CPAP vs BiPAP - Non-Invasive Ventilation EXPLAINED

Summary

In this lesson, Eddie Watson breaks down the differences between CPAP and BiPAP, two types of non-invasive ventilation used to assist patients with respiratory insufficiency or failure. CPAP is beneficial for hypoxemic respiratory failure, helping to keep airways open and recruit collapsed alveoli. BiPAP, on the other hand, is useful for hypercapnic respiratory failure, offering two pressure settings to support ventilation and CO2 clearance. The video also explains when non-invasive ventilation may not be enough, and the need for transitioning to invasive mechanical ventilation in certain cases.

Takeaways

• 😀 CPAP and BiPAP are types of non-invasive ventilation used to support patients with respiratory insufficiency or failure, without the need for an endotracheal tube.
• 😀 CPAP (Continuous Positive Airway Pressure) is primarily beneficial for hypoxemic respiratory failure, such as in patients with congestive heart failure or obstructive sleep apnea.
• 😀 BiPAP (Bi-level Positive Airway Pressure) is suitable for hypercapnic respiratory failure, such as in COPD patients, or a combination of both hypoxemic and hypercapnic failures.
• 😀 Non-invasive ventilation (CPAP and BiPAP) is intended to support patients' breathing but does not cure the underlying respiratory issue, which must be addressed separately.
• 😀 CPAP helps increase intrathoracic pressure, reducing preload and improving cardiac output in patients with heart failure, while also aiding in alveolar recruitment for better gas exchange.
• 😀 CPAP typically delivers a single pressure setting throughout inspiration and expiration, ranging from 5 to 25 cm of water pressure, without going above 20 for acutely ill patients.
• 😀 BiPAP uses two pressures: Inspiratory Positive Airway Pressure (IPAP) for inspiration and Expiratory Positive Airway Pressure (EPAP) for expiration, offering more tailored support for ventilation and oxygenation.
• 😀 The difference between IPAP and EPAP determines the pressure support and tidal volume delivered, impacting ventilation and CO2 clearance.
• 😀 AVAPS (Average Volume Assured Pressure Support) is a newer BiPAP mode that adjusts pressure automatically to maintain a target tidal volume for the patient.
• 😀 Non-invasive ventilation is not enough if hypoxemia or hypercapnia doesn't improve with therapy, if the patient is at risk for aspiration, or if the patient cannot protect their airway. In such cases, intubation may be necessary.

Q & A

What is the primary difference between CPAP and BiPAP?

The primary difference is that CPAP provides a continuous positive airway pressure during both inspiration and expiration, while BiPAP offers two different pressures: inspiratory positive airway pressure (IPAP) during inspiration and expiratory positive airway pressure (EPAP) during expiration.

What types of respiratory failure are treated with non-invasive ventilation?

Non-invasive ventilation is used to treat two types of respiratory failure: type 1 (hypoxemic) respiratory failure, which is characterized by a failure to oxygenate, and type 2 (hypercapnic) respiratory failure, which involves a failure to remove carbon dioxide.

What is the role of CPAP in treating hypoxemic respiratory failure?

CPAP is beneficial for treating hypoxemic respiratory failure, as it increases intrathoracic pressure, reduces preload, and helps to open collapsed alveoli, which ultimately improves oxygenation and reduces the work of breathing.

How does BiPAP assist in treating hypercapnic respiratory failure?

BiPAP helps in treating hypercapnic respiratory failure by providing two distinct pressures. The inspiratory pressure (IPAP) assists in ventilation, while the expiratory pressure (EPAP) helps keep alveoli open for better oxygenation and CO2 clearance.

When is non-invasive ventilation not enough for a patient?

Non-invasive ventilation may not be enough if the patient’s hypoxemia or hypercapnia does not improve despite therapy, if the patient is at risk for aspiration, has excessive secretions, or if they are unable to protect their airway due to lethargy or unconsciousness.

What is the main benefit of CPAP in patients with congestive heart failure?

CPAP helps by increasing intrathoracic pressure, which reduces preload, improves cardiac output, and aids in pushing fluid out of the lungs, thus improving gas exchange and relieving congestion.

How is pressure adjusted in CPAP for critically ill patients?

In CPAP, the pressure is usually set between 5 to 25 or 30 cm of water, but it is recommended to stay below 20 cm of water for critically ill patients to avoid hemodynamic instability and reduce the risk of gastric insufflation, which could lead to aspiration.

What settings are used in BiPAP to ensure effective ventilation?

BiPAP uses two pressure settings: Inspiratory Positive Airway Pressure (IPAP) for inhalation support, and Expiratory Positive Airway Pressure (EPAP) to maintain airway pressure during exhalation. The difference between IPAP and EPAP helps to determine the patient’s tidal volume, influencing CO2 clearance.

What is the concept of pressure support in BiPAP?

Pressure support in BiPAP refers to the difference between the inspiratory (IPAP) and expiratory (EPAP) pressures. A larger difference provides more support for the patient’s tidal volume, which improves ventilation and enhances CO2 clearance.

What is AVAPS and how does it improve BiPAP therapy?

AVAPS stands for Average Volume Assured Pressure Support. It automatically adjusts the pressure support during BiPAP therapy to maintain a target tidal volume by using a feedback loop to either increase or decrease the pressure.