Building a home ventilation programme: population, equipment, delivery and cost.

Home mechanical ventilation (HMV) improves quality of life and survival in patients with neuromuscular disorders (NMD). Developing countries may benefit from published evidence regarding the prevalence, cost of equipment, technical issues and organisation of HMV in NMD, facilitating the development of local turn-key HMV programmes. Unfortunately, such evidence is scattered in the existing literature. We searched Medline for publications in English and French from 2005 to 2020. This narrative review analyses 24 international programmes of HMV. The estimated prevalence (min-max) of HMV is ±7.3/100 000 population (1.2-47), all disorders combined. The prevalence of HMV is associated with the gross domestic product per capita in these 24 countries. The prevalence of NMD is about 30/100 000 population, of which ±10% would use HMV. Nocturnal (8/24 hour), discontinuous (8-16/24 hours) and continuous (>16/24 hours) ventilation is likely to concern about 60%, 20% and 20% of NMD patients using HMV. A minimal budget of about 168€/patient/year (504€/100 000 population), including the cost of equipment solely, should address the cost of HMV equipment in low-income countries. When services and maintenance are included, the budget can drastically increase up to between 3232 and 5760€/patient/year. Emerging programmes of HMV in developing countries reveal the positive impact of international cooperation. Today, at least 12 new middle, and low-income countries are developing HMV programmes. This review with updated data on prevalence, technical issues, cost of equipment and services for HMV should trigger objective dialogues between the stakeholders (patient associations, healthcare professionals and politicians); potentially leading to the production of workable strategies for the development of HMV in patients with NMD living in developing countries.

Did COVID-19 impact Positive Airway Pressure adherence in 2020? A cross-sectional study of 8477 patients with sleep apnea.

BACKGROUND: Whether the COVID-19 pandemic impacts Positive Airway Pressure (PAP) adherence over the long-term is unknown and only preliminary short-term data have been reported. METHODS: With the aim of describing the impact of the first and second waves of COVID-19 on PAP adherence during 2020 in France, we designed a cross-sectional study of Sleep-Apnea (SA)-patients under PAP telemonitoring. To examine PAP adherence in adult SA patients, we assessed de-identified data from a non-profit healthcare provider database during the period January 1, 2019 to December 31, 2020. Included patients met the following criteria: (i) PAP-treated for at least 4 months before January 1, 2019 and with continuous PAP during both 2019 and 2020; (ii) ≥ 360 daily PAP telemonitored data per year. For PAP adherence, data were collected using the PAP-software. RESULTS: 8477/10482 patients were finally included in the analysis [72.4% male, median age 70 years (IQ25-75: 61-77], 25.6% < 62 years old, initial Apnea-Hypopnea Index (AHI) of 41 (31-59)/h. Median PAP adherence was 7.21 (6.12-8.10) h/day in 2020 versus 7.12 (6.05-8.02) h/day in 2019, p < 0.001. The median difference in PAP adherence between the first 2020 lockdown and the corresponding 2019 weeks was 9.75 (CI95% 8.75-10.75) min/day, p < 0.001. The median difference in PAP adherence between the second 2020 lockdown and the corresponding 2019 weeks was 5.00 (CI95% 4.00-6.00) min/day, p < 0.001. If we consider the minimal clinically important difference of 30 min for PAP adherence, 30.4% and 26% of the patients increased their PAP adherence by at least 30 min during the first and second lockdowns respectively; 17.6% and 19.3% of the patients lowered their PAP adherence by at least 30 min in the first and second lockdowns, respectively. CONCLUSION: During the first and second lockdowns, the COVID-19 pandemic had a clinically irrelevant effect on PAP adherence for the study population. Future studies are needed to describe COVID-19 pandemic impact on PAP adherence not only for long-term PAP-treated SA patients but also for incident cases. Trial registration The COVADENE study was registered on March 1st, 2021 on ClinicalTrials.gov (Identifier: NCT04775966).

The effect of tongue elevation muscle training in patients with obstructive sleep apnea: A randomised controlled trial.

