Bart Vrijsen

Skeletal muscle weakness, exercise tolerance and physical activity in adults with cystic fibrosis

The aim of the present study was to investigate the prevalence of muscle weakness and the importance of physical inactivity in cystic fibrosis (CF), and its relationship to exercise tolerance and muscle strength. Exercise tolerance, skeletal and respiratory muscle strength were studied in a group of 64 adults with CF (age 26±8 yrs, FEV1 % predicted 65±19) and in 20 age-matched controls. Physical activity (PA) was assessed in 20 patients and all controls. Quadriceps muscle weakness was present in 56% of the patients. Peak oxygen uptake and 6-min walking distance were below normal in 89 and 75% of patients, respectively. Respiratory muscle strength was normal. The differences remained after correcting for PA. Quadriceps force was correlated to the 6-min walking distance but not to peak oxygen uptake. “Mild” PA (>3 metabolic equivalents (METS)) and the number of steps overlapped with controls, but CF patients had less moderate PA (>4.8 METS). Moderate PA was related to peak oxygen uptake and quadriceps force. Skeletal muscle weakness and exercise intolerance are prevalent in cystic fibrosis. Physical inactivity is a factor significantly contributing to exercise tolerance and skeletal muscle force in adults with cystic fibrosis, but these impairments are in excess to that expected from physical inactivity only.

Definition, discrimination, diagnosis and treatment of central breathing disturbances during sleep

The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a “marker” of disease severity or a “mediator” of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation. Description of the actual approach to differential diagnosis and treatment options in central breathing disturbances http://ow.ly/QsE9304Jt8f

Noninvasive ventilation improves sleep in amyotrophic lateral sclerosis: a prospective polysomnographic study.

STUDY OBJECTIVE To evaluate the effects of noninvasive ventilation (NIV) on sleep in patients with amyotrophic lateral sclerosis (ALS) after meticulous titration with polysomnography (PSG). METHODS In this prospective observational study, 24 ALS patients were admitted to the sleep laboratory during 4 nights for in-hospital NIV titration with PSG and nocturnal capnography. Questionnaires were used to assess subjective sleep quality and quality of life (QoL). Patients were readmitted after one month. RESULTS In the total group, slow wave sleep and REM sleep increased and the arousal-awakening index improved. The group without bulbar involvement (non-bulbar) showed the same improvements, together with an increase in sleep efficiency. Nocturnal oxygen and carbon dioxide levels improved in the total and non-bulbar group. Except for oxygen saturation during REM sleep, no improvement in respiratory function or sleep structure was found in bulbar patients. However, these patients showed less room for improvement. Patient-reported outcomes showed improvement in sleep quality and QoL for the total and non-bulbar group, while bulbar patients only reported improvements in very few subscores. CONCLUSIONS This study shows an improvement of sleep architecture, carbon dioxide, and nocturnal oxygen saturation at the end of NIV titration and after one month of NIV in ALS patients. More studies are needed to identify the appropriate time to start NIV in bulbar patients. Our results suggest that accurate titration of NIV by PSG improves sleep quality. COMMENTARY A commentary on this article appears in this issue on page 511.

Impact of exacerbations of cystic fibrosis on muscle strength.

BackgroundAdult patients with cystic fibrosis have peripheral muscle weakness, which is related to exercise intolerance and poor prognosis. The influence of acute exacerbations on muscle strength has been poorly studied. This study aimed to investigate whether quadriceps force (QF), as assessed with an involuntary technique, changes during intravenous antibiotics therapy (IVAT) for an exacerbation.MethodsQF was measured in 20 patients using twitch stimulation of the femoral nerve at the day of hospitalization (day 1) and at termination (day 14) of the IVAT. Physical activity was monitored during IVAT using a SenseWear armband. Ten stable patients served as control subjects.ResultsQF did not change during exacerbation (potentiated twitch force at day 1: 140 ± 42 N, at day 14: 140 ± 47 N), but a decrease was observed in individual patients. Changes in twitch force during exacerbation were correlated with time spent in activities of at least moderate intensity (r = 0.61, p = 0.007).ConclusionsQF does not systematically decrease during exacerbations of cystic fibrosis. Individual changes in QF are well correlated with daily time spent in activities of at least moderate intensity.

Non-invasive ventilation in amyotrophic lateral sclerosis

Abstract Non-invasive ventilation (NIV) is widely used to improve alveolar hypoventilation in amyotrophic lateral sclerosis. Several studies indicate a better survival when NIV is used, certainly in patients with none to moderate bulbar dysfunction. Data on quality of life (QoL) are rather disputable. Overall QoL is shown to be equivalent in patients with or without NIV, although health-related QoL is shown to be increased in patients with none to moderate bulbar dysfunction. NIV improves sleep quality, although patient-ventilator asynchronies are demonstrated. FVC < 50%, seated or supine, has been widely applied as threshold to initiate NIV. Today, measurements of respiratory muscle strength, nocturnal gas exchange and symptomatic complaints are used as indicators to start NIV. Being compliant with NIV therapy increases QoL and survival. Cough augmentation has an important role in appropriate NIV. Patients have today more technical options and patients with benefit from these advances are growing in number. Tracheal ventilation needs to be discussed when NIV seems impossible or becomes insufficient.

