Manual vs. automated analysis of polysomnographic recordings in patients with chronic obstructive pulmonary disease.

PURPOSE: The sleep quality, as assessed by polysomnography (PSG), of patients with chronic obstructive pulmonary disease (COPD) can be severely disturbed. The manual analysis of PSGs is time-consuming, and computer systems have been developed to automatically analyze PSGs. Studies on the reliability of automated analyses in healthy subjects show varying results, and the purpose of this study was to assess whether automated analysis of PSG by one certain automatic system in patients with COPD provide accurate outcomes when compared to manual analysis. METHODS: In a retrospective study, the full-night polysomnographic recordings of patients with and without COPD were analyzed automatically by Matrix Sleep Analysis software and manually. The outcomes of manual and automated analyses in both groups were compared using Bland-Altman plots and Students' paired t tests. RESULTS: Fifty PSGs from patients with COPD and 57 PSGs from patients without COPD were included. In both study groups, agreement between manual and automated analysis was poor in nearly all sleep and respiratory parameters, like total sleep time, sleep efficiency, sleep latency, amount of rapid eye movement sleep and other sleep stages, number of arousals, apnea-hypopnea index, and desaturation index. CONCLUSION: Automated analysis of PSGs by the studied automated system in patients with COPD has poor agreement with manual analysis when looking at sleep and respiratory parameters and should, therefore, not replace the manual analysis of PSG recordings in patients with COPD.

Effectiveness of a Mobile Health and Self-Management App for High-Risk Patients With Chronic Obstructive Pulmonary Disease in Daily Clinical Practice: Mixed Methods Evaluation Study.

BACKGROUND: Mobile health and self-management interventions may positively affect behavioral change and reduce hospital admissions for patients with chronic obstructive pulmonary disease (COPD). However, not all patients qualify for these interventions, and systematic, comprehensive information on implementation- and compliance-related aspects of mobile self-management apps is lacking. Due to the tendency to target digital services to patients in stable phases of disease, it is especially relevant to focus on the use of these services in broad clinical practice for patients recently discharged from hospital. OBJECTIVE: This study aims to evaluate the effects of a mobile health and self-management app in clinical practice for recently discharged patients with COPD on use of the app, self-management, expectations, and experiences (technology acceptance); patients' and nurses' satisfaction; and hospital readmissions. METHODS: A prototype of the app was pilot tested with 6 patients with COPD. The COPD app consisted of an 8-week program including the Lung Attack Action Plan, education, medication overview, video consultation, and questionnaires (monitored by nurses). In the feasibility study, adult patients with physician-diagnosed COPD, access to a mobile device, and proficiency of the Dutch language were included from a large teaching hospital during hospital admission. Self-management (Partners in Health Scale), technology acceptance (Unified Theory Acceptance and Use of Technology model), and satisfaction were assessed using questionnaires at baseline, after 8 weeks, and 20 weeks. Use was assessed with log data, and readmission rates were extracted from the electronic medical record. RESULTS: A total of 39 patients were included; 76.4% (133/174) of patients had to be excluded from participation, and 48.9% of those patients (65/133) were excluded because of lack of digital skills, access to a mobile device, or access to the internet. The COPD app was opened most often in the first week (median 6.0; IQR 3.5-10.0), but its use decreased over time. The self-management element knowledge and coping increased significantly over time (P=.04). The COPD app was rated on a scale of 1-10, with an average score by patients of 7.7 (SD 1.7) and by nurses of 6.3 (SD 1.2). Preliminary evidence about the readmission rate showed that 13% (5/39) of patients were readmitted within 30 days; 31% (12/39) of patients were readmitted within 20 weeks, compared with 14.1% (48/340) and 21.8% (74/340) in a preresearch cohort, respectively. CONCLUSIONS: The use of a mobile self-management app after hospital discharge seems to be feasible only for a small number of patients with COPD. Patients were satisfied with the service; however, use decreased over time, and only knowledge and coping changed significantly over time. Therefore, future research on digital self-management interventions in clinical practice should focus on including more difficult subgroups of target populations, a multidisciplinary approach, technology-related aspects (such as acceptability), and fine-tuning its adoption in clinical pathways. TRIAL REGISTRATION: Clinicaltrials.gov NCT04540562; https://clinicaltrials.gov/ct2/show/NCT04540562.

Accuracy of transcutaneous carbon dioxide tension measurements during cardiopulmonary exercise testing.

