Impact of tracheostomy tube modalities on ventilatory mechanics: a bench study.

PURPOSE: Tracheostomized patients often present with muscle weakness, altered consciousness, or swallowing difficulties. Hence, the literature is scarce regarding the challenging management of tracheostomy weaning. There is a need to strengthen the understanding of respiratory mechanisms with the different tracheostomy tube modalities that compose this weaning pathway. We aimed to evaluate the impact of these modalities on the work of breathing (WOB), total positive end-expiratory pressure (PEEPtot), and tidal volume (VT). METHODS: With a three-dimensional (3D) printed head mimicking human upper airways, we added a tracheal extension, and pierced to allow insertion of a size 7.0 tracheostomy cannula. The whole was connected to an artificial lung. Three lung mechanics were simulated (normal, obstructive and restrictive). We compared five different tracheostomy tube modalities to a control scenario in which the tube was capped and the cuff was deflated. RESULTS: A marginal difference was observed on the WOB within conditions with a slight increase + 0.004 [95% CI (0.003-0.004); p < 0.001] when the cuff was inflated in the normal and restrictive models and a slight decrease in the obstructive model. The highest PEEPtot that was reached was + 1 cmH2O [95% CI (1-1.1); p < 0.001] with high-flow therapy (HFT) with the cuff inflated in the obstructive model. We observed a statistically significant reduction in VT [up to - 57 mL 95% CI (- 60 to - 54); p < 0.001] when the cuff was inflated, in both the normal and obstructive models. CONCLUSIONS: Our results support the use of conditions that involve cuff deflation. Intermediate modalities with the cuff deflated produced similar results than cannula capping.

A new physiological manikin to test and compare ventilation devices during cardiopulmonary resuscitation.

Background: There is a lack of bench systems permitting to evaluate ventilation devices in the specific context of cardiac arrest. Objectives: The objective of the study is to assess if a new physiological manikin may permit to evaluate the performances of medical devices dedicated to ventilation during cardiopulmonary resuscitation (CPR). Methods: Specific CPR-related features required to reproduce realistic ventilation were implemented into the SAM (Sarthe Anjou Mayenne) manikin. In the first place, the manikin ability to mimic ventilation during CPR was assessed and compared to real-life tracings of airway pressure, flow and capnogram from three out of hospital cardiac arrest (OHCA) patients. In addition, to illustrate the interest of this manikin, ventilation was evaluated during mechanical continuous chest compressions with two devices dedicated to CPR: the Boussignac cardiac arrest device (B-card - Vygon; Ecouen France) and the Impedance Threshold Device (ITD - Zoll; Chelmsford, MA). Results: The SAM manikin enabled precise replication of ventilation tracings as observed in three OHCA patients during CPR, and it allowed for comparison between two distinct ventilation devices. B-card generated a mean, maximum and minimum intrathoracic pressure of 6.3 (±0.1) cmH2O, 18.9 (±1.1) cmH2O and -0.3 (±0.2) cmH2O respectively; while ITD generated a mean, maximum and minimum intrathoracic pressure of -1.6 (±0.0) cmH2O, 5.7 (±0.1) cmH2O and -4.8 (±0.1) cmH2O respectively during CPR. B-card allowed to increase passive ventilation compared to the ITD which resulted in a dramatic limitation of passive ventilation. Conclusion: The SAM manikin is an innovative model integrating specific physiological features that permit to accurately evaluate and compare ventilation devices during CPR.

General nomenclature of air leak patterns: A proposal.

