What are the Types of BPAP Devices?

BPAP devices can be used in chronic respiratory diseases such as COPD and lung cancer, as well as in any respiratory disease affecting the respiratory system such as COVID-19, which has been seen recently. It can also be applied to people who cannot adapt to CPAP or OTOCPAP (single-level positive airway pressure generating devices) devices used for sleep apnea treatment. Devices that produce bi-level positive airway pressure are called BPAPs. Also known as Bilevel CPAP. These devices are generally developed for non-invasive (with mask) use. There are also BPAP devices that are invasive, that is, used through a tracheostomy cannula or an endotracheal tube. The BPAP device applies different pressure as the person inhales and exhales. IPAP is the pressure value applied by the device while the user inhales and EPAP is the pressure value applied while exhaling. EPAP must be less than IPAP. Thus, a pressure difference occurs in the respiratory tract. The pressure difference is used for the treatment of respiratory diseases. BPAP, BPAP ST, BPAP ST AVAPS, OTOBPAP and ASV devices are in the BPAP category. Although these devices are similar to each other in terms of working principle, they are different in terms of some respiratory parameters.

BPAP = Bilevel positive airway pressure = Bilevel continuous positive airway pressure = Two-stage continuous positive airway pressure

BPAP devices applied through the mask are generally used for the treatment of conditions such as chronic obstructive pulmonary disease (COPD), acute and chronic respiratory failure, pneumonia and asthma. Mask application is called “non-invasive”. The application made with medical products such as tracheostomy cannula or endotracheal tube placed inside the body is called "invasive". While there are 4-5 types of respiratory parameters in non-invasive BPAP devices, there are more parameters in invasive ones. Also, BPAP should not be perceived as just a device variant. It actually refers to a breathing mode. Devices that do not contain a breathing mode other than BPAP are called BPAP devices.

Several important considerations play a role in physicians' decision on treatment with BPAP devices. The first of these is that some patients cannot adapt to the high pressure applied continuously. Especially when pressures of 12 cmH2O and above are applied in a single level with CPAP devices, some patients cannot breathe comfortably. For this reason, BPAP devices can be preferred instead of CPAP or OTOCPAP. The second point is that due to the high pressure, there is a problem not only when inhaling, but also when exhaling. This is called expiratory difficulty. Third, obstructive lung diseases such as COPD. In this type of diseases, different pressure application is needed while breathing and exhaling. The fourth issue is hypoventilation syndrome, which develops due to a disease such as obesity.

Non-invasive BPAP devices are especially used in the treatment of lung diseases such as COPD. Some sleep apnea patients also have COPD. In such a case, BPAP devices are preferred over CPAP or OTOCPAP. At the same time, if there is oxygen deficiency, it may be necessary to use an oxygen concentrator next to BPAP devices. All these devices and accessories are medical products that should be used with the recommendations of specialist physicians. Their use with non-physician recommendations may pose risks to human health.

There are 5 types of BPAP devices:

• BPAP Device
• BPAP ST Device
• BPAP ST AVAPS Device
• OTOBPAP Device
• ASV Device

Oxygen passes through the upper respiratory tract and reaches the lungs. In the alveoli (air sacs) at the far end of the lungs, carbon dioxide attached to the hemoglobin in the blood cell is replaced by oxygen. The carbon dioxide is then expelled from the lungs. This cycle ensures the healthy functioning of many systems in the body.

Carbon dioxide gas has a vital place in respiration. If the person has respiratory problems, carbon dioxide gas, which cannot pass from the blood cells to the alveoli, continues to remain in the blood. In this case, the cells cannot carry enough oxygen gas to the tissues. When there is not enough oxygen to the tissues, health problems begin to occur.

Depending on the patient's condition, the type of BPAP and respiratory parameters are determined by the physician. These devices are especially for people who need to reduce the amount of carbon dioxide in their body. The device is applied to the patient and carbon dioxide gas is expelled from the body thanks to the pressure difference created in the respiratory tract. Thus, the oxygen gas taken into the body is transmitted to the tissues through blood cells that release carbon dioxide.

