Clinical, polysomnographic, and CPAP titration features of obstructive sleep apnea: Mixed versus purely obstructive type

Clinical Characteristics and Surgical Outcomes of Obstructive Sleep Apnea Patients With Mixed Apnea Components

OBJECTIVE

This study was aimed to investigate clinical implications of mixed apnea (MA) in patients with obstructive sleep apnea (OSA), particularly whether surgical outcomes differ between OSA patients with and without MA events.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single tertiary medical center.

METHODS

Eighty-eight patients with OSA who underwent multilevel upper airway surgery were included. Patients were divided into 2 groups according to the presence of MA events: "pure group" (n = 30) and "mixed group" (n = 58). The clinical characteristics and surgical outcomes were compared between the 2 groups.

RESULTS

The mixed group included more males (P = .020) and hypertensive patients (P = .009) and had a higher apnea-hypopnea index (AHI; P < .001) than the pure group. The surgical success rate was lower in the mixed group (29.3%) than in the pure group (73.3%; P < .001). Furthermore, the postoperative improvements in total AHI (P < .001), supine AHI (P < .001), and oxygen desaturation index (P = .006) were lower in the mixed group than in the pure group. Logistic regression analysis confirmed that the presence of MA (P = .002) was an independent predictor of poor surgical outcomes in patients with OSA.

CONCLUSION

OSA patients with MA showed different clinical features and poor surgical outcomes compared to those without MA. These results imply that OSA with MA components may have a distinct pathophysiology, and the presence of MA should be considered in the surgical treatment of OSA.

Are We Underestimating the Central Components of the Mixed Apneas?-A Hypothesis for Revised Scoring

PURPOSE

Apneas are classified in three categories, as obstructive, central, and mixed types. Mixed apneas are calculated together with the obstructive events in diagnosing obstructive sleep apnea syndrome (SAS). The clinical significance of mixed apneas needs to be specified.

METHODS

Patients with obstructive SAS having an index of mixed apneas ≥5/hour were evaluated. A new approach was developed to score the mixed apneas, and calculated them together with either obstructive or central type of events, depending on their obstructive and central components. The relationship between the development of complex SAS and the indices of abnormal respiratory events per standard and revised scoring was evaluated.

RESULTS

Ten of 56 patients (17.9%) developed complex SAS at titration polysomnography. The mean index of mixed apneas per standard scoring was significantly higher in patients who did not develop complex SAS ( P = 0.006). The use of newly developed method in scoring mixed apneas resulted that three patients (5.4%) fulfilled the diagnostic criteria for the central SAS at first-night polysomnography ( P < 0.001), and all of them had developed complex SAS at titration night requiring other modes of positive airway pressure therapy than the continuous mode ( P = 0.004). Curve estimation models showed that the change from mixed apneas to central apneas was highly significant in patients developing complex SAS ( r2 = 0.501; P = 0.022).

CONCLUSIONS

Our study showed that the summation of mixed apneas with the obstructive events conventionally underestimates the central components and the diagnosis of central SAS, which are fundamental in the risk stratification of complex SAS.

Clinical Predictors of Mixed Apneas in Patients with Obstructive Sleep Apnea (OSA)

PURPOSE

Mixed events in obstructive sleep apnea (OSA) patients (mixed-OSA) indicate respiratory regulation instability and are essential for OSA pathogenesis and prognosis. It also shows a decreased compliance with continuous positive airway pressure (CPAP). Using predictors to identify mixed-OSA has significant clinical guidance for OSA precise diagnosis and treatment. This study aimed to establish a simple and accessible method for rapid screening of mixed-OSA, thus promoting OSA precise diagnosis.

PATIENTS AND METHODS

A total of 907 patients with suspected OSA were screened, of which 513 OSA patients, including 344 with pure-OSA and 169 with mixed-OSA, were finally included in the study. The clinical characteristics and polysomnography (PSG) parameters of the two OSA groups were compared. Multivariate logistic regression analysis was used to investigate the factors affecting the morbidity of mixed-OSA. The receiver operating characteristic (ROC) curve was used to explore if some convenient PSG parameters can be used to predict mixed-OSA.

RESULTS

About 33% of OSA patients were identified as mixed-OSA. Multivariate logistic regression analysis showed that apnea hypopnea index (AHI) and lowest oxygen saturation (LSO₂) were independently associated with mixed-OSA after adjusting for age, sex, body mass index (BMI), smoking, drinking, hypertension, and Epworth Sleepiness Score (ESS) (AHI: OR=1.046, 95% CI 1.032-1.060, P < 0.001; LSO₂: OR=0.958, 95% CI 0.936-0.981, P < 0.001). ROC curve analysis showed that AHI > 47 or LSO₂ < 77% indicated mixed-OSA. The sensitivity and specificity of AHI> 47 was 0.952 and 0.652, respectively, and 0.822 and 0.675 for LSO₂ < 77%, respectively.

CONCLUSION

Our research found that AHI > 47 or LSO₂ < 77% are independently associated with mixed-OSA and can be used to quickly identify the occurrence of mixed-OSA. Therefore, this study can help detect mixed-OSA and precise individual diagnosis of OSA patients.