BACKGROUND: Measurements of transcutaneous carbon dioxide tension (PtcCO(2)) with current devices are proven to provide clinically acceptable agreement with measurements of partial arterial carbon dioxide tension (PaCO(2)) in several settings but not during cardiopulmonary exercise testing (CPET). OBJECTIVES: The primary objective of this study was to investigate the agreement between PaCO(2) and PtcCO(2) measurements (using a Tosca 500 with a Tosca sensor 92) during CPET. A secondary objective was to investigate the agreement between arterial and transcutaneous oxygen saturation (SaO(2), SpO(2)) as measured with this sensor during CPET. METHODS: In patients with various pulmonary diseases, PtcCO(2) and SpO(2) were continuously measured and compared with arterial blood gas samples during CPET. A maximum bias of 0.5 kPa and 95% limits of agreement (LOA) of 1 kPa between carbon dioxide pressure (PCO(2)) measurements were determined as clinically acceptable. RESULTS: In total 101 'paired' arterial and transcutaneous measurements were obtained from 21 patients. Bias between PaCO(2) and PtcCO(2) was -0.03 kPa with LOA from -0.78 to 0.71 kPa. Bias between SaO(2) and SpO(2) was -1.0% with LOA from -2.83 to 0.83%. CONCLUSIONS: Transcutaneous estimations of PCO(2) and SpO(2) are accurate and can be used in CPET, circumvening the need for arterial cannulation.

Sleep, hypnotics and chronic obstructive pulmonary disease.

The quality of sleep is significantly compromised in many patients with chronic obstructive pulmonary disease (COPD) and may be further diminished when certain comorbidities are present. A reduced sleep quality is associated with daytime consequences like fatigue, psychiatric problems and an impaired quality of life. Sleep induces physiologic alterations in respiratory function, which can become pathologic and may provoke or worsen hypoxemia and hypercapnia in COPD. Dyspnea, cough and excessive mucus production should be optimised to minimise causes for sleep disturbance. Pharmacological therapy may be helpful; sedatives like benzodiazepines and non-benzodiazepine benzodiazepine-receptor agonists (NBBRAs) are (equally) effective in improving sleep quality. Whether or not these hypnotics produce serious adverse respiratory effects during sleep, remains unclear due to opposing studies. Therefore, their use should be as short as possible.

Exercise performance improves in patients with COPD due to respiratory muscle endurance training.

BACKGROUND: Impaired exercise tolerance is frequently observed in patients with COPD. Respiratory muscle endurance training (RMET) by means of normocapnic hyperpnea can be used to improve respiratory muscle function and probably exercise capacity. RMET is not applied on a large scale because complicated equipment is needed to maintain carbon dioxide homeostasis during hyperpnea, which can also be done by enlarging the dead space of the ventilatory system by breathing through a tube. Therefore, tube breathing might be a new, inexpensive method for home-based RMET. The aim of this study was to assess whether home-based RMET by means of tube breathing improves endurance exercise performance in patients with COPD. METHODS: We randomized 36 patients with moderate-to-severe COPD to RMET by paced tube breathing (n = 18) or sham training (control, n = 18). Both groups trained twice daily for 15 min, 7 days per week, for 5 weeks. RESULTS: Patients receiving RMET showed significant improvements in endurance exercise capacity (constant-load exercise on cycle ergometry; 18 min vs 28 min, p < 0.001), in perception of dyspnea (Borg score; 8.4 vs 5.4, p < 0.001), and respiratory muscle endurance capacity (sustainable inspiratory pressure; 25 cm H(2)O vs 31 cm H(2)O, p = 0.005). Quality of life (chronic respiratory disease questionnaire) also improved (78.7 to 86.6, p = 0.001). The control group showed no significant changes. CONCLUSION: Home-based RMET by means of tube breathing leads to a significant improvement of endurance exercise capacity, a reduction in perception of dyspnea, and an improvement in quality of life in patients with moderate-to-severe COPD.

Tube breathing as a new potential method to perform respiratory muscle training: safety in healthy volunteers.