BACKGROUND: Oropharyngeal myofunctional therapy is a multi-component therapy effective to reduce the severity of obstructive sleep apnoea (OSA). However, existing protocols are difficult to replicate in the clinical setting. There is a need to isolate the specific effectiveness of each component of the therapy. OBJECTIVE: To assess the effects of a 6 weeks tongue elevation training programme in patients with OSA. METHODS: We conducted a multicentre randomised controlled trial. Eligible participants were adults diagnosed with moderate OSA who presented low adherence to continuous positive airway pressure therapy (mean use <4 h per night). The intervention group completed a 6 weeks tongue elevation training protocol that consisted in anterior tongue elevation strength and endurance tasks with the Iowa Oral Performance Instrument. The control group completed a 6 weeks sham training protocol that involved expiratory muscle training at very low intensity. Polygraphy data, tongue force and endurance, and OSA symptoms were evaluated pre- and post-intervention. The primary outcome was apneoa-hypopnea index (AHI). RESULTS: Twenty-seven patients (55 ± 11 years) were recruited. According to modified intention-to-treat analysis (n = 25), changes in AHI and c did not significantly differ between groups. Daytime sleepiness (Epworth Sleepiness Scale) and tongue endurance significantly improved in the intervention group compared to the control group (p = .015 and .022, respectively). In the intervention group, 75% of participants had a decrease in daytime sleepiness that exceeded the minimal clinically important difference. CONCLUSION: Six weeks of tongue elevation muscle training had no effect on OSA severity.

Nasal versus oronasal masks for home non-invasive ventilation in patients with chronic hypercapnia: a systematic review and individual participant data meta-analysis.

BACKGROUND: The optimal interface for the delivery of home non-invasive ventilation (NIV) to treat chronic respiratory failure has not yet been determined. The aim of this individual participant data (IPD) meta-analysis was to compare the effect of nasal and oronasal masks on treatment efficacy and adherence in patients with COPD and obesity hypoventilation syndrome (OHS). METHODS: We searched Medline and Cochrane Central Register of Controlled Trials for prospective randomised controlled trials (RCTs) of at least 1 month's duration, published between January 1994 and April 2019, that assessed NIV efficacy in patients with OHS and COPD. The main outcomes were diurnal PaCO2, PaO2 and NIV adherence (PROSPERO CRD42019132398). FINDINGS: Of 1576 articles identified, 34 RCTs met the inclusion criteria and IPD were obtained for 18. Ten RCTs were excluded because only one type of mask was used, or mask data were missing. Data from 8 RCTs, including 290 IPD, underwent meta-analysis. Oronasal masks were used in 86% of cases. There were no differences between oronasal and nasal masks for PaCO2 (0.61 mm Hg (95% CI -2.15 to 3.38); p=0.68), PaO2 (-0.00 mm Hg (95% CI -4.59 to 4.58); p=1) or NIV adherence (0·29 hour/day (95% CI -0.74 to 1.32); p=0.58). There was no interaction between the underlying pathology and the effect of mask type on any outcome. INTERPRETATION: Oronasal masks are the most used interface for the delivery of home NIV in patients with OHS and COPD; however, there is no difference in the efficacy or tolerance of oronasal or nasal masks.

Mask side-effects in long-term CPAP-patients impact adherence and sleepiness: the InterfaceVent real-life study.

BACKGROUND: For some patients, Continuous Positive Airway Pressure (CPAP) remains an uncomfortable therapy despite the constant development of technological innovations. To date, no real life study has investigated the relationship between mask related side-effects (MRSEs) and CPAP-non-adherence (defined as < 4 h/day) or residual-excessive-sleepiness (RES, Epworth-Sleepiness-Scale (ESS) score ≥ 11) in the long-term. METHODS: The InterfaceVent-CPAP study is a prospective real-life cross-sectional study conducted in an apneic adult cohort undergoing at least 3 months of CPAP with unrestricted mask-access (34 different masks). MRSEs were evaluated using visual-analogue-scales, CPAP-data using CPAP-software, sleepiness using ESS. RESULTS: 1484 patients were included in the analysis (72.2% male, median age 67 years (IQ25-75: 60-74), initial Apnea-Hypopnea-Index (AHI) of 39 (31-56)/h, residual AHIflow was 1.9 (0.9-4) events/h), CPAP-treatment lasted 4.4 (2.0-9.7) years, CPAP-usage was 6.8 (5.5-7.8) h/day, the prevalence of CPAP-non-adherence was 8.6%, and the prevalence of RES was 16.17%. Leak-related side-effects were the most prevalent side-effects (patient-reported leaks concerned 75.4% of responders and had no correlation with CPAP-reported-leaks). Multivariable logistic regression analyses evaluating explanatory-variable (demographic data, device/mask data and MRSEs) effects on variables-of-interest (CPAP-non-adherence and RES), indicated for patient-MRSEs significant associations between: (i) CPAP-non-adherence and dry-mouth (p = 0.004); (ii) RES and patient-reported leaks (p = 0.007), noisy mask (p < 0.001), dry nose (p < 0.001) and harness pain (p = 0.043). CONCLUSION: In long-term CPAP-treated patients, leak-related side-effects remain the most prevalent side-effects, but patient-reported leaks cannot be predicted by CPAP-reported-leaks. Patient-MRSEs can be independently associated with CPAP-non-adherence and RES, thus implying a complementary role for MRSE questionnaires alongside CPAP-device-reported-data for patient monitoring. Trial registration InterfaceVent is registered with ClinicalTrials.gov (NCT03013283).

