Nocturnal Pulse Research Articles

Prediction of glaucoma progression by 24-h contact lens sensor profile in patients with normal-tension glaucoma

A single-center prospective cohort study was conducted to investigate whether intraocular pressure (IOP)-related 24-h contact lens sensor (CLS) profile parameters can help predict glaucoma progression in patients with normal-tension glaucoma (NTG). CLS measurements (Triggerfish; SENSIMED, Etagnières, Switzerland) at baseline without medication were performed for 24 h in one eye, following diurnal IOP measurements using Goldmann applanation tonometry at 3-h intervals. Glaucoma progression during the follow-up period of ≥ 2 years was determined based on the Guided Progression Analysis of Humphrey visual fields and/or structural progression using fundus photographs. Among 79 patients (mean values: follow-up periods, 48.1 months; age, 51.5 years; baseline IOP, 14.0 mmHg; mean deviation, − 6.04 dB), 23 showed glaucoma progression. A smaller standard deviation of nocturnal ocular pulse amplitude in the CLS profile, a larger range of diurnal IOP at baseline, and the presence of optic disc hemorrhage (DH) during the study period were significant risk factors for glaucoma progression in the multivariate Cox proportional hazards model (hazard ratio, 0.30/mVeq, 1.23/mmHg, and 4.37/presence of DH; P = 0.016, 0.017, and 0.001, respectively). CLS measurements may be useful for assessing the risk of future glaucoma progression in patients with NTG, providing supplementary information to routine IOP measurements.

Assessing the relationship between lipoprotein(a) levels and blood pressure among hypertensive patients beyond conventional measures. An observational study

High lipoprotein(a) (Lp(a)) levels are associated with an increased risk of arterial hypertension (AHT) and atherosclerotic cardiovascular disease. However, little is known about the detailed profile of AHT based on Lp(a) levels. This observational study focused on elucidating the relationship between Lp(a) concentrations and specific indices obtained from 24-h ambulatory blood pressure (BP) monitoring in hypertensive patients over 18 years of age. We gathered and analyzed data on BP indices along with demographic, epidemiological, clinical, and laboratory variables from 227 hypertensive patients, median age 56 years, including 127 women (56%). After comparing hypertensive patients with Lp(a) levels above and below 125 nmol/L, we found that a 10 mmHg increase in nocturnal systolic BP and all pulse pressure indices (24-h, daytime, and night-time) was associated with an increased risk of high Lp(a) levels by more than 20% and 40%, respectively. Similarly, each 10% increase in the area under the function over time of nocturnal diastolic BP dipping was associated with more than a 30% decrease in the odds of belonging to the elevated Lp(a) levels category. Additionally, Lp(a) levels above 125 nmol/L were associated with higher 24-h, daytime, and night-time systolic BP and pulse pressure load. The relationship between Lp(a) and AHT appears to extend beyond conventional BP measurements, which may be relevant given the prognostic implications of nocturnal BP and pulse pressure indices.

Role of overnight oximetry in assessing the severity of obstructive sleep apnoea in typically developing children: a multicentre study

Background and objectiveCardiorespiratory polygraphy (CRP) is the predominant technology used to diagnose obstructive sleep apnoea (OSA) in tertiary centres in the UK. Nocturnal pulse oximetry (NPO) is, however, cheaper and...

Expedition 5300: limits of human adaptations in the highest city in the world.

Exposure to chronic hypobaric hypoxia imposes a significant physiological burden to more than 80 million humans living above 2500m throughout the world. Among them, 50000 live in the world's highest city, La Rinconada, located at 5000-5300m in southern Peru. Expedition 5300 is the first scientific and medical programme led in La Rinconada to investigate the physiological adaptations and altitude-related health issues in this unique population. Dwellers from La Rinconada have very high haemoglobin concentration (20.3±2.4g/dL; n=57) and those with chronic mountain sickness (CMS) exhibit even higher concentrations (23.1±1.7g/dL; n=150). These values are associated with large total haemoglobin mass and blood volume, without an associated iron deficit. These changes in intravascular volumes lead to a substantial increase in blood viscosity, which is even larger in CMS patients. Despite these large haematological changes, 24h blood pressure monitoring is essentially normal in La Rinconada, but some results suggest impaired vascular reactivity. Echocardiography revealed large right heart dilatation and high pulmonary arterial pressure as well as left ventricle concentric remodelling and grade I diastolic dysfunction. These changes in heart dimension and function tend to be more severe in highlanders with CMS. Polygraphy evaluations revealed a large reduction in nocturnal pulse oxygen saturation (median SpO2 =79%), which is even more severe in CMS patients who also tended to show a higher oxygen desaturation index. The population of La Rinconada offers a unique opportunity to investigate the human responses to chronic severe hypoxia, at an altitude that is probably close to the maximum altitude human beings can permanently tolerate without presenting major health issues.

