CPAP washout prior to reevaluation polysomnography: a sleep surgeon's perspective

Heated humidified high flow nasal cannula therapy in children with obstructive sleep apnea: A randomized cross-over trial

OBJECTIVE/BACKGROUND

Moderate-to-severe obstructive sleep apnea (OSA) is highly prevalent in children with obesity and/or underlying medical complexity. The first line of therapy, adenotonsillectomy (AT), does not cure OSA in more than 50% of these children. Consequently, continuous positive airway pressure (CPAP) is the main therapeutic option but adherence is often poor. A potential alternative which may be associated with greater adherence is heated high-flow nasal cannula (HFNC) therapy; however, its efficacy in children with OSA has not been systematically investigated. The study aimed to compare the efficacy of HFNC with CPAP to treat moderate-to-severe OSA with the primary outcome measuring the change from baseline in the mean obstructive apnea/hypopnea index (OAHI).

PARTICIPANTS/METHODS

This was a single-blinded randomized, two period crossover trial conducted from March 2019 to December 2021 at a Canadian pediatric quaternary care hospital. Children aged 2-18 years with obesity and medical complexity diagnosed with moderate-to-severe OSA via overnight polysomnography and recommended CPAP therapy were included in the study. Following diagnostic polysomnography, each participant completed two further sleep studies; a HFNC titration study and a CPAP titration study (9 received HFNC first, and 9 received CPAP first) in a random 1:1 allocation order.

RESULTS

Eighteen participants with a mean ± SD age of 11.9 ± 3.8 years and OAHI 23.1 ± 21.7 events/hour completed the study. The mean [95% CI] reductions in OAHI (-19.8[-29.2, -10.5] vs. -18.8 [-28.2, -9.4] events/hour, p = 0.9), nadir oxygen saturation (7.1[2.2, 11.9] vs. 8.4[3.5, 13.2], p = 0.8), oxygen desaturation index (-11.6[-21.0, -2.3] vs. -16.0[-25.3, -6.6], p = 0.5) and sleep efficiency (3.5[-4.8, 11.8] vs. 9.2[0.9, 15.5], p = 0.2) with HFNC and CPAP therapy were comparable between conditions.

CONCLUSION

HFNC and CPAP therapy yield similar reductions in polysomnography quantified measures of OSA severity among children with obesity and medical complexities.

TRIAL REGISTRATION

NCT05354401 ClinicalTrials.gov.

Effects of sleep fragmentation and partial sleep restriction on heart rate variability during night

We developed a cross-over study design with two interventions in randomized order to compare the effects of sleep fragmentation and partial sleep restriction on cardiac autonomic tone. Twenty male subjects (40.6 ± 7.5 years old) underwent overnight polysomnography during 2 weeks, each week containing one undisturbed baseline night, one intervention night (either sleep restriction with 5 h of sleep or sleep fragmentation with awakening every hour) and two undisturbed recovery nights. Parameters of heart rate variability (HRV) were used to assess cardiac autonomic modulation during the nights. Sleep restriction showed significant higher heart rate (p = 0.018) and lower HRV-pNN50 (p = 0.012) during sleep stage N1 and lower HRV-SDNN (p = 0.009) during wakefulness compared to the respective baseline. For HR and SDNN there were recovery effects. There was no significant difference comparing fragmentation night and its baseline. Comparing both intervention nights, sleep restriction had lower HRV high frequency (HF) components in stage N1 (p = 0.018) and stage N2 (p = 0.012), lower HRV low frequency (LF) (p = 0.007) regarding the entire night and lower SDNN (p = 0.033) during WASO during sleep. Sleep restriction increases sympathetic tone and decreases vagal tone during night causing increased autonomic stress, while fragmented sleep does not affect cardiac autonomic parameters in our sample.

Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle interventions: secondary analyses of the "MIMOSA" randomized clinical trial

STUDY OBJECTIVES

Lifestyle-induced weight loss is a complementary therapeutic approach for obstructive sleep apnea (OSA). We aimed at identifying the dose-response relationship between weight loss and OSA severity improvement.

