Apneic Events Research Articles

Treatment of sleep-disordered breathing among children with myelomeningocele.

Studies have shown a high prevalence of sleep-disordered breathing (SDB) among children with myelomeningocele (MMC), but there are few published data on the longitudinal care of these patients. The objective of this study was to determine the effectiveness of standard treatments for SDB in children with MMC. The authors analyzed records from three multidisciplinary spina bifida clinics to identify all patients with both MMC and SDB diagnosed by polysomnography (PSG). The primary outcome of this study was a change in apnea-hypopnea index (AHI; the number of apneic or hypopneic events per hour of sleep) before and after clinically recommended SDB treatments. Clinical and demographic variables were recorded and evaluated for possible association with posttreatment improvement of AHI. Analysis included change in AHI (a continuous variable) and whether SDB improved (defined as an AHI < 2.5 or decrease of AHI by ≥ 50% from baseline). Seventy-one eligible patients (aged 2 days-21 years, 52% male) had an initial AHI > 2.5 and had follow-up PSG after treatment for SDB. The mean AHI decreased from 20.5 (SD 21.6) at baseline to 11.6 (SD 15.7) after treatment (p = 0.0006). Children treated with supplemental oxygen and with continuous positive airway pressure had improvement on PSG (18 of 25 and 12 of 18, respectively). Children treated with adenotonsillectomy were less likely to improve (7 of 19). Forty-one patients (58%) improved from a baseline AHI > 2.5 to an AHI < 2.5 after treatment. Children with MMC and SDB who undergo standard SDB treatments guided by pediatric sleep medicine physicians show improvement in PSG parameters after treatment.

Management of Obstructive Sleep Apnea in the Infant: A Systematic Review and Meta-analysis.

To evaluate the improvement in respiratory parameters of infants with obstructive sleep apnea (OSA) treated with medical or surgical intervention. A comprehensive review was completed using the PubMed, Web of Science, Embase, and Cochrane libraries including articles published from 1975 to 2024. Interventions studied included adenotonsillectomy, mandibular distraction osteogenesis (MDO), tongue/lip adhesion, partial glossectomy, floor-of-mouth release, supraglottoplasty, oral appliances, tracheostomy, and positioning. Continuous positive airway pressure (CPAP) served as a control. Outcomes studied included pre- and postintervention obstructive apnea-hypopnea index. Studies included randomized controlled trials and case-control trials. A total of 2161 records were identified, and 59 studies were included in the analysis. Data was extracted following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and pooled using a random-effects model. The primary study outcome established prior to data collection was a change in the apnea-hypopnea index. A meta-analysis of MDO performed in infants for OSA demonstrated an overall pooled mean difference (pre-apnea-hypopnea index minus post-apnea hypopnea index) of 30.1 (95% confidence interval: 22.9, 37.4; 10 studies, 373 patients). No other data was pooled for analysis due to study heterogeneity. All CPAP studies showed apnea resolution. Tailored therapies including supraglottoplasty and tongue-lip adhesion reduced but did not resolve apneic events. Current investigations of the evaluation and treatment of infant OSA are limited by heterogeneity in reporting and study. Mandibular distraction and CPAP are promising.

The Correlation of Computerized Scoring in Home Sleep Apnea Tests with Technician Visual Scoring for Assessing the Severity of Obstructive Sleep Apnea.

Background: Obstructive sleep apnea (OSA) affects a significant proportion of the global population, with many having moderate or severe forms of the disease. Home Sleep Apnea Testing (HSAT) has become the most common method of diagnosing OSA, replacing in-lab polysomnography. Polysmith software Version 11 by Nihon Kohden allows for the automatic scoring of respiratory events. This study aimed to assess the validity of this technology. Study Objectives: The objective was to assess the accuracy of the Polysmith Software Automatic Scoring Algorithm of HSATs in comparison to that of sleep technicians. Methods: One hundred twenty HSATs were scored by both sleep technicians and Polysmith software. The measured values were the respiratory event index (REI), apneic events, and hypopneic events. Agreement between the two methods was reached by utilizing the Kruskal-Wallis test, Pearson correlation coefficient, and Bland-Altman plot, as well as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: The correlation between the REI calculated by the software and technicians proved to be strong overall (r = 0.96, p < 0.0001). The mild OSA group had a moderate correlation (r = 0.45, p = 0.0129). The primary snoring, moderate OSA, and severe OSA groups showed stronger correlations (r = 0.69, p < 0.0001; r = 0.56, p = 0.012; r = 0.71, p < 0.0001). The analysis conducted across all groups demonstrated an average sensitivity of 81%, specificity of 94%, PPV of 82%, and NPV of 94%, with an overall accuracy of 81%. When combining the moderate and severe OSA groups into a single category, the sensitivity was 90%, specificity was 100%, PPV was 100%, and NPV was 91%. Conclusions: OSA can be reliably diagnosed from HSATs with the automated Polysmith software across all OSA disease severity groups, with higher levels of accuracy in moderate/severe OSA and lower levels of accuracy in mild OSA.

