is commonly assessed using a 4-hthreshold, determining the optimal usage time based on clinical outcomes is crucial. While subjective sleepiness often improves with ≥4 h of CPAP usage, an extended duration (≥6 h) may be necessary to impact objective sleepiness. CPAP demonstrated a modest yet clinically meaningful dose-dependent effect on lowering blood pressure. For patients seeking antihypertensive benefits from CPAP therapy, the goal should extend beyond 4 h of use to maximize the therapeutic impact. Recognizing individual variations in sleep duration and responses to CPAP therapy is essential. The adoption of 'individualized goals for CPAP use,' outlining target times for specific outcomes, should also consider an individual's total sleep duration, including periods without CPAP. The impact of CPAP on clinical outcomes may vary, even with the same duration of CPAP use, depending on the period without CPAP use, particularly during the first or second half of sleep. Patients who remove or initiate CPAP midway or have a low CPAP usage frequency may require different forms of guidance. Tailoring patient education to address CPAP usage patterns may be necessary to enhanced satisfaction, self-efficacy, and adherence to therapy. Management of CPAP treatment should be personalized to meet individual needs and adapted based on specific response patterns for achieving treatment efficacy.

Predictors of Continuous Positive Airway Pressure Adherence and Comparison of Clinical Factors and Polysomnography Findings Between Compliant and Non-Compliant Korean Adults With Obstructive Sleep Apnea

OBJECTIVE

Continuous positive airway pressure (CPAP) is the preferred treatment for obstructive sleep apnea (OSA). However, compliance with CPAP therapy varies among studies, and studies on its predictors are insufficient in Korea. This study aimed to identify factors that predict compliance with CPAP therapy in patients with OSA.

METHODS

We retrospectively reviewed medical records, polysomnography (PSG) records, and self-report questionnaires of patients w ith OSA. Criteria for compliance was the use of CPAP devices for ≥4 h per night for ≥70% of the consecutive 30 nights (i.e., 21 days) during the first 3 months of treatment initiation. The patients were classified into two groups: compliant and non-compliant. Logistic regression analyses were performed to identify the clinical factors and PSG parameters associated with CPAP compliance.

RESULTS

Of the 188 participants, 80 were classified into the compliant group and 108 into the non-compliant group. The ratios of stage N1 (p=0.011) and health insurance coverage (p=0.007) were significantly associated with compliance with CPAP, with an explanatory power of 18.6% (R2=0.186, p<0.001).

CONCLUSION

Stage N1 ratio and health insurance coverage were significant predictors of CPAP compliance. It is necessary to confirm whether the relationship between a high stage N1 ratio and compliance can be reproduced in a larger sample and in individuals from other countries.

Self-reported oral moistening disorders in obstructive sleep apnoea: A scoping review

BACKGROUND

Obstructive sleep apnoea (OSA) is a highly prevalent problem with significant consequences. Continuous positive airway pressure (CPAP) and oral mandibular advancement device (MAD) are considered the standard treatments for OSA. Patients may experience self-reported oral moistening disorders (OMDs) (i.e. xerostomia or drooling) at the beginning, throughout and after treatment. This affects oral health, quality of life and treatment effectiveness. The exact nature of the associations between OSA and self-reported OMD is still unknown. We aimed to provide an overview of the associations between self-reported OMD on the one hand and OSA and its treatment (namely CPAP and MAD) on the other hand. In addition, we sought to determine whether OMD affects treatment adherence.

MATERIALS AND METHODS

A literature search in PubMed was performed up to 27 September 2022. Two researchers independently assessed studies for eligibility.

RESULTS

In total, 48 studies were included. Thirteen papers investigated the association between OSA and self-reported OMD. They all suggested an association between OSA and xerostomia but not between OSA and drooling. The association between CPAP and OMD was addressed in 20 articles. The majority of studies have indicated xerostomia as a CPAP side effect; however, some have observed that xerostomia diminishes with CPAP therapy. In 15 papers, the association between MAD and OMD was investigated. In most publications, both xerostomia and drooling have been described as common side effects of MADs. These side effects are often mild and transient, and they improve as patients continue to use their appliance. Most studies found that these OMDs do not cause or are not a strong predictor of non-compliance.

CONCLUSION

Xerostomia is a common side effect of CPAP and MAD, as well as a significant symptom of OSA. It may be regarded as one of the indicators of sleep apnoea. Moreover, MAD therapy can be associated with OMD. However, it seems that OMD may be mitigated by being adherent to the therapy.

Current treatment strategies in managing side effects associated with domiciliary positive airway pressure (PAP) therapy for patients with sleep disordered breathing: A systematic review and meta-analysis

Sleep disordered breathing is commonly treated with positive airway pressure therapy. Positive airway pressure therapy is delivered via a tight-fitting mask with common side effects including: leak, ineffective treatment, residual sleep disordered breathing, eye irritation, nasal congestion, pressure ulcers and poor concordance with therapy. This systematic review and meta-analysis aimed to identify the effectiveness of current treatment strategies for managing side effects associated with positive airway pressure therapy. Five databases were searched and 10,809 articles were screened, with 36 articles included in the review. Studies investigated: dressings, nasal spray/douche, chin straps, heated humidification and interfaces. No intervention either improved or detrimentally affected: positive airway pressure concordance, Epworth Sleepiness Score, residual apnoea hypopnea index or interface leak. The review was limited by study heterogeneity, particularly for outcome measures. Additionally, patient demographics were not reported, making it difficult to apply the findings to a broad clinical population. This review highlights the paucity of evidence supporting treatment strategies to manage side effects of positive airway pressure therapy.