Energy conservation technique improves dyspnoea when patients with severe COPD climb stairs: a randomised crossover study.

In this randomised, crossover trial, 22 patients with severe chronic obstructive pulmonary disease climbed six flights of stairs (108 steps) twice, under two test conditions: (1) energy conservation technique (ECT): participants were asked to rest for at least 5 seconds every three steps and (2) control condition: participants climbed the stairs at their own pace. Significant lower dyspnoea (primary outcome), leg discomfort, minute ventilation and capillary blood lactate under the ECT condition were found, with no change in total task time. CLINICAL TRIAL REGISTRATION: NCT03564028.

Partial failure of CPAP treatment for sleep apnoea: Analysis of the French national sleep database.

BACKGROUND AND OBJECTIVE: Continuous positive airway pressure (CPAP) is the first-line therapy for obstructive sleep apnoea (OSA). Residual apnoea and/or hypopnoea events, that is an apnoea-hypopnoea index (AHI) > 5, during CPAP contribute to treatment drop-out. The clinical scenarios triggering residual events during CPAP use are poorly described. Underlying co-morbidities, especially cardiovascular diseases, lifestyle factors, OSA characteristics at diagnosis and type of mask have been suggested as potential contributors. METHODS: Patients from the prospective French sleep apnoea registry diagnosed with OSA (AHI ≥ 15 events/h) treated with CPAP were included. Logistic regression analysis identified factors associated with a risk of residual AHI > 5 events/h on CPAP. RESULTS: The 12 285 OSA patients were predominantly men (n = 8715, 70.9%), middle-aged (58.2 (49.8; 66.1) years) and obese (median body mass index: 31.3 (27.7; 35.6) kg/m2 ). Most had an AHI ≤ 5 events/h (n = 9573, 77.9%) versus 22.1% with AHI > 5/h. The latter were less CPAP adherent (5.75 (4.01; 7.00) vs 6.00 (4.53; 7.00) h/night). In multivariable analysis, factors associated with residual AHI >5/h were male sex, age, sedentary lifestyle, OSA severity, cardiovascular co-morbidities (heart failure and arrhythmia) and type of interface (orofacial mask versus nasal mask: OR = 2.15 (95%CI: 1.95; 2.37)). A subgroup analysis found that patients using pressures above 10 cm H2 O were 1.43 (95% CI: 1.3; 1.57) times more likely to have residual AHI > 5/h. CONCLUSION: Knowing about risk factors for residual apnoeic-hypopnoeic events may assist in the timely provision of personalized care including the type of PAP therapy, attention to co-morbidities and choice of interface.

Is the 2013 American Thoracic Society CPAP-tracking system algorithm useful for managing non-adherence in long-term CPAP-treated patients?

