A history of home mechanical ventilation: The past, present and future.

This state-of-the-art review provides an overview of the history of home mechanical ventilation (HMV), including early descriptions of mechanical ventilation from ancient and Renaissance perspectives and the mass development of ventilators designed for long-term use during the poliomyelitis epidemic. Seminal data from key clinical trials supports the application of HMV in certain patients with chronic obstructive pulmonary disease, neuromuscular disease and obesity-related respiratory failure. Innovative engineering coupled with refined physiological understanding now permits widespread delivery of home mechanical ventilation to a global population, using portable devices with advanced ventilatory modes and telemonitoring capabilities. Exponential growth in digital technology continues, and ongoing research is needed to understand how to harness clinical and physiological data to benefit patients and healthcare services in a clinically- and cost-effective manner.

Nutrition therapy during noninvasive ventilation: oral or enteral?

PURPOSE OF REVIEW: Critical care nutrition guidelines primarily focus on patients receiving invasive mechanical ventilation, yet noninvasive ventilation (NIV) is an increasingly common intervention. The optimal route of nutrition delivery in patients receiving NIV has not been established. This review aims to describe the implications of NIV on the route of feeding prescribed. RECENT FINDINGS: Five small, mostly observational, studies have quantified energy or protein intake in patients receiving NIV in critical care, which demonstrate intake to be poor. No study has assessed the impact of feeding route on outcomes. The predominant route of feeding observed is oral intake, yet nutrition intake via this route is lower than that from enteral or parenteral nutrition. Barriers to oral intake include fasting for intubation, the inability to remove NIV apparatus to eat, breathlessness, fatigue and poor appetite, while barriers to enteral nutrition include the impact of the naso-enteric tube on the mask seal and potential aspiration. SUMMARY: Until evidence to support the optimal route of feeding is developed, patient safety should be the key driver of route selection, followed by the ability to achieve nutrition targets, perhaps utilizing a combination of routes to overcome barriers to nutrition delivery.

Neural respiratory drive predicts long-term outcome following admission for exacerbation of COPD: a post hoc analysis.

Neural respiratory drive (NRD), as reflected by change in parasternal muscle electromyogram (EMGpara), predicts clinical deterioration and safe discharge in patients admitted to hospital with an acute exacerbation of COPD (AECOPD). The clinical utility of NRD to predict the long-term outcome of patients following hospital admission with an AECOPD is unknown. We undertook a post hoc analysis of a previously published prospective observational cohort study measuring NRD in 120 patients with AECOPD. Sixty-nine (57.5%) patients died during follow-up (median 3.6 years). Respiratory failure was the most common cause of death (n=29; 42%). In multivariate analysis, factors independently associated with an increased mortality included NRD (HR 2.14, 95% CI 1.29 to 3.54, p=0.003), age (HR 2.03, 95% CI 1.23 to 3.34, p=0.006), PaCO2 at admission (HR 1.83, 95% CI 1.06 to 3.06, p=0.022) and long-term oxygen use (HR 2.98, 95% CI 1.47 to 6.03, p=0.002). NRD at hospital discharge could be measured in order to assess efficacy of interventions targeted to optimise COPD and reduce mortality following an AECOPD. Original clinicaltrial.gov number: NCT01361451.

Lumbar punctures in the Acute Medicine Department: indications and evaluation of use.

AIMS: Evaluate the use of lumbar puncture (LP) in the Acute Medical Department of a typical urban district general hospital. Increase the proportion performed on appropriate patients. METHODOLOGY: An observational, single-centre, retrospective examination of patients undergoing LP at Solihull Hospital over four consecutive months. Discussion of findings and LP indications with the Acute Medicine Department. Re-audit over four months. RESULTS: Total LPs performed fell by 65%. The proportion performed on patients presenting with red flags rose by 19% (p=0.0098). The proportion that yielded positive findings rose by 33% (p<0.0001). 72% of patients with red flags had negative LP. CONCLUSIONS: Awareness of indications and observation of practice reduces total LPs performed and increases the proportion performed on appropriate patients.

Supporting patients with hypercapnia.

Hypercapnia is commonly encountered by general and specialist respiratory clinicians. Patients at risk of developing hypercapnic respiratory failure include those with chronic obstructive pulmonary disease (COPD), obesity and neuromuscular disease. Such patients may present to clinicians acutely unwell on the acute medical take or during an inpatient deterioration, or be identified in the stable outpatient setting. In this review, we provide a practical guide to develop clinicians' knowledge, skills and confidence in promptly recognising and managing hypercapnic respiratory failure, and to promote national ventilation quality standards to encourage consistent delivery of high-quality care and optimise outcomes for patients.

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.

Quality of life in patients with chronic respiratory failure on home mechanical ventilation.