Although the devices are similar to each other in terms of working principle, they have differences in terms of some respiratory parameters. All types of BPAP are devices that produce bi-level continuous positive airway pressure. Bi-level means IPAP and EPAP pressures. IPAP is the pressure that builds up in the airway during breathing. In some devices it is designated as “Pi”. EPAP is the pressure in the airway during exhalation. In some devices it is indicated as “Pe”.

IPAP = Inspiratory positive airway pressure = Inspiratory airway pressure

EPAP = Expiratory positive airway pressure = Expiratory airway pressure

If IPAP and EPAP are set to equal value on BPAP devices, the breathing mode changes to CPAP. CPAP stands for single level continuous airway pressure. For example, if the IPAP and EPAP parameters are both set to 10 cmH2O, the application pressure will be single level.

BPAP devices (BPAP S devices) have IPAP and EPAP as respiratory parameters. BPAP ST devices have rate and I/E parameters in addition to IPAP and EPAP. Another name for the rate parameter is frequency. Indicates the number of breaths per minute. The I/E parameter can be expressed as the ratio of the inhalation time to the exhalation time. Some devices use I/T instead of I/E. I/T is the ratio of breathing time to total breathing time. BPAP ST devices contain more respiratory parameters than BPAP devices. This allows BPAP ST devices to keep the patient's breathing more under control.

The I/E parameter is the ratio of the inspiratory time to the expiratory time. The I/E ratio in a healthy adult is usually 1/2. The I/T parameter is the ratio of the inspiratory time to the total respiratory time. It can be specified as I/T or in other words I/(I+E). It is the ratio of the inspiratory time to the sum of the inspiration and expiration times.

I/E = Inspiratory time/expiratory time = Inspiratory time/expiratory time = Inspiratory time/expiratory time

I/T = Inspiratory time/total time = Inspiratory time/total respiratory time = Inspiratory time/total respiratory time

Lying position, sleep stage, obesity, chest wall pathology or neuromuscular diseases may prevent reaching the required air volume during respiration. In cases where the patient needs volumetric respiratory support, BPAP ST AVAPS devices can be used. These devices deliver the targeted volume of air to the patient by increasing or decreasing the pressure. In addition to IPAP, EPAP, rate and I/E parameters, the “volume” parameter can be adjusted on the device.

AVAPS = Average volume assured pressure support = Average volume assured pressure support

OTOBPAP can be used in patients who need to use BPAP or BPAP ST but cannot adapt to high pressure. Lower and upper limits can be set for IPAP and EPAP pressures in OTOBPAP devices. Thus, different pressure ranges are set for the inhalation and exhalation phases. Devices can apply both IPAP pressure and EPAP pressure variably according to the patient's current needs within limits. It can be used in patients who cannot adapt to high pressure, as well as in patients who need variable pressures due to lying position or sleep stage.

The cessation of breathing for more than 10 seconds is called apnea, an increase in the depth of breathing is called hyperpnea, and a decrease in the depth of breathing is called hypopnea. If the depth of breathing first increases, then decreases and finally stops and this respiratory cycle is repeated, it is called Cheyne-Stokes breathing. Cheyne-Stokes respiration and central sleep apnea syndrome can be seen frequently in heart failure patients. BPAP devices used in the treatment of such patients should be able to meet the variable pressure needs. Unnecessarily high pressure may cause more apnea. Therefore, the pressure required by the patient should be applied at the lowest level by the device. The BPAP device that can provide this is the device called ASV (adaptive servo ventilation).

When BPAP is applied non-invasively (with a mask), oral-nasal masks are generally used. In some cases, nasal (nose) or total face masks can be used. If a nasal mask is to be used, the patient should keep his mouth closed to avoid air leakage.

The type of mask to be used is determined by the doctor after the tests. There are 6 types of PAP masks: nasal pillow mask, nasal cannula, nasal mask, oral mask, ora-nasal mask, whole face mask. BPAP devices are suitable for use with all of these mask types. What is important here is what kind of mask the doctor will recommend.

It should not be forgotten that the most important factor for the patient's compliance with BPAP treatment is the type of mask. In addition, features such as the design, size of the mask and the type of material used while producing it can also affect the treatment process positively or negatively.