Respiratory Arrest in a Late Preterm Infant Presenting for a 2-Week Well-Visit.

A 13-day-old, late preterm male, born appropriate for gestational age, presented to the pediatric clinic for his routine 2-week well visit with less than 1-day history of decreased oral intake and lethargy. During the baby's well exam, he acutely decompensated and required resuscitation and transfer to the emergency department, where he was intubated for frequent apneic events. He was admitted to the NICU for management and further workup. Physical examination and initial laboratory tests were unremarkable. An EEG demonstrated electrographic and clinical seizures. His initial MRI was unremarkable, and infection studies revealed the diagnosis. We review the patient's initial presentation, evaluation, hospital course, and the long-term implications of his diagnosis.

Congenital/Primitive Hydrocephalus: Classification, Clinical Aspects, and Rehabilitation Approach

AbstractHydrocephalus is a heterogeneous disorder of cerebrospinal fluid (CSF) flow that leads to abnormal enlargement of the brain ventricles. The prevalence of infant hydrocephalus is approximately one case per 1,000 births. Hydrocephalus occurs due to an imbalance between the production and the absorption of CSF. The causes of hydrocephalus secondary to CSF overproduction are papilloma of the choroid plexus and rarely diffuse hyperplasia of the villi. All the other hydrocephalus forms are secondary to obstruction to normal CSF reabsorption and are also known as obstructive hydrocephalus. According to the location of obstruction, obstructive hydrocephalus can be defined as communicating, when caused by extraventricular obstruction of the CSF flow or decreased resorption of CSF distal to the fourth ventricle in the cisterns of the base or in the subarachnoid spaces, or as not communicating, in case of intraventricular obstruction to fluid flow. There is a third category, common in preterm infants, called external hydrocephalus which is secondary to delayed development of arachnoid function. Hydrocephalus leads to an increase in intraventricular pressure because of the lack of the mechanism regulating the homeostasis of the CSF flow. Increased intraventricular pressure is responsible for the clinical symptoms in affected child. Clinical presentation varies with age. In the neonatal period, prolonged or frequent apneic or bradycardic events, increasing head circumference, presence of sunsetting eyes or upward gaze palsy, evidence of full or tense anterior/posterior fontanelle, and splayed cranial sutures are signs of increased intracranial pressure. In infants, the most common signs are progressive macrocephaly, irritability, nausea/vomiting, headache, gait changes, and regression of developmental milestones. The extent of brain damage depends on the cause that led to hydrocephalus, the patient's age, and the rapidity of onset. The surgical treatment modalities consist of endoscopic ventriculostomy of the third ventricle and ventriculoperitoneal or ventriculoatrial CSF shunt.

Nocturnal Heart Rate Response to Spontaneous Arousals Following Sleep Restriction