Contribution of Transcutaneous PCO2 in Obesity Hypoventilation Syndrome.

More and more patients have obesity-hypoventilation syndrome (OHS) because of the increasing prevalence of obesity. The accuracy of transcutaneous PCO2 (PtcCO2 ) has recently been validated. However, no study evaluated the interest of measuring systematically nocturnal PtcCO2 in the follow-up of patients with OHS and home mechanical ventilation to detect residual nocturnal hypoventilation. We aimed to evaluate the contribution of nocturnal PtcCO2 to assess nocturnal hypoventilation compared with current routine examinations, that is, daytime arterial blood gases and nocturnal pulse oximetry. A prospective monocentric pilot study was conducted from August 2018 to November 2019. Patients with stable OHS and who were treated with home noninvasive ventilation for at least 6 months were eligible to participate. After oral consent, we performed both diurnal arterial blood gases and combined home oximetry and capnography. The primary end point was the presence of residual nocturnal hypoventilation, defined as PaCO2 > 45 mm Hg or bicarbonate ≥ 27 mmol/L, SpO2 < 90% for ≥ 10% of the night, or PtcCO2 > 49 mm Hg for ≥ 10% of the night. A total of 32 subjects were included. Twenty-nine subjects with nocturnal PtcCO2 were analyzed. Eighteen of the 29 subjects showed residual nocturnal hypoventilation. The association of diurnal arterial blood gases and nocturnal pulse oximetry revealed nocturnal hypoventilation in only 9 subjects. Among the 19 subjects with both normal blood gases and normal nocturnal pulse oximetry, 11 had nocturnal hypoventilation with transcutaneous capnography. Only one subject presented with hypoventilation symptoms (asthenia). The assessment of PtcCO2 in comparison with nocturnal pulse oximetry and arterial blood gases provides important information for the diagnosis of residual nocturnal hypoventilation in the subjects with OHS who were ventilated at home.

723 Nocturnal pulse oximetry studies before and after initiation of elexacaftor-tezacaftor-ivacaftor: retrospective review from a single cystic fibrosis center

723 Nocturnal pulse oximetry studies before and after initiation of elexacaftor-tezacaftor-ivacaftor: retrospective review from a single cystic fibrosis center

CREB1 spatio-temporal dynamics within the rat pineal gland

In the rat pineal gland (PG), cyclic AMP responsive element-binding protein 1 (CREB1) participates in the nocturnal melatonin synthesis that rhythmically modulates physiology and behavior. Phosphorylation of CREB1 is one of the key regulatory steps that drives pineal transcription. The spatio-temporal dynamics of CREB1 itself in the different PG cell types have not yet been documented. In this study we analyzed total CREB1 in the rat PG via Western blot and fluorescence immunohistochemistry followed by confocal laser-scanning microscopy and quantitative analysis. Total CREB1 levels remained constant in the PG throughout the light:dark cycle. The distribution pattern of nuclear CREB1 did vary among PG cell types. Pinealocytes emerged to have discrete CREB1 domains within their nucleoplasm that were especially distinct. The number, size, and location of CREB1 foci fluctuated among pinealocytes, within the same PG and among Zeitgeber times (ZTs). A significantly larger dispersion of CREB1-immunoreactive nuclear sites was found at night than during the day. However, the overall transcription activity was mostly conserved between the light and dark phases, as shown by the expression of a particular phosphorylated form of the RNA polymerase II (RNAPII-pSer5CTD). Suppression of the nocturnal norepinephrine pulse by chronic bilateral superior cervical ganglionectomy increased CREB1 dispersion in pinealocyte nuclei at early night, as compared to sham-derived cells. In addition, differences in CREB1 distribution were found between sham-operated and non-operated rats at ZT14. Together, these data suggest that in mature pinealocytes, nuclear CREB1 is subjected to a dynamic spatio-temporal distribution. Further studies are necessary to elucidate the underlying mechanisms and to understand the impact of CREB1 reorganization in the pineal transcriptome.