Leakage is a common issue with PAP therapy and may contribute to short-term non-compliance with treatment. PAP manufacturers use different methods to estimate and report air leaks (median, mean, p90, p95, % of important air leak, time spent on major leaks), which makes the analysis and comparisons challenging. Leak intensity is a well-known parameter of major importance as it can significantly affect the performance of PAP devices. However, there is a lack of knowledge regarding another leakage parameter, namely the leakage pattern. As of now, there is no standard classification for leak patterns in real-life settings. Our objective was to develop and propose a comprehensive nomenclature for leakage patterns observed during nasal auto-PAP therapy. We examined 50 ventilatory polygraphy recordings conducted with auto-PAP, based on data from a prior study in which the unintentional leak flow was precisely measured over time. We have categorized leaks into two main types: continuous leaks, which appear and persist for an extended period, and discontinuous leaks, which vanish more rapidly. Continuous leaks can have both abrupt or gradual apparitions and terminations. Their "shape" can be either interrupted or constant. Discontinuous leaks can have both abrupt or gradual apparitions and terminations. Due to the relatively short observation scale (less than 5 min minutes), this type of leakage is not characterized by a specific shape between apparition and termination. This nomenclature could be a valuable tool that facilitates comparative bench tests or clinical studies. This tool could support manufacturers in developing precise algorithms for leak compensation, residual AHI estimation and the accuracy of CPAP monitoring data. Lastly, establishing a standardized approach for describing and categorizing air leakage patterns could assist clinicians in identifying device-related issues, such as patient discomfort arising from specific types of leakage.

Effect of Intensity of Home Noninvasive Ventilation in Individuals With Neuromuscular and Chest Wall Disorders: A Systematic Review and Meta-Analysis of Individual Participant Data

Introduction: Home noninvasive ventilation (NIV), targeting a reduction of carbon dioxide with a combination of sufficient inspiratory support and backup-rate improves outcomes in patients with chronic obstructive pulmonary disease. The aim of this systematic review with individual participant data (IPD) meta-analysis was to evaluate the effects of intensity of home NIV on respiratory outcomes in individuals with slowly progressive neuromuscular (NMD) or chest-wall disorders (CWD). Methods: Controlled, non-controlled and cohort studies indexed between January-2000 and December-2020 were sought from Medline, Embase and the Cochrane Central Register. Outcomes were diurnal PaCO2, PaO2, daily NIV usage, and interface type (PROSPERO-CRD 42021245121). NIV intensity was defined according to the Z-score of the product of pressure support (or tidal volume) and backup-rate. Results: 16 eligible studies were identified; we obtained IPD for 7 studies (176 participants: 113-NMD; 63-CWD). The reduction in PaCO2 was greater with higher baseline PaCO2. NIV intensity per se was not associated with improved PaCO2 except in individuals with CWD and the most severe baseline hypercapnia. Similar results were found for PaO2. Daily NIV usage was associated with improvement in gas exchange but not with NIV intensity. No association between NIV intensity and interface type was found. Conclusion: Following home NIV initiation in NMD or CWD patients, no relationship was observed between NIV intensity and PaCO2, except in individuals with the most severe CWD. The amount of daily NIV usage, rather than intensity, is key to improving hypoventilation in this population during the first few months after introduction of therapy. (AU)

Detection of Simulated Pediatric Breathing by CPAP/Noninvasive Ventilation Devices.

BACKGROUND: Home CPAP and noninvasive ventilation (NIV) are increasingly used in children. An appropriate choice of the CPAP/NIV device, according to the manufacturer recommendations, should guarantee accurate data collection software. However, not all devices display accurate patient data. We hypothesized that the detection of patient breathing may be expressed as a minimal tidal volume (VTmin ) rather than a minimal weight. The aim of the study was to estimate the VTmin detected by home ventilators when set on CPAP. METHODS: Twelve level I-III devices were analyzed using a bench test. Pediatric profiles were simulated with increasing VT values to determine the VTmin that the ventilator may detect. The duration of CPAP use and the presence/absence of waveform tracings on the built-in software were also gathered. RESULTS: VTmin varied according to the device, ranging from 16-84 mL, independent of level category. The duration of CPAP use was underestimated in all level I devices, which were either not able to display any waveform or only intermittently, until VTmin was reached. The duration of CPAP use was overestimated for the level II and III devices, with the display of different waveforms according to the device as soon as the device was switched on. CONCLUSIONS: Based on the VTmin detected, some level I and II devices may be suitable for infants. A careful testing of the device should be done at CPAP initiation, with a review of data generated from ventilator software.

Effect of Intensity of Home Noninvasive Ventilation in Individuals With Neuromuscular and Chest Wall Disorders: A Systematic Review and Meta-Analysis of Individual Participant Data.

