Comparison of Four Mechanical Insufflation-Exsufflation Devices: Effect of Simulated Airway Collapse on Cough Peak Flow.

BACKGROUND: Mechanical insufflation-exsufflation (MI-E) devices are used to improve airway clearance in individuals with acute respiratory failure. Some MI-E devices measure cough peak flow (CPF) during MI-E to optimize pressure adjustments. The aim was to compare CPF and effective cough volume (ECV: volume expired/coughed > 3 L/s) measurements between 4 MI-E devices under simulated conditions of stable versus collapsed airway. METHODS: Four MI-E devices were tested on the bench. Each device was connected via a standard circuit to a collapsible tube placed in an airtight chamber that was attached to a lung model with adjustable compliance and resistance. Pressure was measured upstream and downstream the collapsing tube; air flow was measured between the chamber and the lung model. Each device was tested in 2 conditions: collapse condition (0 cm H2O) and no-collapse condition (-70 cm H2O). For each condition, 6 combinations of inspiratory/expiratory pressures were applied. CPF was measured at the "mouth level" by the device built-in flow meter and at the "tracheal level" by a dedicated pneumotachograph. Comparisons were performed with non-parametric tests. RESULTS: CPF values measured at the tracheal level and ECV values differed between devices for each inspiratory/expiratory pressure in the collapse and no-collapse conditions (P < .001). CPF values were significantly lower at the tracheal level in the collapse as compared with the no-collapse condition (P < .001 for each device), whereas they were higher at the mouth level (P < .05) for 3 of the 4 devices. CONCLUSIONS: CPF values differed significantly across MI-E devices, highlighting limitation(s) of using only CPF values to determine cough effectiveness. In simulated of airway collapse, CPF increased at the mouth, whereas it decreased at the tracheal level.

Quality of life in patients with slowly progressive neuromuscular disorders dependent on mechanical ventilation.

This cross-sectional study evaluated health-related quality of life (HRQoL) in patients with slowly progressive neuromuscular disorders dependent on mechanical ventilation (MV; ≥16 hours/day). 119 participants, with 9 years (25th-75th percentiles: 4-15 years) of MV dependence, were included. MV was applied via a tracheostomy in 80 participants (67.2%) and non-invasive interfaces in 39 participants (32.8%), including 28 participants (71.8%) with daytime mouthpiece ventilation. HRQoL was rated good or excellent by 81 participants (68.1%), independently from age, diagnosis or respiratory autonomy. On multivariate analysis, time since MV initiation, independence from family member(s), residence in a rural area, ability to go outdoors with MV and tracheostomy were associated with better HRQoL.

Noninvasive Ventilation Automated Technologies: A Bench Evaluation of Device Responses to Sleep-Related Respiratory Events.

BACKGROUND: Noninvasive ventilation (NIV) is the reference standard treatment for most situations of chronic respiratory failure. NIV settings must be titrated to both preserve upper-airway patency and control hypoventilation. Automatic adjustment of pressure support (PS) and expiratory positive airway pressure (EPAP) may facilitate the initiation and follow-up of domiciliary NIV. However, whether the automatic-adjustment algorithms embedded into current devices accurately detect, respond to, and score common sleep-related respiratory events remains unclear. METHODS: A bench was set up to simulate central hypopnea (CH), central apnea (CA), obstructive hypopnea (OH), and obstructive apnea (OA). Four home ventilators were evaluated, with their dedicated modes for automatic PS and EPAP adjustment. RESULTS: All 4 devices increased PS during CH, CA, and OH. However, PS adjustment varied widely in magnitude, with tidal volumes within 100 ± 20% of the target being provided by only 3 devices for CH, one for CA, and one for OH. Two devices increased EPAP for OH and 3 for OA, including one that also increased EPAP for CA. Only 2 devices scored residual hypopnea after simulated CA, and only one scored a residual event after OH. One device scored no event. CONCLUSIONS: Current NIV devices differed markedly in their responses to, and reporting of, standardized sleep-related respiratory events. Further improvements in embedded NIV algorithms are needed to allow more widespread out-of-laboratory initiation and follow-up of NIV.