Short sleep duration is associated with future cardiovascular disease including hypertension, especially in females, but mechanistic evidence is largely lacking. Experimental sleep restriction has been shown to cause short sleep-mediated tachycardia and reduced heart rate variability, indicative of autonomic cardiac instability, in some but not all studies. Heart rate (HR) response to spontaneous cortical arousals can be regarded as an index of autonomic cardiac control given its characteristic temporal pattern. Whether the HR response to cortical arousals is altered during experimental sleep restriction remains unknown. We hypothesized that sleep restriction would result in augmented HR reactivity to spontaneous arousals, and that this response would be more marked in females. We studied 19 young, healthy subjects (eight females, age: 23.5 ± 5 years, body mass index [BMI]: 24.5 ± 3.6 kg/m2). In a randomized, crossover design, participants were tested during a normal sleep (NS, 9 hr sleep opportunity) or sleep restriction (SR, 4 hr sleep opportunity) study arm. Each 16-day study visit consisted of a 4-day study acclimation phase, 9-day experimental sleep perturbation segment, followed by a 3-day recovery period. An overnight polysomnography (PSG) study was conducted on study days 2, 5 and 11 (at baseline and after 1 and 7 days of restricted versus control sleep). A registered PSG technician provided sleep staging and spontaneous arousal scoring, which was confirmed by an investigator with sleep expertise (IMG). For each identified spontaneous arousal, the HR change was quantified for 30 cardiac cycles post-arousal onset and compared to a pre-arousal baseline (average HR 5 – 10 cardiac cycles prior to arousal). An arousal was considered valid for analysis if at least one minute of stage N2 or rapid eye movement (REM) sleep occurred following sleep stage transition and was at least 30 seconds apart from other sleep disturbance-related events (e.g., limb movement, apneic event, etc.). Given low prevalence of slow wave sleep (SWS) arousals, arousals occurring in that sleep stage were excluded from present analysis. Statistical analysis, including repeated measures ANOVA (RMANOVA, p &lt; 0.05) with condition and time (cardiac cycles) as within-subjects factors and sex as the between-subjects factor, was conducted to compare the beat-to-beat HR response to arousal between study conditions. Additionally, average and peak HR responses to spontaneous arousals were compared via RMANOVA with condition and time (study days) as within-subjects and sex as between-subjects factors. HR response to spontaneous arousal in stage two and REM sleep was similar between NS and SR on study day 5 or day 11 (condition × time: p = 0.943, 0.865). Secondary analysis of average and peak HR responsiveness to spontaneous arousals in stage two and REM sleep between conditions and study days was also not statistically different (condition × time: p = 0.193, 0.185). Last, no significant sex differences were detected across comparisons (condition × time × sex: p &gt; 0.05 for all). These findings suggest that a 9-day sleep restriction paradigm may not alter cardiac autonomic function in otherwise healthy adults. Future work is warranted to determine whether these results extend to individuals with established cardiovascular risk factors or cardiovascular disease. Support: NIH T32-DK007013, R01-114676, and CTSA grant UL1-TR002377. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Does ovariectomy exacerbate the cardiorespiratory and metabolic consequences of moderate intermittent hypoxia in female rats?

Intermittent hypoxia (IH) is a major consequence of sleep apnea (SA). IH causes respiratory dysfunction and contributes to numerous co-morbidities of SA including hypertension and obesity. The fact that menopause increases the prevalence of SA and related diseases in women indicates the importance of loss of ovarian function in the pathophysiology. Here, we determined whether experimental loss of ovarian function (ovariectomy; OVX) exacerbates the cardiorespiratory and metabolic consequences of IH. We explored neuroendocrine changes by assessing hormones known to be involved in energy balance, respiratory control, and stress responses (leptin, ACTH and corticosterone). We subjected adult (8 weeks) Sprague Dawley female rats to bilateral OVX (n = 13) or sham operation (n = 14). Rats were housed in pairs, and after two weeks of recovery, animals were exposed to room air (control; n = 16) or to a 7-day moderate IH protocol (n = 11). Within their cage, rats intermittently received a nitrogen-enriched hypoxic mixture, followed by room air for reoxygenation. Each bout of hypoxia lasted 30 seconds (nadir FIO2 = 0.10) and was followed by 5-minutes of reoxygenation (10 cycles/h, for 8hrs between 10h-18h). Apnea frequency, acute responses to hypoxia (FIO2 = 0.12; 120 sec) and hypercapnia (FICO2 = 0.05; 10 min) were measured by whole-body plethysmography. Blood pressure was assessed by the tail cuff method, and body weight was followed throughout the protocol. Plasma corticosterone and leptin were measured by multiplex assays. OVX increased apneic events, whereas IH reduced them; with the highest frequency observed in OVX females maintained in normoxia. Ventilatory responses (hypoxia and CO2) and blood pressure were not affected by IH or OVX. Over the course of the protocol, OVX increased weight gain whereas IH induced weight loss. OVX (but not IH) increased ACTH and corticosterone. IH (but not OVX) reduced leptin. Correlation matrix analysis showed that weight gain was the best predictor of apnea frequency (r = 0.759; p = 0.03). We conclude that loss of ovarian function and related weight gain have the greatest impact on respiratory function during sleep. Additionally, OVX-related activation of the stress pathways may contribute to this process. These results fail to demonstrate a role for OVX in exacerbating the cardiorespiratory and metabolic consequences of IH. Lack of weight gain following IH likely contributes to this finding. This study is supported by operating grants from the Canadian Institutes of Health Research (RK and VJ). NJM is supported by a Sentinel North Partnered Research Chair in Sleep Pharmacometabolism and a Canada Research Chair in Metabolism and Sleep Neurobiology. MG received a doctoral scholarship from the Fonds de Recherche du Québec — Santé (FRQS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Efficacy and safety during endoscopic retrograde cholangiopancreatography (ERCP) under total intravenous anesthesia – propofol alone versus propofol supplemented with dexketa, a comparative study in medical college, Kolkata

