Long-term Recording of Night-Time Respiratory Symptoms in Patients with Stable COPD II-IV

Validation of the LEOSound® monitor for standardized detection of wheezing and cough in children

BACKGROUND

A hallmark of many respiratory conditions is the presence of nocturnal symptoms. Nevertheless, especially in children there is currently still a huge diagnostic gap in detecting nighttime symptoms, which leads to an underestimation of the frequency in clinical practise.

METHODS

We evaluated the clinical applicability and determined the formal test characteristics of the LEOSound ® system, a device for digital long-time recording and automated detection of acoustic airway events. Airway sounds were recorded overnight in 115 children and adolescents (1-17 years) with and without respiratory conditions. The automated classification for "cough" and "wheezing" was subsequently validated against the manual acoustic reassessment by an expert physician.

RESULTS

The general acceptance was good across all age groups and a technically successful recording was obtained in 98 children, corresponding to 92,976 sound epochs (à 30 s) or a total of 774 h of lung sounds. We found a sensitivity of 89% and a specificity of 99% for the automated detection of cough. For detection of wheezing, sensitivity and specificity were both 98%. The cough index and the wheeze index (events per hour) of individual patients showed a strong positive correlation (cough: r_S  = 0.85, wheeze: r_S  = 0.95) and a sufficient agreement of the two assessment methods in the Bland-Altman analysis.

CONCLUSION

Our data show that the LEOSound® is a suitable device for standardized detection of cough and wheezing and hence a promising diagnostic tool to detect nocturnal respiratory symptoms, especially in children. However, a validation process to reduce false positive classifications is essential in clinical routine use.

Long-Term Auscultation in Chronic Obstructive Pulmonary Disease: Renaissance of an Ideograph of Medical Care

BACKGROUND

Electronic auscultation technology has advanced dramatically in the last few years. Therefore, long-term pulmonary auscultation could provide additional information about respiratory system by monitoring acute chronic obstructive pulmonary disease (AECOPD) exacerbations or by identifying wheezing phenotypes amongst stable COPD patients.

OBJECTIVES

Comparison of respiratory sounds in stable versus AECOPD patients recorded with a portable respiratory sound monitor over a period of 24 h.

METHODS

This prospective trial evaluated cough and wheezing events using an auscultation monitor specially developed for this purpose with 4 integrated highly sensitive microphones, in stable and severely AECOPD patients for a period of 24 h in an inpatient setting.

RESULTS

Twenty stable COPD patients (12 male, 60%) and 20 severely exacerbated COPD patients (14 male, 70%) were analyzed. In AECOPD patients, long-term auscultation revealed a significantly higher number of wheezing epochs than stable COPD patients (591 [IQR: 145-1,645] vs. 152 [IQR: 90-400]; p = 0.021). Conversely, cough epochs did not differ between AECOPD and stable COPD patients (213 [IQR: 140-327] vs. 162 [IQR: 123-243]; p = 0.256). The Borg-dyspnea scale, CAT score, and total CCQ score each showed no correlation with wheezing frequency, while CAT and CCQ scores did correlate with coughing frequency.

CONCLUSION

Wheezing, but not coughing, occurs more frequently in AECOPD patients than in stable COPD patients, indicating that severe wheezing is an important clinical sign of exacerbation, while coughing is not. Therefore, the patterns of wheezing and coughing, as assessed by long-term auscultation, differ in stable versus exacerbated COPD patients.

Characteristics of Asthma-related Nocturnal Cough: A Potential New Digital Biomarker

Introduction

The nature of nocturnal cough is largely unknown. It might be a valid marker for asthma control but very few studies characterized it as a basis for better defining its role and its use as clinical marker. This study investigated prevalence and characteristics of nocturnal cough in asthmatics over the course of four weeks.

Methods

In two centers, 94 adult patients with physician-diagnosed asthma were recruited. Patient-reported outcomes and nocturnal sensor data were collected by a smartphone with a chat-based study app.

Results

Patients coughed in 53% of 2212 nights (range: 0–345 coughs/night). Median coughs per hour were 0 (IQR 0–1). Nocturnal cough rates showed considerable inter-individual variance. The highest counts were measured in the first 30 min in bed (4.5-fold higher than rest of night). Eighty-six percent of coughs were part of a cough cluster. Clusters consisted of a median of two coughs (IQR 2–4). Nocturnal cough was persistent within patient.

Conclusion

To the best of the authors’ knowledge, this study is the first to describe prevalence and characteristics of nocturnal cough in asthma over a period of one month, demonstrating that it was a prevalent symptom with large variance between patients and high persistence within patients. Cough events in asthmatics were 4.5 times more frequent within the first 30 min in bed indicating a potential role of positional change, and not more frequent during the early morning hours. An important next step will investigate the association between nocturnal cough and asthma control.

