Nocturnal Monitoring Research Articles

Effects of Sacubitril-Valsartan on Clinical, Echocardiographic, and Polygraphic Parameters in Patients Affected by Heart Failure With Reduced Ejection Fraction and Sleep Apnea.

BackgroundHeart failure with reduced ejection fraction (HFrEF) is a clinical condition frequently diagnosed in clinical practice. In patients affected by HFrEF, sleep apnea (SA) can be detected among the most frequent comorbidities. Sacubitril–valsartan (sac/val) association has been proven to be effective in reducing disease progression and all-cause mortality in HFrEF patients. Sac/val treatment can potentially attenuate SA development via several pathophysiologic mechanisms, including improvement of global hemodynamics, reduction of extracellular fluid overload, and decrease of sympathetic neural activity.MethodsWe recruited 132 patients affected by HFrEF and SA, already under treatment with continuous positive airway pressure (CPAP), which was discontinued 24 h before the scheduled study timepoints. Physical examination, echocardiography, nocturnal cardio-respiratory monitoring, and laboratory tests were performed in each patient at baseline and after a 6-month treatment with sac/val.ResultsAfter 6 months, sac/val induced statistically significant changes in clinical, hemodynamic, biohumoral (NT-proBNP, serum electrolytes, creatinine, and uric acid), and echocardiographic parameters. In particular, cardiac index (CI), both atrial and ventricular volumes and global longitudinal strain (GLS) improved. Moreover, polysomnography, carried out during a temporary CPAP interruption, revealed a significant reduction in global apnea-hypopnea index (AHI) value (p < 0.0001), central AHI (p < 0.0001), obstructive AHI (p < 0.0001), oxygen desaturation index (ODI) (p < 0.0001), and percentage time of saturation below 90% (TC90) (p < 0.0001). The changes of CI, estimated glomerular filtration rate (eGFR), NT-proBNP, and tricuspid annular plane excursion (TAPSE) contributed to 23.6, 7.6, 7.3, and 4.8% of AHI variability, respectively, and the whole model accounted for a 43.3% of AHI variation.ConclusionsOur results suggest that treatment with sac/val is able to significantly improve the cardiorespiratory performance of patients with HFrEF and SA, integrating the positive impact of CPAP. Thus, both CPAP and sac/val therapy may synergistically contribute to lower the risks of both cardiac and pulmonary complications in HFrEF patients with SA.

Clinical Implications of Routine Monitoring of Pulmonary Function and Ventilation in Patients with Duchenne Muscular Dystrophy.

PurposeTo investigate the effect of regular monitoring of pulmonary function and ventilatory status on the initiation of non-invasive ventilation (NIV) between patients who were routinely monitored before receiving NIV and those who were not.Materials and MethodsThis retrospective cohort study included subjects with Duchenne muscular dystrophy (DMD) who first received NIV between 2010 and 2019. The subjects were assigned to either the regular-follow-up (REG) group or the non-REG group, according to their follow-up status, before initiating NIV. We compared the number of emergent cases, the results of nocturnal ventilatory monitoring, and the pulmonary function of each group at initial ventilatory support.ResultsIn total, 73 subjects were enrolled in the REG group and 47 subjects in the non-REG group. There were significantly more emergency cases due to respiratory insufficiency in the non-REG group (12/47, 25.5%) than in the REG group (3/73, 4.1%). At the time of initial ventilatory support, hypoventilatory symptoms were more common and relatively severe in the non-REG group (37/47, 78.7%) than in the REG group (18/73, 24.7%). The average age at initial ventilatory support of the non-REG group was 2.15 years older than that of the subjects in the REG group. Moreover, subjects who were not regularly monitored exhibited greater deterioration in pulmonary function compared to those who were regularly followed up.ConclusionRegular evaluation of pulmonary function and ventilatory status before the onset of ventilatory insufficiency is crucial to reduce the risk of patients with DMD requiring emergency care due to ventilatory insufficiency.