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive procedure and, hence, is distressing for awake patients, requiring an adequate level of anesthesia. Recent advancements have encouraged the use of monitored anesthesia care, that allows the patient to tolerate unpleasant experiences during procedures while maintaining cardio-respiratory function. Usually, propofol-based anesthesia is given in ERCP. The main aim of this study is to compare the effect of propofol alone and propofol with ketamine and dexmedetomidine on the hemodynamics during ERCP, recovery profile, and side effects (if any). Aims and Objectives: (1) To compare efficacy in terms of hemodynamic stability and desaturation events. (2) Recovery and quality of recovery. (3) Pain score. (4) Incidence of post-operative nausea and vomiting. Materials and Methods: This is a comparative double-blinded study. Adult patients from the age group of 18–70 years belonging to the American Society of Anesthesiologists (ASA-I) and ASA-II who had undergone ERCP under total intravenous anesthesia were taken and randomly assigned to either of the two groups. Both groups received 0.01 mg/kg glycopyrrolate, 0.1 mg/kg ondansetron, 0.05 mg/kg midazolam, 50 mcg fentanyl, and 40 mg hyoscine. Group A patients received 30 mg propofol as a bolus dose and then repeated according to requirements. Group B patients received 0.5 mcg/kg dexmedetomidine as a loading dose and 0.3 mcg/kg/h as a maintenance infusion dose. 30 mg propofol was given before negotiating scope and then 1 mL (1:1) mixture of propofol and ketamine was repeated according to requirements. Total propofol consumption, hemodynamics, quality of recovery, and side effects (if any) were recorded at regular intervals. Results: The study showed significant cases in Group A had episodes of hypotension and apneic events, whereas there were very few hemodynamic instability and almost no apneic events in Group B patients. The requirement of propofol was much higher in Group A patients. Conclusion: Dexmedetomidine when used along with propofol and ketamine in ERCP patients reduced the dose requirement of propofol and maintained hemodynamic stability without causing any apneic events.

Brainstem depolarization–induced lethal apnea associated with gain-of-function SCN1AL263V is prevented by sodium channel blockade

Apneic events are frightening but largely benign events that often occur in infants. Here, we report apparent life-threatening apneic events in an infant with the homozygous SCN1AL263V missense mutation, which causes familial hemiplegic migraine type 3 in heterozygous family members, in the absence of epilepsy. Observations consistent with the events in the infant were made in an Scn1aL263V knock-in mouse model, in which apnea was preceded by a large brainstem DC-shift, indicative of profound brainstem depolarization. The L263V mutation caused gain of NaV1.1 function effects in transfected HEK293 cells. Sodium channel blockade mitigated the gain-of-function characteristics, rescued lethal apnea in Scn1aL263V mice, and decreased the frequency of severe apneic events in the patient. Hence, this study shows that SCN1AL263V can cause life-threatening apneic events, which in a mouse model were caused by profound brainstem depolarization. In addition to being potentially relevant to sudden infant death syndrome pathophysiology, these data indicate that sodium channel blockers may be considered therapeutic for apneic events in patients with these and other gain-of-function SCN1A mutations.

