Obesity-related Respiratory Failure Research Articles

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.

Long-Term Mortality following Acute Noninvasive Ventilation for Obesity-Related Respiratory Failure: A Retrospective Single-Centre Study.

Determinants of long-term mortality following acute hypercapnic respiratory failure have been extensively studied in patients with chronic obstructive pulmonary disease. However, respiratory failure due to obesity has not been studied to the same extent. This retrospective survey aims to identify whether admission pH is associated with long-term mortality in patients requiring acute noninvasive ventilation (NIV) for obesity-related respiratory failure (ORRF). Records from April 2013 to March 2020 were accessed from a NIV quality database at an acute teaching hospital. Adults with hypercapnic ORRF requiring acute NIV were included. pH data were grouped by threshold (pH≤ and >7.25) and correlated with time from presentation to death; multivariable analysis was performed using Cox proportional hazards. A total of 277 acute NIV episodes were included. Two-year mortality was similar for patients in both pH categories. Univariable analysis identified pH ≤ 7.25 to increase risk of two-year mortality by 43%. However, multivariable analysis identified that pH was not a significant determinant of long-term mortality, although male sex, older age, and higher admission pCO2 increased the risk of death at two years by 76%, 3% per year of age, and 16% per 1 kPa of pCO2 increase, respectively. Severity of hypercapnia on admission, male sex, and older age are associated with worse two-year mortality in patients requiring acute NIV for ORRF. There is scope for further analyses including investigating the role of domiciliary NIV in ORRF patients.

Home mechanical ventilation: back to basics.

Over recent decades, the use of home mechanical ventilation (HMV) has steadily increased worldwide, with varying prevalence in different countries. The key indication for HMV is chronic respiratory failure with alveolar hypoventilation (e.g., neuromuscular and chest wall disease, obstructive airway diseases, and obesity-related respiratory failure). Most modern home ventilators are pressure-targeted and have sophisticated modes, alarms, and graphics, thereby facilitating optimization of the ventilator settings. However, different ventilators have different algorithms for tidal volume estimation and leak compensation, and there are also several different circuit configurations. Hence, a basic understanding of the fundamentals of HMV is of paramount importance to healthcare workers taking care of patients with HMV. When choosing a home ventilator, they should take into account many factors, including the current condition and prognosis of the primary disease, the patient’s daily performance status, time (hr/day) needed for ventilator support, family support, and financial costs. In this review, to help readers understand the basic concepts of HMV use, we describe the indications for HMV and the factors that influence successful delivery, including interface, circuits, ventilator accessories, and the ventilator itself.

Non-invasive ventilation for obese patients with chronic respiratory failure: Are two pressures always better than one?

Obesity-related respiratory failure is increasingly common but remains under-diagnosed and under-treated. There are several clinical phenotypes reported, including severe obstructive sleep apnoea (OSA), isolated nocturnal hypoventilation with or without severe OSA and OSA complicating chronic obstructive pulmonary disease (COPD). The presence of hypercapnic respiratory failure is associated with poor clinical outcomes in each of these groups. While weight loss is a core aim of management, this is often unachievable, and treatment of sleep-disordered breathing with positive airway pressure (PAP) therapy is the mainstay of clinical practice. Although there are few long-term clinical efficacy trials, the lack of equipoise would prevent the utilization of an untreated control group. The current data support the use of PAP therapy to improve respiratory failure and is associated with improvements in health-related quality of life, reduced healthcare utilization and reduced mortality. Both continuous PAP (CPAP) and non-invasive ventilation (NIV) appear safe and effective in patients with obesity-related respiratory failure and OSA, with or without COPD, and the current evidence would not support a single therapy choice in all patients. There are no studies of CPAP in patients with isolated nocturnal hypoventilation, and NIV would be the current recommendation in this patient group. Whichever starting therapy is used, titration should be performed to correct sleep-disordered breathing and reverse chronic respiratory failure, with consideration of step-down of the treatment based on a clinical re-evaluation. In contrast, failure to reach physiological and clinical treatment targets should lead to the consideration of treatment escalation.

Obesity-related respiratory failure: a new area for extracorporeal lung support?

In the ICU, the main challenges with obese patients are to take into account the pulmonary pathophysiological characteristics when choosing the best management options.

Prospective observational cohort study of patients with weaning failure admitted to a specialist weaning, rehabilitation and home mechanical ventilation centre

ObjectivesAccording to National Health Service England (NHSE) specialist respiratory commissioning specification for complex home ventilation, patients with weaning failure should be referred to a specialist centre. However, there are limited...

Update on clinical trials in home mechanical ventilation.