Disease control in patients with asthma and respiratory symptoms (wheezing, cough) during sleep

INTRODUCTION

The Global Initiative for Asthma (GINA)-defined criteria for asthma control include questions about daytime symptoms, limitation of activity, nocturnal symptoms, need for reliever treatment and patients' satisfaction. Patients with nocturnal symptoms like wheezing and cough often suffer from lower sleep quality and impaired daytime performance. The lack of an appropriate method for standardized and objective monitoring of respiratory symptoms leads to difficulties in asthma management. The aim of this study is to present a new method for automated wheeze and cough detection during sleep and to assess the actual level of asthma control by the Asthma Control Test (ACT).

METHODS

Respiratory symptoms like wheezing and cough were recorded with the LEOSound-Monitor for one night in 55 asthmatic patients in their individual domestic setting. Patients were asked to assess their level of asthma subjectively with the ACT. The study consisted of 37 women and 18 men, with a mean age of 41 years, and a mean BMI of 27 kg/m2. Most of the patients had been taking an ICS/LABA combination and would resort to a SABA as their rescue medication.

RESULTS

60% of the participants were classed as having controlled, and 40% were classed as having partially- or uncontrolled asthma. During sleep wheezing was found in 8 of the 55 asthma patients (14.5%) and coughing was found in 30 patients (54.5%). The median ACT score in wheezing-patients was 14, while in non-wheezing patients it was 21. Uncontrolled asthma was found in 6 of the 8 wheezing-patients. Coughing versus non-coughing patients did not show a significant difference in the ACT-score (20, 22 respectively).

CONCLUSION

Wheezing is a sign of uncontrolled asthma. The ACT-score in wheezing patients is worse compared to patients without wheezing. LEOSound proofed to be a useful tool in providing an objective evaluation of respiratory symptoms, like coughing and wheezing. In clinical practice, this may allow an improvement in asthma therapy.

Day and Night Control of COPD and Role of Pharmacotherapy: A Review

The topic of 24-hour management of COPD is related to day-to-night symptoms management, specific follow-up and patients’ adherence to therapy. COPD symptoms strongly vary during day and night, being worse in the night and early morning. This variability is not always adequately considered in the trials. Night-time symptoms are predictive of higher mortality and more frequent exacerbations; therefore, they should be a target of therapy. During night-time, in COPD patients the supine position is responsible for a different thoracic physiology; moreover, during some sleep phases the vagal stimulation determines increased bronchial secretions, increased blood flow in the bronchial circulation (enhancing inflammation) and increased airway resistance (broncho-motor tone). Moreover, in COPD patients the circadian rhythm may be impaired. The role of pharmacotherapy in this regard is still poorly investigated. Symptoms can be grossly differentiated according to the different phenotypes of the disease: wheezing recalls asthma, while dyspnea is strongly related to emphysema (dynamic hyperinflation) or obstructive bronchiolitis (secretions). Those symptoms may be different targets of therapy. In this regard, GOLD recommendations for the first time introduced the concept of phenotype distinction suggesting the use of inhaled corticosteroids (ICS) particularly when an asthmatic pattern or eosiophilic inflammations are present, and hypothesized different approaches to target symptoms (ie, dyspnea) or exacerbations. Pharmacotherapy should be evaluated and possibly directed on the basis of circadian variations, for instance, supporting the use of twice-daily rapid-action bronchodilators and evening dose of ICS. Recommendations on day and night symptoms monitoring strategies and choice of the specific drug according to patient’s profile are still not systematically investigated or established. This review is the summary of an advisory board on the topic “24-hour control of COPD and role of pharmacotherapy”, held by five pulmonologists, experts in respiratory pathophysiology, pharmacology and sleep medicine.

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Circadian rhythm of COPD symptoms in clinically based phenotypes. Results from the STORICO Italian observational study

Background

Chronic Obstructive Pulmonary Disease (COPD) encompasses various phenotypes that severely limit the applicability of precision respiratory medicine. The present investigation is aimed to assess the circadian rhythm of symptoms in pre-defined clinical COPD phenotypes and its association with health-related quality of life (HR-QoL), the quality of sleep and the level of depression/anxiety in each clinical phenotype.

Methods

The STORICO (NCT03105999) Italian observational prospective cohort study enrolled COPD subjects. A clinical diagnosis of either chronic bronchitis (CB), emphysema (EM) or mixed COPD-asthma (MCA) phenotype was made by clinicians at enrollment. Baseline early-morning, day-time and nocturnal symptoms (gathered via the Night-time, Morning and Day-time Symptoms of COPD questionnaire), HR-QoL (via the St. George’s Respiratory Questionnaire), anxiety and depression levels (via the Hospital Anxiety and Depression Scale), quality of sleep (via COPD and Asthma Sleep Impact Scale), physical activity (via the International Physical Activity Questionnaire) as well as lung function were recorded.