Effects of heated humidification on positive airway pressure side effects in patients with obstructive sleep apnoea: a meta-analysis

PURPOSE

An earlier study found that heated humidification reduced the side effects of positive airway pressure (PAP) in patients with obstructive sleep apnoea (OSA). However, other studies disagreed with this finding. Therefore, we evaluated the relationship between heated humidification and the side effects of PAP in patients with OSA.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, six databases were searched for relevant randomised controlled trials (RCTs) performed from January 1999 to June 2021.

RESULTS

From 1012 retrieved articles, we identified 9 eligible RCTs. Compared to the control group, the heated humidification group reported improvements in dry nose (pooled standardised mean difference [SMD] =  - 0.70, 95% confidence interval [CI] =  - 0.96 to - 0.45, I² = 0%, p < 0.00001), blocked nose (SMD =  - 0.47, 95%CI - 0.69 to - 0.25, I² = 36%, p < 0.0001), runny nose (SMD =  - 0.22, 95%CI - 0.44 to 0, I² = 0%, p = 0.05), dry mouth (SMD =  - 0.62, 95%CI - 0.87 to - 0.37, I² = 0%, p < 0.00001), and dry throat (SMD =  - 0.61, 95%CI - 0.90 to - 0.33, I² = 41%, p < 0.0001), but did not enhance positive airway pressure adherence (pooled mean difference [MD] = 0.24, 95% CI - 0.10 to 0.58, I² = 0%, p = 0.17).

CONCLUSIONS

Heated humidification improved some PAP side effects in patients with OSA but did not increase PAP adherence. Additional large-scale multi-centre RCTs are needed to verify the long-term effects.

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.

Nasal function and CPAP use in patients with obstructive sleep apnoea: a systematic review

PURPOSE

This systematic review was conducted to answer the following 3 questions: 'Does nasal pathology affect CPAP use?', 'What is the effect of CPAP on the nose?' and 'Does treatment of nasal pathology affect CPAP use?'.

METHODS

Pubmed and Scopus databases were searched for articles relevant to the study questions up to October 2020.

RESULTS

Sixty-three articles were selected, of which a majority were observational studies. Most studies identified a correlation between larger nasal cross-sectional area or lower nasal resistance and higher CPAP compliance or lower CPAP pressures; however, nasal symptoms at baseline did not appear to affect CPAP use. The effect of CPAP on the nose remains uncertain: while most studies suggested increased mucosal inflammation with CPAP, those investigating symptoms presented contradictory results, with some reporting an increase and others an improvement in nasal symptoms. Evidence is clearer for nasal surgery leading to an increase in CPAP compliance and a decrease in CPAP pressures, whereas there is little evidence available for the use of topical nasal steroids.

CONCLUSION

There appears to be a link between nasal volumes or nasal resistance and CPAP compliance, an increase in nasal inflammation caused by CPAP and a beneficial effect of nasal surgery on CPAP usage, but no significant effect of CPAP on nasal patency or effect of topical steroids on CPAP compliance. Results are more mitigated with regard to the effect of nasal symptoms on CPAP use and vice versa, and further research in this area would help identify patients who may benefit from additional support or treatment alongside CPAP.

Ventilatory support at home for children: A joint position paper from the Thoracic Society of Australia and New Zealand/Australasian Sleep Association

The goal of this position paper on ventilatory support at home for children is to provide expert consensus from Australia and New Zealand on optimal care for children requiring ventilatory support at home, both non-invasive and invasive. It was compiled by members of the Thoracic Society of Australia and New Zealand (TSANZ) and the Australasian Sleep Association (ASA). This document provides recommendations to support the development of improved services for Australian and New Zealand children who require long-term ventilatory support. Issues relevant to providers of equipment and areas of research need are highlighted.

Pressure adjustment is the most useful intervention for improving compliance in telemonitored patients treated with CPAP in the first 6 months of treatment

PURPOSE

Telemonitoring (TMg) for patients treated with continuous positive airway pressure (CPAP) is now routine care in some sleep labs. The purpose of the present study was to identify technical interventions associated with improved CPAP compliance in a real-life cohort of newly telemonitored patients with obstructive sleep apnea (OSA) during the first 6 months of treatment.

METHODS

All patients with moderate-to-severe OSA (apnea-hypopnea index (AHI) ≥ 15/h) who were newly treated with CPAP were included in the study and telemonitored. A group educational session was scheduled after 1 month. Technical interventions were performed at the patient's request and during scheduled visits and the impact of each intervention on CPAP therapy compliance was collected.

RESULTS

Between May 2018 and Dec 2019, 349 patients newly diagnosed with OSA were hospitalized in the sleep lab for CPAP titration and 212 patients were included (mean age 54.6 ± 13.1 years, mean BMI 31.7 ± 5.8 kg/m², mean AHI 42.8 ± 22.0). TMg acceptance rate was 87%. Mean 6-month compliance was 275 ± 154 min, 13% stopped CPAP, and 17% were non-compliant. Correlations were observed between BMI (r = 0.15, p = 0.029), median and 95th percentile leaks (r = -0.23 and -0.18, p = 0.016 and 0.002), and CPAP compliance. During follow-up, 92 interventions were required, mainly for mask change (n = 80). Pressure modification (n = 16) was the only intervention that increased CPAP use > 30 min/night, p = 0.021.

