New technologies to detect static and dynamic upper airway obstruction during sleep

Polysomnographic phenotype as a risk factor for cardiovascular diseases in patients with obstructive sleep apnea syndrome: a retrospective cohort study

Background

Obstructive sleep apnea syndrome (OSAS) is associated with the development of cardiovascular diseases caused by hypoxemia during sleeping. We classified OSAS phenotypes based on polysomnographic findings and aimed to evaluate that the unique phenotypes would be differentially associated with risk of cardiovascular disease.

Methods

This retrospective and observational study assessed adult patients who underwent polysomnography at the Wonju Severance Christian Hospital from November 2008 to February 2018. The OSAS phenotypes were classified as apnea-predominant, hypopnea-predominant, and respiratory effort-related arousal (RERA)-predominant based on the polysomnography results. The polysomnographic data were collected and analysed, and clinical features such as medical history and comorbidities were assessed by a review of the electronic medical records.

Results

A total of 860 adult patients were classified as apnea-predominant (n=220), hypopnea-predominant (n=119), or RERA-predominant (n=275). The hypopnea-predominant group had significantly higher rates of hyperlipidaemia (P<0.001), heart failure (15.5%, P<0.001), and coronary artery disease (20.9%, P=0.005) than the other groups. After classifying the patients according to severity of the hypopnea index, logistic regression analyses adjusted for age, sex, and smoking history revealed that the hypopnea index increased the risk for coronary artery disease and heart failure.

Conclusions

The hypopnea-predominant group would be a specific phenotype that has a differential association with the risks for coronary artery disease and heart failure.

An Official American Thoracic Society Research Statement: Impact of Mild Obstructive Sleep Apnea in Adults

BACKGROUND

Mild obstructive sleep apnea (OSA) is a highly prevalent disorder in adults; however, whether mild OSA has significant neurocognitive and cardiovascular complications is uncertain.

OBJECTIVES

The specific goals of this Research Statement are to appraise the evidence regarding whether long-term adverse neurocognitive and cardiovascular outcomes are attributable to mild OSA in adults, evaluate whether or not treatment of mild OSA is effective at preventing or reducing these adverse neurocognitive and cardiovascular outcomes, delineate the key research gaps, and provide direction for future research agendas.

METHODS

Literature searches from multiple reference databases were performed using medical subject headings and text words for OSA in adults as well as by hand searches. Pragmatic systematic reviews of the relevant body of evidence were performed.

RESULTS

Studies were incongruent in their definitions of "mild" OSA. Data were inconsistent regarding the relationship between mild OSA and daytime sleepiness. However, treatment of mild OSA may improve sleepiness in patients who are sleepy at baseline and improve quality of life. There is limited or inconsistent evidence pertaining to the impact of therapy of mild OSA on neurocognition, mood, vehicle accidents, cardiovascular events, stroke, and arrhythmias.

CONCLUSIONS

There is evidence that treatment of mild OSA in individuals who demonstrate subjective sleepiness may be beneficial. Treatment may also improve quality of life. Future research agendas should focus on clarifying the effect of mild OSA and impact of effective treatment on other neurocognitive and cardiovascular endpoints as detailed in the document.

Obstructive pressure peak: a new method for differentiation of obstructive and central apneas under auto-CPAP therapy

PURPOSE

Auto-CPAP devices (APAP) are controlled, e.g.,by the respiratory flow and pressure to adjust the treatment pressure to the variable obstruction in sleep apnea syndromes.By obstruction of the upper airway during inspiration,a pressure difference between the lower airways and the mask can be measured. In case of an opening of the pharynx at the end of the obstruction, the pressure decreases immediately. This brief negative pressure, the so-called obstructive pressure peak (OPP) can be used to identify obstruction or open airways with the algorithm of an APAP device. Useless pressure increases, e.g., after central apneas without obstruction may be avoided. We therefore investigated the association of the OPP signal with respiratory events during APAP therapy.

METHODS

In this pilot study, 13 patients with obstructive sleep apnea syndrome were evaluated. Attended automatic CPAP titration (SOMNO balance, Fa Weinmann Hamburg/Germany)was performed. The OPP signal was recorded synchronous lyin parallel with the polysomnographic data. If the OPP signal was within a time range of ± 5 s of the resumption of normal breathing, it was assigned to the event.

RESULTS

A total of 480 sleep-related breathing disorders events were studied. The most common were the mixed apneas associated with more than 90% of all cases with an OPP signal, followed by obstructive sleep apneas (66.7%)and central apneas (38%). The difference in OPP frequency distribution between central apneas and obstructive apneas was significant with p<0.001.

CONCLUSIONS

The analysis of the pressure characteristics of APAP treatment with the registration of OPP allows a further differentiation in obstructed and not obstructed upper airways.