Paradoxical breathing during sleep is associated with increased sleep apnea and reduced ventilatory capacities in high-level spinal cord injury.

Sleep-disordered breathing is highly prevalent in individuals with high-level spinal cord injury. In addition, chest mechanics are known to be altered, leading to paradoxical breathing. Here we investigated the interaction between paradoxical breathing and sleep quality in these patients, and its association with measurements of respiratory function, hypercapnic ventilatory response and peak exercise ventilation. Home-based polysomnography was performed in 13 patients with spinal cord injury (C4 to T4) untreated for sleep-disordered breathing. We defined paradoxical breathing as counterphase between thoracic and abdominal movements during slow-wave and rapid eye movement sleep. Sleep quality, pulmonary function, hypercapnic ventilatory responses and peak exercise ventilation were compared between those with and without paradoxical breathing. Half of individuals presented with nocturnal paradoxical breathing. Despite similar age, body mass index, injury level, time since injury, and respiratory function, those with paradoxical breathing had higher apnea-hypopnea index (13 ± 8 versus 5 ± 3 events per hr) and average sleep heart rate (67 ± 12 versus 54 ± 4 bpm; p < 0.05). Moreover, paradoxical breathing was associated with lower hypercapnic ventilatory response (slope: 0.35 ± 0.17 versus 0.96 ± 0.38) and lower peak exercise ventilation (33 ± 4 versus 48 ± 12 L min-1 ; p < 0.05). Nocturnal respiratory muscle desynchronization could play a role in the pathophysiology of sleep apnea, and could relate to low ventilatory responses to both hypercapnia and exercise in high-level spinal cord injury. Polysomnography may be an important diagnostic tool for these patients for whom therapeutic approaches should be considered to treat this abnormality.

Higher baseline heart rate variability in CCHS patients with progestin-associated recovery of hypercapnic ventilatory response.

After a fortuitous observation of two cases of chemosensitivity recovery in women with congenital central hypoventilation syndrome (CCHS) who took desogestrel, we aimed to evaluate the ventilatory response to hypercapnia of five CCHS patients with or without treatment consisting of desogestrel (DESO) or levonorgestrel (LEVO). Only two patients became responsive to hypercapnia under treatment, according to their basal vagal heart rate variability. These results suggest that heart rate variability may be promising tool to discriminate patients susceptible to become responsive to hypercapnia under DESO-LEVO treatment.Clinical Trials Identifier NCT01243697.

The Effect of Pressure Changes During Mechanical Insufflation-Exsufflation on Respiratory and Airway Physiology.

BACKGROUND: Respiratory muscle weakness can impair cough function, leading to lower respiratory tract infections. These infections are an important contributor to morbidity and mortality in patients with neuromuscular disease. Mechanical insufflation-exsufflation (MIE) is used to augment cough function in these patients. Although MIE is widely used, there are few data to advise on the optimal technique. Since the introduction of MIE, the recommended pressures to be delivered have increased. There are concerns regarding the use of higher pressures and their potential to cause lung derecruitment and upper airway closure. RESEARCH QUESTION: What is the impact of high-pressure MIE (HP-MIE) on lung recruitment, respiratory drive, upper airway flow, and patient comfort, compared with low-pressure MIE (LP-MIE), in patients with respiratory muscle weakness? STUDY DESIGN AND METHODS: Clinically stable patients using domiciliary MIE with respiratory muscle weakness secondary to Duchenne muscle dystrophy, spinal cord injury, or long-term tracheostomy ventilation received LP-MIE (30/-30 cm H2O) and HP-MIE (60/-60 cm H2O) in a random sequence. Lung recruitment, neural respiratory drive, and cough peak expiratory flow were measured throughout, and patients reported comfort and breathlessness following each intervention. RESULTS: A total of 29 patients (10 with Duchenne muscle dystrophy, eight with spinal cord injury, and 11 with long-term tracheostomy ventilation) were included in this study. HP-MIE augmented cough peak expiratory flow compared with LP-MIE (mean cough peak expiratory flow HP-MIE 228 ± 81 L/min vs LP-MIE 179 ± 67 L/min; P = .0001) without any significant change in lung recruitment, neural respiratory drive, or patient-reported breathlessness. However, in patients with more pronounced respiratory muscle weakness, HP-MIE resulted in an increased rate of upper airway closure and patient discomfort that may have an impact on clinical efficacy. INTERPRETATION: HP-MIE did not lead to lung derecruitment or breathlessness compared with LP-MIE. However, it was poorly tolerated in individuals with advanced respiratory muscle weakness. HP-MIE generates more upper airway closure than LP-MIE, which may be missed if cough peak expiratory flow is used as the sole titration target. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT02753959; URL: www. CLINICALTRIALS: gov.

