Question
What is the difference between BiPAP and CPAP?
Answer
- CPAP
- Continuous positive airway pressure consisting of some level of PEEP and a FI02
- The choice for Hypoxemic or “Fluid Events” as in Congestive Heart Failure/ Similar presentation in patients who have missed hemodialysis
- BiPAP
- Bi (two) positive airway pressures, EPAP (PEEP) end positive airway pressure and IPAP inspiratory positive airway pressure
- The Delta pressure between IPAP and EPAP is the level of pressure support that augments tidal volume/minute ventilation
- The choice for hypercapnia, when Tidal Volume is LOW, RR High and needs to be augmented as in COPD exacerbations
When we are using non-invasive ventilation, there are two modes that are used primarily, BiPAP and CPAP.
CPAP is continuous positive airway pressure. We are setting some level of PEEP, or the positive end expiratory pressure. This is the term that we primarily use in a mechanical ventilator for invasive ventilation. This is continuous positive airway pressure over time with some level of positive end expiratory pressure and a FiO2, a fraction of inspired oxygen. CPAP would be the choice for hypoxemic respiratory failure or fluid events as you would see in congestive heart failure, flash pulmonary edema, or someone who has missed hemodialysis. These patients can be extremely fluid-overloaded, and this is a great adjunct to treat shortness of breath in these patients that are suffering from that.
BiPAP is two positive airway pressures. You have expiratory positive airway pressure (EPAP) and inspiratory positive airway pressure (IPAP). I am going to show you this represented in a graph later on. The delta pressure between the inspiratory and expiratory pressures is the level of pressure support that is augmenting your tidal volume or minute ventilation. This would be the choice for a hypercapnic patient.
This Ask the Expert is an edited excerpt from the course, Acute Non-Invasive Ventilation, presented by Rena Laliberte, BS, RRT, CPFT.
