Which CPAP Machine for Sleep Apnea is Right for Me?
For most people new to sleep therapy it can be a difficult task understanding the differences between all the different CPAP device options you have. In most cases, your physician determines the type of therapy device and pressure setting you need but what about the people that have been on therapy for a while and would like to know the different therapy options that are available now but were not available when they were first diagnosed. In all cases we suggest speaking with your physician prior to any therapy device change, but carefully read your options.
CPAP is the most commonly prescribed and proven treatment for sleep apnea. CPAP therapy is sometimes a broad reference to the therapy for treatment of sleep apnea, hypopnea, Upper Airway Resistance Syndrome (UARS), flow limitation, and snoring; however there are many different devices that fall in to the positive airway pressure (PAP) family. Listed below are descriptions of the different therapy devices, their target market and a description about therapy delivery.
CPAP Machines: Fixed Pressure CPAP Machines, Standard CPAP Machines
Standard or Fixed Pressure CPAP Machines have been the long standing staple and recommended treatment for sleep apnea for many years. A fixed pressure CPAP machine delivers pressurized air via a CPAP mask (see: Nasal Pillow CPAP Mask, Full Face CPAP Mask, Nasal CPAP Mask) and that pressurized air provides a pneumatic splint in the airway that keeps it from collapsing during sleep. The pressure measurements are delivered in a range of 4cm/H2O to 20cm/H20, however with a standard or fixed pressure CPAP machine it will only generate 1 specific setting throughout the entire night (excluding ramp time). An example of a fixed pressure CPAP machine would be 12cm/H2O, and that means once the machine has ramped up it will continue to blow out 12cm/H2O the entire course of the night.
People sometimes confuse standard or fixed pressure CPAP with Auto CPAP because their machine comes with a ramp mode feature. However these 2 machines differ greatly in therapy delivery and ramp mode is simply a comfort feature that allows the user to fall asleep on a lower pressure while the machine “ramps up” to the fixed pressure setting, usually over a 20 minute period. While standard or fixed pressure CPAP is the most commonly prescribed device, many users are gravitating to Auto CPAP machines (see more information below).
Examples of Standard or Fixed Pressure CPAP Machines: Philips Respironics System One REMstar Plus DS260HS and REMstar Pro DS460HS, ResMed S9 Elite or S9 Escape, Fisher and Paykel ICON Novo and Premo, Devilbiss IntelliPAP Standard, and Transcend Travel CPAP Machine.
Auto CPAP Machines: Auto Adjusting CPAP Machines, Auto CPAP, Auto Titrating CPAP Machines
Auto CPAP machines are similar to standard CPAP machines in which a single pressure setting is delivered, however this pressure setting can automatically adjust over the night when the machine detects you need more pressure to stabilize the airway. The big question that always comes up is why would you need more pressure? The answer is easy, during the course of the night we enter different stages of sleep and some of those stages are deeper and relax the muscles more, especially those that support the airway. There are also certain positions of sleep that make us more prone to sleep apnea events, like sleeping on your back versus sleeping on your side.
Auto CPAP machines operate on a range of 4cm/H2O to 20cm/H2O and will adjust up and down during the course of the night. Auto CPAP machines can also be programmed to standard or fixed pressure CPAP mode, this is beneficial because your treating physician can determine your compliance and AHI (apnea hypopnea index) between the 2 therapy treatments. Auto CPAP machine can also have the range adjusted and what that means is a minimum pressure can be set as well as a maximum, so if you doctor wants you to stay in a range of 6cm/H2O to 12cm/H2O, the machine is not going to go outside of that range.
Many customers that call in to speak with our technical staff often asks why anyone would choose a standard CPAP machine over an Auto CPAP machine and the answer really comes down to what your physician feel comfortable with prescribing. For those that do not like to go back to the sleep lab every 1-2 years for a pressure adjustment, this is great because the machine will detect the need for more or less pressure as needed.
Examples of Auto Adjusting CPAP Machines: ResMed S9 Autoset and Escape Auto, Philips Respironics System One REMstar Auto DS560HS, Fisher and Paykel ICON Auto , Devilbiss IntelliPAP Auto, RESmart Auto.
Bi-Level Machine: BiPAP Machines, VPAP Machines, Bi-Level PAP Therapy, BPAP
Bi-Level PAP therapy uses 2 levels of pressure to treat sleep apnea, an inspiratory pressure (IPAP) and an expiratory pressure (EPAP). This simply means that a pressure delivered upon inhalation is higher than the pressure upon breathing out and is beneficial to person that has trouble exhaling against standard CPAP pressure. The pressure settings are separated by a pressure support threshold of 3-6 cm/H2O (example: a person on 16cm IPAP and 12cm EPAP have a pressure support of 4cm, the difference between the 2). Bi-Level is the proper name; however most people, physicians included refer to it by a manufacturer trade name of BiPAP, similar to how most people call cotton swabs Q-Tips. BiPAP is Bi-Level; it is also referred to as VPAP, another manufacturer trade name for the same type of therapy. Sounds confusing right?