Effect of Facemask in Congenital Central Hypoventilation Syndrome.

INTRODUCTION: Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder with a mutation in the PHOX2B gene. Patients need ventilatory support by noninvasive ventilation or tracheostomy to treat alveolar hypoventilation. Patients with CCHS have a defect in chemosensitivity signal integration. Recently, due to the COVID-19 pandemic, the entire world has had to get used to wearing medical masks (MM). OBJECTIVES: The aim of the study was to evaluate the effect of an MM on gas exchange and to determine the role of central and peripheral chemoresponsiveness on the partial pressure of transcutaneous carbon dioxide (PtcCO2) in patients with CCHS wearing an MM. METHODS: This study was based on the analysis of recordings obtained without and with an MM during hospitalization and was conducted to assess the impact of MM on PtcCO2 and SpO2 recordings with the SenTec Digital Monitor and their relationships with peripheral CO2 chemosensitivity obtained during tidal breathing measurement and with the hypercapnic hyperoxic ventilatory response. RESULTS: Sixteen patients were included (13 boys) and were 10.2 (7.5; 18.5) years old. The use of an MM had a negative impact on gas exchange in patients with CCHS. The median PtcCO2 increased significantly. Peripheral chemosensitivity correlated with MM-induced PtcCO2 changes (R = -0.72, p = 0.005), but central chemosensitivity (the hypercapnic ventilator response slope) did not (R = -0.22, p = 0.510). CONCLUSION: The use of an MM had a negative impact on gas exchange in patients with CCHS.

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.

Central CO2 chemosensitivity and CO2 controller gain independently contribute to daytime Pco2 in young subjects with congenital central hypoventilation syndrome.

Whether peripheral chemoreceptor response is altered in congenital central hypoventilation syndrome (CCHS) remains debated. Our aim was to prospectively evaluate both peripheral and central CO2 chemosensitivity and to evaluate their correlations with daytime Pco2 and arterial desaturation during exercise in CCHS. To this end, tidal breathing was recorded in patients with CCHS allowing the calculation of loop gain and its components {steady-state controller (assumed to mainly be peripheral chemosensitivity) and plant gains using a bivariate [end-tidal Pco2 ([Formula: see text]) and ventilation] constrained model}, a hyperoxic, hypercapnic ventilatory response test (central chemosensitivity), and a 6-min walk test (arterial desaturation). The results of loop gain were compared with those previously obtained in a healthy group of similar age. The study prospectively included 23 subjects with CCHS, without daytime ventilatory support; the subjects had a median age of 10 (5.6 to 27.4) yr (15 females) with moderate polyalanine repeat mutation (PARM: 20/25, 20/26, n = 11), severe PARM (20/27, 20/33, n = 8), or non-PARM (n = 4). As compared with 23 healthy subjects (4.9-27.0 yr), the subjects with CCHS had a decreased controller gain and an increased plant gain. Mean daytime [Formula: see text] level of subjects with CCHS correlated negatively to both Log(controller gain) and the slope of CO2 response. Genotype was not related to chemosensitivity. Arterial desaturation on exercise correlated negatively with Log(controller) gain but not with the slope of the CO2 response. In conclusion, we demonstrate that peripheral CO2 chemosensitivity is altered in some patients with CCHS and that the daytime [Formula: see text] depends on central and peripheral chemoreceptor responses.NEW & NOTEWORTHY Altered central CO2 chemosensitivity is a hallmark of congenital central hypoventilation syndrome (CCHS). Peripheral CO2 chemosensitivity can be partly assessed by controller gain measurement obtained from tidal breathing recording. In young subjects with CCHS, this study shows that both central and peripheral CO2 sensitivities independently contribute to daytime Pco2. Hypocapnia during nighttime-assisted ventilation is associated with higher peripheral chemosensitivity that is further associated with lesser arterial desaturation at walk.