Longitudinal pilot study of oxygen saturation indices in healthy preterm infants

BackgroundThis study aimed to determine patterns of nocturnal pulse oximetry indices in moderate to late preterm infants, and investigate the relationship between oxygen desaturations, the apnoea hypopnoea index, and both corrected gestational and postnatal age.Methods21 healthy infants born at 32 + 0 - 36 + 6 weeks gestation underwent serial nocturnal pulse oximetry studies and respiratory polygraphy studies until 40 weeks corrected gestational age (CGA). The main outcome measures were number of >3% oxygen desaturations/hour (ODI3), mean oxygen saturations, and number of apnoeas and hypopnoeas/hour.ResultsMedian ODI3 increased between weeks 1 and 3 from 49.9 to 85.4/hour (p = 0.017). Mean oxygen saturations reached a corresponding nadir of 96.0% in week 3, then increased to 96.8% in week 6 (p = 0.019). Mixed effects modelling demonstrated that ODI3 and mean saturations were influenced by postnatal age but not CGA (p < 0.05). Desaturations frequently occurred without an apnoea or hypopnoea.ConclusionODI3 rises then falls during the first 8 weeks of life in moderate to late preterm infants, independently of CGA. These interesting preliminary results highlight the importance of further serial data collection to generate age-specific normal ranges, and develop a better understanding of respiratory control in preterm infants.ImpactThe frequency of >3% oxygen desaturations (ODI3) in healthy moderate to late preterm infants rises then falls after birth, peaking in postnatal week 3. There is a corresponding nadir in mean saturations.There were significant non-linear relationships between ODI3/mean saturations and postnatal age, but not corrected gestational age.The majority of brief oxygen desaturations occurred without an apnoea or hypopnoea.Normal ranges for oxygen saturation indices are not known in this population. These results demonstrate the need for further serial data collection to generate age-specific normal ranges and inform oxygen prescribing guidelines.

Interleukin 8 in children with obstructive sleep apnea before and after adenotonsillectomy

ObjectiveTo assess serum interleukin 8 (IL-8) levels after adenotonsillectomy in children with symptoms suggestive for OSA.Study designProspective interventional study.SettingsThe study was carried out on 30 children with OSA attending ENT clinic of Suez Canal University Hospital.MethodsIncluding, children with sleep-related chronic intermittent hypoxia (CIH) and OSA symptoms performed an elective adenotonsillectomy, and aged (3–12 years). Excluding, children with acute tonsillitis, cardiorespiratory, craniofacial, or diseases affecting IL-8 level as cystic fibrosis, COVID-19 patients, and hepatitis C, taking drugs affecting IL-8 level as benzodiazepines or glutamine supplementation. Children were subjected to full history, clinical examination and laboratory investigations. Nocturnal pulse oximetry (ChoiceMMed) was performed (48–72 h preoperative and 3–4 weeks postoperative) used to determine the number of 4% dips in saturation from baseline, and the nadir saturation (nSAT). IL-8 was measured 1 month pre-operative and 1 month post-operative by flow cytometry using the Human Inflammatory Cytometric Bead Array kit.ResultsThe mean preoperative IL-8 (237.55 p/ml) and oxygen desaturation index (7.77%)cwere statistically significantly higher than mean postoperative IL-8 (207.98 p/ml) and oxygen desaturation index (2.90). The mean pre-operative SpO2 is 98.27 ranged (96.00–100.0%), while the mean postoperative SpO2 is 98.77 ranged (97.00–100.0%), with no statistically significant difference between them (p = 0.069). Preoperative IL-8 (p/ml), postoperative IL-8 (p/ml), and preoperative SpO2 (%) were found to be negatively correlated with IL-8 change.ConclusionIL-8 level significantly decreased after adenotonsillectomy in children with symptoms suggestive for OSA.

Overnight changes in uric acid, xanthine oxidoreductase and oxidative stress levels and their relationships with sleep-disordered breathing in patients with coronary artery disease.