CONCLUSION

Pressure modification was the only adaptation that significantly increased CPAP compliance during the first 6 months. Remote TMg allows providing daily, accurate, and immediate feedback that could help clinicians to confirm that the CPAP treatment is effective.

Seasonal effects on the continuous positive airway pressure adherence of patients with obstructive sleep apnea

OBJECTIVE

This study examined seasonal differences in continuous positive airway pressure (CPAP) therapy adherence among patients with obstructive sleep apnea (OSA).

METHODS

Patients aged ≥20 years with OSA who had used CPAP devices on the automatic setting for >12 consecutive months (n = 141) were included in this retrospective study from December 2015-2016. The information of CPAP use (pressure, hours of actual use) was extracted from database downloaded from patients' CPAP devices. Patients were divided into adherent and non-adherent groups using the cutoff point of 70% CPAP use for ≥4 h daily over the 1-year study period. CPAP use data were averaged for each season.

RESULTS

Patients in the adherent group were significantly older than those in the non-adherent group (p < 0.001). In the adherent group, the rate of ≥4 h daily CPAP use was significantly lower, the daily duration of CPAP use was significantly shorter, and the residual apnea-hypopnea index (AHI; events/hour) was significantly higher in summer than in other seasons (all p < 0.001). In the non-adherent group, the duration of daily CPAP use and the AHI differed significantly between winter and summer (p = 0.008 and p < 0.001, respectively).

CONCLUSIONS

Seasonal changes were associated with the CPAP adherence of patients with OSA. The study findings suggest that there is possibility of increasing the duration of CPAP use by adjusting the bedroom environment in hot and humid seasons.

Summary and Update on Behavioral Interventions for Improving Adherence with Positive Airway Pressure Treatment in Adults

Continuous positive airway pressure (PAP) is still the most efficacious treatment for obstructive sleep apnea when used effectively. Since the availability of PAP 39 years ago there have been considerable technological advances, such as quieter, lighter and smaller machines with better humidification. However, adherence to treatment is still a major problem. This article reviews studies published on behavioral interventions aimed at improving the uptake and maintenance of PAP treatment (January 2016-February 2020). It discusses underlying factors in the poor uptake and discontinuation of treatment and the role of qualitative research to better understand the perspective of the patients.

Prospective Trial of CPAP in Community-Dwelling Adults with Down Syndrome and Obstructive Sleep Apnea Syndrome

Adults with Down syndrome (DS) are predisposed to obstructive sleep apnoea (OSA), but the effectiveness and acceptability of continuous positive airway pressure treatment (CPAP) in this group has rarely been formally assessed. This study was designed as a pilot randomised, parallel controlled trial for one month, continuing as an uncontrolled cohort study whereby the control group also received the intervention. Symptomatic, community-dwelling DS individuals exhibiting ≥10 apnoeas/hypopneas per hour in bed on a Type 3 home sleep study were invited to participate in this study, with follow-up at 1, 3, 6, and 12 months from baseline. Measurements of sleepiness, behaviour, cognitive function and general health were undertaken; the primary outcome was a change in the pictorial Epworth Sleepiness Scale (pESS) score. Twenty-eight participants (19 male) were enrolled: age 28 ± 9 year; body mass index 31.5 ± 7.9 kg/m2; 39.6 ± 32.2 apnoeas/hypopneas per hour in bed; pESS 11 ± 6/24. The pilot randomised controlled trial at one month demonstrated no change between the groups. At 12 months, participant (p = 0.001) pESS and Disruptive (p < 0.0001), Anxiety/Antisocial (p = 0.024), and Depressive (p = 0.008) behaviour scores were reduced compared to baseline. Improvement was noted in verbal (p = 0.001) and nonverbal intelligence scores (p = 0.011). General health scores also improved (p = 0.02). At the end of the trial, 19 participants continued on treatment. Use of CPAP in adults with DS and OSA led to a number of significant, sustained improvements in sleepiness and behavioural/emotional outcomes at 12 months.

Treatment of Obstructive Sleep Apnea: Choosing the Best Positive Airway Pressure Device

Positive airway pressure (PAP) remains primary therapy for most patients with obstructive sleep apnea (OSA). CPAP, APAP, and BPAP are all reasonable therapies that can be used for patients with uncomplicated OSA across the spectrum of disease severity. BPAP should be considered for patients who are nonadherent to CPAP or APAP therapy because of pressure intolerance. Several additional factors should be considered when choosing the type of PAP device for a given patient, including associated symptoms and comorbid medical problems, cost, access to online data management and patient portals, and the portability for the device for patients who travel frequently.

Treatment of Obstructive Sleep Apnea: Achieving Adherence to Positive Airway Pressure Treatment and Dealing with Complications

Obstructive sleep apnea is a common and treatable condition, but therapeutic adherence is limited by numerous factors. Despite advances in positive airway pressure (PAP) technology and a multitude of effective pharmacologic and behavioral therapeutic interventions to overcome the most common barriers to PAP, adherence has not increased significantly over the past 30 years. This review aims to identify the most important factors that impact adherence, common barriers to treatment, and evidence-based treatment strategies to maximize the effectiveness of PAP treatment. Complications of PAP treatment and mitigation techniques are also discussed.

Effect of humidified versus nonhumidified CPAP on inflammatory response and nasopharyngeal symptoms in healthy participants

Introduction

Continuous positive airway pressure (CPAP) may induce nasal inflammation because of mucosal compression or dryness. This study examined the impact of humidified versus nonhumidified CPAP on nasal inflammation and upper airway symptoms.