METHODS

This is a secondary analysis of a 6-month clinical trial in 180 adult, overweight/obese moderate-to-severe OSA patients. Participants were randomized to a standard care, a Mediterranean diet, or a Mediterranean lifestyle arm. All patients were prescribed with continuous positive airway pressure (CPAP), while intervention arms additionally participated in a weight-loss dietary/lifestyle intervention. Based on percent change in weight at 6 months, participants were categorized into a weight-stable/gain (WS/GG) group or 3 weight-loss groups (WLG): < 5%WLG, 5%-10%WLG, and ≥ 10%WLG. Polysomnographic data and OSA symptoms were evaluated preintervention and postintervention.

RESULTS

Respiratory events and oximetry indices improved only in patients who lost weight and improvements were proportional to the degree of weight loss. Median percent change in apnea-hypopnea index (AHI) was -11.7%, - 37.9%, and - 49.3% in the < 5%WLG, 5%-10%WLG, and ≥ 10%WLG, respectively (P < .001). Compared to the WS/GG, the age-, sex-, baseline-, and CPAP use-adjusted relative risk (95% confidence interval) of severe OSA (AHI ≥ 30 events/h) was 0.45 (0.23-0.87) in the 5%-10%WLG and 0.32 (0.17-0.64) in the ≥ 10%WLG; the risk was also lower in the ≥ 10%WLG vs the < 5%WLG (0.42 [0.22-0.82]). Insomnia and daytime sleepiness also improved more in participants exhibiting ≥ 5% weight loss.

CONCLUSIONS

Even a < 5% weight loss can reduce respiratory events, but a ≥ 5% and ideally ≥ 10% weight loss is necessary for reducing the prevalence of severe OSA.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Mediterranean Diet/Lifestyle Intervention in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT02515357; Identifier: NCT02515357.

CITATION

Georgoulis M, Yiannakouris N, Kechribari I, et al. Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle intervention: secondary analyses of the "MIMOSA" randomized clinical trial. J Clin Sleep Med. 2022;18(5):1251-1261.

Mouth Closing to Improve the Efficacy of Mandibular Advancement Devices in Sleep Apnea

RATIONALE

Mouth breathing increases upper airway collapsibility, leading to decreased efficacy of obstructive sleep apnea (OSA) treatments. We hypothesized that the use of mandibular advancement devices (MAD) increases mouth breathing and, thus, using an adhesive mouthpiece (AMT), to prevent mouth breathing, in combination with MAD can improve the treatment efficacy.

OBJECTIVES

To evaluate the efficacy of MAD + AMT in comparison to MAD alone.

METHODS

A prospective crossover pilot study was designed to test this hypothesis. Briefly, adult participants with an apnea-hypopnea index (AHI) between 10-50 events/h at the screening visit were randomized to no treatment (baseline), MAD treatment, AMT treatment, and MAD+AMT treatment. As a primary analysis, absolute AHI was compared between MAD and MAD + AMT arms. Secondary analyses included quantifying the percent change in AHI, percentage of complete (AHI < 5 events/h) and incomplete (AHI 5 - 10 events/h) responders, and the efficacy of AMT alone in comparison with other treatment arms.

RESULTS

A total 21 of participants were included. (Baseline AHI= 24.3±9.9 event/h) The median AHI (Interquartile [IQR]) in the MAD and MAD+AMT arms were 10.5 [5.4-19.6] events/h and 5.6 [2.2-11.7] events/h (p-value= 0.02), respectively. A total of 76% of individuals achieved an AHI < 10 events/h in the MAD + AMT arm vs. 43% in the MAD arm (p-value<0.01). Finally, the observed effect was similar in moderate to severe OSA (AHI ≥15 events/h) in terms of absolute reduction and treatment responders, and AMT alone did not significantly reduce the AHI compared to baseline.

CONCLUSION

Combination of an adhesive mouthpiece and MAD is a more effective therapy than MAD alone. These findings may help improve clinical decision-making in sleep apnea.

