CPAP and Auto CPAP Modes


This is a fixed pressure setting based on a CPAP Titration Study.

Three important pieces of information are required to set up and use a CPAP Machine.

1. Start Pressure

The machine will start at the initial starting pressure.
If the pressure is set too low, the patient may feel like they are 'suffocating' as they are not receiving enough air.
If the pressure is set too high, the patient will feel uncomfortable and may have difficulty breathing out against the strong air pressure.

2. Ramp Time

The ramp time is used so that the patient can fall asleep before the full pressure is reached.
The machine will slowly ramp up (increase) to the required treatment pressure over the ramp time. After the ramp time has elapsed, the machine will stay at the treatment pressure. It will not increase or reduce. If the ramp button is pressed, the machine will go back down to the initial pressure and start the ramp cycle again.

The ramp time can be set between 0 mins (off) and 45/60 Minutes, in 5-minute increments.

Note: Setting the ramp time can be a delicate balance.

  • Too long a ramp time and the patient may fall asleep and suffer apnea/hypopnea events before the treatment pressure is reached.

  • Too short a ramp time and the treatment pressure may be reached before the patient falls asleep. If the treatment pressure is uncomfortable when the patient is awake, they will have to press the ramp button manually to start the ramp cycle again.

3. Treatment Pressure

This is the prescribed pressure based on a titrated sleep study and is the CPAP Machine will run at once the ramp time has elapsed. It will run at this fixed pressure all the time until it has been switched off or the rampcysyme has been restarted.

Auto Mode

The Auto CPAP (APAP) Machine will be set with a minimum and maximum pressure, ideally spanning the patient's treatment pressure. 
Eg. If the Treatment Pressure has been determined as 10cmH20, then an auto range of 6-16cmH20 may be set. Over time. further adjustments may be needed to fine-tune the optimum auto range. 

When the patient is awake and breathing normally, the machine will not need to increase the pressure, so should stay at the minimum setting.
However, during sleep, if/when the airway becomes partially obstructed (SNORING) or fully obstructed (APNEA), the Auto CPAP (APAP) Machine will detect these abnormal breathing events and automatically increase the treatment pressure to open the airway.

This automatic adjustment process will happen throughout sleep to reduce the Apnea (stopping breathing) and Hypopnea (shallow breathing)
The goal is to keep the Apnea/Hypopnea events (AHI) to under 5 events per hour, and the lower the AHI the better.

Two important pieces of information are required to set up and use an Auto CPAP (APAP) Machine

1. Minimum (Starting) Pressure
2. Maximum Pressure

Last updated: 30th May 2022