An Improved Method for Destriping of VIIRS Day/Night Band Images

The VIIRS Day/Night Band (DNB) images have opened a new era of nocturnal monitoring of global ocean, lands, and atmospheric activities at a reasonably high spatial resolution of 742 m. However, the quality of VIIRS day/night band images is seriously affected with periodic horizontal stripe noises. The image quality is further reduced on the along-track scene edges due to the complex banding effects. The noise pattern and amplitude vary according to the observation time, background light condition, and the pixel position/characteristics. To enhance the utility of VIIRS day/night band image data, we developed a novel method to reduce the noise effects and evaluate the denoised output data to ensure its radiometric integrity and quality. The noise pattern is multiplicative in nature and generated due to the detector-to-detector response variation depending on the incident light condition across the scene. Accordingly, the observed pixels in the day and night images were separated into several classes using the Otsu&#x2019;s threshold value. The images recorded during twilight were classified using the solar zenith angles. Pixel-by-pixel correction of the noise effects was done by multiplying the row-wise detector gains and column-wise error factors for each class. This method was tested on several day/night and twilight images captured over the different regions with varying light conditions. The results are excellent in terms of successfully removing the striping noise and reconstructing the denoised images without spatial discontinuity across the scene regardless of its observation condition.

Automatic Home-based Screening of Obstructive Sleep Apnea using Single Channel Electrocardiogram and SPO2 Signals

Obstructive sleep apnea (OSA) is one of the most widespread respiratory diseases today. Complete or relative breathing cessations due to upper airway subsidence during sleep is OSA. It has confirmed potential influence on Covid-19 hospitalization and mortality, and is strongly associated with major comorbidities of severe Covid-19 infection. Un-diagnosed OSA may also lead to a variety of severe physical and mental side-effects. To score OSA severity, nocturnal sleep monitoring is performed under defined protocols and standards called polysomnography (PSG). This method is time-consuming, expensive, and requiring professional sleep technicians. Automatic home-based detection of OSA is welcome and in great demand. It is a fast and effective way for referring OSA suspects to sleep clinics for further monitoring. On-line OSA detection also can be a part of a closed-loop automatic control of the OSA therapeutic/assistive devices. In this paper, several solutions for online OSA detection are introduced and tested on 155 subjects of three different databases. The best combinational solution uses mutual information (MI) analysis for selecting out of ECG and SpO2-based features. Several methods of supervised and unsupervised machine learning are employed to detect apnoeic episodes. To achieve the best performance, the most successful classifiers in four different ternary combination methods are used. The proposed configurations exploit limited use of biological signals, have online working scheme, and exhibit uniform and acceptable performance (over 85%) in all the employed databases. The benefits have not been gathered all together in the previous published methods.

Incidence of ischemic stroke in patients with periodic limb movements in sleep: one-year follow-up

Objective. To assess the influence of periodic limb movements in sleep on the incidence of acute cardiovascular events. Design and methods. Fifty-six participants aged 60–75 years were included in the study. Eligibility criteria included no history of acute cardiovascular events and the presence of 1 or more risk factors for cardiovascular diseases. Nocturnal actigraphy and cardiorespiratory monitoring were performed. Patients with apnea/hypopnea index &gt; 5/h were excluded (n = 6). Based on periodic limb movements index (PLMI) two groups were formed: main (PLMI ≥ 15/h, n = 26) and controls (PLMI &lt; 15/h, n = 24). The groups were prospectively observed during 1 year. The endpoints of the study were cases of acute cardiovascular events. Results. Despite the similar prevalence of common risk factors for cardiovascular diseases in two groups, the patients with PLMI ≥ 15/h have a higher incidence of ischemic stroke within 1 year (odds ratio 1,07). Conclusions. Elevated PLMI might be regarded as a potential predictor for higher risk for ischemic stroke. Nevertheless, further investigations in the field are needed.

Pilot study on nocturnal monitoring of crackles in children with pneumonia.

BackgroundThe clinical diagnosis of pneumonia is usually based on crackles at auscultation, but it is not yet clear what kind of crackles are the characteristic features of pneumonia in children. Lung sound monitoring can be used as a “longtime stethoscope”. Therefore, it was the aim of this pilot study to use a lung sound monitor system to detect crackles and to differentiate between fine and coarse crackles in children with acute pneumonia. The change of crackles during the course of the disease shall be investigated in a follow-up study.Patients and methodsCrackles were recorded overnight from 22:00 to 06:00 h in 30 children with radiographically confirmed pneumonia. The data for a total of 28 800 recorded 30-s epochs were audiovisually analysed for fine and coarse crackles.ResultsFine crackles and coarse crackles were recognised in every patient with pneumonia, but the number of epochs with and without crackles varied widely among the different patients: fine crackles were detected in 40±22% (mean±sd), coarse crackles in 76±20%. The predominant localisation of crackles as recorded during overnight monitoring was in accordance with the radiographic infiltrates and the classical auscultation in most patients. The distribution of crackles was fairly equal throughout the night. However, there were time periods without any crackle in the single patients so that the diagnosis of pneumonia might be missed at sporadic auscultation.ConclusionNocturnal monitoring can be beneficial to reliably detect fine and coarse crackles in children with pneumonia.

