Pathology of unexpected sudden cardiac death: Obstructive sleep apnea is part of the challenge

Chewing Gum in the Larynx: Foreign Body Aspiration or Iatrogenic Artifact? Challenges in Determining the Cause of Death in a Road Traffic Accident Victim With Resuscitation Intervention

Identifying the cause of death in road traffic incidents and the contributing factors is crucial for forensic investigations, public health research, and epidemiological studies. In this case, the discovery of chewing gum in the larynx during an autopsy complicated the forensic diagnostic process and challenged the determination of the primary cause of death. Our case report details a 53-year-old male driver involved in a fatal road traffic accident. First responders found him unconscious and unresponsive. Despite resuscitative efforts, including endotracheal intubation, he could not be revived. The autopsy revealed multiple blunt force injuries from the collision and chewing gum in the larynx. The gum may have been aspirated while driving, potentially causing choking, severe coughing, or reflex cardiac arrest, which could have led to sudden incapacitation and the accident. Alternatively, the gum might have been overlooked during intubation, possibly pushing it deeper into the airway and creating an iatrogenic artifact. The cause of death was attributed to multiple blunt force injuries, specifically head trauma. However, the possibility of foreign body aspiration leading to the accident or the gum being an iatrogenic artifact cannot be ruled out. This case report highlights the potential impact of airway foreign bodies on road accidents and the risk of iatrogenic artifacts during resuscitation. It underscores the importance of thorough airway evaluation, prompt recognition of potential obstructions, and accurate documentation in prehospital settings to prevent worsening obstructions, misdiagnoses, delays in diagnosis, and complications in future cases.

Gas exchange parameters for the prediction of obstructive sleep apnea in infants

STUDY OBJECTIVES

Sleep laboratory polysomnography is the gold standard for obstructive sleep apnea (OSA) diagnosis in infants, but its access remains limited. Oximetry-capnography is another simple and widely used tool that can provide information on the presence of desaturations and alveolar hypoventilation. However, its reliability is debated. This study aimed at examining its use in determining OSA severity in infants.

METHODS

This retrospective study was conducted in a sleep unit in a tertiary hospital in infants < 4 months old with clinical signs of OSA or Pierre Robin sequence who underwent a 1-night polysomnography coupled with oximetry-capnography.

RESULTS

Among the 78 infants included (median [interquartile range] age: 61 [45-89] days at polysomnography), 44 presented with Pierre Robin sequence and 34 presented with isolated airway obstruction. The clinical, sleep, and respiratory characteristics were not significantly different between the 2 subgroups. In the entire cohort, 63.5% had severe OSA. The median obstructive apnea-hypopnea index was 14.5 (7.4-5.9) events/h, peripheral oxygen saturation (SpO2) was 97.4% (96.5-98.1%), and transcutaneous carbon dioxide pressure (PtcCO2) was 41.1 mmHg (38.3-44.9). The optimal threshold to predict an obstructive apnea-hypopnea index > 10 events/h was 6 events/h for an oxygen desaturation index ≥ 3% (sensitivity, 95.7%; specificity, 51.9%) and 2 events/h for an oxygen desaturation index ≥ 4% (sensitivity, 95.7%; specificity, 48.1%).

CONCLUSIONS

Whereas transcutaneous capnography does not appear to be sufficient in predicting severe OSA in infants < 4 months old with Pierre Robin sequence or clinical signs of OSA, oximetry may be a useful alternative for the screening of severe OSA in infants in the absence of polysomnography.

CITATION

Gyapay R, Ioan I, Thieux M, et al. Gas exchange parameters for the prediction of obstructive sleep apnea in infants. J Clin Sleep Med. 2024;20(7):1059-1067.

The value of circadian heart rate variability for the estimation of obstructive sleep apnea severity in adult males

OBJECTIVES

Heart rate variability (HRV) is becoming more prevalent as a measurable parameter in wearable sleep-monitoring devices, which are simple and effective instruments for illness evaluation. Currently, most studies on investigating OSA severity and HRV have measured heart rates during wakefulness or sleep. Therefore, the objective of this study was to investigate the circadian rhythm of HRV in male patients with OSA and its value for the estimation of OSA severity using group-based trajectory modeling.

METHODS

Patients with complaints of snoring were enrolled from the Sleep Center of Shandong Qianfoshan Hospital. Patients were divided into 3 groups according to apnea hypopnea index (AHI in events/h), as follows: (<15, 15≤AHI<30, and ≥30). HRV parameters were calculated using 24 h Holter monitoring, which included time-domain and frequency-domain indices. Circadian differences in the standard deviation of normal to normal (SDNN) were evaluated for OSA severity using analysis of variance, trajectory analysis, and multinomial logistic regression.