Normocapnic hyperpnea has been established as a method of respiratory muscle endurance training (RMET). This technique has not been applied on a large scale because complicated and expensive equipment is needed to maintain CO(2)-homeostasis during hyperpnea. This CO(2)-homeostasis can be preserved during hyperpnea by enlarging the dead space of the ventilatory system. One of the possibilities to enlarge dead space is breathing through a tube. If tube breathing is safe and feasible, it may be a new and inexpensive method for RMET, enabling its widespread use. The aim of this study was to evaluate the safety of tube breathing and investigate the effect on CO(2)-homeostasis in healthy subjects. A total of 20 healthy volunteers performed 10 min of tube breathing (dead space 60% of vital capacity). Oxygen-saturation, PaCO(2), respiratory muscle function, hypercapnic ventilatory response and dyspnea (Borg-score) were measured. Tube breathing did not lead to severe complaints, adverse events or oxygen desaturations. A total of 14 out of 20 subjects became hypercapnic (PaCO(2)>6.0 kPa) during tube breathing. There were no significant correlations between PaCO(2) and respiratory muscle function or hypercapnic ventilatory responses. The normocapnic versus hypercapnic subjects showed no significant differences between decrease in oxygen saturation (-0.7% versus -0.2%, respectively, P=0.6), Borg score (4.3 versus 4.7, P=0.9), respiratory muscle function nor hypercapnic ventilatory responses. Our results show that tube breathing is well tolerated amongst healthy subjects. No complaints, nor desaturations occurred. Hypercapnia developed in a substantial number of subjects. When tube breathing will be applied as respiratory muscle training modality, this potential development of hypercapnia must be considered.

Using the Lower Limit of Normal Instead of the Conventional Cutoff Values to Define Predictors of Pulmonary Function Impairment in Subjects With Chronic Heart Failure.

BACKGROUND: Using the newer lower limit of normal criterion instead of the conventional cutoff values to define pulmonary function abnormalities may result in different predictors of pulmonary function impairment in patients with heart failure. Therefore, we assessed predictors of pulmonary function impairment in subjects with chronic heart failure according to the lower limit of normal in comparison with conventional cutoff values. METHODS: In this prospective cross-sectional study, 164 chronic heart failure subjects (age 68 ± 10 y, 78% men, 88% New York Heart Association class I-II) with left ventricular ejection fraction <40% underwent pulmonary function tests. Predictors of pulmonary function impairment were assessed using the lower limit of normal and conventional cutoff values (ie, 80% predicted value and the fixed ratio of FEV1/FVC <0.7). RESULTS: The lower limit of normal criterion identified an extra independent predictor of diffusion impairment compared with the 80% predicted value; in addition to body mass index, pack-years, and alveolar volume, female sex also turned out to be an independent predictor. A smoking history of ≥10 pack-years was a significant predictor of diffusion impairment and airway obstruction using the lower limit of normal criterion but not using the conventional cutoff values. However, lowering the cutoff points of conventional criteria to match the more stringent lower limit of normal and thus avoid overdiagnosis of diffusion impairment and airway obstruction in the elderly produced similar results as the lower limit of normal. CONCLUSIONS: The lower limit of normal identifies more predictors of diffusion impairment and airway obstruction compared with conventional cutoff values in subjects with chronic heart failure with left ventricular systolic dysfunction. However, lowering the conventional cutoff points yielded similar results as the lower limit of normal. (ClinicalTrials.gov registration NCT01429376.).

Pulmonary function impairment in patients with chronic heart failure: lower limit of normal versus conventional cutoff values.

OBJECTIVE: To determine the prevalence of pulmonary function abnormalities in patients with chronic heart failure (HF) according to recent American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines using the lower limit of normal (LLN) compared to conventional cutoff values. BACKGROUND: Recent ATS/ERS guidelines recommend the use of the LLN instead of the conventional cutoff values to define pulmonary function impairment to avoid misclassification of patients. However, studies addressing the prevalence of pulmonary function abnormalities according to both definitions in patients with chronic HF are lacking. METHODS: In this prospective cross-sectional study, 164 chronic HF outpatients (age 68 ± 10 years, 78% men, 88% New York Heart Association class I-II) with left ventricular ejection fraction < 40% underwent spirometry and measurement of diffusing capacity. Body plethysmography was performed in patients with abnormal spirometry results. RESULTS: Diffusion impairment and airway obstruction were found in 44-58% and 26-37% of the patients, respectively, depending on the definition used (LLN versus conventional cutoff values, p < 0.05). However, restriction was infrequent, irrespective of the definition used (7% versus 5%, respectively, p > 0.05). The LLN identified fewer patients with abnormal lung function, whereas the conventional cutoff values classified more patients with diffusion impairment, airway obstruction, or a mixed category. Twenty-seven percent of patients were misclassified by the conventional cutoff values. CONCLUSION: Pulmonary function abnormalities, especially diffusion impairment and airway obstruction, were highly prevalent in patients with chronic HF. Conventional cutoff values classified more patients with diffusion impairment, airway obstruction, or a mixed category compared to the LLN.

Bronchodilator responsiveness in patients with chronic heart failure.