Methods

Seventeen healthy male subjects with no previous or current history of nasal symptoms were recruited. All subjects underwent 3 hours of nonhumidified CPAP at 12.5 cmH₂O via nasal mask. Among the 17 studied subjects, seven returned to receive a humidified CPAP at 12.5 cmH₂O via nasal mask. The nasal wash leukocyte count was assessed at baseline and after each CPAP setting. The white blood cell (WBC) count and levels of WBCs that are mononuclear cells (including lymphocytes and monocytes) were monitored. A six-point nasal score was also assessed before and after the CPAP intervention.

Results

The nasal wash WBC count (10³/µL) and mononuclear cell level (10³/µL) at baseline, on 12.5 cmH₂O humidified CPAP, and on 12.5 cmH₂O nonhumidified CPAP were significantly different (p = 0.016; p = 0.003). Changes in nasopharyngeal symptoms occurred in 12 of 17 subjects (70.5%) in the nonhumidified group. Participants experienced at least one nasal symptom after application of nonhumidified CPAP at 12.5 cmH₂O.

Conclusion

The present investigation suggests that humidified CPAP was not associated with early nasal inflammation and there were fewer nasopharyngeal symptoms. Further study is required to confirm the results and evaluate the impact of adding heat to the humidified CPAP system.

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.

OSA treatment with CPAP: Randomized crossover study comparing tolerance and efficacy with and without humidification by ThermoSmart

OBJECTIVES

Adherence to continuous positive airway pressure (CPAP) remains an issue, as adverse effects (AE) such as rhinitis, dry/congested nose, dry mouth or throat are commonly experienced. The aim of the study was to compare CPAP efficacy and tolerance in severe obstructive sleep apnea (OSA) patients with or without (w/o) heated humidification using the ThermoSmart system.

METHODS

Multicenter RCT study in which CPAP-naive patients with severe OSA and meeting one or more of the following criteria: >65 years, using >1 drying medication, previous nasal symptoms or nasal surgery, were included. Patients were randomized to CPAP w/o heated humidification for 1 month and then crossed-over to the other treatment arm for another month. Naso-pharyngeal symptoms, Quality of life (FOSQ-10), sleepiness (ESS) and CPAP compliance and efficacy data were collected.

RESULTS

Forty patients were enrolled: age 62 ± 9 years, diagnostic AHI 46.7 ± 15.3/hour. About 70% were using >1 drying medication, mainly antihypertensives. Both treatment modalities were found to normalize AHI and decrease sleepiness with no differences between 2 modes, compliance (4.63 ± 0.39 vs 4.70 ± 0.36 h/night) or leaks (32.4 ± 2.0 versus 31.1 ± 1.7l/min). With heated humidification, there was a significant decrease in nasal symptoms such as dry/congested nose. At the study end, 26 patients preferred ThermoSmart ON, 3 did not have preference and 11 preferred ThermoSmart OFF.

CONCLUSION

ThermoSmart helps to decrease nose and throat discomfort because of CPAP therapy, these effects did not translate to better compliance but patients had a preference for ThermoSmart.

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 effects of heated humidification to nasopharynx on nasal resistance and breathing pattern

Background

Mouth breathing could induce not only dry throat and eventually upper respiratory tract infection, but also snoring and obstructive sleep apnea, while nasal breathing is protective against those problems. Thus, one may want to explore an approach to modify habitual mouth breathing as preferable to nasal breathing. The aim of this study was to investigate the physiological effects of our newly developed mask on facilitation of nasal breathing.

Methods

Thirty seven healthy male volunteers were enrolled in a double blind, randomized, placebo-controlled crossover trial. Participants wore a newly developed heated humidification mask or non-heated-humidification mask (placebo) for 10-min each. Subjective feelings including dry nose, dry throat, nasal obstruction, ease to breathe, relaxation, calmness, and good feeling were asked before and after wearing each mask. In addition, the effects of masks on nasal resistance, breathing pattern, and heart rate variability were assessed.

Results

Compared with the placebo mask, the heated humidification mask improved all components of subjective feelings except for ease to breathe; moreover, decreased nasal resistance and respiratory frequency accompanied a simultaneous increase in a surrogate maker for tidal volume. However, use of the heated humidification mask did not affect heart rate variability

Conclusion

Adding heated humidification to the nasopharynx could modulate breathing patterns with improvement of subjective experience and objective nasal resistance.

Predictors of Continuous Positive Airway Pressure Adherence in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common disease which impacts quality of life, mood, cardiovascular morbidity, and mortality. Continuous positive airway pressure (CPAP) is the first-line treatment for patients with moderate to severe OSA. CPAP ameliorates respiratory disturbances, leading to improvements in daytime sleepiness, quality of life, blood pressure, and cognition. However, despite the high efficacy of this device, CPAP adherence is often sub-optimal. Factors including: socio-demographic/economic characteristics, disease severity, psychological factors, and side-effects are thought to affect CPAP adherence in OSA patients. Intervention studies have suggested that augmented support/education, behavioral therapy, telemedicine and technological interventions may improve CPAP adherence. In this paper, we will extensively review the most common factors including age, gender, race/ethnicity, socioeconomic status, smoking status, severity of OSA, severity of OSA symptoms, psychological variables, social support, marital status/bed partner involvement, dry nose and mouth, mask leak, and nasal congestion that may predict CPAP adherence. We will also extensively review interventions that may increase adherence to CPAP.