Mandibular advancement device design: A systematic review on outcomes in obstructive sleep apnea treatment

Obstructive Sleep Apnea (OSA) is often treated with Mandibular Advancement Devices (MADs). It is unclear whether particular design features are superior to others in terms of OSA alleviation. In order to facilitate clinical decision-making, this systematic review summarizes the objective and subjective outcomes of different available MAD designs. Studies comparing different MAD designs in OSA treatment were searched. After screening 1887 titles and abstracts, 20 original RCTs and six cohort studies were included. 14 articles were systematically reviewed in a meta-analysis. The decrease in AHI was significantly different between some of the MAD designs. The clinical relevance of the observed differences was however limited. Monoblock appliances performed more favorable, compared to bilateral thrust (effect size:-0.37; CI:-1.81 to 0.07). Midline traction appliances performed more favorable, compared to other designs. Custom appliances performed more favorable, compared to thermoplastic appliances (effect size:0.86; CI:-0.62 to 2.35). Furthermore, there were no clinically relevant differences between MAD designs in reduction of ESS, compliance, preference, side effects, and cost effectiveness. With respect to the included trials, presently there is not one superior custom MAD design in OSA treatment regarding the effect on AHI reduction, ESS improvement, compliance, preference, side effects, cost effectiveness, and other disease-related outcomes. We confirm custom MAD designs perform superior to thermoplastic MAD designs.

The role of long-term continuous positive airway pressure in the progression of obstructive sleep apnoea: A longitudinal cohort study

Recent evidence suggests that short-term obstructive sleep apnea (OSA) treatment could affect OSA pathogenesis such as ventilatory control. The aim of our present study was to identify the impact of long-term treatment on the change in pathogenesis and natural progression of OSA. In a longitudinal analysis of a non-obese cohort study, patients with OSA treated with either continuous positive airway pressure (CPAP) or an oral appliance (OA), interrupted their treatment for 1 week and underwent a polysomnography (PSG) off treatment that was compared with their initial PSG taken 5 years before treatment initiation. In all, 154 consecutive patients with OSA who were treated by CPAP using an auto-titrating continuous positive airway pressure device (CPAP-APAP) (n = 112), or by OA (n = 27) or were untreated (n = 15), PSG was performed twice with a median (range) follow-up of 93 (60-176) months. Multivariate logistic regression showed that reduction of body mass index (BMI) and good treatment adherence to be significant predictors of favourable OSA progression, as represented by an improved or unchanged apnea-hypopnea index (AHI) (odds ratios were 5.14 and 2.89, respectively). Amongst the patients with an unchanged BMI and good CPAP-APAP adherence (n = 55), the improvement in AHI was significantly associated with the decrease in supine non-rapid eye movement-AHI and mixed apnoea index/apnoea index, which are generally recognised to be determinants of ventilator instability. These findings suggest that not only weight but also treatment adherence are determinants in the natural progression of OSA severity.

The effectiveness of a weight-loss Mediterranean diet/lifestyle intervention in the management of obstructive sleep apnea: Results of the "MIMOSA" randomized clinical trial

BACKGROUND & AIMS

Although continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA), lifestyle interventions have also emerged as complementary therapeutic choices. We aimed to explore whether the addition of a weight-loss Mediterranean diet/lifestyle intervention to OSA standard care, i.e. CPAP prescription and brief written healthy lifestyle advice, has an incremental effect on improving OSA severity, over the effect of standard care alone.

METHODS

We designed a parallel, randomized, controlled, superiority clinical trial. Eligible participants were adult, overweight men and women, diagnosed with moderate-to-severe OSA [apnea-hypopnea index (AHI)≥ 15 events/h] through an attended overnight polysomnography. Participants were blindly randomized to a standard care group (SCG, n = 65), a Mediterranean diet group (MDG, n = 62) or a Mediterranean lifestyle group (MLG, n = 60). All three study groups were prescribed with CPAP. The SCG additionally received written healthy lifestyle advice, while intervention arms were subjected to a 6-month behavioral intervention aiming at weight loss and increasing adherence to the Mediterranean diet. The MLG also received counselling on physical activity and sleep habits. Polysomnographic data and OSA symptoms were evaluated pre- and post-intervention.