Nocturnal Pressure Controlled Ventilation Improves Sleep Efficiency in Patients Receiving Mechanical Ventilation.

Patients receiving mechanical ventilation commonly experience sleep fragmentation. The present meta-analysis compared the effects of pressure controlled ventilation (PCV) and pressure support ventilation (PSV) on sleep quality. We conducted a search of the PubMed, Embase, and Cochrane Library databases for studies published before November 2023. In this meta-analysis, individual effect sizes were standardized, and the pooled effect size was determined by using random-effects models. The primary outcome was sleep efficiency. The secondary outcomes were wakefulness, percentages of REM (rapid eye movement) sleep and stages 3 and 4 non-REM sleep, the fragmentation index, and the incidence of apneic events. This meta-analysis examined 4 trials that involved 67 subjects. Sleep efficiency was significantly higher in the PCV group than in the PSV group (mean difference 15.57%, 95% CI 8.54%-22.59%). Wakefulness was significantly lower in the PCV group than in the PSV group (mean difference -18.67%, 95% CI -30.29% to -7.04%). The percentage of REM sleep was significantly higher in the PCV group than in the PSV group (mean difference 2.32%, 95% CI 0.20%-4.45%). Among the subjects with a tendency to develop sleep apnea, the fragmentation index was significantly lower in those receiving PCV than PSV (mean difference -40.00%, 95% CI -51.12% to -28.88%). The incidence of apneic events was significantly lower in the PCV group than in the PSV group (risk ratio 0.06, 95% CI 0.01-0.45). Compared with PSV, PCV may improve sleep quality in patients receiving nocturnal mechanical ventilation.

Noncontact Infant Apnea Detection for Hypoxia Prevention With a K-Band Biomedical Radar.

Annually, a significant number of premature infants suffer from apnea, which can easily cause a drop in oxygen saturation levels, leading to hypoxia. However, infant cardiopulmonary monitoring using conventional methods often necessitates skin contact, and they are not suitable for long-term monitoring. This article introduces a non-contact technique for infant cardiopulmonary monitoring and an adjustable apnea detection algorithm. These are developed using a custom-designed K-band continuous-wave biomedical radar sensor system, which features a DC-coupled adaptive digital tuning function. By using radar technology to detect chest motions without physical contact, it is feasible to extract significant biological information regarding an infant's respiration and heartbeat. The proposed algorithm utilizes an adaptively adjusted threshold and personalized apnea warning time to automatically measure the total number of apneic events and their respective durations. Experiments have been conducted in clinical environment, demonstrating that both the accurate cardiopulmonary signals and the apneas of varying durations can be effectively monitored using this method, which suggest that the proposed technique has potential applications both inside and outside of clinical settings.

Respiratory Syncytial Virus Infection and Apnea Risk As Criteria for Hospitalization in Full Term Healthy Infants.

Introduction Apnea is recognized as a serious and potentially life-threatening complication associated with Respiratory Syncope Virus (RSV). The literature reports a wide range of apnea rates for infants with comorbid factors. Prematurity and young chronological age have been historically associated with the risk of apnea in hospitalized infants. Few studies have specifically examined the risk of apnea in healthy infants presenting to the emergency department. Methods This is a retrospective review of infants diagnosed with RSV using a PCR assay. Patients were divided into "mild" and "severe" cohorts based on symptoms at presentation. This study occurred in the NYU Langone Long Island (NYULI) pediatric emergency department (ED), a midsize academic hospital in the Northeast United States. The study included infants <6 months of age, born full term without comorbid conditions such as chronic lung or cardiac conditions, seen in NYULI ED over three consecutive RSV seasons (2017-2020). The primary outcome was the risk of apneic events. Secondary outcomes included hospital admission, ICU admission, length of stay, and supplemental oxygen support. Results The risk of apnea was <2%, regardless of disease severity. There were no significant differences in demographics between mild and severe disease. Cohorts differed significantly in the number of hospitalizations (41 milds vs. 132 severe), ICU admissions (2 milds vs. 27 severe), need for oxygen support (17 milds vs. 92 severe), hospital readmissions (2 milds vs. 42 severe), and length of stay (2 days milds vs. 3 days severe). Conclusions Apnea does not pose a significant risk for healthy full-term infants with RSV disease of any severity. The decision to admit this population to the hospital should be based on clinical presentation and not solely on the perceived risk of apnea.