Nasal function and CPAP compliance

OBJECTIVE

Continuous positive airway pressure (CPAP) is the mainstay therapy for patients with obstructive sleep apnea (OSA) however compliance with CPAP is variable. Nasal ailments, such as nasal congestion are frequently mentioned as a cause for CPAP non-compliance, and potentially could be addressed prior to CPAP initiation, however, no specific criteria or recommendations for the evaluation and management of these patients exist. The aim of this retrospective study is to evaluate the effects of nasal anatomic features and disease on adherence to CPAP therapy for patients with OSA and determine the indications for pre-CPAP nasal treatment by using data obtained at clinical examination.

METHODS

In total, 711 adult patients with initial diagnosis of OSA and an apnea-hypopnea index of ≥20 who were amenable to CPAP were included. We analyzed nasal parameters, past history of nasal disease, subjective symptoms, and disease severity in addition to whether CPAP therapy had been initiated, rate of CPAP therapy use (initial and 1year), treatment continuation rate at 2 months and 1year, and nasal treatments for all patients.

RESULTS

CPAP therapy was initiated in 543 of 711 patients. Nasal resistance was significantly higher in patients who discontinued therapy soon after CPAP initiation. Nasal disease and nasal parameters were not found to be predictors of treatment adherence at 1year. Allergic rhinitis, moderate to severe nasal congestion at bedtime, slight or extensive sinus opacification, and a high nasal septum deviation score were found to be independent predictors of nasal treatment, while strong awareness of nasal congestion, a past history of sinusitis, and a total nasal resistance (supine position) of ≥0.35Pa/cm³/s were independent predictors of surgical treatment.

CONCLUSION

Long-term CPAP therapy adherence in patients with OSA can be predicted from initial CPAP adherence. Nasal disease and nasal parameters are important factors for early CPAP therapy discontinuation and should be adequately treated before therapy initiation to ensure long-term adherence. Indications for pre-CPAP nasal treatment and nasal surgery for patients with OSA can be predicted from the data obtained at the first examination, and these patients should be treated differently from those without OSA.

Heated humidification did not improve compliance of positive airway pressure and subjective daytime sleepiness in obstructive sleep apnea syndrome: A meta-analysis

Introduction

We performed a meta-analysis on whether heated humidification during positive airway pressure (PAP) could improve compliance and subjective daytime sleepiness in obstructive sleep apnea syndrome (OSAS) patients.

Materials and methods

We searched PubMed, EMBASE, Medline, Cochrane Library, Clinical Trials, Web of Science and Scopus from inception to Oct 29, 2017. We made meta-analysis on the all available randomized controlled trials (RCTs) which assessed effects of heated humidification intervention on PAP compliance and subjective daytime sleepiness, by subgroups of automatic adjusting positive airway pressure/ continuous positive airway pressure (APAP/CPAP) usage and patients with/without upper airway symptoms prior to PAP therapy.

Results

A total of nine RCTs were evaluated finally in this meta-analysis. When all the studies were pooled, heated humidification did not improve PAP usage time [weighted mean difference(WMD) = 13.28, 95% confidence interval(CI): -5.85 to 32.41, P = 0.17] or Epworth sleepiness scale (ESS) score (WMD = -0.63, 95% CI: -1.32 to 0.07, P = 0.08). In terms of PAP usage time, heated humidification failed to enhance compliance in both APAP (WMD = 22.34, 95%CI: -21.08 to 65.77, P = 0.31) or CPAP subgroup (WMD = 11.09, 95%CI: -10.21 to 32.40, P = 0.31) and it was also ineffective among patients with upper airway symptoms prior to PAP therapy (WMD = 22.74, 95% CI: -7.77 to 53.24, P = 0.14) or without (WMD = 13.22, 95%CI: -35.84 to 62.29, P = 0.60). In terms of ESS score, heated humidification did not reduce ESS scores in both APAP (WMD = -1.59, 95% CI: -3.81 to 0.64, P = 0.16) or CPAP subgroup (WMD = -0.39, 95% CI: -1.16 to 0.37, P = 0.32) and it was also helpless among patients with upper airway symptoms prior to PAP therapy (WMD = -1.17, 95% CI: -3.10 to 0.75, P = 0.23) or without (WMD = -0.30, 95%CI: -2.25 to 1.66, P = 0.76).

Conclusion

Heated humidification during PAP therapy improves neither the compliance nor ESS scores in OSAS patients, no matter what types of PAP or whether the patients had upper airway symptoms prior to PAP therapy. But to the population with upper airway symptoms and the APAP users, the conclusions were limited because of small sample size and possible selection bias. More attentions should be paid to these potentially possible benefited subgroups.

3D patient-specific numerical modeling of the soft palate considering adhesion from the tongue

Collapse of the soft palate in the upper airway contributes to obstructive sleeping apnea (OSA). In this study, we investigate the influence of the adhesion from the tongue on the soft palate global response. This is achieved using a cohesive zone finite element approach. A traction-separation law is determined to describe the adhesion effect from the surface tension of the lining liquid between the soft palate and the tongue. According to pull-off experimental tests of human lining liquid from the oral surface of the soft palate, the corresponding cohesive properties, including the critical normal traction stress and the failure separation displacement, are obtained. The 3D patient-specific soft palate geometry is accounted for, based on one specific patient's computed tomography (CT) images. The calculation results show that influence of the adhesion from the tongue surface on the global response of the soft palate depends on the length ratio between the cohesive length and the soft palate length. When the length of the cohesive zone is smaller than half of the soft palate length, the adhesion's influence is negligible. When the adhesion length is larger than 70 percent of soft palate length, the adhesion force contributes to preventing the soft palate from collapsing towards to the pharynx wall, i.e. the closing pressure is more negative than in the no adhesion case. These results may provide useful information to the clinical treatment of OSA patients.