OBJECTIVE: The aim of this study was to evaluate the effect of inhaled bronchodilators on pulmonary function and dyspnea in patients with chronic heart failure (HF). BACKGROUND: Conflicting data exist on whether bronchodilators may improve pulmonary function and dyspnea in patients with chronic HF. METHODS: In this retrospective observational study we analyzed data of 116 chronic HF outpatients with systolic dysfunction who underwent spirometry and Borg dyspnea measurements before and after inhalation of 400 µg salbutamol and 80 µg ipratropium. Patients with chronic obstructive pulmonary disease (COPD) or asthma were excluded. RESULTS: Bronchodilators fully reversed airway obstruction (AO) in 25 of 64 (39.1%) patients with pre-bronchodilator AO. All spirometric measurements, except for forced vital and inspiratory capacities, improved significantly post-bronchodilation. Absolute and percent improvements in forced expiratory volume in 1 s (FEV1) were more pronounced in patients with persistent AO post-bronchodilation compared to those without AO (0.19 ± 0.18 L and 8.4 ± 7.3% versus 0.11 ± 0.12 L and 4.3 ± 4.0%, p < 0.05). Significant bronchodilator responsiveness of FEV1 (>200 mL and >12%) was noted in 12.1% and was more frequent in patients with persistent AO and fully reversible AO than in those without AO (23.1% and 16.0% versus 1.9%, p < 0.05). We measured a small, albeit significant improvement in dyspnea (0.7 ± 1.2 versus 0.9 ± 1.3, p = 0.002). CONCLUSIONS: Inhaled bronchodilators may have an additional role in the management of patients with chronic HF because of their potential to improve pulmonary function, especially in those with AO. The clinical usefulness and possible adverse events of bronchodilators need to be further established.

COPD in chronic heart failure: less common than previously thought?

BACKGROUND: Using a fixed ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) < 0.70 instead of the lower limit of normal (LLN) to define chronic obstructive pulmonary disease (COPD) may lead to overdiagnosis of COPD in elderly patients with heart failure (HF) and consequently unnecessary treatment with possible adverse health effects. OBJECTIVE: The aim of this study was to determine COPD prevalence in patients with chronic HF according to two definitions of airflow obstruction. METHODS: Spirometry was performed in 187 outpatients with stable chronic HF without pulmonary congestion who had a left ventricular ejection fraction <40% (mean age 69 ± 10 years, 78% men). COPD diagnosis was confirmed 3 months after standard treatment with tiotropium in newly diagnosed COPD patients. RESULTS: COPD prevalence varied substantially between 19.8% (LLN-COPD) and 32.1% (GOLD-COPD). Twenty-three of 60 patients (38.3%) with GOLD-COPD were potentially misclassified as having COPD (FEV1/FVC < 0.7 but > LLN). In contrast to patients with LLN-COPD, potentially misclassified patients did not differ significantly from those without COPD regarding respiratory symptoms and risk factors for COPD. CONCLUSIONS: One fifth, rather than one third, of the patients with chronic HF had concomitant COPD using the LLN instead of the fixed ratio. LLN may identify clinically more important COPD than a fixed ratio of 0.7.

Temazepam 10mg does not affect breathing and gas exchange in patients with severe normocapnic COPD.

BACKGROUND: Benzodiazepines can improve sleep quality, but are also thought to cause respiratory depression in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to assess the effects of temazepam on indices of circadian respiratory function, dyspnea, sleep quality, and sleepiness in patients with severe COPD and insomnia. METHODS: In a double-blind, randomized, placebo-controlled, cross-over study in 14 stable patients with COPD (mean FEV(1) 0.99+/-0.3L) with insomnia, polysomnography with continuous transcutaneous capnography and oximetry, arterial gas sampling, hypercapnic ventilatory response, multiple sleep latency test, Epworth Sleepiness Scale, dyspnea and sleep visual analogue scales (VAS) were performed at baseline, after one week of temazepam 10mg at bedtime and after one week of placebo. RESULTS: Temazepam did not cause statistically significant changes in mean transcutaneous carbon dioxide tension during sleep compared to placebo (5.9+/-1.0 kPa vs. 6.3+/-1.4 kPa, p-value 0.27), nor in mean oxygen saturation (92+/-3% vs. 92+/-2%, p-value 0.31), nor in any of the other investigated variables, except for the total sleep time and sleep latency VAS, which improved with temazepam. CONCLUSIONS: One week usage of temazepam 10mg does not influence circadian respiratory function, dyspnea, and sleepiness in patients with stable, severe, normocapnic COPD and insomnia and it improves total sleep time and subjective sleep latency. However, this is a preliminary explorative study for assessing the feasibility to perform a larger study on this topic. The clinical implications of this study are very limited.