Detecting central apneas using multichannel signals in premature infants.

Objective. Monitoring of apnea of prematurity, performed in neonatal intensive care units by detecting central apneas (CAs) in the respiratory traces, is characterized by a high number of false alarms. A two-step approach consisting of a threshold-based apneic event detection algorithm followed by a machine learning model was recently presented in literature aiming to improve CA detection. However, since this is characterized by high complexity and low precision, we developed a new direct approach that only consists of a detection model based on machine learning directly working with multichannel signals.Approach. The dataset used in this study consisted of 48 h of ECG, chest impedance and peripheral oxygen saturation extracted from 10 premature infants. CAs were labeled by two clinical experts. 47 features were extracted from time series using 30 s moving windows with an overlap of 5 s and evaluated in sets of 4 consecutive moving windows, in a similar way to what was indicated for the two-step approach. An undersampling method was used to reduce imbalance in the training set while aiming at increasing precision. A detection model using logistic regression with elastic net penalty and leave-one-patient-out cross-validation was then tested on the full dataset.Main results. This detection model returned a mean area under the receiver operating characteristic curve value equal to 0.86 and, after the selection of a FPR equal to 0.1 and the use of smoothing, an increased precision (0.50 versus 0.42) at the expense of a decrease in recall (0.70 versus 0.78) compared to the two-step approach around suspected apneic events.Significance. The new direct approach guaranteed correct detections for more than 81% of CAs with lengthL≥ 20 s, which are considered among the most threatening apneic events for premature infants. These results require additional verifications using more extensive datasets but could lead to promising applications in clinical practice.

The Beginning of the AI-Enabled Preventative PAP Therapy Era: A First-in-Human Proof of Concept Interventional Study.

Positive Airway Pressure (PAP) therapy is the most common and efficacious treatment for Obstructive Sleep Apnea (OSA). However, it suffers from poor patient adherence due to discomfort and may not fully alleviate all adverse consequences of OSA. Identifying abnormal respiratory events before they have occurred may allow for improved management of PAP levels, leading to improved adherence and better patient outcomes. Our previous work has resulted in the successful development of a Machine-Learning (ML) algorithm for the prediction of future apneic events using existing airflow and air pressure sensors available internally to PAP devices. Although researchers have studied the use of ML for the prediction of apneas, research to date has focused primarily on using external polysomnography sensors that add to patient discomfort and has not investigated the use of internal-to-PAP sensors such as air pressure and airflow to predict and prevent respiratory events. We hypothesized that by using our predictive software, OSA events could be proactively prevented while maintaining patients' sleep quality. An intervention protocol was developed and applied to all patients to prevent OSA events. Although the protocol's cool-down period limited the number of prevention attempts, analysis of 11 participants revealed that our system improved many sleep parameters, which included a statistically significant 31.6% reduction in Apnea-Hypopnea Index, while maintaining sleep quality. Most importantly, our findings indicate the feasibility of unobtrusive identification and unique prevention of each respiratory event as well as paving the path to future truly personalized PAP therapy by further training of ML models on individual patients.

Positional Therapy for Obstructive Sleep Apnea: Therapeutic Modalities and Clinical Effects

Obstructive sleep apnea (OSA) is characterized by recurrent occurrences of partial or complete collapse of the upper airway during sleep, leading to shallow breathing or breathing pauses. These repeated breathing disruptions can result in intermittent hypoxia, hypercapnia, hyperactivity of the sympathetic nervous system, and fragmented sleep patterns. Left untreated, OSA can have significant health implications, including various symptoms and serious consequences. Positional OSA is a subtype of OSA where during sleep, the severity of apnea events is significantly higher in the supine position. This condition can worsen respiratory parameters, such as apnea/hypopnea events, oxygen desaturation and arousals, and cardiovascular burdens. Positional therapy is a treatment approach used for patients with positional OSA. Typically, positional therapy involves encouraging the patient to avoid sleeping on their back, and instead sleep in a lateral position. Various modalities for positional therapy exist, including positional training using a tennis ball, alarm, or vest, and sleep positioning pillows. Novel electric-operated postural devices have also been developed. Positional therapy has shown promise in improving apneic events and lowest oxygen saturation in patients with position-dependent sleep apnea. In comparison to positive airway pressure treatment, positional therapy has been reported to demonstrate non-inferior effects, while achieving better compliance. Consequently, positional therapy can be a cost-effective and non-invasive therapeutic alternative for managing positional OSA.