Factors influencing adherence to continuous positive airway pressure treatment in obstructive sleep apnea and mortality associated with treatment failure - a national registry-based cohort study

OBJECTIVES

Adherence to continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea (OSA) is crucial. Our aim was to identify protective and risk factors against the discontinuation of CPAP treatment in patients with OSA and to estimate the mortality risk in those who were non-adherent to CPAP therapy.

METHODS

This was a registry-based cohort study from 37 centers across Sweden with OSA patients on CPAP in the Swedevox Swedish national registry between July 2010 and March 2017.

RESULTS

In 16,425 patients (70.8% men) with complete follow-up data after 1.2 ± 0.8 years the adjusted relative risk ratio (aRRR) for the discontinuation of CPAP was 0.57 (95% confidence interval (CI) 0.50-0.65) for use of humidifier, 0.87 (95% CI 0.82-0.92) for increasing age per 10 years, 0.80 (95% CI 0.77-0.83) for increasing apnea hypopnea index (AHI) per 5 units/hour, and 0.96 (95% CI 0.95-0.97) per increased unit on the Epworth Sleepiness Scale (ESS). Increasing BMI was associated with increased adherence up to BMI 35. Women and patients with hypertension ran an increased risk of discontinuing CPAP treatment, aRRR 1.28 (95% CI 1.12-1.46) and 1.24 (95% CI 1.12-1.42) respectively. The adjusted hazard ratio (HR) for mortality was 1.74 (95% CI 1.32-2.28) among those who did not adhere to CPAP (median follow-up period 2.4 years after the one year adherence evaluation).

CONCLUSION

Use of humidifier is associated with greater adherence to CPAP treatment. Other factors predicting adherence are increasing age, more severe OSA and overweight up to BMI 35, whereas female gender and coexisting hypertension are risk factors for discontinuation of CPAP. Failure to adhere to CPAP is associated with increased mortality.

Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing

PURPOSE

Mucosal drying during continuous positive airway pressure (CPAP) therapy is problematic for many patients. This study assessed the influence of ambient relative humidity (rH) and air temperature (T) in winter and summer on mask humidity during CPAP, with and without mask leak, and with or without heated humidification ± heated tubing.

METHODS

CPAP (8 and 12 cmH₂O) without humidification (no humidity [nH]), with heated humidification controlled by ambient temperature and humidity (heated humidity [HH]) and HH plus heated tubing climate line (CL), with and without leakage, were compared in 18 subjects with OSA during summer and winter.

RESULTS

The absolute humidity (aH) and the T inside the mask during CPAP were significantly lower in winter versus summer under all applied conditions. Overall, absolute humidity differences between summer and winter were statistically significant in both HH and CL vs. nH (p < 0.05) in the presence and absence of mouth leak. There were no significant differences in aH between HH and CL. However, in-mask temperature during CL was higher (p < 0.05) and rH lower than during HH. In winter, CPAP with CL was more likely to keep rH constant at 80% than CPAP without humidification or with standard HH.

CONCLUSION

Clinically-relevant reductions in aH were documented during CPAP given under winter conditions. The addition of heated humidification, using a heated tube to avoid condensation is recommended to increase aH, which could be useful in CPAP users complaining of nose and throat symptoms.

Influencing factors on CPAP adherence and anatomic characteristics of upper airway in OSA subjects

Although continuous positive airway pressure (CPAP) is the most effective treatment modality, poor adherence still remains a problem for obstructive sleep apnea (OSA) treatment and there is little evidence regarding how this might be improved. This study aims to analyze the anatomic and clinical factors of OSA subjects who failed to comply with CPAP therapy.The medical records of 47 OSA subjects who received CPAP therapy as a first-line treatment modality were retrospectively reviewed. The medical records were reviewed for demographic and polysomnographic data and anatomic findings of the nasal cavity and oropharynx.24 patients who adhered to CPAP therapy and 23 patients who were nonadherent were enrolled in the study. There were no statistically significant differences in sleep parameters between CPAP-adherent patients and CPAP nonadherent subjects. Mean body mass index of CPAP nonadherent group was significantly higher than CPAP adherent group. Higher grades of septal deviation and hypertrophic change of the inferior turbinate were observed more in the CPAP nonadherent group. In addition, CPAP nonadherent subjects showed considerably bigger tonsils and higher grade palatal position comparing with the CPAP adherent subjects. Subjective discomfort including inconvenience, mouth dryness, and chest discomfort were the main problems for OSA subjects who did not comply with CPAP therapy.Excessive upper airway blockage in the nasal cavity and oropharynx was predominant in CPAP nonadherent subjects, which might cause the reported subjective discomfort that reduces CPAP compliance. Therefore, resolution of these issues is needed to enhance CPAP compliance for control of OSA.

Effectiveness of intranasal sodium hyaluronate in mitigating adverse effects of nasal continuous positive airway pressure therapy

BACKGROUND

Nasal continuous positive airway pressure (CPAP) in moderate-to-severe cases of obstructive sleep apnea can cause nasal discomfort and other undesirable problems.