Reproducibility of nighttime home blood pressure measured by a wrist-type nocturnal home blood pressure monitoring device.

The authors investigated the reproducibility of nighttime home blood pressure (BP) measured by a wrist‐type BP monitoring device. Forty‐six hypertensive patients (mean 69.0±11.6 years, 56.5% male) self‐measured their nighttime BP hourly using simultaneously worn wrist‐type and upper arm‐type nocturnal home BP monitoring devices at home on two consecutive nights. Using the average 7.4±1.3 measurements on the first night and the average 7.0 ± 1.8 measurements on the second night, the authors assessed the reliability and the reproducibility of nighttime BP measured on the two nights. The difference between nights in systolic BP (SBP) measured by the wrist‐device was not significant (1.6±7.0 mmHg, p = .124), while the difference in diastolic BP (DBP) was marginally significant (1.4±4.9 mmHg, p = .050). The intraclass correlation coefficients (ICCs) for agreement between nights were high both in SBP and DBP average (SBP: 0.835, DBP: 0.804). Averaging only three points of SBP resulted in lower ICC values, but still indicated good correlations (ICC > 0.6). On the other hand, the correlations of the standard deviation and average real variability of SBP between nights were low, with ICCs of 0.220 and 0.436, respectively. In conclusion, the average SBP values measured on the first night were reliable even when averaging only three readings. The reproducibility of nighttime BP variability seemed inferior to that of BP average; it might be better to measure nighttime BP over multiple nights to assess BP variability. However, this hypothesis needs verification in other study population. In addition, our study population had well‐controlled BP, which limits the generalizability of this findings to all hypertensive patients.

Association Between Sleep Apnea and Valvular Heart Diseases.

Background: Although sleep respiratory disorders are known as a relevant source of cardiovascular risk, there is a substantial lack of trials aimed to evaluate the eventual occurrence of associations between sleep apnea (SA) and valvular heart diseases (VHD).Methods: We recruited 411 patients referring to our sleep disorder unit, among which 371 had SA. Ninety-three subjects with SA also suffered from VHD. Physical examination, echocardiography, nocturnal cardio-respiratory monitoring, and laboratory tests were performed in each patient. Patient subgroups were comparatively evaluated through cross-sectional analysis.Results: A statistically significant increase in the prevalence of VHD was detected in relation to high apnea hypopnea index (AHI) values (p = 0.011). Obstructive sleep apnea occurrence was higher in SA patients without VHD (p < 0.0001). Conversely, central and mixed sleep apneas were more frequent among SA patients with VHD (p = 0.0003 and p = 0.002, respectively). We observed a direct correlation between AHI and BMI values (p < 0.0001), as well as between AHI and serum uric acid levels (p < 0.0001), high sensitivity C-reactive protein (p < 0.0001), and indexed left ventricular end-diastolic volume (p < 0.015), respectively. BMI and VHD resulted to be the main predictors of AHI values (p < 0.0001).Conclusions: Our study suggests that a significant association can occur between SA and VHD. It is clinically relevant that when compared to SA patients without VHD, higher frequencies of central and mixed apneas were found in subjects with SA and VHD. Moreover, after elevated BMI, VHD represented the second predictor of AHI values.

Sleep increases leaks and asynchronies during home noninvasive ventilation: a polysomnographic study.