INTRODUCTION: Home noninvasive ventilation (NIV), targeting a reduction of carbon dioxide with a combination of sufficient inspiratory support and backup-rate improves outcomes in patients with chronic obstructive pulmonary disease. The aim of this systematic review with individual participant data (IPD) meta-analysis was to evaluate the effects of intensity of home NIV on respiratory outcomes in individuals with slowly progressive neuromuscular (NMD) or chest-wall disorders (CWD). METHODS: Controlled, non-controlled and cohort studies indexed between January-2000 and December-2020 were sought from Medline, Embase and the Cochrane Central Register. Outcomes were diurnal PaCO2, PaO2, daily NIV usage, and interface type (PROSPERO-CRD 42021245121). NIV intensity was defined according to the Z-score of the product of pressure support (or tidal volume) and backup-rate. RESULTS: 16 eligible studies were identified; we obtained IPD for 7 studies (176 participants: 113-NMD; 63-CWD). The reduction in PaCO2 was greater with higher baseline PaCO2. NIV intensity per se was not associated with improved PaCO2 except in individuals with CWD and the most severe baseline hypercapnia. Similar results were found for PaO2. Daily NIV usage was associated with improvement in gas exchange but not with NIV intensity. No association between NIV intensity and interface type was found. CONCLUSION: Following home NIV initiation in NMD or CWD patients, no relationship was observed between NIV intensity and PaCO2, except in individuals with the most severe CWD. The amount of daily NIV usage, rather than intensity, is key to improving hypoventilation in this population during the first few months after introduction of therapy.

Responses of Bilevel Ventilators to Unintentional Leak: A Bench Study.

BACKGROUND: The impact of leaks has mainly been assessed in bench models using continuous leak patterns which did not reflect real-life leakage. We aimed to assess the impact of the pattern and intensity of unintentional leakage (UL) using several respiratory models. METHODS: An active artificial lung (ASL 5000) was connected to three bilevel-ventilators set in pressure mode; the experiments were carried out with three lung mechanics (COPD, OHS and NMD) with and without upper airway obstruction. Triggering delay, work of breathing, pressure rise time, inspiratory pressure, tidal volume, cycling delay and the asynchrony index were measured at 0, 6, 24 and 36 L/min of UL. We generated continuous and inspiratory UL. RESULTS: Compared to 0 L/min of UL, triggering delays were significantly higher with 36 L/min of UL (+27 ms) and pressure rise times were longer (+71 ms). Cycling delays increased from -4 [-250-169] ms to 150 [-173-207] ms at, respectively 0 L/min and 36 L/min of UL and work of breathing increased from 0.15 [0.12-0.29] J/L to 0.19 [0.16-0.36] J/L. Inspiratory leakage pattern significantly increased triggering delays (+35 ms) and cycling delays (+263 ms) but decreased delivered pressure (-0.94 cmH2O) compared to continuous leakage pattern. Simulated upper airway obstruction significantly increased triggering delay (+199 ms), cycling delays (+371 ms), and decreased tidal volume (-407 mL) and pressure rise times (-56 ms). CONCLUSIONS: The pattern of leakage impacted more the device performances than the magnitude of the leakage per se. Flow limitation negatively reduced all ventilator performances.

Efficacy of Nasal High-Flow Oxygen Therapy in Chronic Obstructive Pulmonary Disease Patients in Long-Term Oxygen and Nocturnal Non-Invasive Ventilation during Exercise Training.

High-flow oxygen therapy (HFOT) improves gas exchange and dead space washout and reduces the level of work required for breathing. This study aimed to evaluate pulmonary rehabilitation (PR) combined with HFOT in COPD patients treated with nocturnal non-invasive ventilation (NIV) and long-term oxygen therapy (LTOT). In particular, we sought to discover whether the addition of HFOT during exercise training could improve patients' performance, mainly with regard to their Six-Minute Walking Test (6MWT) outcomes, and reduce the exacerbation rates, periods of rehospitalization or need to resort to unscheduled visits. Thirty-one COPD subjects (13 female) who used nocturnal NIV were included in a randomized controlled trial and allocated to one of two groups: the experimental group (EG), with 15 subjects, subjected to PR with HFOT; and the control group (CG), with 16 subjects, subjected to PR without HFOT. The primary outcome of the study was the observation of changes in the 6MWT. The secondary outcome of the study was related to the rate of exacerbation and hospitalization. Data were collected at baseline and after one, two and three cycles of cycle-ergometer exercise training performed in 20 supervised sessions of 40 min thrice per week, with a washout period of 3 months between each rehabilitation cycle. Statistical significance was not found for the 6MWT distance (W = 0.974; p = 0.672) at the last follow-up, but statistical significance was found for the Borg scale in regard to dyspnea (W = 2.50; p < 0.001) and fatigue (W = 2.00; p < 0.001). HFOT may offer a positive option for dyspnea-affected COPD patients in the context of LTOT and nocturnal NIV.

