What is involved in a home sleep apnea test (HSAT) for diagnosing sleep apnea?

Home Sleep Apnea Test (HSAT) for Diagnosing Sleep Apnea

A home sleep apnea test (HSAT) is a medical diagnostic tool that monitors breathing patterns during sleep at home, using sensors that measure airflow, respiratory effort, and blood oxygen levels to detect obstructive sleep apnea in uncomplicated adult patients with signs of moderate to severe OSA. 1

Components and Technical Requirements of HSAT

• HSAT devices typically include sensors for nasal pressure, chest and abdominal respiratory inductance plethysmography, and pulse oximetry to monitor breathing patterns and oxygen levels during sleep 1
• Unlike laboratory polysomnography, HSAT devices do not include EEG, EOG, or EMG sensors, which means they cannot accurately determine sleep versus wake periods 1
• A technically adequate HSAT requires a minimum of 4 hours of recording that encompasses the patient's habitual sleep period 1
• HSAT produces a respiratory event index (REI) based on monitoring time rather than actual sleep time, which may underestimate the severity of OSA compared to polysomnography's apnea-hypopnea index (AHI) 1

Patient Selection for HSAT

• HSAT is appropriate only for uncomplicated adult patients with signs and symptoms indicating increased risk of moderate to severe OSA 1
• Increased risk is indicated by excessive daytime sleepiness plus at least two of: habitual loud snoring, witnessed apnea/gasping/choking, or diagnosed hypertension 1
• HSAT should not be used in patients with conditions that increase risk of non-obstructive sleep-disordered breathing (e.g., heart failure, stroke history, neuromuscular conditions, chronic opiate use) 1
• HSAT is contraindicated in patients with suspected non-respiratory sleep disorders (e.g., insomnia, narcolepsy, parasomnias) 1
• HSAT should not be used for general screening of asymptomatic populations 1

HSAT Process and Administration

• The test must be ordered by a physician after a face-to-face examination (in person or via telemedicine) 1
• The patient takes the device home and wears it during their normal sleep time 1
• Recording is typically conducted for at least one night 1
• The raw data must be reviewed and interpreted by a physician who is either board-certified in sleep medicine or overseen by a board-certified sleep medicine physician 1
• Automatically scored data alone should not be used for diagnosis, as current algorithms have limited diagnostic accuracy 1

Limitations and Follow-up

• HSAT is less sensitive than polysomnography and may underestimate OSA severity due to inability to detect sleep versus wake and hypopneas associated only with cortical arousals 1
• If a single HSAT is negative, inconclusive, or technically inadequate, polysomnography should be performed rather than repeating the HSAT 1
• False negative results occur in approximately 54% of individuals with negative HSATs who subsequently undergo polysomnography 2
• Patients with low pre-test probability for moderate-severe OSA are less likely to have confirmatory HSAT results (61% vs 84% in high pre-test probability patients) 2

Clinical Significance

• Untreated OSA increases risk of serious health complications including hypertension, heart failure, atrial fibrillation, coronary artery disease, stroke, and type 2 diabetes 1
• Proper diagnosis and treatment of OSA can reduce all-cause and cardiovascular mortality 1
• The accurate diagnosis through appropriate testing is essential for improving individual health, promoting public safety, and reducing healthcare expenses 1

Common Pitfalls to Avoid

• Using HSAT for patients with complicated medical conditions or suspected non-respiratory sleep disorders 1
• Relying solely on automatically scored data without physician review of raw data 1
• Repeating HSAT after a negative or inconclusive test instead of proceeding to polysomnography 1
• Using HSAT for general screening of asymptomatic populations 1
• Failing to recognize that HSAT may underestimate OSA severity compared to polysomnography 1