In patients treated with noninvasive ventilation, sleep-related breathing changes can modify patient-ventilator interactions, which could reduce its effectiveness. The aim of this prospective observational study was to determine the impact of sleep/wake state on leaks, upper airway obstructive events, and asynchronies in patients treated by long-term noninvasive ventilation. Stable patients adapted to noninvasive ventilation were considered for nocturnal polysomnography. Unintentional leaks, upper airway obstructive events, and asynchronies were compared between sleep and awake periods. Twenty-eight patients were enrolled. Underlying diagnoses were neuromuscular disease (n = 11), chest wall disease (n = 8), and obesity-hypoventilation (n = 9). Leaks were more frequent in sleep than in awake periods, with a median of 10% (interquartile range [IQR], 0%-75%) vs 1% (IQR, 0%-9%) of time (P < .001), respectively. During sleep, asynchronies with and without associated leak affected 27% of breaths (IQR, 16%-39%) compared with non-leak-related asynchronies that were recorded in 8% (IQR, 3%-25%) of breaths (P < .001). Asynchronies affecting more than 10% of total breaths were more frequent in sleep (25 patients, 89%) than in awake time (8 patients, 29%; P = .25). Eleven patients (39%) presented with 5 or more upper airway obstructive events without reduction in ventilatory drive per hour of sleep. In patients adapted to home noninvasive ventilation, leaks, asynchronies, and upper airway obstructive events are frequent during the night and are concentrated in sleep periods. Asynchronies are often associated with leaks. These findings may have clinical implications considering that in patients with low sleep efficiency respiratory events could be underestimated if sleep is not evaluated. Martí S, Ferré A, Sampol G, etal. Sleep increases leaks and asynchronies during home noninvasive ventilation: a polysomnographic study. J Clin Sleep Med. 2022;18(1):225-233.

Determinants of response to hypercapnia and to progressive and transient hypoxia in obstructive sleep apnea patients.

The knowledge regarding the control of breathing during wakefulness in patients affected by obstructive sleep apnea (OSAS) is still challenging. The aim of this study is firstly to analyze hypoxic and hypercapnic ventilatory response in OSA patients in comparison to controls and secondly, to investigate correlations between chemosensivity and both lung function tests, such as arterial blood gas analysis and spirometric parameters, and clinical characteristics, such as age and BMI. Seventeen never treated OSA patients (16M; 53±13.2 years; BMI=34.5±8.1; AHI=45±14.7) underwent nocturnal cardiopulmonary monitoring test, complete lung function tests (spirometry, lung volumes and arterial blood gas analysis on room air). Read's rebreathing test was used to evaluate hypercapnic ventilatory response (HVR<inf>CO2</inf>); hypoxic ventilatory response (HVR<inf>O2</inf>) was studied through progressive and transient methods. The response was expressed in terms of slope of linear regression for HVR<inf>CO2</inf> and of hyperbolic curve for HVR<inf>O2</inf> between minute ventilation (VE) or mean inspiratory flow (VT/Ti) and PetCO<inf>2</inf> or PetO<inf>2</inf>. The OSA group showed increased transient, but not progressive, HVR<inf>O2</inf> and a lower HVR<inf>CO2</inf>. A lower HVR<inf>CO2</inf> was predicted by greater values of BMI (P<0.01). Progressive HVR<inf>O2</inf> increased with age and lower FEV<inf>1</inf>/VC, while transient HVR<inf>O2</inf> (P<0.05) was inversely correlated with the nocturnal lowest SaO<inf>2</inf> (P<0.01). Nocturnal intermittent hypoxic stimuli increases daytime glomic reactivity to transient hypoxia, while BMI is the main independent determinants of the bulbar response to hypercapnia in normocapnic OSAS patients.

NOCTURNAL HOME VERSUS AMBULATORY BLOOD PRESSURE MONITORING IN CHILDREN AND ADOLESCENTS: FEASIBILITY AND PATIENTS PREFERENCE