RESULTS

A total of 187 OSA patients were recruited. Seven patients were excluded post-randomization and 53/180 (29%) were lost to follow-up. No harms from the interventions applied were reported. According to intention-to-treat analysis (n = 180), mean (95% confidence interval) AHI change was -4.2 (-7.4, -1.0) for the SCG, -24.7 (-30.4, -19.1) for the MDG and -27.3 (-33.9, -20.6) for the MLG. Post-intervention age-, sex-, baseline- and CPAP use-adjusted AHI was significantly lower in the MDG and the MLG compared to the SCG (mean difference: -18.0, and -21.2, respectively, both P < 0.001), and the differences remained significant after further adjustment for body-weight change (P = 0.004 and 0.008, respectively). Other respiratory event indices, daytime sleepiness and insomnia were also significantly lower in both intervention arms compared to the SCG (all P < 0.05). The MLG only presented higher percent rapid-eye-movement sleep and lower daytime sleepiness compared to the MDG (both P < 0.05). Results were similar in the per-protocol analysis (n = 127).

CONCLUSIONS

A dietary/lifestyle intervention on top of standard care leads to greater improvements in OSA severity and symptomatology compared to standard care alone. Benefits are evident regardless of CPAP use and weight loss.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02515357, https://clinicaltrials.gov/ct2/show/NCT02515357.

The Course of Obstructive Sleep Apnea Syndrome in Patients With Acromegaly During Treatment

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is common in active acromegaly and negatively influences quality of life, morbidity, and mortality. This prospective study with 3 predetermined timepoints and a standardized treatment protocol investigates changes in sleep parameters during the first 2.5 years of acromegaly treatment.

METHODS

Before initiation of acromegaly treatment (medical pretreatment followed by surgery), polysomnography (PSG) was performed in 27 consecutive patients with treatment-naive acromegaly. PSG was repeated after 1 year (N = 24) and 2.5 years (N = 23), and anthropometric and biochemical parameters were obtained.

RESULTS

At baseline, 74.1% of the patients was diagnosed with OSAS. The respiratory disturbance index (RDI; P = 0.001), oxygen desaturation index (ODI; P = 0.001), lowest oxygen saturation (LSaO2; P = 0.007) and the Epworth Sleepiness Scale (ESS; P < 0.001) improved significantly during treatment, with the greatest improvement in the first year. After 2.5 years of treatment, all patients had controlled acromegaly. Of the 16 patients with repeated PSG and OSAS at baseline, 11 (68.8%) were cured of OSAS. Changes in RDI, ODI, LSaO2, and ESS correlated with insulin-like growth factor 1 levels.

CONCLUSION

OSAS has a high prevalence in active acromegaly. There is a substantial decrease in prevalence and severity of OSAS following acromegaly treatment, with the largest improvement during the first year. Most patients recover from OSAS following surgical or biochemical control of the acromegaly. Therefore, a PSG is advised after diagnosis of acromegaly. When OSAS is present, it should be treated and PSG should be repeated during acromegaly treatment.

Randomized crossover study of tongue-retaining device and positive airway pressure for obstructive sleep apnea

PURPOSE

To compare the efficacy of tongue-retaining device (TRD) versus continuous positive airway pressure (CPAP) for treatment of obstructive sleep apnea (OSA).

STUDY DESIGN

Randomized crossover study.

SUBJECTS AND METHODS

Thirty-six patients with a mean age of 52.7 ± 10.6 years were enrolled. Inclusion criteria were age ≥ 18 years, apnea-hypopnea index (AHI) ≥ 5 events/h, and minimum oxygen saturation (SO₂) ≥ 70% from polysomnography (PSG). Exclusion criteria were severe periodontal disease, unstable cardiopulmonary or neurological diseases, and/or total sleep time < 2 h. A 1-week wash-in period was followed by questionnaires and randomization into two groups: TRD/CPAP and CPAP/TRD (18 patients each). After 3 weeks of intervention, questionnaires were re-administered and WatchPAT was performed. After a 1-week wash-out period, patients were switched to the other treatment. Primary outcome was AHI. Secondary outcomes were SO₂, Functional Outcomes of Sleep Questionnaire (FOSQ), and Epworth Sleepiness Scale (ESS) scores, treatment side effects, and adherence.