Sleep Apnea and Serum Serotonin Level Pre- and Post-PAP Therapy: A Preliminary Study

Introduction

The high prevalence of obstructive sleep apnea (OSA), which impairs quality of life for numerous patients and leads to various OSA complications, has contributed to the continued interest in this disorder. The role of serotonin (5-HT) in many physiological processes, studies on its connection with the circadian system, and relationship to changes in sleep architecture are insufficient to assess the interaction of this neurotransmitter with nocturnal hypoxia. The aim of this study was to determine changes in sleep patterns and serum serotonin levels before and after positive airway pressure (PAP) therapy in patients with OSA.

Methods

The study involved 30 OSA patients (27 men and 3 women) who were treated with PAP for 3 months. Polysomnography using the GRASS TELEFACTOR (USA) and blood collection were conducted before and after PAP courses. Determination of serum serotonin was performed by high-performance liquid chromatography (HPLC). PAP therapy was performed using an automatic Prisma 20A (Germany) continuous positive airway pressure (CPAP) device.

Results

The use of PAP for 3 months revealed a significant improvement as measured by sleep data and serotonin levels (before: apnea index [AI] 17.2 eV/h, after: 2.4 eV/h p = 0.001; SpO₂ < 90% − 45.7 min vs. 6.2 min p = 0.001; serotonin 20.3 ng/mL vs. 26.03 ng/mL p = 0.036].

Conclusion

Our results demonstrate an improvement in sleep patterns. There was an increase in serum serotonin levels in OSA patients following PAP therapy, which could be an effect of intermittent hypoxia decline, and could be used as criteria for the effectiveness of PAP and an improvement in sleep quality.

[Telemonitoring in continuous positive airway pressure-treated patients with obstructive sleep apnoea syndrome: An algorithm proposal]

Most of the continuous positive airway pressure (CPAP) devices currently in use allow telemonitoring of observance, leaks and the apnoea-hypopnoea index (AHI). La Société française de recherche et de médecine du sommeil (SFRMS) and La Société de pneumologie de langue française (SPLF) workgroup offer to CPAP prescribers and to home care providers a scientific document which has the following purposes: to underline the relevance of the telemonitoring of leaks and the AHI, to define alert thresholds, to describe the principal mechanisms generating excessive leaks and high AHI, and to propose a diagnostic algorithm.

Implication of mixed sleep apnea events in adult patients with obstructive sleep apnea-hypopnea syndrome

PURPOSE

Although mixed sleep apnea (MSA) is one of the three types of sleep apnea, it is not considered a separate disease entity. It is generally seen as a part of obstructive sleep apnea-hypopnea syndrome (OSAHS), but its implications are often ignored. In this study, we examined its features and the potential impact on OSAHS patients.

METHODS

Subjects diagnosed with OSAHS by polysomnography (PSG) were enrolled. All participants underwent physical checkups and tests of blood biochemistry. They were anthropometrically, clinically, and polysomnographically studied.

RESULTS

MSA events were common in patients with severe OSAHS patients. There were significant differences between the pure OSAHS group and its mixed counterpart in apnea-hypopnea indices during REM (AHI_REM) and non-REM (AHI_NREM) and in percentages of N2 or N3 sleep. Logistic regression analysis showed that, after adjustment of other parameters, patients with MSA events were mostly male, had higher body mass index (BMI), higher scores on Epworth Sleepiness Scales (ESS), higher triglyceride (TG) levels, and higher apnea-hypopnea index (AHI). The combined predictive probability of the aforementioned variables was 0.766 (95% CI = 0.725~0.806; sensitivity 61.6%, specificity 82.1%).

CONCLUSIONS

Our study suggested that MSA was related to the stability of the ventilatory control in OSAHS patients. MSA events occur more frequently in patients with severe OSAHS, and male gender, obesity, daytime sleepiness, and elevated TG levels were risk factors for the mixed OSAHS.

Prevalence and Characteristics of Central Compared to Obstructive Sleep Apnea: Analyses from the Sleep Heart Health Study Cohort

STUDY OBJECTIVES

Determine the prevalence of central sleep apnea (CSA) in a large community-based cohort using current definitions and contrast the clinical characteristics of subjects with CSA to those with obstructive sleep apnea (OSA) and no sleep apnea.

METHODS

A cross sectional analysis of baseline data from 5,804 participants of the Sleep Heart Health study was performed. Subjects meeting contemporary diagnostic criteria for CSA and Cheyne Stokes respiration (CSR) were compared to those without sleep apnea and those with OSA. Demographic data, medical comorbidities, medication use, and sleep related symptoms were compared between the groups.

RESULTS

The prevalences of CSA and Cheyne Stokes respiration (CSR) in this sample were 0.9 (95% confidence intervals [CI]: 0.7-1.2)% and 0.4 (95% CI: 0.3-0.6)%, respectively. Individuals with CSA were older, had lower body mass indexes (BMI), lower Epworth Sleepiness Scale scores, and were more likely to be male than individuals with obstructive sleep apnea OSA. Among those with self-reported heart failure (HF), OSA was much more common at 55.1% (95% CI: 45.6-64.6) than CSA 4.1% (95% CI: 0.3-7.9).

CONCLUSIONS

This is the largest community-based study of the prevalence and characteristics of CSA to date and demonstrates a prevalence of CSA that is intermediate to those previously noted. Contrary to prior data from clinic based samples, individuals with heart failure were much more likely to have OSA than CSA.