Abstract Objective: To evaluate the feasibility of nighttime blood pressure (BP) assessed by home (HBP) monitoring in children and adolescents and compare with ambulatory (ABP) monitoring. Design and method: Apparently healthy children and adolescents (age 6–18 yeas) referred for elevated BP were subjected to (i) 24 h ABP monitoring (Microlife WatchBP O3), (ii) HBP monitoring during daytime (7 days, duplicate morning and evening measurements) and nighttime (3 nights, 3 hourly readings/night; Microlife WatchBP Home-N). Participants filled a questionnaire (Likert-type scale questions) evaluating the acceptance and compliance, stress, inconvenience, sleep disturbance, ease, feasibility, and preference regarding nighttime ABP and HBP monitoring. Score for each question ranged from 0 to 4 (4 indicating highest disturbance/difficulty). Results: 84 subjects were analyzed (mean age 13.3 ± 2.8, BMI 25.2 ± 4.9 kg/m2, 49 males, 15 with 24 h ABP &gt; = 95th percentile). Nighttime HBP monitoring was feasible in all subjects (average number of monitoring nights 2.9 ± 0.4 [range 1–3] and nighttime HBP readings 7.9 ± 1.6 [range 2–9]). Participants reported a worse score regarding stress and inconvenience with nighttime ABP than HBP (1.2 ± 0.8 vs. 0.9 ± 0.7 respectively, p &lt; 0.01), despite similar sleep disturbance (1.7 ± 1.4 vs. 1.6 ± 1.3, p = NS). 12% reported severe sleep disturbance with nighttime ABP and 8% with nighttime HBP. Worse ease and feasibility score was reported for nighttime ABP than HBP (1.3 ± 1.1 vs. 0.9 ± 1.0, p = 0.02). Optimal compliance with doctor's instructions was reported by 67% for nighttime HBP vs. 68% for ABP (p = NS). 74% reported that they prefer nighttime HBP versus ABP for their next assessment. Conclusions: These results indicate that in children and adolescents nocturnal HBP monitoring is feasible and tends to be superior to nocturnal ABP in terms of overall acceptance and preference.

NOCTURNAL HOME VERSUS AMBULATORY BLOOD PRESSURE MONITORING IN CHILDREN AND ADOLESCENTS: ASSOCIATION WITH PRECLINICAL TARGET-ORGAN DAMAGE

Abstract Objective: To evaluate the relationship between nighttime blood pressure (BP) assessed by home (HBP) or ambulatory (ABP) monitoring with preclinical damage in children and adolescents. Design and method: Apparently healthy children and adolescents (age 6–18 yeas) referred for elevated BP were subjected to (i) 24 h ABP monitoring (Microlife WatchBP O3), (ii) 7-day HBP monitoring during daytime (duplicate morning and evening measurements) and nighttime (3 nights, 3 readings/night) (Microlife WatchBP Home-N), and measurement of (iii) carotid intima-media thickness (cIMT) and carotid distensibility coefficient (cDC), (iv) carotid-femoral pulse wave velocity (PWV; Complior device), and (v) echocardiographic left ventricular mass index (LVMI). Results: 94 individuals were analyzed (mean age 13.2 ± 2.8 years, 54 males, BMI 24.8 ± 5.2 kg/m2, 18 with 24 h ABP &gt; 95th centile). Daytime HBP was slightly lower than daytime ABP (difference -2.0 ± 6.4/-0.8 ± 5.0 mmHg, systolic/diastolic, p &lt; 0.01/NS), whereas nighttime HBP was slightly higher than nighttime ABP (2.5 ± 7.1/2.1 ± 6.2 mmHg, p &lt; 0.01/ &lt; 0.01). There was a strong association between ABP and HBP (daytime r = 0.83/0.79 and nighttime 0.79/0.60, systolic/diastolic) (all p &lt; 0.05). Nighttime systolic ABP and HBP were associated with all indices of target-organ damage (LVMI r = 0.36/0.30 for ABP/HBP; cIMT 0.47/0.49; cCD -0.31/-0.25; PWV 0.50/0.56 (p = NS for HBP-ABP comparisons). The agreement between nighttime HBP and ABP in identifying: (i) subjects with asleep ABP &gt; 90th percentile was 73% (kappa 0.38, p &lt; 0.01) and (ii) non-dippers 55% (kappa 0.16). Conclusions: These results suggest that in children and adolescents nocturnal HBP monitoring is feasible, is strongly correlated with nighttime ABP and gives similar correlations with preclinical target-organ damage. The agreement between these methods in identifying individuals with nocturnal hypertension is satisfactory, whereas for non-dippers it is moderate.

Comparison of nighttime measurement schedules using a wrist-type nocturnal home blood pressure monitoring device.

