How To Find The Best CPAP Pressure Settings
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Setting the appropriate CPAP pressure level is the key to successful treatment. The ideal pressure is the minimum pressure level required to prevent apnea during sleep and in various sleep positions. At the same time, this pressure value should be able to eliminate snoring and maintain normal blood oxygen saturation throughout the night.
In this article, we’ll discuss why to adjust CPAP pressure, situations in which your CPAP pressure settings may need to be adjusted, and the steps to adjust and set your CPAP, with a focus on finding the best CPAP pressure for you.
Why Need To Adjust CPAP Pressure?
To eliminate sleep apnea, the continuous positive airway pressure required by each person is different, and the pressure value required by the same patient in different situations is not a constant value.
- The amount of pressure required varies depending on the position you sleep in. When you sleep in the supine position, higher pressure is required to eliminate sleep apnea than when you sleep in the side-lying position.
- The pressure setting varies with the sleep phase. During REM sleep, the pressure required to remove sleep apnea is higher than that during NREM sleep.
- As patients gain weight, their need for higher pressure levels increases.
After heavy drinking, the pressure required to remove sleep apnea is higher.
- When you have a cold or rhinitis, nasal resistance increases, and the required continuous positive airway pressure increases.
Some studies have also found that after a period of continuous positive airway pressure treatment, the pressure level required by patients is reduced, which may be related to the improvement of patients’ respiratory control function and the disappearance of upper airway edema after continuous positive airway pressure treatment.
If the CPAP pressure value is set too high, the patient will not be able to tolerate it, which may lead to treatment failure; if the pressure value is too low, sleep apnea cannot be completely eliminated to achieve the best treatment effect.
Because in the early stage of continuous positive airway pressure treatment for patients with severe sleep apnea syndrome, the REM sleep period will be significantly prolonged. If the pressure is not set enough, the upper airway will still be partially or even completely blocked during this sleep period, resulting in severe hypoxemia.
When To Adjust CPAP Pressure？
Waking up in the middle of the night or having the mask taken off
If you are always woken up by the CPAP machine in the middle of the night when you are sleeping, or always wake up to find that the mask has been taken off and put aside at some point, it is possible that your pressure needs to be readjusted.
Snoring
If you are wearing a CPAP machine and still snore, it means that the pressure of the machine is not adjusted properly. But please note that a leaky mask may also cause snoring. A leaky mask will cause some air to escape, which may reduce the pressure for a period of time. Check the mask for leaks before adjusting the pressure of the machine.
Still sleepy during the day
Inadequate CPAP therapy can also result in excessive awakenings during sleep, which may require adjustments to the pressure.
AHI data is greater than 5
AHI stands for the number of upper airway collapses in one hour. In simple terms, it checks how many times your breathing stops or partial breathing occurs. This number indicates the severity of your sleep apnea.
Less than 5 times in an hour – Normal sleep
5 to 15 times an hour – Mild sleep apnea
15 to 30 times an hour – Moderate sleep apnea
More than 30 times in an hour – Severe sleep apnea
The ideal AHI residual for sleep apnea therapy should be less than 5. If your CPAP therapy data shows that your residual AHI is 5 or higher, you should see your doctor or sleep specialist to adjust your pressure.
CPAP Pressure Setting And Adjustment
At present, the standard procedure for determining the optimal pressure is for technicians to be on duty all night to perform manual pressure titration under polysomnography (PSG). This is why patients are generally required to go to the sleep center of a regular hospital for polysomnography before buying a ventilator to titrate an optimal treatment pressure for them so that they can perform non-invasive ventilation treatment through a home ventilator.
The traditional method of setting the continuous positive airway pressure is to perform polysomnography in the sleep examination room again after the patient is diagnosed with sleep apnea syndrome while using nasal continuous positive airway pressure.
When falling asleep, first set a lower pressure level, such as 4-6 cmH2O (0.39-0.59 kPa). As the patient falls asleep, gradually increase the continuous positive airway pressure level based on changes in snoring, apnea, blood oxygen, etc., generally by increasing it by 2 cmH2O (0.196 kPa) each time, until sleep apnea and snoring disappear, and the blood oxygen saturation is normal and remains above 90%.
At the same time, closely observe the breathing changes in each sleep stage, especially the REM sleep stage, and increase the pressure value of continuous positive airway pressure when necessary. In order to eliminate apnea during sleep in various positions and prevent the adverse effects of drinking, the set value can be increased by 2cmH2O (0.196 kPa) as the final treatment pressure, provided that the patient can tolerate it.
Our experience is that in order to ensure that the patient can fall asleep well when setting the continuous positive airway pressure, the CPAP machine can be replaced with a more comfortable BiPAP machine.