RESULTS

A total of 228 patients were enrolled, 47 with mild OSA, 48 moderate, and 133 severe. Patients with severe OSA exhibited reduced triangular index and higher very low frequency than those in the other groups. Circadian HRV showed that nocturnal SDNN was considerably higher than daytime SDNN in patients with severe OSA. The difference among the OSA groups was significant at 23, 24, 2, and 3 o'clock sharp between the severe and moderate OSA groups (all P<0.05). The heterogeneity of circadian HRV trajectories in OSA was strongly associated with OSA severity, including sleep structure and hypoxia-related parameters. Among the low-to-low, low-to-high, high-to-low, and high-to-high groups, OSA severity in the low-to-high group was the most severe, especially compared with the low-to-low and high-to-low SDNN groups, respectively.

CONCLUSIONS

Circadian HRV in patients with OSA emerged as low daytime and high nocturnal in SDNN, particularly in men with severe OSA. The heterogeneity of circadian HRV revealed that trajectories with low daytime and significantly high nighttime were more strongly associated with severe OSA. Thus, circadian HRV trajectories may be useful to identify the severity of OSA.

Computed Tomography versus Sleep Endoscopy (DISE) to Predict the Effectiveness of Mandibular Advancement Devices in Adult Patients with Obstructive Sleep Apnea: A Protocol for Systematic Review

Obstructive sleep apnea is a sleep disorder with a high prevalence in the world population. The mandibular advancement device is one of the options for treating obstructive sleep apnea. Neck computed tomography and drug-induced sleep endoscopy are complementary diagnostic tests that may help predict the effectiveness of mandibular advancement devices. This study aims to analyze the best method for predicting the effectiveness of mandibular advancement devices in the therapeutic approach to obstructive sleep apnea. PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science Core Collection databases will be comprehensively searched. We will include randomized clinical trials, non-randomized prospective or retrospective clinical studies, case controls, cohort studies, and case series. Two authors will independently conduct data extraction and assess the literature quality of the studies. The analysis of the included literature will be conducted by Revman 5.3 software. The outcomes that will be analyzed are craniofacial characteristics, cephalometric assessments, site and type of obstruction of the upper airway, mean values of the apnea-hypopnea index, and SaO2 verified in the initial and follow-up polysomnography. This study will provide reliable, evidence-based support for the clinical application of mandibular advancement devices for obstructive sleep apnea.

Autopsy for Medical Diagnostics: Finding the Cause of Sudden Unexpected Death through Investigation of the Cardiac Conduction System by Serial Sections

Sudden unexpected death (SUD) is a fatal event that occurs in an apparently healthy subject in a way that such an abrupt outcome could have not been predicted. SUD-including sudden intrauterine unexplained death (SIUD), sudden neonatal unexpected death (SNUD), sudden infant death syndrome (SIDS), sudden unexpected death of the young (SUDY), and sudden unexpected death in the adult (SUDA)-occurs as the first manifestation of an unknown underlying disease or within a few hours of the presentation of a disease. SUD is a major unsolved, shocking form of death that occurs frequently and can happen at any time without warning. For each case of SUD, a review of clinical history data and performance of a complete autopsy, particularly focused on the study of the cardiac conduction system, were carried out according to the necropsy protocol devised by the Lino Rossi Research Center, Università degli Studi di Milano, Italy. Research cases collected and selected for this study were represented by 75 SUD victims that were subdivided into 15 SIUD, 15 SNUD, 15 SUDY, and 15 SUDA victims. After a routine autopsy and clinical history analysis, death remained unexplained, and hence a diagnosis of SUD was assigned to 75 subjects, which included 45 females (60%) and 30 (40%) males ranging in age from 27 gestational weeks to 76 years. Serial sections of the cardiac conduction system disclosed frequent congenital alterations of the cardiac conduction system in fetuses and infants. An age-related significant difference in distribution among the five age-related groups was detected for the following anomalies of the conduction system: central fibrous body (CFB) islands of conduction tissue, fetal dispersion, resorptive degeneration, Mahaim fiber, CFB cartilaginous meta-hyperplasia, His bundle septation, sino-atrial node (SAN) artery fibromuscular thickening, atrio-ventricular junction hypoplasia, intramural right bundle branch, and SAN hypoplasia. The results are useful for understanding the cause of death for all SUD cases that were unexpected and would have otherwise remained unexplained, so as to motivate medical examiners and pathologists to perform more in-depth studies.

