APAP – or Automatic Positive Airway Pressure- is a medical grade device quite similar in function with a CPAP machine. The PAP based devices help delivering a given prescribed air pressure into the airways of the patient, in order to maintain the airways from collapsing. Patients with Central Sleep Apnea or OSA – Obstructive Sleep Apnea need such a device to help combat their apnea events. The air pressure delivered by an APAP is set just as to help push through any obstructions and keep the airways clear and open.
The air flow that comes through a PAP machine will generally feel as close as possible to natural breathing, yet it helps ensuring that all obstructions are avoided successfully. An APAP machine comprises three important parts:
CPAP- or Continuous Positive Air Pressure- devices are usually set to deliver a single pressure setting. The sleep specialist is the one who will determine the required pressure setting for the patient, following a sleep study. However, one of the biggest problems faced by patients wearing a CPAP is this single pressure. Some patients find it extremely difficult to exhale against a high pressure coming from the unit. The patient requires a higher setting upon inhalation to maintain the airways open, but upon exhalation this high pressure feels quite uncomfortable.
This is exactly where an APAP differs from the CPAP. The APAP machines have 2 types of different pressure settings- a lower pressure setting which is the most reduced pressure that is needed by the patient in order to prevent his apnea events, and a higher pressure setting. APAP devices operate based on extremely complex algorithms that help delivering pressure on a “breath-by-breath” basis, just as needed by the patient. The device is capable of delivering a most natural pressure pattern, following the breathing waveform of the patient. Once the two different pressure levels are set, the machine will deliver pressurized air that stays in between these levels- never higher and never below the minimum required amount of pressure.
APAP machines use different algorithms and technologies, so not all machines are the same. However, your physician is the one who will redirect you towards the most efficient type of air pressure therapy in your case. You might need an APAP, but your doctor might also tell you that a CPAP with a fixed pressure is just enough in your case. APAP machines are also more expensive, but they cater mostly to patients with more precise and complex requirements in terms of oxygen therapy.