Home mechanical ventilation (HMV) is a treatment for chronic respiratory failure that has shown clinical and cost effectiveness in patients with underlying COPD, obesity-related respiratory failure and neuromuscular disease (NMD). By treating chronic respiratory failure with adequate adherence to HMV, improvement in patient-reported outcomes including health-related quality of life (HRQoL) have been evaluated using general and disease-specific quantitative, semi-qualitative and qualitative methods. However, the treatment response in terms of trajectory of change in HRQoL is not uniform across the restrictive and obstructive disease groups. In this review, the effect of HMV on HRQoL across the domains of symptom perception, physical wellbeing, mental wellbeing, anxiety, depression, self-efficacy and sleep quality in stable and post-acute COPD, rapidly progressive NMD (such as amyotrophic lateral sclerosis), inherited NMD (including Duchenne muscular dystrophy) and obesity-related respiratory failure will be discussed.

Novel breathing pattern analysis: Symmetric Projection Attractor Reconstruction improves identification of impending COPD re-exacerbations - a retrospective cohort analysis.

Respiratory waveforms can be reduced to simple metrics, such as rate, but this may miss information about waveform shape and whole breathing pattern. A novel analysis method quantifying the whole waveform shape identifies AECOPD earlier. https://bit.ly/3M6uIEB.

Sleep disorders in pregnancy.

Sleep disturbances are common in pregnancy and affect sleep quality. The maternal body is going through constant physical and physiological changes to adapt to the growing fetus. Sleep disorders may manifest at any point during pregnancy; some may result in adverse maternal or fetal outcomes. A strong clinical suspicion is crucial to identify sleep disorders in pregnancy and their management should be evaluated with a multidisciplinary team approach. In this review, we provide an overview of changes in sleep during pregnancy and summarise the key features of common sleep disorders in pregnancy, including practical tips on their management. Educational aims: To provide an overview of common sleep disorders in pregnancy and their management options.To highlight the impact of the physiological changes in pregnancy on sleep.To outline the type of sleep studies available to investigate sleep disorders in pregnancy.

ERS International Congress 2021: highlights from the Respiratory Intensive Care Assembly.

Early Career Members of Assembly 2 (Respiratory Intensive Care) attended the European Respiratory Society International Congress through a virtual platform in 2021. Sessions of interest to our assembly members included symposia on the implications of acute respiratory distress syndrome phenotyping on diagnosis and treatment, safe applications of noninvasive ventilation in hypoxaemic respiratory failure, and new developments in mechanical ventilation and weaning, and a guidelines session on applying high-flow therapy in acute respiratory failure. These sessions are summarised in this article.

Home parasternal electromyography tracks patient-reported and physiological measures of recovery from severe COPD exacerbation.

Physiological phenotyping using daily home-based assessments reveals early improvement in load-capacity-drive imbalance following #AECOPD and feasibility of home parasternal electromyography measurement, which tracks symptoms, health status and spirometry https://bit.ly/3o6I0Ty.

Highlights from the Respiratory Failure and Mechanical Ventilation 2020 Conference.

The Respiratory Intensive Care Assembly of the European Respiratory Society organised the first Respiratory Failure and Mechanical Ventilation Conference in Berlin in February 2020. The conference covered acute and chronic respiratory failure in both adults and children. During this 3-day conference, patient selection, diagnostic strategies and treatment options were discussed by international experts. Lectures delivered during the event have been summarised by Early Career Members of the Assembly and take-home messages highlighted.

Chest radiography is a poor predictor of respiratory symptoms and functional impairment in survivors of severe COVID-19 pneumonia.

BACKGROUND: A standardised approach to assessing COVID-19 survivors has not been established, largely due to the paucity of data on medium- and long-term sequelae. Interval chest radiography is recommended following community-acquired pneumonia; however, its utility in monitoring recovery from COVID-19 pneumonia remains unclear. METHODS: This was a prospective single-centre observational cohort study. Patients hospitalised with severe COVID-19 pneumonia (admission duration ≥48 h and oxygen requirement ≥40% or critical care admission) underwent face-to-face assessment at 4-6 weeks post-discharge. The primary outcome was radiological resolution of COVID-19 pneumonitis (Radiographic Assessment of Lung Oedema score <5). Secondary outcomes included clinical outcomes, symptom questionnaires, mental health screening (Trauma Screening Questionnaire, seven-item Generalised Anxiety Disorder assessment and nine-item Patient Health Questionnaire) and physiological testing (4-m gait speed (4MGS) and 1-min Sit-to-Stand (STS) tests). RESULTS: 119 patients were assessed between June 3, 2020 and July 2, 2020 at median (interquartile range (IQR)) 61 (51-67) days post-discharge: mean±sd age 58.7±14.4 years, median (IQR) body mass index 30.0 (25.9-35.2) kg·m-2, 62% male and 70% ethnic minority. Despite radiographic resolution of pulmonary infiltrates in 87%, modified Medical Research Council Dyspnoea (breathlessness) scale grades were above pre-COVID-19 baseline in 44%, and patients reported persistent fatigue (68%), sleep disturbance (57%) and breathlessness (32%). Screening thresholds were breached for post-traumatic stress disorder (25%), anxiety (22%) and depression (18%). 4MGS was slow (<0.8 m·s-1) in 38% and 35% desaturated by ≥4% during the STS test. Of 56 thoracic computed tomography scans performed, 75% demonstrated COVID-19-related interstitial and/or airways disease. CONCLUSIONS: Persistent symptoms, adverse mental health outcomes and physiological impairment are common 2 months after severe COVID-19 pneumonia. Follow-up chest radiography is a poor marker of recovery; therefore, holistic face-to-face assessment is recommended to facilitate early recognition and management of post-COVID-19 sequelae.