Quality versus emergency: How good were ventilation fittings produced by additive manufacturing to address shortages during the COVID19 pandemic?

OBJECTIVE: The coronavirus disease pandemic (COVID-19) increased the risk of shortage in intensive care devices, including fittings with intentional leaks. 3D-printing has been used worldwide to produce missing devices. Here we provide key elements towards better quality control of 3D-printed ventilation fittings in a context of sanitary crisis. MATERIAL AND METHODS: Five 3D-printed designs were assessed for non-intentional (junctional and parietal) and intentional leaks: 4 fittings 3D-printed in-house using FDeposition Modelling (FDM), 1 FDM 3D-printed fitting provided by an independent maker, and 2 fittings 3D-printed in-house using Polyjet technology. Five industrial models were included as controls. Two values of wall thickness and the use of coating were tested for in-house FDM-printed devices. RESULTS: Industrial and Polyjet-printed fittings had no parietal and junctional leaks, and satisfactory intentional leaks. In-house FDM-printed fittings had constant parietal leaks without coating, but this post-treatment method was efficient in controlling parietal sealing, even in devices with thinner walls (0.7 mm vs 2.3 mm). Nevertheless, the use of coating systematically induced absent or insufficient intentional leaks. Junctional leaks were constant with FDM-printed fittings but could be controlled using rubber junctions rather than usual rigid junctions. The properties of Polyjet-printed and FDM-printed fittings were stable over a period of 18 months. CONCLUSIONS: 3D-printing is a valid technology to produce ventilation devices but requires care in the choice of printing methods, raw materials, and post-treatment procedures. Even in a context of sanitary crisis, devices produced outside hospitals should be used only after professional quality control, with precise data available on printing protocols. The mechanical properties of ventilation devices are crucial for efficient ventilation, avoiding rebreathing of CO2, and preventing the dispersion of viral particles that can contaminate health professionals. Specific norms are still required to formalise quality control procedures for ventilation fittings, with the rise of 3D-printing initiatives and the perspective of new pandemics.

Predictors of Hospitalization and Superinfection in Viral Respiratory Tract Infections Between Influenza and Paramyxoviruses: The SUPERFLUOUS Study.

BACKGROUND: Viral respiratory tract infections (VRTIs) are among the most common diseases, but the risks of superinfection for different virus species have never been compared. METHODS: Multicenter retrospective study conducted among adults who tested positive for VRTIs with reverse-transcription polymerase chain reaction. We compared characteristics between influenza (A or B) and paramyxoviruses (respiratory syncytial virus, parainfluenza virus types 1 and 3, and human metapneumovirus) and identified predictors of superinfection and hospitalization.s. RESULTS: Five hundred ninety patients had VRTI, including 347 (59%) influenza and 243 paramyxovirus infections with comparable rates of superinfections (53% vs 60%). In multivariate analyses, the predictors of superinfections were age >75 years (adjusted odds ratio, 2.37 [95% confidence interval, 1.65-3.40]), chronic respiratory disease (1.79 [1.20-2.67]), and biological abnormalities, including neutrophil count >7000/µL (1.98 [1.34-2.91)], eosinophil count <50/µL (2.53 [1.61-3.98], and procalcitonin level >0.25ng/mL (2.8 [1.65-4.73]). The predictors of hospitalization were age >75 years old (adjusted odds ratio, 3.49 [95% confidence interval, 2.17-5.63]), paramyxovirus infection (2.28 [1.39-3.75]), long-term use of inhaled corticosteroids (2.49 [1.13-5.49]), and biological abnormalities, including neutrophil count >7000/µL (2.38 [1.37-4.12)] and procalcitonin level >0.25ng/mL (2.49 [1.23-5.02]). Kaplan-Meier survival curves showed that influenza-infected patients had a higher mortality rate than those with paramyxovirus infections (8.9% vs 4.5%, respectively; P = .02). CONCLUSIONS: Our study revealed a high rate of superinfection (56%), not related to viral species. However influenza virus was associated with a poorer prognosis than paramyxoviruses, pleading for a broader and large-scale vaccination of individual at risk of VRTIs.

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.

Impact of Mechanical Ventilation Methods on the Life Perception of Subjects With Duchenne Muscular Dystrophy: French Cross-Sectional Survey.