Effect of depression on phase coherence between respiratory sinus arrhythmia and respiration during sleep in patients with obstructive sleep apnea.

Introduction: A high prevalence of major depressive disorder (MDD) among Obstructive Sleep Apnea (OSA) patients has been observed in both community and clinical populations. Due to the overlapping symptoms between both disorders, depression is usually misdiagnosed when correlated with OSA. Phase coherence between respiratory sinus arrhythmia (RSA) and respiration (λ RSA-RESP) has been proposed as an alternative measure for assessing vagal activity. Therefore, this study aims to investigate if there is any difference in λ RSA-RESP in OSA patients with and without MDD. Methods: Electrocardiograms (ECG) and breathing signals using overnight polysomnography were collected from 40 OSA subjects with MDD (OSAD+), 40 OSA subjects without MDD (OSAD-), and 38 control subjects (Controls) without MDD and OSA. The interbeat intervals (RRI) and respiratory movement were extracted from 5-min segments of ECG signals with a single apneic event during non-rapid eye movement (NREM) [353 segments] and rapid eye movement (REM) sleep stages [298 segments]. RR intervals (RRI) and respiration were resampled at 10 Hz, and the band passed filtered (0.10-0.4 Hz) before the Hilbert transform was used to extract instantaneous phases of the RSA and respiration. Subsequently, the λ RSA-RESP between RSA and Respiration and Heart Rate Variability (HRV) features were computed. Results: Our results showed that λ RSA-RESP was significantly increased in the OSAD+ group compared to OSAD- group during NREM and REM sleep. This increase was accompanied by a decrease in the low frequency (LF) component of HRV. Discussion: We report that the phase synchronization index between RSA and respiratory movement could provide a useful measure for evaluating depression in OSA patients. Our findings suggest that depression has lowered sympathetic activity when accompanied by OSA, allowing for stronger synchronization between RSA and respiration.

An explainable deep-learning architecture for pediatric sleep apnea identification from overnight airflow and oximetry signals

Deep-learning algorithms have been proposed to analyze overnight airflow (AF) and oximetry (SpO2) signals to simplify the diagnosis of pediatric obstructive sleep apnea (OSA), but current algorithms are hardly interpretable. Explainable artificial intelligence (XAI) algorithms can clarify the models-derived predictions on these signals, enhancing their diagnostic trustworthiness. Here, we assess an explainable architecture that combines convolutional and recurrent neural networks (CNN + RNN) to detect pediatric OSA and its severity. AF and SpO2 were obtained from the Childhood Adenotonsillectomy Trial (CHAT) public database (n = 1,638) and a proprietary database (n = 974). These signals were arranged in 30-min segments and processed by the CNN + RNN architecture to derive the number of apneic events per segment. The apnea-hypopnea index (AHI) was computed from the CNN + RNN-derived estimates and grouped into four OSA severity levels. The Gradient-weighted Class Activation Mapping (Grad-CAM) XAI algorithm was used to identify and interpret novel OSA-related patterns of interest. The AHI regression reached very high agreement (intraclass correlation coefficient > 0.9), while OSA severity classification achieved 4-class accuracies 74.51% and 62.31%, and 4-class Cohen’s Kappa 0.6231 and 0.4495, in CHAT and the private datasets, respectively. All diagnostic accuracies on increasing AHI cutoffs (1, 5 and 10 events/h) surpassed 84%. The Grad-CAM heatmaps revealed that the model focuses on sudden AF cessations and SpO2 drops to detect apneas and hypopneas with desaturations, and often discards patterns of hypopneas linked to arousals. Therefore, an interpretable CNN + RNN model to analyze AF and SpO2 can be helpful as a diagnostic alternative in symptomatic children at risk of OSA.

Phenotypical Characterization of Obstructive Sleep Apnea in Premature Infants using Polysomnography.

