BiPAP vs. CPAP: What are the differences?
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What is the difference between BiPAP and CPAP?
Both BiPAP and CPAP machines have a turbine, tube, oronasal mask, and humidifier. BiPAP draws in room air, then filters and pressurizes it. The pressurized air is delivered to your airway through the tube and the oronasal mask you wear while you sleep.
However, while CPAP has a single air pressure setting, BiPAP allows for a difference in inhalation and exhalation pressure. For example, if your blood oxygen is very low, your doctor may recommend that you increase the inhalation pressure to get more air into your lungs. However, exhaling at above-average air pressure can be difficult. A bi-level pressure setting lowers the pressure as you exhale, making breathing more natural and comfortable. Also, if you have too much carbon dioxide in your blood, a lower exhalation pressure means you don’t have to work as hard to exhale and get rid of the excess carbon dioxide. A bi-level air pressure setting enhances your body’s ability to breathe in and out.
There is one main difference between CPAP and BiPAP: CPAP machines are set to a single pressure, while BiPAP machines are set to two different pressures—one for inhaling and one for exhaling. CPAP machines are primarily used to treat obstructive sleep apnea (OSA), while BiPAP machines are used to treat central sleep apnea, complex sleep apnea, or COPD.
| CPAP | BiPAP | |
|---|---|---|
|
Pressure |
Continuous Pressure
Same pressure during exhalation and inhalation |
Continuous Pressure
Pressures are different between inhalation and exhalation. Higher for inhaling. Lower for Exhaling. |
|
Usage Scenarios |
Used in the field and at home, less complicated devices for delivery |
Not commonly used in the field or at home due to the complexity of delivery/devices |
|
Monitor |
Needs little monitoring. Set it and it’s good |
Needs monitoring of delivered pressures |
|
Indications |
Generally recommended for obstructive sleep apnea (OSA) |
Used for more complex breathing problems such as central sleep apnea(CSA)/heart/lung/neuro disorders that require additional airway support during sleep (CHF & COPD & PARKINSON) |
|
Pros |
Most common type of sleep apnea treatment
Covered under most insurance plans |
Smaller and quieter than CPAP machines
More effective for certain types of sleep apnea |
|
Cons |
Can be loud and bulky
Some people find them difficult to use |
Generally more expensive than CPAP machines |
How It Works
CPAP Machines: CPAP machines deliver therapeutic air to the wearer only at a specific pressure, and it doesn’t change unless you change it manually. CPAP machines maintain a constant pressure throughout the night and are used to treat most cases of OSA.
BiPAP Machines: BiPAPs can have two different air pressures: one for inhaling and one for exhaling. They are called Inspiratory Positive Airway Pressure (IPAP) and Expiratory Positive Airway Pressure (EPAP). BiPAP therapy pressures are usually higher during inhalation and lower during exhalation. The lower expiratory pressure can make exhalation more comfortable.
Pressure Setting
CPAP Machines: There is only one pressure setting parameter, which is usually adjusted between 4 – 20 cmH2O. For example, when treating sleep apnea, the pressure may be set at an appropriate value based on factors such as the degree of airway obstruction in the patient, generally 8 – 12 cmH2O.
BiPAP Machines: There are two pressure setting parameters, IPAP and EPAP. IPAP is generally adjusted from 8 – 10 cmH2O, and the range is usually 10 – 25 cmH2O; EPAP starts from 3 – 5 cmH2O, and the range is generally 4 – 10 cmH2O, and the difference between IPAP and EPAP is generally 4 – 10 cmH2O, which determines the strength of ventilation support.
Applicable Diseases
CPAP Machines: Mainly used to treat obstructive sleep apnea syndrome, and also used for diseases such as cardiogenic pulmonary edema. By keeping the airway open, it improves the patient’s apnea and hypopnea during sleep.
BiPAP Machines: Commonly used in acute exacerbation of chronic obstructive pulmonary disease (COPD), type II respiratory failure, etc. It can better assist the patient’s breathing, help expel carbon dioxide, and improve ventilation function.