Results

606 COPD subjects (age 71.4 ± 8.2 years, male 75.1%) were studied. 57.9, 35.5 5.3 and 1.3% of the sample belonged to the CB, EM, MCA and EM + CB phenotypes respectively. The vast majority of subjects reported early-morning and day-time symptoms (79.5 and 79.2% in the CB and 75.8 and 77.7% in the EM groups); the proportion suffering from night-time symptoms was higher in the CB than in the EM group (53.6% vs. 39.5%, p = 0.0016). In both CB and EM, indiscriminately, the presence of symptoms during the 24-h day was associated with poorer HR-QoL, worse quality of sleep and higher levels of anxiety/depression.

Conclusions

The findings highlight the primary classificatory role of nocturnal symptoms in COPD.

Trial registration

Trial registration number: NCT03105999, date of registration: 10th April 2017.

Time course of nocturnal cough and wheezing in children with acute bronchitis monitored by lung sound analysis

Cough and wheezing are the predominant symptoms of acute bronchitis. Hitherto, the evaluation of respiratory symptoms was limited to subjective methods such as questionnaires. The main objective of this study was to objectively determine the time course of cough and wheezing in children with acute bronchitis. The impact of nocturnal cough on parent's quality of life was assessed as secondary outcome. In 36 children (2-8 years), the frequency of nocturnal cough and wheezing was recorded during three nights by automated lung sound monitoring. Additionally, parents completed symptom logs, i.e., the Bronchitis Severity Score (BSS), as well as the Parent-proxy Children's Acute Cough-specific Quality of Life Questionnaire (PAC-QoL). During the first night, patients had 34.4 ± 52.3 (mean ± SD) cough epochs, which were significantly reduced in night 5 (13.5 ± 26.5; p < 0.001) and night 9 (12.8 ± 28.1; p < 0.001). Twenty-two patients had concomitant wheezing, which declined within the observation period as well. All subjective parameters (BSS, Cough log and PAC-QoL) were found to be significantly correlated with the objectively assessed cough parameters.Conclusion: Long-term recording of cough and wheezing offers a useful opportunity to objectively evaluate the time course of respiratory symptoms in children with acute bronchitis. To assess putative effects of pharmacotherapy on nocturnal bronchitis symptoms, future studies in more homogeneous patient groups are needed. What is Known: • Cough and wheezing are the predominant symptoms of acute bronchitis. • There is a diagnostic gap in long-term assessment of these respiratory symptoms, which needs to be closed to optimize individual therapies. What is New: • Long-term recording of nocturnal cough and wheezing allows for objective evaluation of respiratory symptoms in children with acute bronchitis and provides a tool to validate the efficacy of symptomatic bronchitis therapies.

Comparison of Nocturnal Cough Analysis in Healthy Subjects and in Patients with Cystic Fibrosis and Primary Ciliary Dyskinesia: A Prospective Observational Study

BACKGROUND

Cough is a key symptom in patients with cystic fibrosis (CF) and primary ciliary dyskinesia (PCD).

OBJECTIVE

The study objectives were to test whether cough is related to parameters reflecting their disease severity and whether CF and PCD differ in cough frequency.

METHODS

In this prospective observational study, we used a microphone-based monitoring system (LEOSound® Monitor) to count the coughs in healthy subjects (HS) and in stable patients with CF and PCD (25 subjects per group) on 2 consecutive nights.

RESULTS

The median number of coughs/h in the HS, CF, and PCD groups was 0.0, 1.3, and 0.5 on the first night and 0.0, 2.3, and 0.2 on the second night, respectively. Patients with CF and PCD coughed more than HS (p < 0.001 and p = 0.009, respectively) and CF patients coughed more than PCD patients (p = 0.023). A multivariable mixed model analysis revealed forced expiratory volume in 1 s as an independent risk factor for increased cough frequency in patients. The reliability for repeated measurements was higher for cough epochs/h than for coughs/h (intraclass correlation coefficient: 0.75 and 0.49, respectively).

CONCLUSIONS

Patients with CF cough more than patients with PCD. The cough frequency in CF and PCD is associated with parameters reflecting disease severity. Cough frequency is a possible endpoint in clinical trials and cough epochs/h may be more useful than coughs/h.

Description of nighttime cough epochs in patients with stable COPD GOLD II-IV

Purpose

Chronic cough is one of the main symptoms of COPD. Ambulatory objective monitoring provides novel insights into the determinants and characteristics of nighttime cough in COPD.

Materials and methods

Nighttime cough was monitored objectively by LEOSound lung sound monitor in patients with stable COPD II–IV. In 30 patients, with 10 patients in each stage group, nighttime cough was analyzed for epoch frequency, epoch severity (epoch length and coughs per epoch), and pattern (productive or nonproductive).

Results

Cough was found in all patients ranging from 1 to 294 events over the recording period. In 29 patients, cough epochs were monitored, ranging from 1 to 75 epochs. The highest amount of cough epochs was found in patients with COPD stage III. Active smokers had significantly more productive cough epochs (61%) than nonsmokers (24%).

Conclusion

We found a high rate of nighttime cough epochs in patients with COPD, especially in those in stage III. Productive cough was predominantly found in patients with persistent smoking. LEOSound lung sound monitor offers a practical and valuable opportunity to evaluate cough objectively.