RESULTS

Nine patients withdrew, so 27 patients were included in the final analysis. Mean AHI decreased from 38.7 ± 24.0 to 2.5 ± 0.5 and 12.7 ± 2.6 events/h for CPAP and TRD, respectively (95% confidence interval of mean differences 4.65-15.62; p < 0.001). There was no significant difference in ESS and FOSQ scores between treatments. Common adverse effects were drooling, tongue numbness, and pain for TRD; and nasal blockage, mask compression, and difficult portability for CPAP.

CONCLUSIONS

CPAP was superior to TRD for resolving PSG parameters; however, both similarly improved QOL and daytime sleepiness. TRD might be considered a short-term alternative treatment for OSA.

TRIAL REGISTRATION

NCT02788487.

Therapeutic CPAP Level Predicts Upper Airway Collapsibility in Patients With Obstructive Sleep Apnea

Study Objectives

Upper airway collapsibility is a key determinant of obstructive sleep apnea (OSA) which can influence the efficacy of certain non-continuous positive airway pressure (CPAP) treatments for OSA. However, there is no simple way to measure this variable clinically. The present study aimed to develop a clinically implementable tool to evaluate the collapsibility of a patient's upper airway.

Methods

Collapsibility, as characterized by the passive pharyngeal critical closing pressure (Pcrit), was measured in 46 patients with OSA. Associations were investigated between Pcrit and data extracted from patient history and routine polysomnography, including CPAP titration.

Results

Therapeutic CPAP level, demonstrated the strongest relationship to Pcrit (r2=0.51, p < .001) of all the variables investigated including apnea-hypopnea index, body mass index, sex, and age. Patients with a mildly collapsible upper airway (Pcrit ≤ -2 cmH2O) had a lower therapeutic CPAP level (6.2 ± 0.6 vs. 10.3 ± 0.4 cmH2O, p < .001) compared to patients with more severe collapsibility (Pcrit > -2 cmH2O). A therapeutic CPAP level ≤8.0 cmH2O was sensitive (89%) and specific (84%) for detecting a mildly collapsible upper airway. When applied to the independent validation data set (n = 74), this threshold maintained high specificity (91%) but reduced sensitivity (75%).

Conclusions

Our data demonstrate that a patient's therapeutic CPAP requirement shares a strong predictive relationship with their Pcrit and may be used to accurately differentiate OSA patients with mild airway collapsibility from those with moderate-to-severe collapsibility. Although this relationship needs to be confirmed prospectively, our findings may provide clinicians with better understanding of an individual patient's OSA phenotype, which ultimately could assist in determining which patients are most likely to respond to non-CPAP therapies.

Development of a Clinical Pathway and Technical Aspects of Upper Airway Stimulation Therapy for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common disease with high morbidity and related mortality. Narrowing and collapse of the pharyngeal airway during sleep characterize the disease, resulting in a decrease (hypopnea) or a complete cessation (apnea) of oronasal airflow. Upper airway stimulation (UAS), using electrical neurostimulation of the hypoglossal nerve (n. XII) synchronized with ventilation, is a novel, evolving treatment option. UAS was found to be an effective treatment in CPAP-intolerant patients. The treatment success is partly due to the strict selection of the patients, based on previous findings. Furthermore, post-operative follow-up is needed in order to maintain or improve treatment outcome. Therefore, a clinical pathway, which provides structure and standardization, is crucial. In this paper, the aim is to discuss the technical aspects of UAS therapy and to describe a clinical pathway to organize the care process of UAS for OSA in a structured and standardized way.

Evaluation of Continuous Negative External Pressure (cNEP) for the Treatment of Obstructive Sleep Apnea: A Pilot Study

STUDY OBJECTIVES

To determine if the application of continuous negative external pressure (cNEP) is effective and safe in individuals with obstructive sleep apnea (OSA) during an overnight in-laboratory sleep study.