We investigated the optimal nighttime home blood pressure (BP) measurement schedule for wrist BP monitoring. Fifty hypertensive patients (mean age 68.9 ± 11.3 years) self‐measured their nighttime BP hourly using a wrist‐type nocturnal home BP monitoring device at home on two consecutive nights. Using the average 7.2 ± 1.5 measurements per night, we compared the clock‐based index (average of three measurements at 2:00, 3:00, and 4:00 a.m.) and the bedtime‐based index (average of three measurements at 2, 3, and 4 h after bedtime). The clock‐based average was significantly higher than the bedtime‐based average for both systolic BP (2.7 ± 8.2 mmHg, P = .002) and diastolic BP (1.9 ± 5.1 mmHg, P < .001). Compared to the average of all measurements throughout a night (the same definition of ambulatory BP monitoring, ie, from the time point of going to bed to awakening), the clock‐based average was comparable (systolic/diastolic BP: −0.5 ± 5.5/−0.2 ± 3.7), whereas the bedtime‐based average was significantly lower (−3.3 ± 5.0/−2.1 ± 3.6). Thus, the repeated measurement of wrist‐measured nighttime BP at three clock‐based time points per night provided reliable values. Further prospective studies of larger populations are required to confirm the optimal nighttime BP measurement schedule for wrist BP monitoring for the prediction of cardiovascular events.

Obstructive Sleep Apnea, Palatal Morphology, and Aortic Dilatation in Marfan Syndrome Growing Subjects: A Retrospective Study.

The main cause of mortality in Marfan syndrome (MS) is aortic disease. Obstructive sleep apnea (OSA) is highly prevalent in MS, and it is also associated with cardiovascular risk and maxillary deformities. The aim of this research was to analyze the possible relations between OSA, palatal morphology, and aortic root diameters in growing subjects. A group of 15 growing subjects with MS and a control group of healthy peers was selected. All of them underwent nocturnal polygraphic monitoring, digital dental casts, and transthoracic echocardiography. The results showed that OSA indexes and aortic diameters were significantly higher in the study group. Transversal palatal dimension was smaller in MS patients. Moreover, OSA severity was not related with maxillary contraction severity in MS. No correlation between OSA severity and increased aortic diameters occurred. A high prevalence of OSA, increased aortic dimensions, and significant contraction of palatal dimensions were observed in MS compared with the control group. None of these single factors may directly be associated with aortic dilation, but together, they might contribute to the development and progression of aortic aneurysm from a young age.

Swayne’s hartebeest (Alcelaphus buselaphus swaynei): home range and activity patterns in Maze National Park, Ethiopia

Abstract Home range and activity patterns of animals are important elements for wildlife management and conservation practices. We examined seasonal home range and daily activity patterns of the endangered Swayne’s hartebeest (Alcelaphus buselaphus swaynei) in Maze National Park, Ethiopia. We tracked two groups of Swayne’s hartebeests in open grassland for 1 year. Each group’s daily activities (0700–1900 h) and GPS locations were recorded at 15-min intervals on 5 days every month. Activities were grouped into five behavioral categories: feeding, resting, traveling, vigilance, and other. In addition, we carried out nocturnal monitoring during full moon periods to further document movements patterns. We produced 95% and 50% kernel density estimates (KDE) of home range sizes for each group. Home range estimates did not vary across seasons. Feeding and traveling peaked during the early morning and late afternoon, whereas resting occurred most frequently during the midday hours in both seasons. The proportion of time spent feeding was higher during the dry season, whereas a greater proportion of time was spent resting during the wet season. Vigilance behavior occurred consistently throughout the day during both seasons. Time spent feeding and traveling did not vary significantly between seasons. Activity patterns of Swayne’s hartebeests are strongly influenced both by time of day and season, while home range size is less influenced by seasonality and may instead reflect temporal variation in food availability. Our findings will help to inform management strategies and conserve one of the last two extant populations of Swayne’s hartebeests.

Clinical significance of nocturnal home blood pressure monitoring and nocturnal hypertension in Asia.