BACKGROUND: Whereas telemedicine usage is growing, the only clinical algorithm for Continuous Positive Airway Pressure (CPAP) adherence management is that stipulated by the 2013 American Thoracic Society (ATS). The capacity of the latter to predict non-adherence in long-term CPAP-treated patients has not been validated. METHODS: Patients from the prospective real-life InterfaceVent study (NCT03013283, study conducted in an adult cohort undergoing at least 3 months of CPAP) and eligible for ATS algorithm usage were analysed. The residual device Apnea-Hypopnea-Index (AHIflow) and High Large Leak (HLL) thresholds proposed in the ATS algorithm were evaluated for predicting adherence (i.e. AHIflow > 10/h, HLLs 95th > 24 L/min for ResMed® devices and ResMed® nasal mask, HLLs 95th > 36 l/min for ResMed® devices and ResMed® oronasal masks, HLLs > 1 h for Philips® devices and HHLs > 60 l/min for Fisher & Paykel® devices). Adherence was defined according to the 2013 ATS algorithm (i.e. CPAP use > 4 h/j for at least 70% of days). RESULTS: 650/1484 patients eligible for ATS algorithm usage were analysed (15.38% non-adherent, 74% male with a median (IQ25-75) age of 68 (61-77) years, a body mass index of 30.8 (27.7-34.5) kg/m2, an initial AHI of 39 (31-55) events/h, and CPAP-treatment-duration of 5.1 (2.2-7.8) years). Logistic regression analysis demonstrated no significant relationship between the ATS proposed AHIflow or HLL thresholds and non-adherence. Complementary ROC curve analysis failed to determine satisfactory AHIflow and HLL thresholds. CONCLUSION: When managing non-adherence in long-term CPAP-treated patients, our data do not validate absolute AHIflow or HLL thresholds in general. TRIAL REGISTRATION: The INTERFACE-VENT study is registered on ClinicalTrials.gov (Identifier: study ( NCT03013283 ).

Technological advances in home non-invasive ventilation monitoring: Reliability of data and effect on patient outcomes.

Home non-invasive mechanical ventilation (NIV) has become a well-established treatment for patients with chronic hypercapnic respiratory failure. NIV monitoring has been developed to evaluate the effectiveness of mechanical ventilation on patient outcomes, with built-in systems providing data on compliance, leaks and respiratory parameters. Although these data seem intuitively useful, two main concerns have been raised in the literature: (i) are they reliable and (ii) to what extent does their use improve patient outcomes. These two concerns are currently relevant since the very recent development of telemonitoring provides the possibility of adjusting ventilator settings remotely, based on the longitudinal assessment of NIV parameters and respiratory variables provided by the system. This may influence the future management strategies of health organizations for patients under home NIV. This narrative review describes technological advances in patient monitoring using home mechanical ventilation with a main focus on data provided by built-in NIV monitoring systems. The use of these systems is discussed, including their advantages and limitations in different clinical situations, and perspectives for long-term patient monitoring are discussed.

Nasal high flow does not improve exercise tolerance in COPD patients recovering from acute exacerbation: A randomized crossover study.

BACKGROUND AND OBJECTIVE: We hypothesized that by reducing respiratory work and improving gas exchange, nasal high flow (NHF) would improve exercise tolerance in patients with chronic obstructive pulmonary disease (COPD) following respiratory exacerbation. METHODS: This was a monocentric, randomized, controlled crossover study. Patients with severe to very severe COPD carried out two high-intensity constant work-rate exercise tests (CWRET) with and without NHF on two consecutive days. The primary outcome was the mean difference in endurance time between both conditions. The secondary aims included vastus lateralis oxygenation (StO2 ), dyspnoea, leg discomfort, maximal inspiratory pressure (MIP), transcutaneous CO2 pressure (PtcCO2 ), respiratory rate (RR), heart rate (HR) and pulsed O2 saturation (SpO2 ), as well as the patients' opinions of the device. RESULTS: A total of 19 patients were included (mean forced expiratory volume in 1 s = 28.7 ± 10.8%, age = 62.1 ± 9.1 years). No significant differences in endurance time during the CWRET were found between the two test conditions (-66.58 (95% CI: -155.9 to 22.7) s, P = 0.12). StO2 , PtCO2 and HR were reduced at the end of the exercise with NHF (-2.1% (95% CI: -4.3 to -0.0); -1.3 mm Hg (95% CI: -2.5 to -0.2); -2.7 bpm (95% CI: -5.0 to -0.5), respectively, P ≤ 0.05). No significant differences were found for any of the other secondary outcomes. Half of the patients evaluated the device as being moderately to very uncomfortable. CONCLUSION: NHF during exercise did not increase endurance time in patients with COPD following exacerbation. CLINICAL TRIAL REGISTRATION: NCT03058081 at clinicaltrials.gov.