Does one size fit all? An update on chronic ventilatory support in different respiratory illnesses.

Home noninvasive ventilation (HNIV) improves outcomes in different disease categories. In this article, we discuss indications for when and how to initiate HNIV in COPD, obesity hypoventilation syndrome (OHS) and neuromuscular disorders (NMD). While in COPD, significant diurnal hypercapnia and high-intensity HNIV are essential ingredients for success, in NMD and OHS, early respiratory changes are best detected during sleep through oxy-capnography associated (or not) with respiratory polygraphy. In COPD and OHS, it is crucial to consider the coexistence of obstructive sleep apnoea because treatment with continuous positive airway pressure may be the simplest and most effective treatment that should be proposed even in hypercapnic patients as first-line therapy. In NMD, the need for continuous HNIV and eventual switching to tracheostomy ventilation makes this group's management more challenging. Achieving successful HNIV by improving quality of sleep, quality of life and keeping a good adherence to the therapy is a challenge, above all in COPD patients. In OHS patients, on top of HNIV, initiation of other interventions such as weight loss management is crucial. More resources should be invested in improving all these aspects. Telemonitoring represents a promising method to improve titration and follow-up of HNIV.

An exposed/unexposed cohort study assessing the effectiveness, the safety and the survival of patients established on home non-invasive ventilation after 80 years old.

BACKGROUND: Little is known about the use of long-term non-invasive ventilation (NIV) in the elderly. We aimed to assess if the effectiveness of long-term NIV of patients ≥ 80 years (older) was not greatly inferior to that of patients < 75 years (younger). METHODS: This retrospective exposed/unexposed cohort study included all patients established on long-term NIV treated at Rouen University Hospital between 2017 and 2019. Follow-up data were collected at the first visit following NIV initiation. The primary outcome was daytime PaCO2 with a non-inferiority margin of 50% of the improvement of PaCO2 for older patients compared to younger patients. RESULTS: We included 55 older patients and 88 younger patients. After adjustment on the baseline PaCO2, the mean daytime PaCO2 was reduced by 0.95 (95% CI: 0.67; 1.23) kPa in older patients compared to1.03 (95% CI: 0.81; 1.24) kPa in younger patients for a ratio of improvements estimated at 0.95/1.03 = 0.93 (95% CI: 0.59; 1.27, one-sided p = 0.007 for non-inferiority to 0.50). Median (interquartile range) daily use was 6 (4; 8.1) hours in older versus 7.3 (5; 8.4) hours in younger patients. No significant differences were seen in the quality of sleep and NIV safety. The 24-months survival was 63.6% in older and 87.2% in younger patients. CONCLUSIONS: effectiveness and safety seemed acceptable in older patients, with a life expectancy long enough to expect a mid-term benefit, suggesting that initiation of long-term NIV should not be refused only based on age. Prospective studies are needed.

Experience of being chair and co-chair of the ECMC and reasons why you should be the NEXT.

This article provides testimonials of the past and current chairs and co-chairs of the ECMC (@EarlyCareerERS) and a glimpse of the NEXT programme, along with participants' experiences. https://bit.ly/3LzvqKf.

Lessons from COVID-19 in the management of acute respiratory failure.