Nasal High-Flow Therapy during Exercise in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.

Background: Several studies have evaluated the effect of nasal high-flow (NHF) therapy to enhance exercise performance and tolerance in patients with chronic obstructive pulmonary disease (COPD); however, results are disparate. Objective: The aim of this systematic review and meta-analysis was to assess the effect of NHF therapy as an adjuvant to exercise training on functional exercise capacity in patients with COPD. Data Sources: An electronic search was performed in the following databases: PubMed, the Cochrane Central Register of Controlled Trials, the Physiotherapy Evidence Database, ScienceDirect, the Web of Science, OpenGrey, ClinicalTrials.gov, and European Respiratory Society and American Thoracic Society databases. Data Extraction: Two authors independently selected relevant randomized trials (parallel-group or crossover design), extracted data, assessed the risk of bias, and rated the quality of the evidence. Synthesis: Eleven studies were included, involving 408 participants (eight full papers and three conference abstracts). Most studies had a high risk of bias or other methodological limitations. The use of NHF therapy during a single session increased functional exercise capacity (standardized mean difference, 0.36 [95% confidence interval (CI), 0.03 to 0.69]; P = 0.03, heterogeneity [I2 = 83%]). When conference abstracts were included in the pooled analysis, the estimated effect did not change (P = 0.006). The use of NHF therapy throughout a pulmonary rehabilitation program (parallel-group randomized controlled trials) increased functional exercise capacity at 4-12 weeks compared with training without NHF therapy (standardized mean difference, 0.34 [95% CI, 0.00-0.68]; P = 0.05, heterogeneity [I2 = 18%]). Conclusions: There is very-low-quality to low-quality evidence that NHF therapy improves functional exercise capacity. Patient responses to NHF therapy were highly variable and heterogeneous, with benefits ranging from clinically trivial to worthwhile.

Protective Recommendations for Non-invasive Ventilation During COVID-19 Pandemic: A Bench Evaluation of the Effects of Instrumental Dead Space on Alveolar Ventilation.

INTRODUCTION: With the current COVID-19 pandemic, concerns have raised regarding the risk for NIV to promote airborne transmission. In case of hospital admission, continuation of therapy in patients undergoing chronic NIV is necessary and several protective circuit configurations have been recommended to reduce the risk of aerosol dissemination. However, all these configurations increase instrumental dead space. We therefore designed this study to evaluate their effects on the tidal volume (VTE) required to preserve stable end-tidal CO2 partial pressure (PETCO2) with constant respiratory rate. METHODS: A bench consisting of a test lung connected to an adult-sized mannequin head was set up. The model was ventilated through usual domiciliary configuration (single limb circuit with facial vented mask) which was used as reference. Then, five different circuit configurations including non-vented facial mask with viral/bacterial filter, modification of leak position, and change from single to double-limb circuit were evaluated. For each configuration, pressure support (PS) was gradually increased to reach reference PETCO2. Resulting VTE was recorded as primary outcome. RESULTS: Reference PETCO2 was 38(0) mmHg, with a PS set at 10 cmH2O, resulting in a VTE of 432(2) mL. Compared to reference, all the configurations evaluated required substantial increase in VTE to preserve alveolar ventilation, ranging from +79(2) to +216(1) mL. CONCLUSIONS: Modifications of NIV configurations in the context of COVID-19 pandemic result in substantial increase of instrumental dead space. Re-evaluation of treatment efficiency and settings is crucial whenever protective measures influencing NIV equipment are considered.