OBJECTIVE

The aim of our study was to test the effects of sodium hyaluronate on nasal problems that patients experienced in their daily lives, sleepiness, nasal resistance to airflow, nasal mucociliary clearance, changes in inflammatory markers, and compliance to CPAP in three groups of patients with obstructive sleep apnea syndrome on CPAP therapy.

METHODS

A total of 102 patients with a confirmed diagnosis of obstructive sleep apnea syndrome (apnea-hypopnea index [AHI] of ≥10/hour) were randomized into three treatment groups: (1) hyaluronate plus CPAP, (2) saline solution plus CPAP, and (3) CPAP-only groups. Outcome measures were the extent of improvement in the Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) mean scores, sleepiness, nasal resistance to airflow, nasal mucociliary clearance, changes in inflammatory markers, and compliance to CPAP. Significant improvement in each outcome measure was determined by comparing scores at baseline and after 4 weeks for each treatment group.

RESULTS

Significant improvement in the MiniRQLQ overall mean score was observed both in the hyaluronate plus CPAP (p < 0.00001) and saline solution plus CPAP groups (p < 0.01), although the hyaluronate plus CPAP group had better improvement compared with the saline solution plus CPAP group (0.24 versus 0.12, respectively). An increase in nasal inflammatory markers and saccharin transit test score was observed in all three groups, although it was statistically lower in the hyaluronate plus CPAP group (all p < 0.001).

CONCLUSION

Intranasal hyaluronate showed significant benefits in patients who received CPAP therapy, but future studies over a longer period of time after treatment should be performed to corroborate our findings.

Treatment of Obstructive Sleep Apnea: Achieving Adherence to Positive Airway Pressure Treatment and Dealing with Complications

Obstructive sleep apnea is a common and treatable condition, but therapeutic adherence is limited by numerous factors. Despite advances in positive airway pressure (PAP) technology and a multitude of effective pharmacologic and behavioral therapeutic interventions to overcome the most common barriers to PAP, adherence has not increased significantly over the past 30 years. This review aims to identify the most important factors that impact adherence, common barriers to treatment, and evidence-based treatment strategies to maximize the effectiveness of PAP treatment. Complications of PAP treatment and mitigation techniques are also discussed.

Treatment of Obstructive Sleep Apnea: Choosing the Best Positive Airway Pressure Device

Positive airway pressure (PAP) remains primary therapy for most patients with obstructive sleep apnea (OSA). CPAP, APAP, and BPAP are all reasonable therapies that can be used for patients with uncomplicated OSA across the spectrum of disease severity. BPAP should be considered for patients who are nonadherent to CPAP or APAP therapy because of pressure intolerance. Several additional factors should be considered when choosing the type of PAP device for a given patient, including associated symptoms and comorbid medical problems, cost, access to online data management and patient portals, and the portability for the device for patients who travel frequently.

Sleep apnea: a review of diagnostic sensors, algorithms, and therapies

While public awareness of sleep related disorders is growing, sleep apnea syndrome (SAS) remains a public health and economic challenge. Over the last two decades, extensive controlled epidemiologic research has clarified the incidence, risk factors including the obesity epidemic, and global prevalence of obstructive sleep apnea (OSA), as well as establishing a growing body of literature linking OSA with cardiovascular morbidity, mortality, metabolic dysregulation, and neurocognitive impairment. The US Institute of Medicine Committee on Sleep Medicine estimates that 50-70 million US adults have sleep or wakefulness disorders. Furthermore, the American Academy of Sleep Medicine (AASM) estimates that more than 29 million US adults suffer from moderate to severe OSA, with an estimated 80% of those individuals living unaware and undiagnosed, contributing to more than $149.6 billion in healthcare and other costs in 2015. Although various devices have been used to measure physiological signals, detect apneic events, and help treat sleep apnea, significant opportunities remain to improve the quality, efficiency, and affordability of sleep apnea care. As our understanding of respiratory and neurophysiological signals and sleep apnea physiological mechanisms continues to grow, and our ability to detect and process biomedical signals improves, novel diagnostic and treatment modalities emerge.

OBJECTIVE

This article reviews the current engineering approaches for the detection and treatment of sleep apnea.

APPROACH

It discusses signal acquisition and processing, highlights the current nonsurgical and nonpharmacological treatments, and discusses potential new therapeutic approaches.

MAIN RESULTS

This work has led to an array of validated signal and sensor modalities for acquiring, storing and viewing sleep data; a broad class of computational and signal processing approaches to detect and classify SAS disease patterns; and a set of distinctive therapeutic technologies whose use cases span the continuum of disease severity.

SIGNIFICANCE

This review provides a current perspective of the classes of tools at hand, along with a sense of their relative strengths and areas for further improvement.

Model identifies causes of nasal drying during pressurised breathing

Patients nasally breathing pressurised air frequently experience symptoms suggestive of upper airway drying. While supplementary humidification is often used for symptom relief, the cause(s) of nasal drying symptoms remains speculative. Recent investigations have found augmented air pressure affects airway surface liquid (ASL) supply and inter-nasal airflow apportionment. However the influence these two factors have on ASL hydration is unknown. The purpose of this study is to determine how ASL supply and airflow apportionment affect ASL hydration status for both ambient and pressurised air breathing conditions. This is done by modifying and adapting a nasal air-conditioning and ASL supply model. Model predictions of change in inter-nasal airflow apportionment closely follow in-vivo results and demonstrate for the first time abnormal ASL dehydration occurring during augmented pressure breathing. This work quantitatively establishes why patients nasal breathing pressurised air frequently report adverse airway drying symptoms. The findings from this investigation demonstrate that both nasal airways simultaneously experience severe ASL dehydration during pressurised breathing.