Accumulated evidence supports the efficacy of noninvasive respiratory support therapies in coronavirus disease 2019 (COVID-19)-related acute hypoxaemic respiratory failure, alleviating admissions to intensive care units. Noninvasive respiratory support strategies, including high-flow oxygen therapy, continuous positive airway pressure via mask or helmet and noninvasive ventilation, can be alternatives that may avoid the need for invasive ventilation. Alternating different noninvasive respiratory support therapies and introducing complementary interventions, like self-proning, may improve outcomes. Proper monitoring is warranted to ensure the efficacy of the techniques and to avoid complications while supporting transfer to the intensive care unit. This article reviews the latest evidence on noninvasive respiratory support therapies in COVID-19-related acute hypoxaemic respiratory failure.

Diagnosing sleep disordered breathing in patients with chronic pulmonary disease: which test for which patient?

Overnight polysomnography should be the first-line diagnostic test in patients with severe respiratory disease. However, if access to polysomnography is limited, overnight polygraphy can be used as an alternative first-line diagnostic. https://bit.ly/3KlmFED.

International use of objective structured clinical examinations in respiratory training: a European Respiratory Society early career member survey.

This international overview of the use of objective structured clinical examinations (OSCEs) in respiratory training highlights the heterogeneity in use between countries as well as the positive experience of OSCEs amongst users https://bit.ly/3Zee6zP.

ERS International Congress 2022: highlights from the Respiratory Intensive Care Assembly.

Early Career Members of Assembly 2 (Respiratory Intensive Care) attended the 2022 European Respiratory Society (ERS) International Congress in Barcelona, Spain. The conference covered acute and chronic respiratory failure. Sessions of interest to our Assembly members and to those interested in respiratory critical care included the state-of-the-art session on respiratory critical care, the journal session (ERS/Lancet) on acute respiratory distress syndrome (ARDS) phenotyping into precision medicine, and sessions on specificity of coronavirus disease 2019 ARDS and its post-critical care. A symposium on treatment of acute respiratory failure in patients with COPD and innovations in mechanical ventilation either in the intensive care unit or at home were also reported upon. These sessions are summarised in this article.

Decannulation in congenital central hypoventilation syndrome.

RATIONALE: Patients with congenital central hypoventilation syndrome (CCHS) require long-term ventilation to ensure gas exchange and to prevent deleterious consequences for neurocognitive development. Two ventilation modes may be used for these patients depending on their tolerance, one invasive by tracheostomy and the other noninvasive (NIV). For patients who have undergone a tracheostomy, transition to NIV is possible when they meet predefined criteria. Identifying the conditions favorable for weaning from a tracheostomy is critical for the success of the process. OBJECTIVE: The aim of the study was to share our experience of decannulation in a reference center; we hereby describe the modality of ventilation and its effect on nocturnal gas exchange before and after tracheostomy removal. METHODS: Retrospective observational study at Robert Debré Hospital over the past 10 years. The modalities of decannulation and transcutaneous carbon dioxide recordings or polysomnographies before and after decannulation were collected. RESULTS: Sixteen patients underwent decannulation following a specific procedure for transition from invasive to NIV. All decannulations were successful. The median age at decannulation was 12.6 [9.4; 14.1] years. Nocturnal gas exchange was not significantly different before and after decannulation, while expiratory positive airway pressure and inspiratory time increased significantly. An oronasal interface was chosen in two out of three patients. The median duration of hospital stay for decannulation was 4.0 [3.8; 6.0] days. CONCLUSION: Our study underlines that decannulation and transition to NIV are achievable in CCHS children using a well-defined procedure. Patient preparation is crucial to the success of the process.

Respiratory muscle metabolic activity on PET/CT correlates with obstructive ventilatory defect severity and prognosis in patients undergoing lung cancer surgery.

