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

Introduction: Night-time respiratory symptoms have a considerable impact on sleep and life quality in patients with chronic obstructive pulmonary disease (COPD). Lack of awareness of night-time symptoms can lead to worsened COPD control. Automated long-term monitoring of respiratory symptoms with LEOSound enables assessment of nocturnal wheezing and cough.

Methods: In this observational study we investigated the prevalence and severity of cough and wheezing in patients with stable COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) II-IV] disease for two consecutive nights with the LEOSound system. 48 patients (30 males, 63%) were eligible for inclusion, median age was 67 years, and body mass index (BMI) was 25.3 kg/m.

Results: In 15 out of 48 patients (31%), we found wheezing periods for at least 10-minute duration. Wheezing periods >30 minutes were monitored in seven patients and wheezing periods >60 minutes were monitored in three patients. The maximum duration of wheezing was 470 minutes in one patient with COPD II. The median wheezing rate differed between the COPD stages and between active and non-active smokers. Cough was found in 42 patients (87.5%) with a range of 1-326 events. The cough-period-index in night one was 0.83 n/hour (P25:0.33||P75: 2.04) and night two 0.97 n/hour (P25:0.25||P75: 1.9). Most of the cough events were non-productive with a median of 0.86.

Conclusions: Night-time symptoms are common in COPD patients. LEOSound offers an opportunity to evaluate objectively night-time symptoms like wheezing and cough in patients with COPD which remain otherwise unnoticed. We found a high incidence of night-time wheezing in these patients, which was related to persistant smoking.