To use objective quantification of polysomnographic (PSG) parameters in premature infants to define the severity and nature of obstructions (partial hypopnea vs. total obstruction), along with the impact on sleep fragmentation and oxygenation patterns. Retrospective comparison of PSG features in 207 infants (<12 months) referred for sleep disordered breathing. Our study groups included term (> = 37 weeks GA, n = 162) and premature (<37 weeks GA, n = 45) infants. Groups were compared for OSA sleep-stage-specific apnea hypopnea (AHI) indexes (REM and NREM), hypopnea indexes (HI), obstructive apnea indexes (OI) and arousal indexes. Oxygenation was assessed as % of time with SpO2 < 90%, nadir with apneic events and frequency of SpO2 desaturations (>3%) calculated as stage-specific O2 desaturation indexes. Overall, premature infants had greater apnea severity (AHI premature 13.9/h vs. Term 7.9/h, p = 0.018). Additional analyses showed that the primary difference between premature and term infants is seen in the group with partial obstructions (HI index) and severe OSA (OAHI> = 10/h). Premature infants also had greater arousal indexes (premature 13.8/h vs. term 10.5/h, p = 0.003). Although the percentage of time <90% at night and the median SpO2 nadir during apneic events was similar in premature vs. term, O2 desaturation indexes were greater in premature infants (10.3/h in term vs. 18.3/h in prematurity, p = 0.03). Children born premature have an OSA phenotype in infancy characterized by greater severity mostly due to frequent partial obstructions (hypopneas) rather than full obstructions (obstructive apnea). Prematurity is also associated with more intermittent hypoxemia and sleep fragmentation. 3 Laryngoscope, 134:1933-1938, 2024.

Enhancing OSA Assessment with Explainable AI.

Explainable Artificial Intelligence (xAI) is a rapidly growing field that focuses on making deep learning models interpretable and understandable to human decision-makers. In this study, we introduce xAAEnet, a novel xAI model applied to the assessment of Obstructive Sleep Apnea (OSA) severity. OSA is a prevalent sleep disorder that can lead to numerous medical conditions and is currently assessed using the Apnea-Hypopnea Index (AHI). However, AHI has been criticized for its inability to accurately estimate the effect of OSAs on related medical conditions. To address this issue, we propose a human-centric xAI approach that emphasizes similarity between apneic events as a whole and reduces subjectivity in diagnosis by examining how the model makes its decisions. Our model was trained and tested on a dataset of 60 patients' Polysomnographic (PSG) recordings. Our results demonstrate that the proposed model, xAAEnet, outperforms models with traditional architectures such as convolutional regressor, autoencoder (AE), and variational autoencoder (VAE). This study highlights the potential of xAI in providing an objective OSA severity scoring method.Clinical relevance- This study provides an objective OSA severity scoring technique which could improve the management of apneic patients in clinical practice.

Respiratory Event-Induced Blood Pressure Oscillations Vary by Sleep Stage in Sleep Apnea Patients.

Obstructive sleep apnea (OSA) pathologically stresses the cardiovascular system. Apneic events cause significant oscillatory surges in nocturnal blood pressure (BP). Trajectories of these surges vary widely. This variability challenges the quantification, characterization, and mathematical modeling of BP surge dynamics. We present a method of aggregating trajectories of apnea-induced BP surges using a sample-by-sample averaging of continuously recorded BP. We applied the method to recordings of overnight BP (average total sleep time: 4.77 ± 1.64 h) for 10 OSA patients (mean AHI: 63.5 events/h; range: 18.3-105.4). We studied surges in blood pressure due to obstructive respiratory events separated from other such events by at least 30 s (274 total events). These events increased systolic (SBP) and diastolic (DBP) BP by 19 ± 7.1 mmHg (14.8%) and 11 ± 5.6 mmHg (15.5%), respectively, relative to mean values during wakefulness. Further, aggregated SBP and DBP peaks occurred on average 9 s and 9.5 s after apnea events, respectively. Interestingly, the amplitude of the SBP and DBP peaks varied across sleep stages, with mean peak ranging from 128.8 ± 12.4 to 166.1 ± 15.5 mmHg for SBP and from 63.1 ± 8.2 to 84.2 ± 9.4 mmHg for DBP. The aggregation method provides a high level of granularity in quantifying BP oscillations from OSA events and may be useful in modeling autonomic nervous system responses to OSA-induced stresses.