BACKGROUND AND OBJECTIVE: Respiratory muscle activity is increased in patients with chronic respiratory disease. 18 F-FDG-PET/CT can assess respiratory muscle activity. We hypothesized that respiratory muscles metabolism was correlated to lung function impairment and was associated to prognosis in patients undergoing lung cancer surgery based on the research question whether respiratory muscle metabolism quantitatively correlates with the severity of lung function impairment in patients? Does respiratory muscle hypermetabolism have prognostic value? METHODS: Patients undergoing 18 F-FDG-PET/CT and pulmonary function tests prior to lung cancer surgery were identified. Maximum Standardized Uptake Value (SUVm) were measured in each respiratory muscle group (sternocleidomastoid, scalene, intercostal, diaphragm), normalized against deltoid SUVm. Respiratory muscle hypermetabolism was defined as SUVm >90th centile in any respiratory muscle group. Clinical outcomes were collected from a prospective cohort. RESULTS: One hundred fifty-six patients were included, mostly male [110 (71%)], 53 (34%) with previous diagnosis of COPD. Respiratory muscle SUVm were: scalene: 1.84 [1.51-2.25], sternocleidomastoid 1.64 [1.34-1.95], intercostal 1.01 [0.84-1.16], diaphragm 1.79 [1.41-2.27]. Tracer uptake was inversely correlated to FEV1 for the scalene (r = -0.29, p < 0.001) and SCM (r = -0.17, p = 0.03) respiratory muscle groups and positively correlated to TLC for the scalene (r = 0.17, p = 0.04). Respiratory muscle hypermetabolism was found in 45 patients (28.8%), who had a lower VO2 max (15.4 [14.2-17.5] vs. 17.2 mL/kg/min [15.2-21.1], p = 0.07) and poorer overall survival when adjusting to FEV1% (p < 0.01). CONCLUSION: Our findings show respiratory muscle hypermetabolism is associated with lung function impairment and has prognostic significance. 18 F-FDG/PET-CT should be considered as a tool for assessing respiratory muscle activity and to identify high-risk patients.

Short-term cognitive loading deteriorates breathing pattern and gas exchange in adult patients with congenital central hypoventilation syndrome.

Question: Human PHOX2B mutations result in life-threatening sleep-related hypoventilation (congenital central hypoventilation syndrome, CCHS). Most patients retain ventilatory activity when awake through a respiratory-related cortical network. We hypothesised that this need to mobilise cortical resources to breathe would lead to breathing-cognition interferences during cognitive loading. Patients and methods: Seven adult CCHS patients (five women; median age 21) performed standard neuropsychological tests (paced auditory serial addition test - calculation capacity, working memory, sustained and divided attention; trail making test - visuospatial exploration capacity, cognitive processing speed, attentional flexibility; Corsi block-tapping test - visuospatial memory, short-term memory, working memory) during unassisted breathing and under ventilatory support. Ventilatory variables and transcutaneous haemoglobin oxygen saturation were recorded. Cortical connectivity changes between unassisted breathing and ventilatory support were assessed using electroencephalographic recordings (EEG). Results: Baseline performances were lower than expected in individuals of this age. During unassisted breathing, cognitive loading coincided with increased breathing variability, and decreases in oxygen saturation inversely correlated with an increasing number of apnoeic cycles per minute (rho -0.46, 95% CI -0.76 to -0.06, p=0.01). During ventilatory support, cognitive tasks did not disrupt breathing pattern and were not associated with decreased oxygen saturation. Ventilatory support was associated with changes in EEG cortical connectivity but not with improved test performances. Conclusions: Acute cognitive loads induce oxygen desaturation in adult CCHS patients during unassisted breathing, but not under ventilatory support. This justifies considering the use of ventilatory support during mental tasks in CCHS patients to avoid repeated episodes of hypoxia.

Highlights from the Respiratory Failure and Mechanical Ventilation 2022 Conference.

The Respiratory Intensive Care Assembly of the European Respiratory Society gathered in Berlin to organise the second Respiratory Failure and Mechanical Ventilation Conference in June 2022. The conference covered several key points of acute and chronic respiratory failure in adults. During the 3-day conference, ventilatory strategies, patient selection, diagnostic approaches, treatment and health-related quality of life topics were addressed by a panel of international experts. Lectures delivered during the event have been summarised by Early Career Members of the Assembly and take-home messages highlighted.