Serum uric acid (UA) level is associated with the high cumulative incidence or prevalence of coronary artery disease (CAD), and hyperuricemia is considered as an independent risk marker for CAD. Sleep-disordered breathing (SDB) is also associated with an increased risk of CAD. Several studies have shown that SDB is associated with hyperuricemia, but the mechanisms are unclear. We measured serum levels of UA and xanthine oxidoreductase (XOR) activity and urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), all of which were assessed at 6 p.m. and the following 6 a.m. in males with CAD. In addition, nocturnal pulse oximetry was performed for the night. Overall 32 eligible patients with CAD were enrolled. Serum UA levels significantly increased overnight. (5.32 ± 0.98 mg/dl to 5.46 ± 1.02 mg/dl, p < 0.001) Moreover, XOR activity and urinary 8-OHdG levels significantly increased from 6 p.m. to 6 a.m. Furthermore, 3% Oxygen desaturation index (ODI) was correlated with the overnight changes in XOR activity (r = 0.36, P = 0.047) and urinary 8-OHdG levels (r = 0.41, P = 0.02). In addition, 3%ODI was independently correlated with the changes in XOR activity (correlation coefficient, 0.36; P = 0.047) and 8-OHdG (partial correlation coefficient, 0.63; P = 0.004) in multivariable analyses. SDB severity was associated with the overnight changes in XOR activity and urinary 8-OHdG, suggesting that SDB may be associated with oxidative stress via UA production. This trial is registered at University Hospital Medical Information Network (UMIN), number: UMIN000021624.

Nocturnal pulse wave amplitude attenuations are associated with long-term cardiovascular events

ObjectivesPhotoplethysmography (PPG) is an established technology for detecting pulse rate and pulse wave irregularities. However, whether temporal variations in pulse wave amplitudes, reflecting a combination of acute hemodynamic or autonomic responses to changes in overall vascular function, carry prognostic information remains unclear. To quantify nocturnal temporal pulse wave amplitude (PWA) attenuations and evaluate its association with long-term cardiovascular (CV) events in a large, racially diverse sample of men and women. MethodsTemporal PWA attenuations were determined based on the slopes between the upper and lower envelopes of PPGs derived from overnight polysomnography of 1957 participants (899 men, 1058 women, mean age 68.2 ± 9.1 years) of the Multi-Ethnic Study of Atherosclerosis. The nocturnal PWA attenuation index was defined as the cumulative duration of all PWA attenuation events relative to total sleep duration. ResultsNocturnal PWA attenuation index was greater in men than in women by almost 13% (16.3 ± 8.9% vs. 14.4 ± 7.9%, p < 0.001). The nocturnal PWA attenuation index was highest in Chinese-American participants (17.9 ± 9.2%) and lowest in African-Americans (13.5 ± 8.1%). During a median follow-up of 4.9 years, 94 CV events occurred. In multivariable Cox proportional hazard analysis adjusted for typical confounders, the nocturnal PWA attenuation index <15.2% was associated with CV events (HR = 1.58 [1.02–2.45], p = 0.042). ConclusionsNocturnal PWA attenuation index is inversely associated with the risk of CV events, particularly in men and African-Americans. The PPG-derived nocturnal PWA attenuation index could be simply obtained from smart wearable consumer devices and may provide a low-cost, accessible and scalable CV risk marker.

Sleep apnea in school-age children living at high altitude

IntroductionAmong adults, sleep apnea is more common in highlanders than in lowlanders. We evaluated the sleep apnea prevalence in children living at high altitude compared to age-matched low-altitude controls. MethodsHealthy children, 7-14 y of age, living at 2500-3800m in the Tien Shan mountains, Kyrgyzstan, were prospectively studied in a health post at 3250m. Healthy controls of similar age living at 700-800m were studied in a University Hospital at 760m in Bishkek. Assessments included respiratory sleep studies scored according to pediatric standards, clinical examination, medical history, and the pediatric sleep questionnaire (PSQ, range 0 to 1 with increasing symptoms). ResultsIn children living at high altitude (n = 37, 17 girls, median [quartiles] age 10.8y [9.6;13.0]), sleep studies revealed: mean nocturnal pulse oximetry 90% (89;91), oxygen desaturation index (ODI, >3% dips in pulse oximetry) 4.3/h (2.5;6.7), apnea/hypopnea index (AHI) total 1.7/h (1.0;3.6), central 1.6/h (1.0;3.3), PSQ 0.27 (0.18;0.45). In low-altitude controls (n=41, 17 girls, age 11.6y [9.5;13.0], between-groups comparison of age P=0.69) sleep studies revealed: pulse oximetry 97% (96;97), ODI 0.7/h (0.2;1.2), AHI total 0.4/h (0.1;1.0), central 0.3/h (0.1;0.7), PSQ 0.18 (0.14;0.31); P<0.05, all corresponding between-group comparisons. ConclusionsIn school-age children living at high altitude, nocturnal oxygen saturation was lower, and the total and central AHI were higher compared to children living at low altitude. The greater score of sleep symptoms in children residing at high altitude suggests a potential clinical relevance of the nocturnal hypoxemia and subtle sleep-related breathing disturbances.