INTRODUCCIÓN: Durante la actual pandemia de COVID-19 ha surgido la preocupación sobre el posible riesgo de que la ventilación no invasiva (VNI) promueva la transmisión aérea. En el caso de ingreso hospitalario, es necesario continuar con el tratamiento de aquellos pacientes tratados con VNI crónica y se han recomendado varias configuraciones protectoras de los circuitos para reducir el riesgo de diseminación por aerosoles. Sin embargo, todas estas configuraciones aumentan el espacio muerto instrumental. Así, diseñamos este estudio para evaluar los efectos de estas configuraciones sobre el volumen corriente (VCE) necesario para mantener estable la presión parcial de CO2 al final del volumen corriente espirado (PETCO2) con una frecuencia respiratoria constante. MÉTODOS: Se construyó un modelo experimental que constaba de un pulmón de prueba conectado a una cabeza de maniquí de tamaño adulto. El modelo recibió ventilación utilizando la configuración domiciliaria habitual (circuito de rama única con máscara facial ventilada), lo que se utilizó como referencia. Después se evaluaron cinco configuraciones diferentes del circuito, incluidas la máscara facial sin ventilación con filtro antiviral/antibacteriano, la modificación de la posición de la fuga y el cambio de circuito de rama única a doble rama. Para cada configuración, la presión de soporte (PS) se incrementó gradualmente hasta alcanzar la PETCO2 de referencia. El VCE resultante se registró como resultado primario. RESULTADOS: La PETCO2 de referencia fue de 38(0) mmHg, con una PS fijada en 10 cmH2O, lo que resultó en un VCE de 432(2) mL. En comparación con la referencia, todas las configuraciones evaluadas requirieron un aumento sustancial del VCE para preservar la ventilación alveolar, en un rango entre +79(2) mL y +216(1) mL. CONCLUSIONES: Las modificaciones de las configuraciones de VNI en el contexto de la pandemia de COVID-19 resultan en un aumento sustancial del espacio muerto instrumental. Reevaluar la eficacia y los ajustes del tratamiento es fundamental cuando se ponen en consideración unas medidas de protección que influyen en el equipo de VNI.

Exercise intolerance in pulmonary arterial hypertension: insight into central and peripheral pathophysiological mechanisms.

Exercise intolerance is a cardinal symptom of pulmonary arterial hypertension (PAH) and strongly impacts patients' quality of life (QoL). Although central cardiopulmonary impairments limit peak oxygen consumption (V' O2peak ) in patients with PAH, several peripheral abnormalities have been described over the recent decade as key determinants in exercise intolerance, including impaired skeletal muscle (SKM) morphology, convective O2 transport, capillarity and metabolism indicating that peripheral abnormalities play a greater role in limiting exercise capacity than previously thought. More recently, cerebrovascular alterations potentially contributing to exercise intolerance in patients with PAH were also documented. Currently, only cardiopulmonary rehabilitation has been shown to efficiently improve the peripheral components of exercise intolerance in patients with PAH. However, more extensive studies are needed to identify targeted interventions that would ultimately improve patients' exercise tolerance and QoL. The present review offers a broad and comprehensive analysis of the present literature about the complex mechanisms and their interactions limiting exercise in patients and suggests several gaps in knowledge that need to be addressed in the future for a better understanding of exercise intolerance in patients with PAH.

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.

Impact of Interface Type on Noninvasive Ventilation Efficacy in Patients With Neuromuscular Disease: A Randomized Cross-Over Trial / Impacto del tipo de mascarilla en la eficacia de la ventilación no invasiva en pacientes con enfermedad neuromuscular: un ensayo clínico aleatorizado cruzado

Background and objective: Around 25% of patients with neuro-muscular diseases (NMD) are treated by home noninvasive ventilation (NIV) through an oronasal mask. However, there is growing evidence that nasal masks require lower NIV pressures and result in fewer residual obstructive events. We hypothesized that nasal masks would improve efficacy and reduce side effects compared to oronasal masks in this population.Methods: open label, cross-over, randomized, study in 2 tertiary care hospitals. Patients with NMD treated by home NIV were randomized for one-week periods to nasal and oronasal interfaces respectively (cross-over). At the end of each period, nocturnal polygraphy (monitoring mouth opening) under NIV, synchronized with transcutaneous partial pressure in CO2 (tcCO2) was performed. Data were collected from the NIV built-in software and NIV side-effects were collected. Intention-to-treat and per protocol analyses were performed. The primary outcome was mean nocturnal SpO2. The secondary outcomes were: percentage of sleep with SpO2<90%, oxygen desaturation index (ODI), mean tcCO2, mean duration of mouth opening during sleep, level of non-intentional leaks and side-effects.Results: Thirty patients with NMD were included. There were no between-group differences for either the primary or secondary outcomes. Post hoc comparisons showed that changing between interfaces reduced NIV efficacy: mean nocturnal SpO2 (p=0.04), ODI (p=0.01), mean tcCO2 (p=0.048), side-effects (p=0.008). (AU)