METHODS

A prospective, open-label pilot study in subjects with documented OSA recruited from the patient population at one sleep clinic. The intervention was application and titration of cNEP during overnight polysomnography.

RESULTS

Of the 15 subjects studied (mean apnea-hypopnea index [AHI] at baseline, 43.9 events/h), 13 (87%) were responders to cNEP: 9 had an excellent response (AHI < 5 events/h) and 4 had a partial response (AHI < 50% baseline and < 15 events/h). Three minor, self-limited adverse events occurred, which appeared related to contact pressure of the cNEP device on the skin.

CONCLUSIONS

In this pilot study, cNEP appears to be safe and effective during short-term use in subjects with OSA. Further studies are warranted.

Pre-operative screening for obstructive sleep apnoea

Sleep disordered breathing, especially obstructive sleep apnoea (OSA), has a high and increasing prevalence. Depending on the apnoea and hypopnoea scoring criteria used, and depending on the sex and age of the subjects investigated, prevalence varies between 3% and 49% of the general population. These varying prevalences need to be reflected when considering screening for OSA. OSA is a cardiovascular risk factor and patients are at risk when undergoing medical interventions such as surgery. Screening for OSA before anaesthesia and surgical interventions is increasingly considered. Therefore, methods for screening and the rationale for screening for OSA are reviewed in this study.

Long-term efficacy of an oral appliance in early treated patients with obstructive sleep apnea

PURPOSE

The purpose of the present study was to evaluate the long-term efficacy of oral appliances (OAs) in early treated patients with obstructive sleep apnea (OSA).

METHOD AND PATIENTS

Polysomnographic sleep recordings without and with an OA were performed at treatment start and in patients who had been continuously treated with OAs for at least 15 years.

RESULTS

Nine patients (eight men) with a median age of 68.1 years (interquartile range (IQR) 60.0 to 76.3 years) and a median treatment time of 16.5 years (IQR 16.3 to 18.0 years) were included. The apnea-hypopnea index decreased from a median of 17.3 (IQR 9.7 to 26.5) to 7.2 (IQR 4.0 to 9.6; p = 0.03) at the short-term follow-up. After long-term use, the apnea-hypopnea index was 32.4 (IQR 22.2 to 58.8) without the device and 35.1 (IQR 13.6 to 46.2) with it (p = 0.08). There were increases in the apnea-hypopnea index, both without the device (p = 0.02) and with it (p = 0.008). The degree of mandibular advancement did not differ between the two study occasions (p = 1.0).

CONCLUSIONS

Patients treated with oral appliances may experience deteriorations in disease severity and treatment efficacy during continuous long-term OA treatment. Regular follow-up schedules with renewed sleep apnea recordings should be considered for these patients in order to avoid suboptimal or a total loss of effects on sleep apneas.

Comparison of effects of OSA treatment by MAD and by CPAP on cardiac autonomic function during daytime

PURPOSE

The present study compared the effects of mandibular advancement therapy (MAD) with continuous positive airway pressure therapy (CPAP) on daytime cardiac autonomic modulation in a wide range of obstructive sleep apnea (OSA) patients under controlled conditions in a randomized, two-period crossover trial.

METHODS

Forty OSA patients underwent treatment with MAD and with CPAP for 12 weeks each. At baseline and after each treatment period, patients were assessed by polysomnography as well as by a daytime cardiac autonomic function test that measured heart rate variability (HRV), continuous blood pressure (BP), and baroreceptor sensitivity (BRS) under conditions of spontaneous breathing, with breathing at 6, 12, and 15/min.

RESULTS

Both CPAP and MAD therapy substantially eliminated apneas and hypopneas. CPAP had a greater effect. During daytime with all four conditions of controlled breathing, three-minute mean values of continuous diastolic BP were significantly reduced for both MAD and CPAP therapy. At the same time, selective increases due to therapy with MAD were found for HRV high frequency (HF) values. No changes were observed for BRS in either therapy mode.

CONCLUSIONS

These findings indicate that both MAD and CPAP result in similar beneficial changes in cardiac autonomic function during daytime, especially in blood pressure. CPAP is more effective than MAD in eliminating respiratory events.