Acute impact of continuous positive airway pressure on nasal patency

BACKGROUND

Continuous airflow in the upper airway can cause discomfort, leading to nasopharyngeal complaints. The aim of the present study is to evaluate the acute effects of continuous positive upper-airway pressure on nasal patency in awake normal subjects.

METHODS

Twenty-seven adults (17 men; 10 women; age range, 18 to 43 years) were exposed to continuous airway pressure (20 cmH₂ O) in the nasal cavity, delivered by a continuous positive airway pressure (CPAP) device through a nasal mask for 2 hours. Visual analogue scale (VAS) of nasal obstruction, Nasal Obstruction Symptom Evaluation (NOSE) modified scale, acoustic rhinometry (AR), and peak nasal inspiratory flow (PF) were measured before and after the use of CPAP.

RESULTS

There was an increase in nasal obstruction scores both on the VAS (p < 0.05) and on the NOSE scale (p < 0.05), as well as a reduction in nasal cavity volume on AR (p < 0.05) and a decline in PF (p < 0.05). Subjects were stratified into 2 groups: with and without symptoms of allergic rhinitis. Nasal parameters were significantly worse in the rhinitis group, with higher nasal obstruction scores on the VAS (p = 0.001) and NOSE scale (p < 0.001) and decreased PF (p < 0.001).

CONCLUSION

Acute exposure to positive pressure via CPAP is associated with subjective and objective reductions in nasal patency. In individuals with allergic nasal symptoms, deterioration is even more severe than in patients without these symptoms.

Positive Airway Pressure Therapy for Obstructive Sleep Apnea

Positive airway pressure (PAP) is considered first-line therapy for moderate to severe obstructive sleep apnea and may also be considered for mild obstructive sleep apnea, particularly if it is symptomatic or there are concomitant cardiovascular disorders. Continuous PAP is most commonly used. Other modes, such as bilevel airway pressure, autotitrating positive airway pressure, average volume assured pressure support, and adaptive support ventilation, play important roles in the management of sleep-related breathing disorders. This article outlines the indications, description, and comfort features of each mode. Despite the proven efficacy of PAP in treating obstructive sleep apnea syndrome and its sequelae, adherence to therapy is low. Close follow-up of patients for evaluation of adherence to and effectiveness of treatment is important.

Nasal airway responses to nasal continuous positive airway pressure breathing: An in-vivo pilot study

The nasal cycle, through variation in nasal airflow partitioning, allows the upper airway to accommodate the contrasting demands of air conditioning and removal of entrapped air contaminants. The purpose of this study was to investigate the influence of nasal continuous positive airway pressure (nCPAP) breathing has on both nasal airflow partitioning and nasal geometry. Using a custom-made nasal mask, twenty healthy participants had the airflow in each naris measured during normal nasal breathing followed by nCPAP breathing. Eight participants also underwent magnetic resonance imaging (MRI) of the nasal region during spontaneous nasal breathing, and then nCPAP breathing over a range of air pressures. During nCPAP breathing, a simultaneous reduction in airflow through the patent airway together with a corresponding increase in airway flow within the congested nasal airway were observed in sixteen of the twenty participants. Nasal airflow resistance is inversely proportional to airway cross-sectional area. MRI data analysis during nCPAP breathing confirmed airway cross-sectional area reduced along the patent airway while the congested airway experienced an increase in this parameter. During awake breathing, nCPAP disturbs the normal inter-nasal airflow partitioning. This could partially explain the adverse nasal drying symptoms frequently reported by many users of this therapy.

The effects of non-invasive respiratory support on oropharyngeal temperature and humidity: a neonatal manikin study

OBJECTIVE

Heating and humidification of inspired gases is routine during neonatal non-invasive respiratory support. However, little is known about the temperature and humidity delivered to the upper airway. The International Standards Organization (ISO) specifies that for all patients with an artificial airway humidifiers should deliver ≥33 g/m(3) absolute humidity (AH). We assessed the oropharyngeal temperature and humidity during different non-invasive support modes in a neonatal manikin study.

METHODS

Six different modes of non-invasive respiratory support were applied at clinically relevant settings to a neonatal manikin, placed in a warmed and humidified neonatal incubator. Oropharyngeal temperature and relative humidity (RH) were assessed using a thermohygrometer. AH was subsequently calculated.

RESULTS

Measured temperature and RH varied between devices. Bubble and ventilator continuous positive airway pressure (CPAP) produced temperatures >34°C and AH >38 g/m(3). Variable flow CPAP resulted in lower levels of AH than bubble or ventilator CPAP, and AH decreased with higher gas flow. High-flow (HF) therapy delivered by Optiflow Junior produced higher AH with higher gas flow, whereas with Vapotherm HF the converse was true.

CONCLUSIONS

Different non-invasive devices deliver inspiratory gases of variable temperature and humidity. Most AH levels were above the ISO recommendation; however, with some HF and variable flow CPAP devices at higher gas flow this was not achieved. Clinicians should be aware of differences in the efficacy of heating and humidification when choosing modes of non-invasive respiratory support.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update

Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features.