Hot Topics in Noninvasive Ventilation: Report of a Working Group at the International Symposium on Sleep-Disordered Breathing in Leuven, Belgium

During the last few decades, attention has increasingly focused on noninvasive ventilation (NIV) in the treatment of chronic respiratory failure. The University of Leuven and the University Hospitals Leuven therefore chose this topic for a 2-day working group session during their International Symposium on Sleep-Disordered Breathing. Numerous European experts took part in this session and discussed (1) NIV in amyotrophic lateral sclerosis (when to start NIV, NIV and sleep, secretion management, and what to do when NIV fails), (2) recent insights in NIV and COPD (high-intensity NIV, NIV in addition to exercise training, and NIV during exercise training), (3) monitoring of NIV (monitoring devices, built-in ventilator software, leaks, and asynchronies) and identifying events during NIV; and (4) recent and future developments in NIV (target-volume NIV, electromyography-triggered NIV, and autoregulating algorithms).

Noninvasive ventilation in amyotrophic lateral sclerosis: effects on sleep quality and quality of life

Objectives: Little is known about the effects of noninvasive ventilation (NIV) on sleep quality in amyotrophic lateral sclerosis (ALS). We aim to evaluate the long-term effects of NIV on sleep quality and quality of life in patients with ALS. Methods: In this prospective observational study, 13 ALS patients were followed for one year after initiating NIV. We evaluated sleep quality, quality of life and functional status with several questionnaires: Epworth sleepiness Scale (ESS), Pittsburg sleep quality index (PSQI), Short Form 36 Health Questionnaire (SF-36), McGill Quality of Life questionnaire (McGillQoL) and revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores (ALSFRS-R). Results: Median and interquartile range (IQR) at the start of NIV was 59 (53–65) years. The ALSFRS-R at start was 30 (24–37) (median, IQR), with three patients having severe bulbar impairment (ALSFRS-R-bulbar ≤ 9). The PaCO2 at start of NIV treatment was 48 (43–52) mmHg (median, IQR). During the one-year follow-up period, a significant decrease in the ALSFRS-R was observed. The impact of NIV in a short term (1 month) revealed a statistically significant decrease in ESS, decrease in total PSQI and of four PSQI subscales and improvement of almost all subscales of the McGill questionnaire. Long-term analyses (9 months to 1 year) revealed that amelioration in ESS and total PSQI was sustained. Conclusion: We conclude that accurately titrated NIV in ALS patients can stabilize sleep quality and quality of life for at least one year, despite significant disease progression.

Upper Airway Obstruction during Noninvasive Ventilation Induced by the Use of an Oronasal Mask

In patients with neuromuscular disorders, no randomized studies have been performed whether nasal or oronasal masks should be preferred. Oronasal masks are often used in acute respiratory failure, while nasal masks are preferred in patients with chronic respiratory failure. However, the use of nasal masks can result in mouth leaks with implications on sleep quality. To reduce these leaks, oronasal masks have been applied during home noninvasive ventilation (NIV). Until now, upper airway obstruction during NIV has been thought to be induced by nasal obstruction, pharyngeal collapse, and/or glottis closure. We report a case indicating another cause of upper airway obstruction: use of an oronasal mask can induce obstructive events in the upper airways, possibly resulting in sleep fragmentation and decreased efficiency of NIV.

Patient-ventilator asynchrony, leaks and sleep in patients with amyotrophic lateral sclerosis

Abstract Sleeping with non-invasive ventilation (NIV) in amyotrophic lateral sclerosis appears to be accompanied by a high patient-ventilator asynchrony (PVA) index. This prospective observational cohort study quantifies PVA and leaks, and searches for effects of these events on sleep after polysomnographic NIV titration. Full-video polysomnography, with incorporation of transcutaneous carbon dioxide and ventilator software, was used to analyse sleep epoch-by-epoch and respiratory events and PVA breath-by-breath in 35 patients (17 non-bulbar). After diagnostic polysomnography, NIV was titrated during three consecutive nights. Sleep, PVA and leaks were evaluated at discharge and after one month. Results showed that non-bulbar patients improved in sleep architecture and oxygen and carbon dioxide levels while bulbar patients only improved oxygen saturation. PVA remained present at discharge (non-bulbar 54 (21–101) and bulbar 31 (9–39)/h sleep) and one month (non-bulbar 31 (9–39) and bulbar 32 (17–55)/h sleep), with ineffective effort as most prominent asynchrony. Leaks also persisted after titration (non-bulbar 16.6 (3.1–44.6) and bulbar 5.1 (0.0–19.5)% of total sleep time (TST)) and one month (non-bulbar 7.7 (1.4–29.3) and bulbar 12.7 (0.0–35.2)% TST). PVA and leaks have none to minor effect on sleep architecture. In conclusion, although PVA and leaks remain present after meticulous NIV titration, these events seem not to interfere with sleep.

Randomized cross-over trial of ventilator modes during non-invasive ventilation titration in amyotrophic lateral sclerosis

Non‐invasive ventilation (NIV) improves survival, quality of life and sleep in patients with amyotrophic lateral sclerosis (ALS). Nevertheless, NIV titration is conducted in different ways. We aim to provide more insight into NIV titration by comparing the effects of a spontaneous (S) and spontaneous‐timed (ST) modes on gas exchange, sleep architecture and patient‐ventilator asynchronies (PVAs).