Photo from Unsplash
Originally Posted On: https://www.sinoriko.com/what-is-ahi-score%ef%bc%9f/
What is the AHI Score?
AHI (Apnea-Hypopnea Index) is a core indicator for assessing sleep apnea-hypopnea syndrome (SAHS), which is used to quantify the frequency of abnormal breathing events per hour of sleep. Its value directly reflects the severity of the disease and guides treatment.
AHI is the sum of apnea and hypopnea events per hour. This index is a key indicator for assessing the severity of obstructive sleep apnea (OSA).
Apnea: A condition during sleep in which the airway is completely blocked, causing breathing to stop for more than 10 seconds.
Hypopnea: refers to partial airway obstruction resulting in a decrease in airflow of more than 30% lasting for more than 10 seconds, accompanied by a decrease in oxygen saturation.
AHI obtains data through polysomnography (PSG) technology, combined with multi-dimensional physiological signals such as electroencephalogram, oculogram, respiratory airflow, blood oxygen saturation, etc., to count the total number of apnea (complete cessation of airflow ≥10 seconds) and hypopnea (airflow decrease ≥50% accompanied by decreased blood oxygen or awakening) that occur every hour during the patient’s sleep. For example, if the patient has 60 apnea and hypopnea events throughout the night and the total sleep time is 6 hours, the AHI is 60/6=10 times/hour.
AI (Apnea Index)
The AI is the number of apnea events (Apnea) per hour. It is a component of the AHI that focuses specifically on the number of complete apneas, excluding hypopnea events. AI focuses more on apnea events caused by complete airway obstruction, measuring the complete closure of the airway. This indicator is often used to assess the severity of sleep apnea, especially the frequency of complete airway obstruction during sleep.
HI (Hypopnea Index)
The Hypopnea Index (HI) is the number of hypopnea events per hour. It specifically counts the frequency of hypopnea events, which reflect a partial airway obstruction, resulting in a reduction in air flow rather than a complete cessation. Hypopnea events are often accompanied by a drop in oxygen saturation, and although the airway is not completely closed, it still affects the quality of breathing. Like AI, HI is part of AHI, but it focuses solely on hypopnea events.
AHI Score Range
Understanding the AHI score is crucial to determining treatment progress. Therefore, we need to understand the range of AHI scores and correctly understand each AHI score.
According to the AHI value, the severity of sleep apnea and hypopnea can be divided into the following levels:
- AHI ≤ 5: Normal breathing during sleep, without obvious apnea or hypopnea.
- 5<AHI≤15: Mild sleep apnea or hypopnea, meaning 5 to 15 apneas or hypopneas occur per hour.
- 15<AHI≤30: Moderate sleep apnea or hypopnea, meaning 15 to 30 apneas or hypopneas occur per hour.
- AHI>30: Severe sleep apnea or hypopnea, meaning more than 30 apneas or hypopneas occur per hour.
Sleep Apnea AHI Chart
| AHI | Rating |
|---|---|
|
AHI＜5
|
Normal
|
|
AHI 5~14
|
Mild Sleep Apnea
|
|
AHI 15~29
|
Moderate Sleep Apnea
|
|
AHI≥30
|
Severe Sleep Apnea
|
Factors that Prevent the AHI Score From Being Reduced
If your AHI won’t go down, there could be several reasons:
Mask leakage: The mask is not worn properly and does not fit the face well, resulting in a lot of leakage. This will not only affect the use effect and comfort, but also cause fluctuations in the AHI score. At this time, it is necessary to regulate the tightness of the mask, generally the headband can be inserted 1-2 fingers.
Inappropriate CPAP settings: The CPAP settings are very important for lowering the AHI. If the pressure setting of the CPAP machine is incorrect, apnea and hypopnea events may not be effectively controlled. It is recommended to contact a technician to ensure that the CPAP settings are appropriate for your specific situation.
Inappropriate mask selection: The mask is the part that connects to the CPAP machine. If the mask does not fit or is uncomfortable, it may cause air leakage or poor sealing, affecting the effectiveness of the machine. It is recommended to choose a mask that fits your face shape and comfort, and ensure that it is worn and adjusted correctly.
Mouth breathing: Another type of air leakage is caused by opening the mouth. A few people open their mouths to breathe after wearing a ventilator at night, which also affects the machine’s recording of the AHI score. If you habitually open your mouth to breathe, you can choose a mouth-nose mask.
Irregular use: CPAP therapy requires continuous use every night to maintain regularity. If you frequently interrupt or irregularly use the CPAP, the AHI may not be effectively reduced. It is recommended to develop good usage habits, use the CPAP every night, and try to avoid interruptions.
Tiredness: If you are too tired during the day, you will snore when you sleep at night, especially those with obstructive sleep apnea. The more tired you are during the day, the more severe your apnea will be. A home sleep apnea machine may not completely solve the problem, and the AHI score on the sleep report will fluctuate.
Other potential problems: The inability to reduce AHI may also be related to other potential problems, such as excessive weight, nasal obstruction, medication use, etc. It is recommended to contact a sleep specialist for a comprehensive evaluation and diagnosis to find out the specific reasons why AHI cannot be reduced and take appropriate measures.
How to Reduce the AHI Score
Adjust CPAP Machine Settings
Increase pressure setting: If the CPAP machine’s pressure is insufficient, the maximum pressure of the machine can be appropriately increased to ensure the therapeutic effect.
Check for mask leaks: Mask leaks can cause the machine to mistakenly register leaks as apnea, so make sure the mask is worn correctly and fits your face. If the leak is severe, you may need to change to a suitable mask.
Prevent mouth breathing: Some users will still open their mouths to breathe when using a CPAP machine, which will affect the machine’s accurate recording of the AHI score. It is recommended to use an oronasal mask or a chin rest to fix the chin to prevent mouth breathing.
Regular treatment: Patients need to maintain regular CPAP therapy and avoid interruptions in treatment to keep the AHI value stable.
Improve the Wearing Method
Wear the mask correctly: Make sure the mask is worn correctly to avoid air leaks.
Use a suitable mask: If the mask does not fit properly, it may cause air leakage or be uncomfortable to wear, affecting the treatment effect.
Adjust Your Lifestyle
Avoid alcohol and smoking before bedtime: These behaviors relax the upper airway muscles and increase the risk of apnea.
Weight management: Proper weight management can help reduce the risk of airway obstruction.
Exercise regularly: Appropriate exercise can improve cardiopulmonary function and improve sleep quality.
Ensure adequate sleep time: Ensure 7-8 hours of sleep every day, try to fall asleep before 23:00 at night, and avoid drinking strong tea, coffee, and other stimulating drinks before going to bed.
Regular review and adjustment: Regularly review the sleep monitoring results and AHI score, and make adjustments based on the patient’s specific situation to maintain the stability of the treatment effect.
Optimization of the sleeping environment: Improving the sleeping environment, maintaining a suitable room temperature and a quiet environment, etc., will help improve sleep quality and reduce fluctuations in AHI values.