Patient Comfort
CPAP Machines: Some patients may find it more difficult to exhale because the airway pressure is the same throughout the breathing process. If the pressure is not set properly, patients may find it difficult to adapt to this continuous positive pressure.
BiPAP Machines: Since there are two different pressure levels, it is more in line with the physiological breathing process of the human body and provides other assistance during the inhalation and exhalation stages. Most patients feel that breathing is more natural and relatively easier to accept.
Understanding CPAP Machines
CPAP is also called continuous positive airway pressure (CPAP), and is often called a semi-automatic ventilator. CPAP provides continuous pressure throughout the respiratory cycle.
When breathing with CPAP, the ventilator will provide a constant pressure during inspiration. When the patient then exhales, the CPAP will continue to apply pressure throughout the exhalation process.
CPAP machine settings are as follows:
A single pressure, measured in centimeters of water (cmH2O)
The percentage of inspired oxygen (FiO2), set from 21% to 100%
CPAP is commonly used in patients with the following respiratory conditions:
Acute pulmonary edema
Obstructive sleep apnea
Obesity hypoventilation syndrome (Pickwick syndrome)
Uses and Indications for CPAP Therapy
Airway collapse can occur for a variety of reasons, and CPAP is used in many cases to keep the airway open. Airway collapse is commonly seen in adults and children with breathing problems such as obstructive sleep apnea (OSA), which is when breathing stops or pauses during sleep. OSA can occur for a variety of reasons, such as obesity, low muscle tone, enlarged adenotonsils, etc.
CPAP can be used in the neonatal intensive care unit (NICU) to treat premature infants whose lungs are not fully developed and who may have respiratory distress syndrome due to surfactant deficiency.
Doctors can also use CPAP to treat hypoxia and reduce the work of breathing in infants with acute infectious processes such as bronchiolitis and pneumonia or airway collapse such as tracheomalacia. It is used to treat hypoxic respiratory failure associated with congestive heart failure, increasing cardiac output and improving V/Q matching.
CPAP can help deliver oxygen through PEEP before an artificial airway is placed during endotracheal intubation.
It can be used to successfully extubate patients who may still benefit from positive pressure but may not require invasive ventilation, such as obese patients with obstructive sleep apnea (OSA) or patients with congestive heart failure.
Understanding BiPAP Machines
Bi-level ventilator, also known as bi-level positive airway pressure (BPAP). BPAP provides two different pressures during the respiratory cycle. BiPAP was originally a ventilation method pioneered by Respironics Ltd. Co in the early 1990s for non-invasive positive pressure ventilation. BiPAP can be adjusted to two different pressure levels: one for inspiration and the other for expiration. BiPAP ventilators are usually only used for patients with sleep disorders such as central sleep apnea (CSA), complex sleep apnea (CompSA), congestive heart failure (CHF) and chronic obstructive pulmonary disease. Chronic obstructive pulmonary disease).
When a patient is on a BiPAP machine, the machine will provide a constant pressure during inspiration. As the patient exhales, the machine will provide a different, lower pressure during exhalation.
Generally, the inspiratory pressure of BiPAP is similar to that of single-level CPAP, and its purpose is to open the collapsed airway and maintain normal ventilation. There is a pressure when you exhale, which is lower than the inspiratory pressure. When you exhale, it is more in line with your natural breathing and eliminates carbon dioxide in your body.
The ventilator settings for BiPAP are as follows:
Inspiratory positive airway pressure (IPAP), in cmH2O
Expiratory positive airway pressure (EPAP), in cmH2O
Percentage of inspired oxygen (FiO2), set from 21% to 100%
The main clinical use of BPAP is in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). BPAP can help you breathe for conditions such as:
Chronic obstructive pulmonary disease (COPD)
Obstructive sleep apnea
Obesity hypoventilation syndrome
Pneumonia
Asthma attacks
Poor breathing after surgery
Neurological disorders that disrupt breathing
Understanding the different BiPAP modes (BiPAP ST and AVAPS)
BiPAP machines typically operate on the simple principle of assigning IPAP and EPAP values to produce the required tidal volume, which is the difference between the two numbers. Spontaneous Timing (ST) modes have also been introduced, which are able to assign a Breaths Per Minute (BPM) value, allowing the machine to monitor the number of breaths per minute taken by the wearer. If the machine detects that the person is not taking that number of breaths, they are prompted to take a breath.