Adherence to CPAP with a nasal mask combined with mandibular advancement device versus an oronasal mask: a randomized crossover trial.

PURPOSE: Evidence for the management of CPAP-treated obstructive sleep apnea suggests that oronasal masks reduce mouth leaks at the expense of higher pressures and poorer adherence. Some authors have proposed the use of mandibular advancement devices in combination with nasal masks to address this. The aim of this study was to assess adherence to CPAP after 1 month's use of a nasal mask with a mandibular advancement device and to compare adherence with an oronasal mask. METHODS: A randomized crossover trial design to assess whether a mandibular advancement device combined with a nasal mask would improve CPAP adherence compared to an oronasal mask. RESULTS: There was no improvement in CPAP adherence and self-reported interface-related pain was significantly higher with the combined treatment. CONCLUSIONS: Although the combined treatment reduced pressures, likely by improving upper airway patency, it may only be appropriate for a small number of patients due to associated discomfort. TRIAL REGISTRATION: NCT01889472.

Contribution of obstructive sleep apnoea to arterial stiffness: a meta-analysis using individual patient data.

BACKGROUND: Arterial stiffness, measured by pulse wave velocity (PWV), is a strong independent predictor of late cardiovascular events and mortality. It is recognised that obstructive sleep apnoea (OSA) is associated with cardiovascular comorbidities and mortality. Although previous meta-analyses concluded that PWV is elevated in OSA, we feel that an individual patient data analysis from nine relatively homogeneous studies could help answer: to what extent does OSA drive arterial stiffness? METHODS: Individual data from well-characterised patients referred for suspicion of OSA, included in nine studies in which carotid-femoral PWV was measured using a Complior device, were merged for an individual patient data meta-analysis. RESULTS: 893 subjects were included (age: 56±11 (mean±SD), 72% men, 84% with confirmed OSA). Body Mass Index varied from 15 to 81 kg/m2 (30±7 kg/m2). PWV ranged from 5.3 to 20.5 m/s (10.4±2.3 m/s). In univariate analysis, log(PWV) was strongly related to age, gender, systolic blood pressure, presence of type 2 diabetes (all p<0.01) as well as to dyslipidaemia (p=0.03) and an Epworth Sleepiness Scale score ≥9 (p=0.04), whereas it was not related to obesity (p=0.54), a severe Apnoea-Hypopnoea Index (p=0.14), mean nocturnal saturation (p=0.33) or sleep time with oxygen saturation below 90% (p=0.47). In multivariable analysis, PWV was independently associated with age, systolic blood pressure and diabetes (all p<0.01), whereas severe OSA was not significantly associated with PWV. CONCLUSION: Our individual patient meta-analysis showed that elevated arterial stiffness in patients with OSA is driven by conventional cardiovascular risk factors rather than apnoea parameters.

Ventilatory support or respiratory muscle training as adjuncts to exercise in obese CPAP-treated patients with obstructive sleep apnoea: a randomised controlled trial.

BACKGROUND: Obstructive sleep apnoea (OSA) and obesity are interdependent chronic diseases sharing reduced exercise tolerance and high cardiovascular risk. INTERVENTION: A 3-month intervention with innovative training modalities would further improve functional capacity and cardiovascular health than usual cycle exercise training in already continuous positive airway pressure (CPAP)-treated obese patients with OSA. METHODS: Fifty three patients (35

Development and validation of a simple tool for the assessment of home noninvasive ventilation: the S3-NIV questionnaire.

Patient-centred outcomes are significantly modified by long-term home noninvasive ventilation (NIV), but a short, self-administered, specific tool for routine clinical assessment is lacking. The aim of this study was to develop and validate the S3-NIV questionnaire, a short questionnaire to measure respiratory symptoms, sleep quality and NIV-related side effects.Patients with stable disease who were under long-term home NIV were recruited from three outpatient NIV services. Questionnaire development consisted of a selection of core items for analysis, followed by item reduction, validation and test-retest reliability.338 patients completed a 22-item questionnaire. 11 items were removed because of non-scalability (n=2), redundancy (n=8) and lack of fit (n=1). The final version of the S3-NIV questionnaire consisted of 11 items covering two dimensions: "respiratory symptoms" (Cronbach's α=0.84) and "sleep & NIV-related side effects" (Cronbach's α=0.77). Convergent validity was high between the "respiratory symptoms" subscale of the S3-NIV questionnaire and the St George's Respiratory Questionnaire (rho= -0.76, p<0.001), and between the "sleep & NIV-related side effects" subscale and the Quebec Sleep Questionnaire (rho=0.51, p<0.001). The S3-NIV questionnaire had good test--retest reliability after 4 weeks (intraclass correlation coefficient=0.72).The S3-NIV questionnaire is a short, valid and repeatable self-completed tool for the routine clinical assessment of patients undergoing home NIV.