Exposure to a nocturnal light pulse simultaneously and differentially affects stridulation and locomotion behaviors in crickets.

It is crucial for living organisms to be in synchrony with their environment and to anticipate circadian and annual changes. The circadian clock is responsible for entraining organisms' activity to the day-night rhythmicity. Artificial light at night (ALAN) was shown to obstruct the natural light cycle, leading to desynchronized behavioral patterns. Our knowledge of the mechanisms behind these adverse effects of ALAN, however, is far from complete. Here we monitored the stridulation and locomotion behavior of male field crickets (Gryllus bimaculatus), raised under light:dark conditions, before, during, and after exposure to a nocturnal 3-h pulse of different ALAN intensities. The experimental insects were then placed under a constant light regime (of different intensities); their behavior was continuously monitored; and the period of their daily activity rhythms was calculated. The light pulse treatment induced a simultaneous negative (suppressing stridulation) and positive (inducing locomotion) effect, manifested in significant changes in the average level of the specific activity on the night of the pulse compared to the preceding and the following nights. The transition to constant light conditions led to significant changes in the period of the circadian rhythms. Both effects were light-intensity-dependent, indicating the importance of dark nights for both individual and population synchronization.

Novel Indices to Improve the Diagnostic Ability of Nocturnal Oximetry in Children with OSAS

Nocturnal pulse oximetry (NOx) is an alternative diagnostic test for obstructive sleep apnea syndrome (OSAS) in childhood yet with variable diagnostic performance. Our aim was to apply advanced signal analysis to develop novel and more accurate NOx indices. We studied 45 children aged 3-10 years who underwent adenotonsillectomy for adenotonsillar hypertrophy and OSAS symptoms. Participants performed NOx before and three months after surgery, and the changes in McGill oximetry score (MOS), oxygen desaturation ≥3% index (ODI3), and the novel parameters-cumulative saturation area (CSA) and oxygen saturation sample entropy (SSE)-were assessed. There was a significant improvement (p < 0.001) in all NOx indices. When pre- and post-adenotonsillectomy NOx recordings were compared, the MOS had an area under the curve (AUC) of 0.811 with 63.2% sensitivity and 100% specificity at a cutoff >1. The AUC of ODI3 was 0.994, with 97.8% sensitivity and 91.1% specificity at a cutoff of >3.6 events per hour. The CSA and SSE had an AUC of 1.00, with 100% sensitivity and specificity at a cutoff of >293 and >0.99, respectively. We conclude that the herein-introduced indices-CSA and SSE-hold promise in improving the diagnostic ability of NOx in children suspected of OSAS.

Non-dipping pulse rate and chronic changes of the kidney in patients with chronic kidney disease.

An insufficient decrease in nocturnal pulse rate (PR), non-dipping PR, reflects autonomic imbalance and is associated with cardiovascular events and all-cause mortality. We aimed to investigate the clinical and microanatomical structural findings associated with the non-dipping PR status in patients with chronic kidney disease (CKD). This cross-sectional study included 135 patients who underwent ambulatory blood pressure monitoring and kidney biopsy concurrently at our institution between 2016 and 2019. Non-dipping PR status was defined as (daytime PR-nighttime PR)/daytime PR <0.1. We compared clinical parameters and microstructural changes in the kidney between patients with and without non-dipping PR, including 24 h proteinuria, glomerular volume, and Mayo Clinic/Renal Pathology Society Chronicity Score. The median age was 51 years (interquartile range: 35-63), 54% of which were male, and the median estimated glomerular filtration rate was 53.0 (30.0-75.0) mL/min/1.73 m2. Non-dipping PR status was observed in 39 patients. Patients with non-dipping PR were older and had worse kidney function, higher blood pressure, greater prevalence of dyslipidemia, lower hemoglobin levels, and a larger amount of urinary protein excretion than patients with dipping PR. Patients with non-dipping PR had more severe glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriosclerosis. In the multivariable analysis, the severe chronic changes of the kidney were associated with non-dipping PR status after adjusting for age, sex, and other clinical parameters (odds ratio = 20.8; 95% confidence interval, 2.82-153; P = 0.003). This study is the first to indicate that non-dipping PR is significantly associated with chronic microanatomical changes in the kidneys of patients with CKD.