Detailed Steps For Setting CPAP Pressure
Here are the detailed steps for determining your desired CPAP pressure setting and adjustment:
1. Initial Pressure Setting: For mild patients, usually start with a pressure of 8cmH2O. If the snoring stops, try to adjust it down by 2cmH2O.
Moderate patients usually start with 10cmH2O, and the subsequent adjustment is the same as for mild patients.
Severe patients need to start adjusting from 12cmH2O.
2. Titration Study: An overnight titration study is done to observe your breathing pattern and adjust your ventilator settings as needed.
During a titration study, your technician will gradually increase the settings until they find the setting that best suits your needs.
3. Automatic Positive Airway Pressure (APAP): APAP allows automatic adjustment of pressure within a certain range, automatically increasing pressure according to airway resistance.
4. Individual Differences: The required pressure setting is not directly related to the severity of OSA. Some patients with mild OSA may need higher pressure. Some patients with severe OSA may adapt to lower-pressure settings.
5. Influence of Sleeping Posture: If sleep apnea symptoms worsen when lying on your back, the CPAP pressure needs to be adjusted at the same time.
6. Equipment Factors: Different ventilator models can provide different maximum pressures. Single-level ventilators usually have a maximum of 20cmH2O, while dual-level ventilators can reach 25 or 30cmH2O.
In addition, after understanding the above, here are some other things to note:
Avoid adjusting pressure settings alone, as this may result in poor treatment or side effects.
Follow up with an engineer or professional regularly to adjust settings based on treatment effectiveness.
When using an auto-CPAP device, make sure you understand how it works so you can communicate effectively with your professional about whether the settings are appropriate.
Alternative Pressure Setting Methods
1. Confirm the diagnosis of sleep apnea syndrome and set the continuous positive airway pressure treatment pressure at the same time within one night. The patient’s examination time is divided into two parts. The first part is used to confirm sleep apnea syndrome, and the second part is used to set the continuous positive airway pressure treatment pressure. This can save patients’ expenses. However, it was later found that most patients who set the treatment pressure value by this method were required to reset and replace the mask, which increased the financial burden on patients.
2. After sleep apnea syndrome is diagnosed, the CPAP pressure value can be determined at home without relying on the results of polysomnography.
On the first night, the technician goes to the patient’s home and instructs the patient on how to use the CPAP machine and the blood oxygen saturation meter, setting a low-pressure value of 5 to 7 cmH2O (0.49 to 0.69 kPa). The technician can leave after 1 to 2 hours of treatment.
The next day, based on the blood oxygen saturation values recorded at night and the improvement of the patient’s condition, it is determined whether the pressure is appropriate. If it is not enough, the pressure value is gradually increased every day until the treatment is successful. This can save 1/3 to 1/2 of medical expenses and reduce the workload of medical staff.
3. After the diagnosis of sleep apnea syndrome was confirmed by sleep breathing monitoring with a polygraph, the blood oxygen saturation was monitored at the patient’s home with a blood oxygen saturation monitor on the first night, and the measurement result was used as the baseline value before treatment.
Then during the day in the hospital, technicians will teach the patients how to use the CPAP machine, select and wear a nasal mask, and select an empirical treatment pressure based on experience, combined with the patient’s body shape and severity of the disease, which is generally 8-12 cmH2O (0.785-1.18 kPa). The technicians will observe the patients for a few hours during their lunch break, and then the patients will take the CPAP machine home and try it out while sleeping at night.
Most patients can basically master the use of the machine and the adjustment of the nasal mask after 2 to 3 days of learning and experimenting at night. At the same time, ask the patient’s family to pay attention to whether the patient snores or has sleep apnea. If so, increase the pressure by 2 cmH2O (0.196 kPa) and contact the doctor by phone at any time to report the usage and solve any problems in time.
After about one week of trial, the patient can master the use of the CPAP machine proficiently. After the snoring during sleep disappears, the blood oxygen saturation during sleep is measured again. The result is compared with the blood oxygen saturation result before treatment. If the lowest blood oxygen saturation is above 90% and there is no obvious fluctuation in blood oxygen, it proves that the pressure is appropriate. Otherwise, continue to increase the continuous positive upper airway pressure.
Conclusion
Overall, determining the desired CPAP pressure setting is a process that combines initial evaluation, professional medical advice, and personal comfort. The initial setting is set by a professional based on the severity of the condition and is fine-tuned through titration studies. Patient feedback is also critical to adjustments to ensure that the sleep process is both effective and comfortable. Good communication with your healthcare provider and regular follow-up visits and monitoring are key to ensuring the CPAP pressure setting is appropriate.
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