### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
Hello, What oxygen levels are considered dangerous? My father has had a C Pap machine for 8 years now. I noticed the last time that I was visiting, that he was falling asleep in the middle of the day, after sleeping for 8 hours. And he seemed extremely tired. I asked if he had his machine checked , which he said that he had it checked. I told my mom to get an oxygen meter and to check his levels, especially when she see s him getting sleepy or falling asleep. When should they be concerned or I should ask, what levels are dangerous that they should reach out to his doctor?

### output:

Hello.thanks for posting at Chat Doctor. According to the history you have provided, I suppose your father is suffering from sleep apnea, that's why the CPAP machine. It helps to keep the airway open in people whose airways tend to close while they sleep. As you day he has got the machine checked for its functionality, but you also need to get it checked to ascertain whether it's really helping the patient. Sometimes the pressure of air coming from the CPAP is not sufficient to keep the airways open. So I guess the pressure of the CPAP machine needs to be increased. All CPAP machines have a data card slot which a memory card can be put, and all information can be downloaded. It will give you data about the number of hours he is using the machine, the average pressures and the apnea hypopnea index. This will give you sufficient information for his problems. Additionally, since airways close during sleeping, oxygen concentration also falls. An oxygen saturation of greater than 85 % is acceptable. If it remains below 85 you have to see your doctor. Also, the machine data can only be read with a special software which will be available with your doctor. Wishing you good health. Regards