Implications of Inflammatory and Oxidative Stress Markers in the Attenuation of Nocturnal Blood Pressure Dipping.

To date, no model has jointly encompassed clinical, inflammatory, and redox markers with the risk of a non-dipper blood pressure (BP) profile. We aimed to evaluate the correlation between these features and the main twenty-four-hour ambulatory blood pressure monitoring (24-h ABPM) indices, as well as to establish a multivariate model including inflammatory, redox, and clinical markers for the prediction of a non-dipper BP profile. This was an observational study that included hypertensive patients older than 18 years. We enrolled 247 hypertensive patients (56% women) with a median age of 56 years. The results showed that higher levels of fibrinogen, tissue polypeptide-specific antigen, beta-2-microglobulin, thiobarbituric acid reactive substances, and copper/zinc ratio were associated with a higher risk of a non-dipper BP profile. Nocturnal systolic BP dipping showed a negative correlation with beta-globulin, beta-2-microglobulin, and gamma-globulin levels, whereas nocturnal diastolic BP dipping was positively correlated with alpha-2-globulin levels, and negatively correlated with gamma-globulin and copper levels. We found a correlation between nocturnal pulse pressure and beta-2-microglobulin and vitamin E levels, whereas the day-to-night pulse pressure gradient was correlated with zinc levels. Twenty-four-hour ABPM indices could exhibit singular inflammatory and redox patterns with implications that are still poorly understood. Some inflammatory and redox markers could be associated with the risk of a non-dipper BP profile.

No Difference in Sleep Desaturations Severity between Patients with Wake-Up and Non-Wake-Up Stroke: A PRESS Study Results.

Wake-up stroke (WUS) is a certain type of ischemic stroke in which a patient wakes up with a new neurological deficit due to cerebral ischemia. Sleep-disordered breathing is an independent risk factor for stroke, but the role of nocturnal oxygen desaturation in the pathophysiology of WUS is still insufficiently explored. According to several studies, patients with WUS have a significantly more severe sleep apnea syndrome and lower mean blood oxygen saturation. This study aimed to assess the severity of nocturnal desaturations in acute WUS and non-WUS patients using nocturnal pulse oximetry. The cohort of 225 consecutive patients with neuroimaging-verified acute cerebral ischemia was prospectively enrolled. For further analyses, 213 subjects with known WUS/non-WUS status were selected (111 males and 102 females, average age 70.4 ±12.9, median baseline NIHSS = 5, median baseline mRS = 3). Patients were divided into the WUS group (n = 45) and the non-WUS group (n = 168). Overnight pulse oximetry was performed within 7 days of the stroke onset and data of both of the studied groups were compared. We found oxygen desaturation index (ODI) in the WUS group was 14.5 vs. 16.6 (p = 0.728) in the non-WUS group, basal O2 saturation was 92.2% vs. 92.5% (p = 0.475), average low O2 saturation was 90.3% vs. 89.6% (p = 0.375), minimal O2 saturation was 79.5% vs. 80.6% (p = 0.563), and time with O2 saturation <90% (T90) was 4.4% vs. 4.7% (p = 0.729). In the studied sample, monitored respiratory parameters including ODI, basal O2 saturation, average low O2 saturation, minimal O2 saturation, and T90 did not significantly differ between groups of WUS and non-WUS patients.

