From the Guidelines
Mixed sleep apnea is defined as a combination of both central sleep apnea (CSA) and obstructive sleep apnea (OSA) episodes during sleep, as noted in patients with heart failure (HF) 1. This condition is characterized by the presence of both obstructive and central sleep apnea episodes, making it complex to diagnose and treat.
- The obstructive component occurs when the airway becomes physically blocked,
- while the central component occurs when the brain temporarily fails to send proper signals to the breathing muscles. According to the 2016 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure, sleep-disordered breathing, including mixed sleep apnea, occurs in more than one-third of patients with HF 1. The diagnosis of mixed sleep apnea can be made using advanced home testing equipment or overnight polysomnography, which can distinguish between the different types of apnea events occurring throughout the night 1. Treatment options may include nocturnal oxygen supplementation, continuous positive airway pressure (CPAP), bi-level positive airway pressure (BiPAP), and adaptive servo-ventilation (ASV), although the effectiveness of these interventions on major outcomes in HF patients is still being studied 1. It is essential to note that the treatment of mixed sleep apnea should be individualized, taking into account the patient's specific condition and medical history, as some interventions, such as ASV, may not be recommended in certain cases, like patients with HFrEF and predominantly CSA 1.
From the Research
Definition of Mixed Sleep Apnea
Mixed sleep apnea is a type of sleep apnea that combines elements of both obstructive and central sleep apnea. It is characterized by a combination of obstructive and central apneic events, where the patient experiences both upper airway obstruction and a lack of respiratory effort 2, 3, 4, 5, 6.
Clinical Characteristics
Studies have shown that mixed sleep apnea is associated with certain clinical characteristics, including:
- A higher apnea-hypopnea index (AHI) 2, 6
- Lower oxygen saturation levels 2, 4, 6
- Increased frequency of apneic events during non-REM and REM sleep 4, 6
- Higher body mass index (BMI) 6
- Higher scores on the Epworth Sleepiness Scale (ESS) 6
- Elevated triglyceride (TG) levels 6
Diagnosis and Treatment
Mixed sleep apnea can be diagnosed using polysomnography (PSG) and can be treated with continuous positive airway pressure (CPAP) therapy 2, 4, 6. However, the treatment of mixed sleep apnea can be challenging, and the use of CPAP therapy may not always be effective 4, 5.
Association with Other Sleep Disorders
Mixed sleep apnea has been associated with other sleep disorders, including obstructive sleep apnea-hypopnea syndrome (OSAHS) 6 and treatment-emergent central sleep apnea (TE-CSA) 4. The presence of mixed sleep apnea may also be a predictor of the development of TE-CSA 4.
Scoring and Classification
The scoring and classification of mixed sleep apnea can be complex, and different studies have used different methods to classify and score mixed apneic events 2, 3, 4, 5, 6. However, most studies agree that mixed sleep apnea is a distinct type of sleep apnea that requires separate consideration and treatment.