Maximal exercise capacity in patients with obstructive sleep apnoea syndrome: a systematic review and meta-analysis.

Maximal aerobic capacity is a strong health predictor and peak oxygen consumption (V'O2peak) is considered a reflection of total body health. No systematic reviews or meta-analyses to date have synthesised the existing data regarding V'O2peak in patients with obstructive sleep apnoea (OSA).A systematic review of English and French articles using PubMed/MEDLINE and Embase included studies assessing V'O2peak in OSA patients either in mL·kg-1·min-1 compared with controls or in % predicted. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence.Mean V'O2peak expressed in mL·kg-1·min-1 was significantly lower in patients with OSA than in controls (mean difference -2.7 mL·kg-1·min-1; p<0.001; n=850). This reduction in V'O2peak was found to be larger in non-obese patients (body mass index <30 kg·m-2). Mean V'O2peak % pred was 89.9% in OSA patients (n=643).OSA patients have reduced maximal aerobic capacity, which can be associated with increased cardiovascular risks and reduced survival in certain patient subgroups. Maximal exercise testing can be useful to characterise functional limitation and to evaluate health status in OSA patients.

Monitoring mandibular movements to detect Cheyne-Stokes Breathing.

BACKGROUND: The patterns of mandibular movements (MM) during sleep can be used to identify increased respiratory effort periodic large-amplitude MM (LPM), and cortical arousals associated with "sharp" large-amplitude MM (SPM). We hypothesized that Cheyne Stokes breathing (CSB) may be identified by periodic abnormal MM patterns. The present study aims to evaluate prospectively the concordance between CSB detected by periodic MM and polysomnography (PSG) as gold-standard. The present study aims to evaluate prospectively the concordance between CSB detected by periodic MM and polysomnography (PSG) as gold-standard. METHODS: In 573 consecutive patients attending an in-laboratory PSG for suspected sleep disordered breathing (SDB), MM signals were acquired using magnetometry and scored manually while blinded from the PSG signal. Data analysis aimed to verify the concordance between the CSB identified by PSG and the presence of LPM or SPM. The data were randomly divided into training and validation sets (985 5-min segments/set) and concordance was evaluated using 2 classification models. RESULTS: In PSG, 22 patients (mean age ± SD: 65.9 ± 15.0 with a sex ratio M/F of 17/5) had CSB (mean central apnea hourly indice ± SD: 17.5 ± 6.2) from a total of 573 patients with suspected SDB. When tested on independent subset, the classification of CSB based on LPM and SPM is highly accurate (Balanced-accuracy = 0.922, sensitivity = 0.922, specificity = 0.921 and error-rate = 0.078). Logistic models based odds-ratios for CSB in presence of SPM or LPM were 172.43 (95% CI: 88.23-365.04; p < 0.001) and 186.79 (95% CI: 100.48-379.93; p < 0.001), respectively. CONCLUSION: CSB in patients with sleep disordered breathing could be accurately identified by a simple magnetometer device recording mandibular movements.

Impact of concomitant medications on obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is characterized by repeated episodes of apnoea and hypopnoea during sleep. Little is known about the potential impact of therapy drugs on the underlying respiratory disorder. Any influence should be taken into account and appropriate action taken, including drug withdrawal if necessary. Here, we review drugs in terms of their possible impact on OSA; drugs which (1) may worsen OSA; (2) are unlikely to have an impact on OSA; (3) those for which data are scarce or contradictory; and (4) drugs with a potentially improving effect. The level of evidence is ranked according to three grades: A - randomized controlled trials (RCTs) with high statistical power; B - RCTs with lower power, non-randomized comparative studies and observational studies; C - retrospective studies and case reports. Our review enabled us to propose clinical recommendations. Briefly, agents worsening OSA or inducing weight gain, that must be avoided, are clearly identified. Drugs such as 'Z drugs' and sodium oxybate should be used with caution as the literature contains conflicting results. Finally, larger trials are needed to clarify the potential positive impact of certain drugs on OSA. In the meantime, some, such as diuretics or other antihypertensive medications, are helpful in reducing OSA-associated cardiovascular morbidity.

