Inhibition of ventilatory motor output increases expiratory retro palatal compliance during sleep

Research Priorities for Patients with Heart Failure and Central Sleep Apnea. An Official American Thoracic Society Research Statement

Background: Central sleep apnea (CSA) is common among patients with heart failure and has been strongly linked to adverse outcomes. However, progress toward improving outcomes for such patients has been limited. The purpose of this official statement from the American Thoracic Society is to identify key areas to prioritize for future research regarding CSA in heart failure.

Methods: An international multidisciplinary group with expertise in sleep medicine, pulmonary medicine, heart failure, clinical research, and health outcomes was convened. The group met at the American Thoracic Society 2019 International Conference to determine research priority areas. A statement summarizing the findings of the group was subsequently authored using input from all members.

Results: The workgroup identified 11 specific research priorities in several key areas: 1) control of breathing and pathophysiology leading to CSA, 2) variability across individuals and over time, 3) techniques to examine CSA pathogenesis and outcomes, 4) impact of device and pharmacological treatment, and 5) implementing CSA treatment for all individuals

Conclusions: Advancing care for patients with CSA in the context of heart failure will require progress in the arenas of translational (basic through clinical), epidemiological, and patient-centered outcome research. Given the increasing prevalence of heart failure and its associated substantial burden to individuals, society, and the healthcare system, targeted research to improve knowledge of CSA pathogenesis and treatment is a priority.

Characteristics and Consequences of Non-apneic Respiratory Events During Sleep

Rationale

Current scoring criteria of non-apneic events (ie, hypopnea) require the presence of oxyhemoglobin desaturation and/or arousal. However, other sleep study parameters may help to identify abnormal respiratory events (REs) and assist in making more accurate diagnosis.

Objectives

To investigate whether non-apneic REs without desaturation or cortical arousal are associated with respiratory and cardiac consequences.

Methods

Thirteen participants with sleep disturbances (snoring and/or excessive day time sleepiness), were screened using attended in laboratory polysomnography (PSG) while monitoring pressure and airflow via a nasal mask with an attached pneumotach. To separate the contribution of the upper airway resistance (RUA) and total pulmonary resistance (RL), supraglottic and esophageal pressures were measured using Millar pressure catheters. RL and RUA were calculated during baseline and hypopneas. RL was defined as the resistive pressure divided by the maximal flow during inspiration and expiration. Hypopnea was defined 30% decrease in flow with 3% desaturation and/or cortical arousal. REs was defined as 30% decrease in the flow without desaturation and/or cortical arousal. In eight subjects continuous positive airway pressure (CPAP) was titrated to optimal pressure. R-R interval (RRI) was defined as consecutive beat-to-beat intervals on single lead electrocardiograph (ECG) during baseline, RE/hypopnea and on optimal CPAP.

Results

REs associated with increased expiratory RUA (14.6 ± 11.3 vs. 7.5 ± 4.5 cmH2O L-1 s-1; p < .05), and increased expiratory RL relative to baseline (29.2 ± 14.6 vs. 20.9 ± 11.0 and 23.7 ± 12.1 vs. 14.3 ± 5.6 cmH2O L-1 s-1 during inspiration and expiration, respectively; p < .05). RRI decreased significantly following RE and hypopnea relative to baseline (804.8 ± 33.1 vs. 806.4 ± 36.3 vs. 934.3 ± 45.8 ms; p < .05). Optimal CPAP decreased expiratory RUA (4.0 ± 2.5 vs. 7.5 ± 4.5 cmH2O L-1 s-1; p < .05), decreased inspiratory RL (12.6 ± 14.1 vs. 7.5 ± 4.5 cmH2O L-1 s-1; p < .05), and allowed RRI to return to baseline (p < .05). RRI dips index was an independent predictor of sleep-disordered breathing (SDB) when non-apneic REs were accounted for in symptomatic patients (p < .05).

Conclusions

Non-apneic REs without cortical arousal or desaturation are associated with significant respiratory and heart rate changes. Optimal CPAP and the reduction of resistive load are associated with the normalization of heart rate indicating potential clinical benefit.

Obstructive sleep apnea-hypopnea syndrome: Etiology and diagnosis

Sleep disordered breathing is a common chronic condition in the general population. This review will highlight the prevalence of different types of sleep apnea in general and obstructive type in particular in the United States and Middle East. Despite the extensive research studies on the sleep apnea pathogenesis, the exact mechanism is not well known. Obesity, however, is the leading risk factor to upper airway narrowing and obstruction and main contributor to the escalating prevalence of morbidity worldwide including the Arab countries. Due to the serious consequences of the untreated sleep disordered breathing, this article will emphasize on the importance of early recognition, key clinical manifestations, and how to treat and prevent the disease.