High-flow therapy: physiological effects and clinical applications.

Humidified high-flow therapy (HFT) is a noninvasive respiratory therapy, typically delivered through a nasal cannula interface, which delivers a stable fraction of inspired oxygen (F IO2 ) at flow rates of up to 60 L·min-1. It is well-tolerated, simple to set up and ideally applied at 37°C to permit optimal humidification of inspired gas. Flow rate and F IO2 should be selected based on patients' inspiratory effort and severity of hypoxaemia. HFT yields beneficial physiological effects, including improved mucociliary clearance, enhanced dead space washout and optimisation of pulmonary mechanics. Robust evidence supports its application in the critical care setting (treatment of acute hypoxaemic respiratory failure and prevention of post-extubation respiratory failure) and emerging data supports HFT use during bronchoscopy, intubation and breaks from noninvasive ventilation or continuous positive airway pressure. There are limited data on HFT use in patients with hypercapnic respiratory failure, as an adjunct to pulmonary rehabilitation and in the palliative care setting, and further research is needed to validate the findings of small studies. The COVID-19 pandemic raises questions regarding HFT efficacy in COVID-19-related hypoxaemic respiratory failure and concerns regarding aerosolisation of respiratory droplets. Clinical trials are ongoing and healthcare professionals should implement strict precautions to mitigate the risk of nosocomial transmission. EDUCATIONAL AIMS: Provide a practical guide to HFT setup and delivery.Outline the physiological effects of HFT on the respiratory system.Describe clinical applications of HFT in adult respiratory and critical care medicine and evaluate the supporting evidence.Discuss application of HFT in COVID-19 and aerosolisation of respiratory droplets.

Novel modes of non-invasive ventilation in chronic respiratory failure: a narrative review.

Home non-invasive ventilation (NIV) is central in the management of chronic hypercapnic respiratory failure and is associated with improvements in clinically relevant outcomes. Home NIV typically involves delivery of fixed positive inspiratory and expiratory airway pressures. These pressures do not reflect physiological changes to respiratory mechanics and airway calibre during sleep, which may impact on physiological efficacy, subsequent clinical outcomes, and therapy adherence. Novel ventilator modes have been designed in an attempt to address these issues. Volume-assured pressure support modes aim to automatically adjust inspiratory pressure to achieve a pre-set target tidal volume. The addition of auto-titrating expiratory pressure to maintain upper airway calibre is designed for patients at risk of upper airway collapse, such as obese patients and those with obstructive sleep apnoea complicating their hypercapnic failure. Heterogeneity in setup protocols, patient selection and trial design limit firm conclusions to be drawn on the clinical efficacy of these modes. However, there are data to suggest that compared to fixed-pressure NIV, volume-assured modes may improve nocturnal carbon dioxide, sleep quality and ventilator adherence in select patients. The use of the forced oscillation technique to identify expiratory flow limitation and adjust expiratory pressure to eliminate it is the most recent addition to these advanced modes and is yet to be assessed in formal clinical trials.

Sleep disordered breathing and chronic obstructive pulmonary disease: a narrative review on classification, pathophysiology and clinical outcomes.

Chronic obstructive pulmonary disease (COPD) causes load-capacity-drive imbalance in both wakefulness and sleep, principally driven by expiratory flow limitation and hyperinflation. Sleep imposes additional burdens to the respiratory muscle pump, driven by changes in respiratory muscle tone, neural respiratory drive and consequences of the supine position. COPD patients are therefore at higher risk of decompensation during sleep, which may manifest as altered sleep architecture, isolated nocturnal desaturation, sleep hypoventilation and restless legs. Each form of sleep disordered breathing in COPD is associated with adverse clinical and patient-reported outcomes, including increased risk of exacerbations, hospitalisation, cardiovascular events, reduced survival and poorer quality of life. COPD-obstructive sleep apnoea (OSA) overlap syndrome represents a distinct clinical diagnosis, in which clinical outcomes are significantly worse than in either disease alone, including increased mortality, risk of cardiovascular events, hospitalisation and exacerbation frequency. Sleep disordered breathing is under-recognised by COPD patients and their clinicians, however early diagnosis and management is crucial to reduce the risk of adverse clinical outcomes. In this narrative review, we describe the pathophysiology of COPD and physiological changes that occur during sleep, manifestations and diagnosis of sleep disordered breathing in COPD and associated clinical outcomes.