Explanation of sleep and respiratory metrics
Explanation of sleep and respiratory metrics reported by the Wesper PDF report
Apnea/Hypopnea Index (AHI): The average number of apneas and hypopneas calculated per hour of sleep time. AHI may differ when the desaturation threshold is set at 3% or 4%. As per AASM guidelines, sleep apnea severity is calculated as follows: Normal/No Sleep Apnea: AHI = 0-4.99, Mild: 5-14.99, Moderate: 15-29.99, Severe: >30
Central Apnea Index (CAI): The average number of central apneas and central hypopneas calculated per hour of sleep time. CAI may differ when the desaturation threshold is set at 3% or 4%.
Percent Central Apnea (%CA): The percentage of apneas that were determined to be central apneas, compared to obstructive apneas.
Oxygen Desaturation Index (ODI): The average number of oxygen desaturations per hour of sleep time. ODI may differ when the desaturation threshold is set at 3% or 4%.
Respiratory Event Index (REI): The average number of apneas and hypopneas calculated per hour of recording time. REI is typically similar, but not identical, to AHI. REI may differ when the desaturation threshold is set at 3% or 4%.
Respiratory Disturbance Index (RDI): The number of apneas, hypopneas, and respiratory effort related arousals (RERAs) per hour of sleep time.
REM AHI: The apnea/hypopnea index (AHI) calculated only during Rapid Eye Movement (REM) sleep. REM AHI may differ when the desaturation threshold is set at 3% or 4%.
NREM AHI: The apnea/hypopnea index (AHI) calculated only during Non-Rapid Eye Movement (NREM) sleep. NREM AHI may differ when the desaturation threshold is set at 3% or 4%.
Total Apnea: The total number of apneas detected. An apnea is defined as a respiratory event with at least a 90% drop in airflow volume that corresponds to an oxygen desaturation by at least 3% from baseline.
Total Hypopnea: The total number of hypopneas detected. A hypopnea is defined as a respiratory event with at least a 30% drop in airflow volume for 10 seconds or longer, that corresponds to an oxygen desaturation by at least 3% from baseline.
Total RERA: The total number of respiratory event related arousals detected. A RERA is defined as a series of breaths occurring for at least 10 seconds associated with an ever-increasing respiratory effort against a narrowed upper airway that terminates with arousal from sleep before criteria for a true apnea or hypopnea event are met.
Obstructive Apnea: The total number of apneas detected that were determined to be obstructive. An obstructive apnea is defined as a respiratory event with increased respiratory effort, at least a 90% drop in airflow volume for 10 seconds or longer, and corresponds to an oxygen desaturation by at least 3% from baseline.
Central Apnea: The total number of central apneas detected. A central apnea is defined as a respiratory event with a lack of respiratory effort, at least a 90% drop in airflow volume for 10 seconds or longer, and corresponds to an oxygen desaturation by at least 3% from baseline.
Mixed Apnea: The total number of mixed apneas detected. A mixed apnea is defined as a respiratory event absent of respiratory effort and airflow in the first section of the event and respiratory effort without airflow in the last section.
Obstructive Hypopnea: The total number of hypopneas detected that were determined to be obstructive. An obstructive hypopnea is defined as a respiratory event with increased respiratory effort, at least a 30% drop in airflow volume for 10 seconds or longer, and corresponds to an oxygen desaturation by at least 3% from baseline.
Central Hypopnea: The total number of central hypopneas detected. A central hypopnea is defined as a respiratory event with a lack of respiratory effort, at least a 30% drop in airflow volume for 10 seconds or longer, and corresponds to an oxygen desaturation by at least 3% from baseline.
Mixed Hypopnea: The total number of mixed hypopneas detected. A mixed hypopnea is defined as a respiratory event absent of respiratory effort and airflow in the first section of the event and respiratory effort without airflow in the last section.
Other: The total number of undefined respiratory events that did not meet the criteria for an apnea, hypopnea, or RERA.
SPO2: Blood oxygen saturation percentage. SPO2 is reported as the maximum (highest) recorded, the mean (average) recorded, and minimum (lowest) recorded.
T90: The total amount of time the patient has an SPO2 of less than 90%.
T88: The total amount of time the patient has an SPO2 of less than 88%
Hypoxic Burden: The total area under the respiratory event-related desaturation curve.
Heart Rate: Heart beats per minute. Heart rate is reported as the maximum (highest) recorded, the mean (average) recorded, and minimum (lowest) recorded.
Snore Time: The total time snoring was detected during sleep.
Total Sleep Time: The total time the patients was detected as asleep.
Sleep Efficiency: The percentage of time the patient was asleep out of the time the patient attempted to sleep.
Light Sleep Time: The total time the patient is detected in light sleep.
Deep Sleep Time: The total time the patient is detected in deep sleep.
REM Sleep Time: The total time the patient is detected in REM sleep.
Sleep Latency: The time it took the patient to fall asleep for the first time.