BACKGROUND: The life expectancy of individuals with Duchenne muscular dystrophy has improved considerably with the use of mechanical ventilation to manage respiratory insufficiency. The choice between continuous noninvasive ventilation (NIV) and invasive ventilation is guided both by local logistical considerations and by clinical considerations, but the choice depends largely on patient preference. It is important to know the effects of ventilatory dependence and the method used (ie, continuous NIV or invasive ventilation) on subjects' quality of life. METHODS: This was a cross-sectional prospective survey of 192 subjects with Duchenne muscular dystrophy using mechanical ventilation in France. Subjects were grouped and compared according to dependence on mechanical ventilation and the ventilation methods used. RESULTS: Regardless of the mechanical ventilation method, subjects with gastrostomy tubes reported more frequent emergency consultations for digestive problems (22.5% vs 4.6%, P = .001). Subjects with invasive ventilation reported more insomnia than those with continuous NIV (23.8% vs 8.5%, P = .04). The latter reported more ineffective cough than the invasive ventilation group (72.3% vs 49.2%, P = .02). Overall, the subjects in our sample were satisfied with their medical care, regardless of dependence level or ventilation type. More specifically, 86.1% of subjects with intermittent NIV and 83.6% of ventilator-dependent subjects were satisfied. CONCLUSIONS: Continuous and invasive mechanical ventilation did not affect the perception of quality of life for our subjects with Duchenne muscular dystrophy, apart from more insomnia, which can be explained by the fact that they required frequent repositioning in bed. Different pressure-relief mattresses should be tested and compared to prevent the development of pressure ulcers, which may improve the sleep patterns of these patients.

Impact of medical care, including use of anti-infective agents, on prognosis of COVID-19 hospitalized patients over time.

INTRODUCTION: The effect of anti-infective agents in COVID-19 is unclear. The impact of changes in practice on prognosis over time has not been evaluated. METHODS: Single center, retrospective study in adults hospitalized in a medicine ward for COVID-19 from March 5th to April 25th 2020. Patient characteristics were compared between two periods (before/after March 19th) considering French guidelines. The aim of the study was to evaluate how medical care impacted unfavorable outcome, namely admission to intensive care unit (ICU) and/or death. RESULTS: A total of 132 patients were admitted: mean age 59.0±16.3 years; mean C-reactive protein (CRP) level 84.0±71.1 mg/L; 46% had a lymphocyte count <1000/mm3. Prescribed anti-infective agents were lopinavir-ritonavir (n=12), azithromycin (AZI) (n=28) and AZI combined with hydroxychloroquine (HCQ) (n=52). There was a significant decrease in ICU admission, from 43% to 12%, between the two periods (P<0.0001). Delays until transfer to ICU were similar between periods (P=0.86). Pulmonary computerized tomography (CT)-scans were performed significantly more often with time (from 50% to 90%, P<0.0001), and oxygen-dependency (53% vs 80%, P=0.001) and prescription of AZI±HCQ (from 25% to 76%, P<0.0001) were also greater over time. Multivariate analyses showed a reduction of unfavorable outcome in patients receiving AZI±HCQ (hazard ratio [HR]=0.45, 95% confidence interval [CI: 0.21-0.97], P=0.04), particularly among an identified category of individuals (lymphocyte ≥1000/mm3 or CRP ≥100 mg/L). CONCLUSION: The present study showed a significant decrease in admission to ICU over time, which was probably related to multiple factors, including a better indication of pulmonary CT-scan, oxygen therapy, and a suitable prescription of anti-infective agents.

Response of Home-Use Adaptive Pressure Modes to Simulated Transient Hypoventilation.