Bi-Level are less commonly prescribed sleep therapy devices, making up only about 15% of the sleep therapy market. Unless specifically prescribed due to other pre-existing conditions, Bi-Level therapy is typically used for one of these 2 reasons:
- A person with such severe apnea that requires a fixed CPAP pressure that is too high (i.e. 15cm/H2O). Many sleep labs have a protocol that states when a person gets to a certain pressure threshold to switch them over to Bi-Level.
- It’s meant to assist in compliance, a person who is non-compliant, meaning they do not use the CPAP machine, may benefit from a Bi-Level device that provides the comfort of exhaling against a lower pressure than the pressure they are breathing in.
Examples of BiLevel Machines: Resmed VPAP S, Philips Respironics System One DS660HS, Devilbiss IntelliPAP Bi_level
Auto Bi-Level: Auto BiPAP, Auto Adjusting BiLevel
Auto Bi-level devices use a combination of Bi-Level technology and Auto CPAP technology and istead of having one fixed IPAP pressure and one fixed EPAP pressure, these two pressure settings auto adjust based on therapy need. So how does the device know when to increase the IPAP (inspiratory pressure) and when to increase the EPAP (expiratory pressure? The EPAP pressure (the lower number in your BiPAP/Bi-level setting) is the pressure used to eliminate obstructive apneas and stabilize the airway, meaning to keep it patent and open while the IPAP pressure is used to eliminate hypopnea, flow limitation and any residual snoring. A pressure support number is established to instruct the machine the differences in pressure between the IPAP and EPAP, this pressure setting is typically between 3cm/H2O and 6cm/H2O.
Much like Auto CPAP machines, the Auto Bi-Levels can operate in 2 modes which are the standard Bi-Level mode or Auto adjust mode. Many of the candidates for Auto Bi-Level have the same determining factors as the standard Bi-Level candidates listed in the above description for Bi-Level.
Examples of Auto Bi-Level Devices: ResMed S9 VPAP Auto, Philips Respironics System One DS760HS, Devilbiss IntelliPAP Bi-Level Auto.
Bi-Level ST: BiPAP S/T, VPAP ST, Bi-Level Spontaneous Timed
Bi-Level ST devices operate with the same IPAP and EPAP concept of traditional Bi-Levels/BiPAPs however they carry the fancy ST acronym behind their name that means Spontaneous Timed. The devices are non-invasive ventilators. So what does this mean? Unlike traditional Bi-Level/BiPAP where the IPAP and EPAP (your breaths in and breaths out) are determined by the user (you), the ST mode has a timed eupneic rate that establishes when you are to breathe in and breathe out. To put this in easier terms to understand, the standard Bi-Level reacts to your breathing where the Bi-Level ST when time you when to breathe in and breathe out.
So who are the target candidates for BiPAP ST and VPAP ST? People that have COPD (chronic obstructive pulmonary disease), people that have neuromuscular diseases and people that suffer from obesity hypoventilation. These are not commonly prescribed devices and usually come with a hefty price tag. Device settings are specific and should be determined and adjusted upon the recommendation of your treating physician.
Examples of Bi-Level ST: ResMed VPAP S/T, Philips Respironics BiPAP AVAPS, Breas Bi-Level ST
ASV: BiPAP Auto SV, VPAP Adapt SV, Adaptive Pressure Support Servo-Ventilators
The Philips Respironics BiPAP AutoSV and the ResMed VPAP Adapt are adaptive pressure support servo-ventilators. These specialized servo-ventilators are used for the treatment of Complex Sleep Apnea (CompSA), otherwise referred to as CPAP induced central sleep apnea (CSA), periodic breathing such as Cheyne-Stokes Respiration. These are not commonly prescribed devices and should be directed by a sleep specialist for device settings.
What is the difference between these 2 devices? Essentially there is not much difference between the 2 though they are the only 2 manufacturers that have these devices on the market that are used and cleared for the treatment of the above disorders. The algorithm for the Philips Respironics device targets peak flow while the ResMed device targets minute ventilation, essentially the same common goal with slight variations in delivery method. These devices DO NOT have an auto titrating algorithm, the component used to establish airway patency (keep the airway open) is a fixed pressure and the auto adjusting component is the pressure support which is used to treat the periodic breathing or Complex central events.
Examples of Auto Servo-Ventilators: Philips Respironics BiPAP AutoSV and ResMed VPAP Adapt.