CPAP Machine or Auto Machine - Which type is best for me?
This is a very common question, and simply answered by referring to the table below;
| CPAP or Auto - Which machine is most suitable for me? | CPAP | Auto CPAP (APAP) |
| I know the pressure I need |  | |
| I have a doctor’s prescription (script) | | |
| I do not know the pressure I need |  | |
| It has been more than 3 years since my last sleep study | | |
CPAP or Auto?
Constant Positive Airway Pressure (CPAP) machines treat Obstructive Sleep Apnea (OSA). They are set to the treatment pressure the patient's body requires (we do this for you). This is usually based on a sleep study and doctor's prescription or a previous machine setting. This treatment pressure is the pressure required to keep the patient's airway open during sleep.
Even if the patient is still awake, the machine will still put out this constant pressure.
If you do not know your prescribed treatment pressure, usually we can't supply a CPAP machine as we don't know what to set it to.
The Automatic Positive Airway Pressure (APAP or Auto) machines are set up with a minimum and maximum setting. The auto machine adjusts up and down between this range throughout the sleep period to treat Obstructive Sleep Apnea (OSA). Usually the auto machine will stay at the minimum (start pressure) while the patient is awake. During sleep, the auto machine will increase and reduce the pressure as required (see example graph below). Typically the pressure is higher when the patient is sleeping on their back and less when on their side. The pressure will also vary depending on the different sleep stages, The auto machine will cope with all these changes by varying the pressure automatically as required.
"In my personal opinion, this is more comfortable and smarter way of providing the required therapy for OSA patients."
In the future, the treatment pressure may change due to weight gain or weight loss, ageing, loss of muscle tone in the throat, etc. The auto machine will keep adjusting automatically to the correct pressure, often without the need for another sleep study.
Central Sleep Apnea (CSA)
A very low percentage of patients have Central Sleep Apnea (CSA)
Positive Airway Pressure is not suitable for treating CSA alone as the airway is already open.
However, patients with CSA will often have Obstructive Sleep Apnea (OSA) which can be treated with CPAP Therapy.
If you have CSA and/or CHF as well as OSA please consult your doctor for advice, and ask them to provide you with a prescription for the type of machine they recommend to treat your condition.
Pressure Graph Example
The graph below shows the difference between CPAP and AUTO Machine operating pressures over an 8 hour sleep period.
The CPAP Machine builds up to the treatment pressure over the ramp period, then stays at that constant pressure for the rest of the night. The treatment pressure needs to be set on the high side of the patients particular requirements to allow for different sleep positions (Eg. a higher pressure is needed when the patient is sleeping on their back due to gravity closing the airway more)
The Auto Machine varies the pressure during the sleep period to determine the optimum lowest pressure needed to treat Obstructive Sleep Apnea. In the example above, the pressure needed to be higher than the prescribed treatment pressure of 10cmH20 on three brief occasions. Most of the time the pressure needed was much less (Mean Pressure was 6.5cmH20). This means that the patient typically receives a more comfortable sleeping experience as the pressure is lower overall. This helps patients tolerate CPAP therapy more easily and increases overall compliance (usage). Patients often report that Auto (APAP) therapy is more comfortable than CPAP therapy.
Simple Car Analogy
Imagine you have the choice of a car.
Either automatic or manual, but the manual will only have one gear or one speed.
An automatic car will select the correct gear. An auto machine will select the correct pressure all the time. Easy.
A manual car with only one gear (is there such a thing these days?) is not the most efficient or smart way to drive.
In my opinion, it is the same with CPAP therapy, Auto (APAP) therapy is better than fixed (CPAP) pressure for many reasons.
The price difference is only $200. which would you choose?
- Last updated 30th September 2017