BACKGROUND: Adaptive servoventilation (ASV) is a recently developed ventilation mode designed to stabilize ventilation in patients with central sleep apnea and Cheyne-Stokes respiration. Alternatively, modes aiming to maintain average ventilation over several breaths, such as average volume-assured pressure support (AVAPS) and intelligent volume-assured pressure support (iVAPS), could be efficient during ventilation instability by reducing central events. These modes are available on a variety of devices. This bench evaluation studied the response of these different modes and devices to simulated transient hypoventilation events. METHODS: Three home ventilation devices operating in ASV modes (AirCurve S10 VAuto, ResMed; DreamStation autoSV, Philips; Prisma CR, Löwenstein) and 2 ventilators with the AVAPS mode (DreamStation BiPAP, Philips; Lumis iVAPS, ResMed) were evaluated during transient central hypopnea/hypoventilation simulations characterized by a constant breathing frequency of 15 breaths/min and a progressive decrease of tidal volume (VT) from 500 mL to 50 mL, in 18, 12, 9, and 6 breaths, respectively, followed by a progressive return to the baseline at the same rate. RESULTS: The AirCurve S10 VAuto reacted to a VT decrease between 80% and 50% of baseline VT. DreamStation BiPAP and Prisma CR reacted when VT decreased to between 60% and 30% of baseline VT, whereas the AVAPS response to hypopnea occurred during the crescendo phase of hypopnea/hypoventilation VT. The iVAPS response was between that of the AirCurve S10 VAuto and the other ASV devices. Among the ASV devices, the minimum VT was higher with AirCurve S10 VAuto, followed by the Prisma CR and the DreamStation BiPAP. Minimum VT was not influenced by AVAPS and was improved by iVAPS without outperforming the AirCurve S10 VAuto. Maximum VT was increased by iVAPS, whereas ASV devices did not induce a significant VT overshoot. CONCLUSIONS: ASV devices improved central hypopnea/hypoventilation events without inducing hyperpnea events and therefore were better adapted than AVAPS and iVAPS devices, with notable differences in their responses to hypoventilation events.

Peak Cough Flow Fails to Detect Upper Airway Collapse During Negative Pressure Titration for Cough-Assist.

OBJECTIVE: To study the ability of peak cough flow (PCF) and effective cough volume, defined as the volume exsufflated >3 L/s, to detect upper airway collapse during mechanical insufflation-exsufflation (MI-E) titration in neuromuscular patients. DESIGN: Prospective observational study. SETTING: Rehabilitation hospital. PARTICIPANTS: Patients (N=27) with neuromuscular disease causing significant impairment of chest wall and/or diaphragmatic movement. INTERVENTIONS: The lowest insufflation pressure producing the highest inspiratory capacity was used. Exsufflation pressure was decreased from -20 cm H2O to -60/-70 cm H2O, in 10-cm H2O decrements, until upper airway collapse was detected using the reference standard of flow-volume curve analysis (after PCF, abrupt flattening or flow decrease vs previous less negative exsufflation pressure). MAIN OUTCOME MEASURES: PCF and effective cough volume profiles during expiration with MI-E. RESULTS: Upper airway collapse occurred in 10 patients during titration. Effective cough volume increased with decreasing expiratory pressure then decreased upon upper airway collapse occurrence. PCF continued to increase after upper airway collapse occurrence. In 5 other patients, upper airway collapse occurred at the initial -20 cm H2O exsufflation pressure, and during titration, PCF increased and effective cough volume remained unchanged at <200 mL. PCF had 0% sensitivity for upper airway collapse, whereas effective cough volume had 100% sensitivity and specificity. CONCLUSION: Of 27 patients, 15 experienced upper airway collapse during MI-E titration. Upper airway collapse was associated with an effective cough volume decrease or plateau and with increasing PCF. Accordingly, effective cough volume, but not PCF, can detect upper airway collapse.

Effect and impact of mechanical ventilation in myotonic dystrophy type 1: a prospective cohort study.

Few studies have assessed the impact of home ventilation in patients with myotonic dystrophy type 1 (DM1) and no specific recommendations are available. We assessed the survival associated with category of home ventilation adherence of patients with DM1 followed up at a home ventilation unit using a Cox proportional hazards model. 218 patients were included; those who refused or delayed their acceptance of non-invasive ventilation were at higher risk for severe events (invasive ventilation or death) (P=0.03). Risk of death was associated with orthopnoea (HR 2.37; 95% CI 1.17 to 4.80; P<0.02) and adherence category (100 to 90% vs >75%: HR 3.26; 95% CI 1.32 to 8.04; P<0.03). Failure to use home ventilation as prescribed may be associated with increased mortality in patients with DM1.