Effect of Respiratory Events on Health-Related Quality of Life in Patients Treated with Long-Term Noninvasive Ventilation

Background: Long-term noninvasive ventilation (NIV) can increase or maintain health-related quality of life (HRQoL) for patients with chronic hypercapnic respiratory failure (CHRF). Evidence from studies systematically assessing how NIV-specific factors influence HRQoL is limited. Objectives: The objective of this study was to describe HRQoL measured by the Severe Respiratory Insufficiency Questionnaire (SRI) in patients with CHRF treated with long-term NIV and to analyze the associations between HRQoL and hypoxemia, hypercapnia, and respiratory events such as apneas, hypopneas (AHI), and patient ventilator asynchrony (PVA) occurring during long-term NIV. Methods: We included sixty-seven stable patients with established long-term NIV due to neuromuscular disease or thoracic cage disorders in a prospective cross-sectional study at Oslo University Hospital. Patients answered the SRI and underwent daytime arterial blood gases, nocturnal pulse oximetry, sleep polygraphy, and nocturnal transcutaneous CO₂. Results: The mean global SRI for 62 patients was 64.8 ± 14.5, with the highest score in SRI Social Relationships (79.5 ± 15.6). There were no differences in HRQoL between the different patient groups. Compliant patients had a significantly higher score in SRI Attendant and Sleep. Residual nocturnal hypoxemia affected both the subscale SRI “Respiratory Complaints” and SRI “Attendant Symptoms and Sleep.” Persisting daytime hypercapnia, nocturnal hypoventilation, and high AHI affected the subscale SRI “Anxiety” negatively, while frequent PVA was associated with a lower score in SRI “Physical Function.” Conclusion: In a group of patients with long-term NIV, undesired respiratory events during NIV are associated with lower HRQoL in several of the SRI subscales. We suggest designing interventional studies to confirm the possible relationship between HRQoL and respiratory events during long-term NIV.

Nocturnal Pulse Event Frequency Is Reduced in Multiple System Atrophy.

Risk of sudden death in multiple system atrophy (MSA) is greatest during sleep with unknown mechanisms. We compared nocturnal pulse event frequency in 46 MSA patients and age-/sex-matched controls undergoing overnight pulse oximetry. Nocturnal oxyhemoglobin desaturation indices and pulse event indices (PEIs) were recorded, and relationships between pulse oximetry variables and survival were analyzed. MSA patients had lower PEI (3.1± 5.3 vs. 12.8± 10.8, p< 0.001) despite greater hypoxic burden and similar frequency of respiratory events. Nocturnal pulse events were not associated with severity of daytime autonomic failure. Two MSA patients had suspected sudden death, both with severely reduced PEI. MSA patients have fewer nocturnal pulse events compared with controls, despite similar respiratory event frequency, suggesting abnormal cardiac responses to sleep-disordered breathing. Whether this contributes to sudden death in MSA requires further study. ANN NEUROL 2023;93:205-212.

Machine learning-based classification of circadian rhythm characteristics for mild cognitive impairment in the elderly.

Using wrist-wearable sensors to ecological transient assessment may provide a more valid assessment of physical activity, sedentary time, sleep and circadian rhythm than self-reported questionnaires, but has not been used widely to study the association with mild cognitive impairment and their characteristics. 31 normal cognitive ability participants and 68 MCI participants were monitored with tri-axial accelerometer and nocturnal photo volumetric pulse wave signals for 14 days. Two machine learning algorithms: gradient boosting decision tree and eXtreme gradient boosting were constructed using data on daytime physical activity, sedentary time and nighttime physiological functions, including heart rate, heart rate variability, respiratory rate and oxygen saturation, combined with subjective scale features. The accuracy, precision, recall, F1 value, and AUC of the different models are compared, and the training and model effectiveness are validated by the subject-based leave-one-out method. The low physical activity state was higher in the MCI group than in the cognitively normal group between 8:00 and 11:00 (P < 0.05), the daily rhythm trend of the high physical activity state was generally lower in the MCI group than in the cognitively normal group (P < 0.05). The peak rhythms in the sedentary state appeared at 12:00-15:00 and 20:00. The peak rhythms of rMSSD, HRV high frequency output power, and HRV low frequency output power in the 6h HRV parameters at night in the MCI group disappeared at 3:00 a.m., and the amplitude of fluctuations decreased; the amplitude of fluctuations of LHratio nocturnal rhythm increased and the phase was disturbed; the oxygen saturation was between 90 and 95% and less than 90% were increased in all time periods (P < 0.05). The F1 value of the two machine learning algorithms for MCI classification of multi-feature data combined with subjective scales were XGBoost (78.02) and GBDT (84.04). By collecting PSQI Scale data combined with circadian rhythm characteristics monitored by wrist-wearable sensors, we are able to construct XGBoost and GBDT machine learning models with good discrimination, thus providing an early warning solution for identifying family and community members with high risk of MCI.