For example, a BiPAP might be set to:
Inspiratory Pressure – 10
Expiratory Pressure – 5
In this case, the BiPAP will provide an IPAP of 10 and an EPAP of 5.
A BiPAP ST can be set to:
Inspiratory Pressure – 10
Expiratory Pressure – 5
12 BPM (breaths per minute)
Similar to a regular BiPAP, the BiPAP ST will deliver an IPAP of 10 and an EPAP of 5, and will monitor if you inhale 12 times in one minute. Please note: the ST will not breathe for you, but will prompt the user to breathe.
Another recently introduced BiPAP mode is Average Volume Assured Pressure Support (AVAPS). AVAPS is characterized by its ability to automatically adjust pressure support to meet the patient’s needs, thereby ensuring the patient’s average tidal volume. Therefore, AVAPS can be adjusted according to the development of the disease and the needs of the patient, achieving both patient comfort and improved ventilation efficiency.
Uses and Indications for BiPAP Therapy
While most people with varying degrees of OSA can use CPAP, the following related conditions are better treated with BiPAP:
CSA (central sleep apnea). Bilevel positive airway pressure (BIPAP) is effective for people with hypercapnic central sleep apnea (associated with hypoventilation).
Higher CPAP pressures. The pressure of the machine is measured in centimeters of water, or cmH2O for short. CPAP and APAP machines are limited to 20 cmH2O. BiPAP machines can be set up to 25. If you have low oxygen levels, you may need higher pressures to effectively treat your sleep apnea.
Obesity hypoventilation syndrome (OHS). This form of sleep breathing disorder is common in people with a high body mass index (BMI). They may breathe too shallowly or too slowly during sleep, which can lead to hypoventilation – also known as respiratory depression. It can also cause high levels of carbon dioxide (CO2) in the blood, leading to hypoxia, which can cause heart or respiratory failure if complete lack of oxygen continues unchecked for more than a few minutes.
COPD/Overlap syndrome. Overlap syndrome is the term for when someone has any type of sleep apnea and COPD. Overlap syndrome can lead to a number of potentially serious health complications that can be treated with a BiPAP. Recent estimates suggest that up to 65% of people with OSA also have COPD. With higher inspiratory pressure and lower expiratory pressure, a BiPAP can help rebalance your blood oxygen and CO2 levels while you sleep and improve your overall breathing throughout the night.
Other common reasons for using BiPAP include:
CPAP intolerance. If you cannot tolerate a CPAP machine, BiPAP can be used as an alternative. However, BiPAP is traditionally more expensive than CPAP.
Need for increased ventilation. If you have lung disease or any other condition that requires assistance with breathing in and out, BiPAP may be a better choice than a CPAP machine. Talk to your doctor about using BiPAP if you have obstructive and restrictive factors such as central sleep apnea, obesity hypoventilation, COPD, or overlap syndrome.
Which is better – CPAP or BiPAP?
Human psychology is such that if two subjects are compared with each other, the conclusion shows that one of them is better. But in the case of CPAP and BiPAP, such a comparison is not entirely correct. CPAP and BiPAP are not better or worse, they are different. The most important thing to remember is that each device has its own indications and each device produces the best treatment effect. The greater comfort when using BiPAP devices compared to CPAP is also subjective. For most patients, the main thing is often not the ventilation mode, but the choice and process of getting used to the mask. In summary, we noticed that there are many devices for BiPAP and CPAP treatment. They all have different characteristics and solve various medical problems. When going to the hospital, you should choose the treatment machine for your disease according to the clinician’s prescription. In addition, everyone should learn more about relevant knowledge when purchasing the machine.
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