Nocturnal home blood pressure (BP) monitoring has been used in clinical practice for ~20 years. The authors recently showed that nocturnal systolic BP (SBP) measured by a home BP monitoring (HBPM) device in a Japanese general practice population was a significant predictor of incident cardiovascular disease (CVD) events, independent of office and morning home SBP levels, and that masked nocturnal hypertension obtained by HBPM (defined as nocturnal home BP ≥ 120/70 mmHg and average morning and evening BP < 135/85 mmHg) was associated with an increased risk of CVD events compared with controlled BP (nocturnal home BP < 120/70 mmHg and average morning and evening BP < 135/85 mmHg). This evidence revealed that (a) it is feasible to use a nocturnal HBPM device for monitoring nocturnal BP levels, and (b) such a device may offer an alternative to ambulatory BP monitoring, which has been the gold standard for the measurement of nocturnal BP. However, many unresolved clinical problems remain, such as the measurement schedule and conditions for the use of nocturnal HBPM. Further investigation of the measurement of nocturnal BP using an HBPM device and assessments of the prognostic value are thus warranted. Asians are at high risk of developing nocturnal hypertension due to high salt sensitivity and salt intake, and the precise management of their nocturnal BP levels is important. Information and communication technology‐based monitoring devices are expected to facilitate the management of nocturnal hypertension in Asian populations.

Simultaneous self-monitoring comparison of a supine algorithm-equipped wrist nocturnal home blood pressure monitoring device with an upper arm device.

A nocturnal home blood pressure (BP) monitoring device that measures nighttime BP levels accurately with less sleep disturbance is needed for the 24‐h management of hypertension. Here we conducted the first comparison study of simultaneous self‐monitoring by both a supine position algorithm‐equipped wrist nocturnal home BP monitoring device, the HEM‐9601T (NightView; Omron Healthcare) with a similar upper arm device, the HEM‐9700T (Omron Healthcare) in 50 hypertensive patients (mean age 68.9 ± 11.3 years). Both devices were worn on the same non‐dominant arm during sleep over two nights. The patients self‐measured their nighttime BP by starting nocturnal measurement mode just before going to bed. In total, 694 paired measurements were obtained during two nights (7.2 ± 1.5 measurements per night), and the mean differences (±SD) in systolic BP between the devices was 0.2 ± 10.2 mmHg (p = .563), with good agreement. In the comparison of nighttime BP indices, the difference in average SBP at 2:00, 3:00, and 4:00 AM and the average SBP of 1‐h interval measurements was −0.5 ± 5.5 mmHg (p = .337), with good agreement. The HEM‐9601T substantially reduced sleep disturbance compared to the upper arm‐type device. The newly developed HEM‐9601T (NightView) can thus accurately measure BP during sleep without reducing the wearer's sleep quality.

Automatic Recognition, Segmentation, and Sex Assignment of Nocturnal Asthmatic Coughs and Cough Epochs in Smartphone Audio Recordings: Observational Field Study.

BackgroundAsthma is one of the most prevalent chronic respiratory diseases. Despite increased investment in treatment, little progress has been made in the early recognition and treatment of asthma exacerbations over the last decade. Nocturnal cough monitoring may provide an opportunity to identify patients at risk for imminent exacerbations. Recently developed approaches enable smartphone-based cough monitoring. These approaches, however, have not undergone longitudinal overnight testing nor have they been specifically evaluated in the context of asthma. Also, the problem of distinguishing partner coughs from patient coughs when two or more people are sleeping in the same room using contact-free audio recordings remains unsolved.ObjectiveThe objective of this study was to evaluate the automatic recognition and segmentation of nocturnal asthmatic coughs and cough epochs in smartphone-based audio recordings that were collected in the field. We also aimed to distinguish partner coughs from patient coughs in contact-free audio recordings by classifying coughs based on sex.MethodsWe used a convolutional neural network model that we had developed in previous work for automated cough recognition. We further used techniques (such as ensemble learning, minibatch balancing, and thresholding) to address the imbalance in the data set. We evaluated the classifier in a classification task and a segmentation task. The cough-recognition classifier served as the basis for the cough-segmentation classifier from continuous audio recordings. We compared automated cough and cough-epoch counts to human-annotated cough and cough-epoch counts. We employed Gaussian mixture models to build a classifier for cough and cough-epoch signals based on sex.ResultsWe recorded audio data from 94 adults with asthma (overall: mean 43 years; SD 16 years; female: 54/94, 57%; male 40/94, 43%). Audio data were recorded by each participant in their everyday environment using a smartphone placed next to their bed; recordings were made over a period of 28 nights. Out of 704,697 sounds, we identified 30,304 sounds as coughs. A total of 26,166 coughs occurred without a 2-second pause between coughs, yielding 8238 cough epochs. The ensemble classifier performed well with a Matthews correlation coefficient of 92% in a pure classification task and achieved comparable cough counts to that of human annotators in the segmentation of coughing. The count difference between automated and human-annotated coughs was a mean –0.1 (95% CI –12.11, 11.91) coughs. The count difference between automated and human-annotated cough epochs was a mean 0.24 (95% CI –3.67, 4.15) cough epochs. The Gaussian mixture model cough epoch–based sex classification performed best yielding an accuracy of 83%.ConclusionsOur study showed longitudinal nocturnal cough and cough-epoch recognition from nightly recorded smartphone-based audio from adults with asthma. The model distinguishes partner cough from patient cough in contact-free recordings by identifying cough and cough-epoch signals that correspond to the sex of the patient. This research represents a step towards enabling passive and scalable cough monitoring for adults with asthma.