Recent Progress in Long-Term Sleep Monitoring Technology

Sleep is an essential physiological activity, accounting for about one-third of our lives, which significantly impacts our memory, mood, health, and children's growth. Especially after the COVID-19 epidemic, sleep health issues have attracted more attention. In recent years, with the development of wearable electronic devices, there have been more and more studies, products, or solutions related to sleep monitoring. Many mature technologies, such as polysomnography, have been applied to clinical practice. However, it is urgent to develop wearable or non-contacting electronic devices suitable for household continuous sleep monitoring. This paper first introduces the basic knowledge of sleep and the significance of sleep monitoring. Then, according to the types of physiological signals monitored, this paper describes the research progress of bioelectrical signals, biomechanical signals, and biochemical signals used for sleep monitoring. However, it is not ideal to monitor the sleep quality for the whole night based on only one signal. Therefore, this paper reviews the research on multi-signal monitoring and introduces systematic sleep monitoring schemes. Finally, a conclusion and discussion of sleep monitoring are presented to propose potential future directions and prospects for sleep monitoring.

Single channel photoplethysmography-based obstructive sleep apnea detection and arrhythmia classification

BACKGROUND

Simplified and easy-to-use monitoring approaches are crucial for the early diagnosis and prevention of obstructive sleep apnea (OSA) and its complications.

OBJECTIVE

In this study, the OSA detection and arrhythmia classification algorithms based on single-channel photoplethysmography (PPG) are proposed for the early screening of OSA.

METHODS

Thirty clinically diagnosed OSA patients participated in this study. Fourteen features were extracted from the PPG signals. The relationship between the number of features as inputs of the support vector machine (SVM) and performance of apnea events detection was evaluated. Also, a multi-classification algorithm based on the modified Hausdorff distance was proposed to recognize sinus rhythm and four arrhythmias highly related with SA.

RESULTS

The feature set composed of meanPP, SDPP, RMSSD, meanAm, and meank1 could provide a satisfactory balance between the performance and complexity of the algorithm for OSA detection. Also, the arrhythmia classification algorithm achieves the average sensitivity, specificity and accuracy of 83.79%, 95.91% and 93.47%, respectively in the classification of all four types of arrhythmia and regular rhythm.

CONCLUSION

Single channel PPG-based OSA detection and arrhythmia classification in this study can provide a feasible and promising approach for the early screening and diagnosis of OSA and OSA-related arrhythmias.

Sudden death in individuals with obstructive sleep apnoea: protocol for a systematic review and meta-analysis

INTRODUCTION

Obstructive sleep apnoea (OSA) is a form of sleep-disordered breathing, characterised by blockage of the airway, snoring, gasping for air during sleep, daytime sleepiness and fatigue. OSA is associated with increased risk of cardiovascular and cerebrovascular morbidity and mortality, and sudden cardiac death (SCD). The magnitude of this risk varies in the literature and therefore we aim to systematically assess this risk. This study protocol proposes a meta-analysis and systematic review aimed to estimate the magnitude of the association between OSA, 'sudden death' and cardiovascular death.

METHODS

We will conduct a systematic review and meta-analysis of studies published from the inception of each database, which report the risk of 'sudden death' or cardiovascular death (including SCD) in individuals diagnosed with OSA versus persons without OSA. The primary outcome of interest in this study will be the relative risk of 'sudden death' in patients diagnosed with OSA in comparison to those without an OSA diagnosis. We will search the following electronic research databases: PubMed (MEDLINE), Cochrane, OVID (Healthstar), OVID (Medline), Scopus and Joana Briggs Institute EBP Database. This protocol was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines. The checklist for this document is included in the supplemental material. Two reviewers will screen articles for inclusion criteria, extracting appropriate data and evaluating the quality of the included studies. The methodological quality of studies will be appraised using an appropriate tool. Funnel plots and the Egger's test will be employed to evaluate potential publication bias. We will fit random-effects model with inverse-variance methods for the pooling effect estimates. We will conduct a meta-regression analysis, using numerous variables of interest including age, gender, race, body mass index, hypertension and diabetes, to explore sources of study heterogeneity.

PROSPERO REGISTRATION NUMBER

CRD42020164941.

ETHICS AND DISSEMINATION

No ethics clearance was required for this protocol, for no primary data are being collected on research subjects. Only secondary analysis of pre-existing data in scientific databases will be evaluated. The findings of this meta-analysis will be published in a peer-reviewed journal and presented at scientific conferences. These results may assist professionals in the prevention and management of OSA and SCD.