Effects of 1-month withdrawal of ventilatory support in hypercapnic myotonic dystrophy type 1.

BACKGROUND AND OBJECTIVE: The benefits of domiciliary non-invasive ventilation (NIV) in myotonic dystrophy type 1 (DM1) are unclear. We sought to determine the effects of elective discontinuation of ventilatory support for 1 month in DM1 patients receiving NIV for chronic hypercapnic respiratory failure. METHODS: At baseline, 12 patients underwent polysomnography, and assessment of subjective (Epworth Sleepiness Scale) and objective (Oxford Sleep Resistance Test) sleepiness, fatigue (Fatigue Severity Scale), respiratory function including muscle strength, arterial blood gas (ABG), hypercapnic ventilatory response (HCVR), Blood Pressure, peripheral arterial tonometry (PAT) and pulse wave velocity (PWV). They also completed the SF36. Testing was repeated (Visit 2) 1 month after elective cessation of NIV and again (Visit 3) 1 month after NIV reintroduction. RESULTS: No changes were seen in SF36, sleepiness or fatigue, respiratory function, muscle strength nor HCVR. Likewise, there were no changes in Blood Pressure, PAT or PWV. Mean nocturnal SpO2 deteriorated off NIV and improved on resumption (mean ± SD = 95.02 ± 1.90%, 92.23 ± 3.61% and 95.08 ± 2.28%, P = 0.006 change Visit 1 to Visit 2, 0.009 Visit 2 to Visit 3). Daytime PaCO2 (arterial partial pressure of carbon dioxide) was 43.13 ± 4.20 mm Hg, 46.28 ± 2.25 mm Hg and 43.87 ± 2.85 mm Hg, P = 0.056 and 0.017 over the same intervals. CONCLUSION: DM1 patients derive little benefit in symptoms or quality of life from NIV. Nocturnal and diurnal ventilatory functions deteriorate slightly off NIV for 1 month, but this does not appear to be due to changes in HCVR or respiratory function. HCVR changes may be of primary CNS origin given stability on or off NIV.

Mandibular position and movements: Suitability for diagnosis of sleep apnoea.

BACKGROUND AND OBJECTIVE: Mandibular movements (MMs) and position during sleep reflect respiratory efforts related to increases in upper airway resistance and micro-arousals. The study objective was to assess whether MM identifies sleep-disordered breathing (SDB) in patients with moderate to high pre-test probability. METHODS: This was a prospective study of 87 consecutive patients referred for an in-laboratory sleep test. Magnetometer-derived MM signals were incorporated into standard polysomnography (PSG). Respiratory events detected with MM analysis were compared with PSG for respiratory disturbance index (RDI) with a blinded scoring. All records were scored manually according to American Academy of Sleep Medicine rules. Primary outcome was to rule-in obstructive sleep apnoea syndrome (OSAS) defined as RDI cut-off value ≥5 or 15/h total sleep time (TST). RESULTS: High concordance emerged between MM and PSG-derived RDI with high temporal coincidence between events (R2 = 0.906; P < 0.001). The mean diagnostic accuracy of MM for OSAS using RDI MM cut-off values of 5.9 and 13.5 was 0.935 (0.86-0.97) and 0.913 (0.84-0.95), with a mean positive likelihood ratio (LLR+) of 3.73 (2.7-20.4) and 8.46 (2.3-31.5), respectively. Receiver operating characteristic (ROC) curves at PSG cut-off values of 5 and 15/h TST had areas under the curve (AUC) of 0.96 (95% CI: 0.89-0.99) and 0.97 (95% CI: 0.91-0.99) (P < 0.001), respectively. MM analysis accurately identified SDB at different levels of severity. CONCLUSION: RDI assessed by MM is highly concordant with PSG, suggesting a role of ambulatory MM recordings to screen for SDB in patients with moderate to high pre-test probability.