Long-term Nocturnal Non-invasive Ventilation Research Articles

Sleep-Related Breathing Complaints in Chronic Obstructive Pulmonary Disease.

This review presents the normal physiologic changes in ventilation during sleep and how they can be detrimental to chronic obstructive pulmonary disease (COPD). Sleep-related breathing disorders (SRBDs) in COPD lead to higher morbidity and mortality if left unrecognized and untreated. The diagnosis of SRBDs requires a high index of suspicion, as symptoms may overlap with other sleep disorders. Mortality risk is improved when patients with COPD with OSA (overlap syndrome) are treated with positive airway pressure and when long-term nocturnal noninvasive ventilation is started on chronic stable hypercapnic COPD. Treatment of isolated nocturnal oxygen desaturation has not been associated with improved survival.

Obesity Hypoventilation: Traditional Versus Nontraditional Populations.

Obesity hypoventilation syndrome is the most frequent cause of chronic hypoventilation and is increasingly more common with rising obesity rates. It leads to considerable morbidity and mortality, particularly when not recognized and treated adequately. Long-term nocturnal noninvasive ventilation is the mainstay of treatment but evidence suggests that CPAP may be effective in stable patients. Specific perioperative management is required to reduce complications. Some unique syndromes associated with obesity and hypoventilation include rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation (ROHHAD), and Prader-Willi syndrome. Congenital central hypoventilation syndrome (early or late-onset) is a genetic disorder resulting in hypoventilation. Several acquired causes of chronic central hypoventilation also exist. A high level of clinical suspicion is required to appropriately diagnose and manage affected patients.

Electromyography-Based Respiratory Onset Detection in COPD Patients on Non-Invasive Mechanical Ventilation.

To optimize long-term nocturnal non-invasive ventilation in patients with chronic obstructive pulmonary disease, surface diaphragm electromyography (EMGdi) might be helpful to detect patient-ventilator asynchrony. However, visual analysis is labor-intensive and EMGdi is heavily corrupted by electrocardiographic (ECG) activity. Therefore, we developed an automatic method to detect inspiratory onset from EMGdi envelope using fixed sample entropy (fSE) and a dynamic threshold based on kernel density estimation (KDE). Moreover, we combined fSE with adaptive filtering techniques to reduce ECG interference and improve onset detection. The performance of EMGdi envelopes extracted by applying fSE and fSE with adaptive filtering was compared to the root mean square (RMS)-based envelope provided by the EMG acquisition device. Automatic onset detection accuracy, using these three envelopes, was evaluated through the root mean square error (RMSE) between the automatic and mean visual onsets (made by two observers). The fSE-based method provided lower RMSE, which was reduced from 298 ms to 264 ms when combined with adaptive filtering, compared to 301 ms provided by the RMS-based method. The RMSE was negatively correlated with the proposed EMGdi quality indices. Following further validation, fSE with KDE, combined with adaptive filtering when dealing with low quality EMGdi, indicates promise for detecting the neural onset of respiratory drive.

Low Levels of PaO2 after Long-term Noninvasive Ventilation are a Poor Prognostic Factor in Patients with Restrictive Thoracic Disease.

Objective The effects of partial pressure of arterial oxygen (PaO2) after introducing long-term noninvasive ventilation (NIV) on the prognosis of patients with restrictive thoracic disease and chronic respiratory failure are not exactly known. Methods Data from 141 patients with restrictive thoracic disease under long-term nocturnal NIV were retrospectively examined. We divided the patients into 2 groups according to the daytime PaO2 value while breathing spontaneously with prescribed oxygen at 12 months after introducing NIV: PaO2≥80 Torr group (n=76) and PaO2<80 Torr group (n=65). Results During the 4-year follow-up, the mortality was significantly higher in the PaO2<80 Torr group than in the PaO2≥80 Torr group (50.8% vs. 32.9%, p=0.03). Independent factors associated with the 4-year mortality after introducing NIV determined by a multivariate logistic regression analysis were a low body mass index [odds ratio (OR) 0.87; 95% confidence interval (CI) 0.77 to 0.97; p=0.01], assisted mode with NIV (OR 4.11; 95% CI, 1.79 to 9.45; p=0.0009), hospitalization during the first year of introducing NIV (OR 1.72; 95% CI, 1.06 to 2.79; p=0.03), and daytime PaO2<80 Torr at 12 months after introducing NIV (OR 2.30; 95% CI, 1.03 to 5.10; p=0.04). Conclusion A low daytime PaO2 at 12 months after introducing NIV was an independent risk factor for mortality. Keeping the daytime PaO2≥80 Torr through the adjustment of the nocturnal NIV settings or increased diurnal supplemental oxygen may help improve the prognosis in patients with restrictive thoracic disease who are under NIV.