Genotype and other determinants of respiratory function in myotonic dystrophy type 1.

New treatments are being developed for myotonic dystrophy type 1 (DM1). To evaluate their efficacy, knowledge about the natural history of respiratory dysfunction and its relationship with the genotype will be crucial. Also needed is information on factors predicting the time-course of respiratory function in DM1. Using data from 283 patients, we built a segmented linear mixed-effects regression model to assess respiratory function changes over time. Respiratory variables associated with the CTG repeat number were identified by multivariate linear regression analysis. Cox proportional-hazards regression was used to estimate hazard ratios (HRs) for starting non-invasive ventilation (NIV). Higher CTG repeat number was associated with peak cough flow impairment (p = 0.007) and with lower values for maximal inspiratory pressure (p <0.0001) and upright vital capacity. A vital capacity decline over time was associated with older age at first evaluation (p <0.0001), higher CTG repeat number (p <0.0001), and higher baseline body mass index (p = 0.0004). NIV initiation was associated with lower peak cough flow (p <0.001) after age and PaCO2 adjustment. Earlier and closer monitoring with routine peak cough flow determination in adults with congenital DM1, combined with weight control, may diminish the risk of respiratory complications and optimise other aspects of management.

Outcomes of Hospitalised Muscular Dystrophy Patients.

BACKGROUND: In France, referral centres in teaching hospitals were created 10 years ago to provide MD patients with treatments and follow-up designed to prevent complications and improve outcomes. Respiratory failure is a major cause of death among subjects with MD, and its prevention and treatment can serve as a touchstone for assessing the effectiveness of MD care pathways. OBJECTIVE: We report data from a preliminary study of admissions of MD patients in France and of factors associated with mortality, with special emphasis on respiratory failure [RF]. METHODS: Retrospective analysis of the data from the French nationwide hospital database [Programme de M é dicalisation des syst é mes d'information, PMSI] for 2009 and 2010. RESULTS: 7187 admissions of patients with MD were included in the study. Most admissions were to teaching hospitals [5913/7187, 82.3%]. 302 [4.2%] patients were admitted for RF requiring invasive ventilation, 924 [12.9%] for RF requiring only NIV or high-flow oxygen therapy, and 5961 [82.9%] required no respiratory assistance. 494 [6.9%] admissions occurred on an emergency basis. 77/7187 [1.1%] patients died while hospitalised. Teaching-hospital admission was associated with lower frequencies of emergency admission [3.08% vs. 24.5%, p < 0.01] and in-hospital death [0.71% vs. 2.75%, p < 0.01]. CONCLUSIONS: Our data suggest that there is room for improvement in care pathways for MD patients requiring admission. Admission to referral centres may provide the best outcomes.Further studies are needed to assess associations between healthcare pathways and outcomes of MD subjects.

Impact of Noninvasive Ventilation on Lung Volumes and Maximum Respiratory Pressures in Duchenne Muscular Dystrophy.

BACKGROUND: Duchenne muscular dystrophy (DMD) is a sex-linked genetic disorder in which progressive impairment of skeletal muscle function eventually leads to severe respiratory failure requiring continuous noninvasive ventilation (NIV) at home. A current focus of debate is whether NIV may slow the decline in respiratory function or, on the contrary, worsen respiratory function when started early. Our objective here was to describe the effects of NIV on vital capacity (VC) and maximum respiratory pressures in DMD. METHODS: We analyzed retrospective data from 71 subjects with DMD, including VC, maximum static respiratory pressures, and sniff nasal inspiratory pressure before and after NIV initiation. The declines in these variables from the highest value to the most recent value were computed. RESULTS: Although respiratory function continued to deteriorate over time, NIV introduction was followed by significant slowing in the annual rates of decline in VC (from 4.28 to 1.36 percent predicted), maximum inspiratory pressure (from 2.77 to 1.48 cm H2O), and maximum expiratory pressure (from 2.00 to 1.00 cm H2O). NIV had no effect on sniff nasal inspiratory pressure. CONCLUSIONS: Introducing NIV in subjects with DMD was followed by slowing of the declines in VC and in maximum static inspiratory and expiratory pressures.