Home mechanical ventilation (HMV) is an increasingly common intervention and is initiated for a range of pathological processes, including neuromuscular disease (NMD), chronic obstructive pulmonary disease (COPD) and obesity related respiratory failure. There have been important recent data published in this area, which helps to guide practice by indicating which populations may benefit from this intervention and the optimum method of setting up and controlling sleep disordered breathing. Recent superficially conflicting data has been published regarding HMV in COPD, with a trial in post-exacerbation patients suggesting no benefit, but in stable chronic hypercapnic patients suggesting a clear and sustained mortality benefit. The two studies are critiqued and the potential reasons for the differing results are discussed. Early and small trial data is frequently contradicted with larger randomised controlled trials and this has been the case with diaphragm pacing being shown to be potentially harmful in the latest data, confirming the importance of non-invasive ventilation (NIV) in NMD such as motor neurone disease. Advances in ventilator technology have so far appeared quicker than the clinical data to support their use; although small and often unblinded, the current data suggests equivalence to standard modes of NIV, but with potential comfort benefits that may enhance adherence. The indications for NIV have expanded since its inception, with an effort to treat sleep disordered breathing as a result of chronic heart failure (HF). The SERVE-HF trial has recently demonstrated no clear advantage to this technology and furthermore detected a potentially deleterious effect, with a worsening of all cause and cardiovascular mortality in the treated group compared to controls. The review serves to provide the reader with a critical review of recent advances in the field of sleep disordered breathing and HMV.

Medium-term cost-effectiveness of an automated non-invasive ventilation outpatient set-up versus a standard fixed level non-invasive ventilation inpatient set-up in obese patients with chronic respiratory failure: a protocol description

IntroductionObesity is an escalating issue, with an accompanying increase in referrals of patients with obesity-related respiratory failure. Currently, these patients are electively admitted to hospital for initiation of non-invasive ventilation...

P301 A Large Retrospective Evaluation Of Domiciliary And Outpatient Initiation Of Home Mechanical Ventilation

Introduction and objectives Home Mechanical Ventilation (HMV) for patients with chronic ventilatory failure (CVF) often requires hospital admission for initiation of treatment. There are limited data evaluating the efficacy, efficiency and safety of initiating HMV in the domiciliary setting. Our centre has undertaken over 200 ‘home set-ups’ and we have evaluated outcomes in these patients. Methods Patients with CVF who had HMV initiated in the domiciliary or outpatient setting were identified from our hospital database and data were retrospectively collected from their hospital records. Results 214 patients with CVF were set-up at home between 2004 to 2013. Notes were available for 193 (90%) patients, mean (SD) age 59 (14) years, 63% male. The majority of patients had Motor Neuron Disease (MND)(30%) or obesity related respiratory failure (23%). Baseline lung function and arterial blood gas parameters are shown in Table 1. 178 (92%) patients had HMV initiated in their home; 15 attended the outpatient clinic for set-up. Three patients subsequently required hospital admission to support adaptation to HMV. Following initiation, 135 (70%) patients were assessed as compliant with HMV, defined as >4 h self-reported use each night. Patients with MND had the lowest compliance rate with only 30 (52%) achieving this usage. If those with MND are excluded, overall compliance was 77% which is similar to our inpatient initiated HMV compliance rate of 83% (n = 224) and to case series reported by other centres. Patients with few symptoms of nocturnal hypoventilation had a lower compliance rate (55%) than more symptomatic patients (71%). In patients who were compliant with HMV, mean (SD) time until >4 h use per night was 27 (60) days, but 33 (17%) patients achieved this usage after the first night. Those who became compliant with HMV had a mean of 2.9 (3.2) home visits and 1.4 (1.8) phone calls each. Conclusion Establishing HMV in the domiciliary and outpatient setting can be effectively and safely achieved, even in patients with marked nocturnal hypoventilation. Apart from patients with MND or those who are minimally symptomatic, ‘home set-up’ of HMV does not appear to affect compliance significantly.

S84 The effect of patient ventilator asynchrony (PVA) on health related quality of life during initiation of home mechanical ventilation (HMV)

IntroductionPoor patient-ventilator interaction has been shown to adversely affect respiratory muscle unloading, sleep quality, gas exchange and patient comfort whilst on ventilation. We hypothesised that nocturnal PVA during the first...

S86 Change in patient demographics and Home Mechanical Ventilation (HMV) set up for patients with chronic respiratory failure between 2006 and 2012

IntroductionHMV is standard therapy for long term management of chronic respiratory failure in patients with neuromuscular disease (NMD), chest wall disease (CWD), chronic obstructive pulmonary disease (COPD) and obesity related...

S133 Observational cohort study of outcome of patients referred to a regional weaning centre

IntroductionData on outcome of the patients referred to weaning and rehabilitation centres are limited. In this observational cohort study, we report the outcomes of patients referred to a specialist complex...

P274 Seasonal variation in initiation and discontinuation of domiciliary non-invasive ventilation: a 12-month cohort study

IntroductionDomiciliary non-invasive ventilation (NIV) is an established treatment for patients with chronic respiratory failure. Although the proportion of patients that discontinue NIV is reported from clinical trial data, observational cohort...

S67 Phenotypic differences between obese patients with eucapnic and hypercapnic sleep-disordered breathing (SDB)

BackgroundObesity-related SDB requiring domiciliary non-invasive ventilation (NIV) can present as (1) eucapnic obstructive sleep apnoea (OSA) (2) hypercapnic OSA (PaCO2 >6 kPa) (3) hypercapnic OSA with obesity hypoventilation syndrome (OHS)...