High‐intensity non‐invasive ventilation in stable hypercapnic COPD: Evidence of efficacy and practical advice

Patients with end-stage chronic obstructive pulmonary disease (COPD) frequently develop chronic hypercapnic respiratory failure (CHRF), with disabling symptoms and poor survival. The use of long-term nocturnal non-invasive ventilation (NIV) to treat CHRF in COPD has long been subject of debate due to conflicting evidence. However, since the introduction of high-intensity NIV (HI-NIV) in COPD, physiological and clinical benefits have been shown. HI-NIV refers to specific ventilator settings used for NIV aimed at achieving normocapnia or the lowest partial arterial carbon dioxide pressure (PaCO2 ) values as possible. This review will provide an overview of existing evidence of the efficacy of HI-NIV stable COPD patients with CHRF. Secondly, we will discuss hypotheses underlying NIV benefit in stable hypercapnic COPD, providing insight into better patient selection and hopefully more individually titrated HI-NIV. Finally, we will provide practical advice on how to initiate and follow-up patients on HI-NIV, with special emphasis on monitoring that should be available during the initiation and follow-up of HI-NIV, and will discuss more extended monitoring techniques that could improve HI-NIV treatment in the future.

Pre-flight assessment in patients with obesity hypoventilation syndrome.

Reduced atmospheric pressure during air travel can cause significant hypoxaemia in some patients with respiratory disease. Our aims were to investigate the degree of hypoxaemia in patients with obesity hypoventilation syndrome (OHS) during hypoxic challenge test (HCT), and to identify any predictors of a positive HCT. Thirteen patients underwent assessment, including HCT, lung function and incremental shuttle walk test. All had OHS well controlled with long-term nocturnal non-invasive ventilation (NIV). Patients with chronic obstructive pulmonary disease were excluded. A positive HCT was defined according to the British Thoracic Society (BTS) recommendation as arterial oxygen tension (PaO₂) <6.6 kPa and/or oxygen saturation <85%. Mean age was 57 (± 11) years. Mean body mass index was 51.7 (± 12) kg/m(2) . Mean baseline PaO₂ and arterial carbon dioxide tension (PaCO₂) were 10.2 (9.5-11.3) kPa and 5.2 (3.7-6.8) kPa, respectively. Seven patients (54%) had a positive HCT. The correlation between baseline PaO₂ and PaO₂ at the end of the HCT was not statistically significant (r = 0.433, P = 0.184). A negative correlation was observed between baseline PaCO₂ and PaO₂ at the end of the HCT (r = -0.793, P = 0.004). A positive correlation was observed between the distance walked and the PaO₂ at the end of the HCT (r = 0.608, P = 0.047). OHS is a risk factor for severe hypoxaemia during air travel even if the ventilatory failure is well controlled. An HCT before air travel is advisable in all OHS patients. Those with positive HCT may use NIV or have oxygen on-board as per BTS recommendation.

The evolution of practice of noninvasive ventilation: epidemiologic outcomes and patient’s preference