Antecedentes y objetivo: Alrededor del 25% de los pacientes con enfermedades neuromusculares (ENM) son tratados mediante ventilación no invasiva (VNI) a través de una máscara oronasal. Sin embargo, existen crecientes indicios de que las máscaras nasales requieren presiones de VNI más bajas y resultan en menos eventos obstructivos residuales. Nuestra hipótesis fue que las máscaras nasales mejorarían la eficacia y reducirían los efectos secundarios en comparación con las máscaras oronasales en esta población.Métodos: Estudio abierto, cruzado, aleatorizado en 2 hospitales de atención terciaria. Los pacientes con ENM tratados mediante VNI domiciliaria fueron aleatorizados durante períodos de una semana de duración a las mascarillas nasales y oronasales, alternativamente (cruzado). Al final de cada período se realizó una polisomnografía nocturna (con monitorización de la apertura bucal) con VNI, sincronizada con la medición transcutánea de la presión parcial de CO2 (tcCO2). Los datos se recopilaron utilizando el software integrado en la VNI y se recogieron los efectos secundarios de la VNI. Se realizaron análisis por intención de tratar y por protocolo. El criterio de valoración principal fue la SpO2 nocturna media. Los criterios secundarios fueron: porcentaje de sueño con SpO2<90%, índice de desaturación de oxígeno (IDO), tcCO2 media, duración media de la apertura bucal durante el sueño, nivel de fugas no intencionales y efectos secundarios.Resultados: Se incluyeron 30 pacientes con ENM. No hubo diferencias entre los grupos para los resultados primarios o secundarios. Las comparaciones a posteriori mostraron que cambiar mascarillas reducía la eficacia de la VNI: SpO2 nocturna media (p=0,04), IDO (p=0,01), tcCO2 media (p=0,048) y efectos secundarios (p=0,008). (AU)

Impact of Interface Type on Noninvasive Ventilation Efficacy in Patients With Neuromuscular Disease: A Randomized Cross-Over Trial.

BACKGROUND AND OBJECTIVE: Around 25% of patients with neuro-muscular diseases (NMD) are treated by home noninvasive ventilation (NIV) through an oronasal mask. However, there is growing evidence that nasal masks require lower NIV pressures and result in fewer residual obstructive events. We hypothesized that nasal masks would improve efficacy and reduce side effects compared to oronasal masks in this population. METHODS: open label, cross-over, randomized, study in 2 tertiary care hospitals. Patients with NMD treated by home NIV were randomized for one-week periods to nasal and oronasal interfaces respectively (cross-over). At the end of each period, nocturnal polygraphy (monitoring mouth opening) under NIV, synchronized with transcutaneous partial pressure in CO2 (tcCO2) was performed. Data were collected from the NIV built-in software and NIV side-effects were collected. Intention-to-treat and per protocol analyses were performed. The primary outcome was mean nocturnal SpO2. The secondary outcomes were: percentage of sleep with SpO2<90%, oxygen desaturation index (ODI), mean tcCO2, mean duration of mouth opening during sleep, level of non-intentional leaks and side-effects. RESULTS: Thirty patients with NMD were included. There were no between-group differences for either the primary or secondary outcomes. Post hoc comparisons showed that changing between interfaces reduced NIV efficacy: mean nocturnal SpO2 (p=0.04), ODI (p=0.01), mean tcCO2 (p=0.048), side-effects (p=0.008). CONCLUSION: Nasal masks did not improve NIV efficacy or reduce side effects compared to oronasal masks in patients with NMD treated by home NIV. The efficacy of NIV is reduced during the transition to another interface, requiring close monitoring. Registration number: NCT03458507.