Maximizing detection probability for effective large‐scale nocturnal bird monitoring

AbstractAimOur specific objectives were to (a) estimate detection probabilities of nocturnal bird species, after taking into account survey‐specific covariates, and (b) investigate the influence of site‐specific covariates on owl and nightjar abundance, integrating effects of imperfect detection.InnovationWe conceived a survey protocol to estimate probabilities of detection and estimates of abundance of owls and nightjars in a large area, the Basque Country, northern Spain.Main ConclusionsOur results show that detection probability was strongly influenced by playback broadcast and by observer experience. Date irregularly affected species according to their reproductive periods, and we also found that vocal activity gradually diminished proportionally to the hour after sunset. Tawny owl (Strix aluco) was the most abundant and widely distributed species. Its abundance was positively related to forest areas (mainly pine timber forests) and decreased in large urban and agricultural areas. Open space species were less common. Barn owls (Tyto alba), little owls (Athene noctua), Eurasian scops owls (Otus scops) and long‐eared owls (Asio otus) avoided forest areas, but showed different responses to agriculture, grass‐fields, scrub and urban areas. Finally, European nightjar (Caprimulgus europaeus) was moderately frequent, and its abundance was favoured by scrub areas and, weakly, by eucalyptus patches, whereas it was negatively affected by large forest areas. We have shown that it is fundamental to consider the effects of survey‐specific covariates in the methodology design and analytical development. Our results also indicate some ecological adaptations and population changes in the nocturnal bird community following an increase in urbanization and in the extent of timber plantations, and also the simplification of natural habitats.

The well-being of medical students: A biopsychosocial approach.

Mental health problems among medical students have been widely reported, but the predisposing and perpetuating factors and biological concomitants are poorly understood. Adopting a biopsychosocial approach, we studied well-being in a group of Australian medical students, focusing on sleep, autonomic and immune mechanisms, as well as mental, social and physical well-being, health-related behaviours, and daily functioning. Fourth-year medical students (N = 151) completed comprehensive assessments, including laboratory-based and nocturnal autonomic monitoring via ambulatory bioharness, a psychiatric diagnostic interview, and questionnaires assessing sleep quality and psychosocial and physical well-being. A blood sample was taken to quantify the inflammatory marker C-reactive protein. Sleep, mood and activity was additionally monitored daily for 7 days. A sizable minority of students reported diminished physical, mental and psychosocial well-being. We also found concerning levels of sleep disturbance and social and occupational impairment in a subset of students. The strong co-occurrence of problems across symptom domains supported a biopsychosocial interdependence of health and well-being states. Maladaptive coping behaviours were apparent, notably hazardous alcohol consumption, which was associated with a clinically significant elevation in C-reactive protein levels (> 3 mg/L). We documented, for the first time, significantly diminished nocturnal heart rate variability in medical students with a mental health diagnosis. Nocturnal heart rate variability was strongly associated with sleep quality, daytime autonomic stress reactivity, as well as occupational and social functioning. Well-being is a multifaceted phenomenon firmly interlinked with sleep, autonomic and immune function, health behaviours and functional outcomes. Our novel findings supported a key role for nocturnal autonomic function in promoting sleep quality and mental well-being. Interventions could focus on sleep hygiene and health behaviours as a buffer for well-being and teach more adaptive strategies for coping with the stresses of medical training.