One of the most important developments in the field of mechanical ventilation over the past 15 years has been the emergence of noninvasive ventilation (NIV) as an increasing part of the critical care armamentarium [1]. Noninvasive positive-pressure ventilation (NPPV) is the delivery of mechanical ventilation to patients with respiratory failure without the requirement of an artificial airway. Although NPPV is often used for long-term nocturnal or continuous support of patients with forms of chronic respiratory failure [2], its use is increasingly popular in varied clinical situations in the intensive care unit (ICU) setting as high-level evidence supporting its use continues to accumulate [3–5]. The attraction for NPPV relates primarily to its advantages over invasive mechanical ventilation (Table 1). It has been shown to comparatively decrease resource utilization and circumvent the myriad of complications associated with invasive mechanical ventilation such as upper airway trauma, ventilator-associated pneumonia, and compromise of speech and swallowing [6, 7]. NPPV should, however, be considered in some cases an alternative to invasive mechanical ventilation rather than its replacement [8–12]. Keys to the success of NPPV and to improve clinical outcomes of patients with acute respiratory failure are careful patient selection and a well-designed clinical protocol because failure of NPPV only delays potentially more definitive therapy with invasive ventilation [13]. Decades of experience during the polio epidemics [14, 15] and subsequently [16–18] established long-term nocturnal noninvasive ventilation stabilizes gas exchange and improves symptoms in patients with chronic respiratory failure. For home mechanical ventilation, noninvasive ventilation has a number of advantages over invasive mechanical ventilation, including greater ease of administration, reduced need for skilled caregivers, elimination of tracheostomy-related complications, enhanced patient comfort, and lower cost [19, 20]. However, as is the case in the acute setting, not all patients with chronic respiratory failure are good candidates for noninvasive ventilation. Long-term mechanical ventilation at home now incorporates both ventilator-dependent ([16 h per day ventilatory support) and ventilator-assisted (primarily nocturnal only) individuals, using a variety of devices and interfaces including invasive ventilation and NIV techniques [21]. The diversity of conditions and variability in level of care needed by these individuals means that introducing and maintaining long-term ventilation in the home requires skill and experience on the part of the prescribing center, particularly if the patient is using ventilatory support on a near continuous basis or has a tracheostomy in place for the delivery of ventilation [22–24]. Additionally, introducing medical technology into the home raises a number of issues for the patient and caregivers, as well as local health services, which need to be identified on an individual basis [25, 26].

Long-term non-invasive ventilation in COPD after acute-on-chronic respiratory failure

COPD patients who remain hypercapnic after acute respiratory failure requiring mechanical ventilation have a poor prognosis. Long-term nocturnal non-invasive ventilation (NIV) may be beneficial for these patients. We hypothesized that stable patients on long-term NIV would experience clinical worsening after withdrawal of NIV. We included 26 consecutive COPD patients (63 ± 6 years, 58% male, FEV(1) 31 ± 14% predicted) who remained hypercapnic after acute respiratory failure requiring mechanical ventilation. After a six month run-in period, during which all patients received NIV, they were randomised to either continue (ventilation group, n = 13) or to stop NIV (withdrawal group, n = 13). The primary endpoint was time to clinical worsening defined as an escalation of mechanical ventilation. All patients remained stable during the run-in period. After randomisation the withdrawal group had a higher probability of clinical worsening compared to the ventilation group (p = 0.0018). After 12 months, ten patients (77%) in the withdrawal group, but only two patients (15%) in the ventilation group, experienced clinical worsening (p = 0.0048). Six-minute walking distance increased in the ventilation group. COPD patients who remain hypercapnic after acute respiratory failure requiring mechanical ventilation may benefit from long-term NIV.

The Effects of Withdrawing Long-Term Nocturnal Non-Invasive Ventilation in COPD Patients

ABSTRACTPatients with ventilatory failure due to chronic obstructive pulmonary disease (COPD) are increasingly managed with long-term non-invasive positive pressure ventilation (NIPPV) and this may improve survival. NIPPV can frequently be interrupted but there are few data detailing the short-term effects and none on the longer-term consequences of treatment withdrawal. Ten patients withdrew from NIPPV for 1 week and were randomised to restart NIPPV or to continued withdrawal for up to 6 months. Outcomes assessed included daytime blood gases, nocturnal ventilation, lung function, exercise capacity and health status. After 1 week of withdrawal PaO2, PaCO2, nocturnal oximetry, lung function and exercise capacity did not change, but mean nocturnal transcutaneous CO2 (6.3 (1) vs. 7.6 (1.1) kPa p = 0.04) and daytime blood gas bicarbonate (30.3 (4.5) vs. 31.2 (3.9) mmol/L p = 0.04) rose. During a 6-month period of withdrawal of nocturnal NIPPV, daytime PaCO2 (6 (1.1) vs. 7.5 (1.3) kPa p = 0.002) increased and health status (total St George's Respiratory Questionnaire score 55.5 (6.3) vs. 65.6 (10) p = 0.006) worsened. Three out of five patients met a priori criteria to restart NIPPV in the continued withdrawal group. Short interruptions to domiciliary NIPPV used to manage chronic ventilatory failure as a consequence of COPD do not cause a rapid clinical deterioration but nocturnal ventilation worsens and daytime bicarbonate levels increase following 1 week's cessation. Thereafter, daytime PaCO2 rises and health status worsens, supporting the role of long-term NIPPV in the management of such patients.