What’s the difference between BiPAP vs. CPAP?
CPAP stands for continuous positive airway pressure. In other words, there is a continuous pressure regardless whether the patient is breathing in or out. CPAP only has one pressure setting.
BiPAP has two pressure settings: inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP). While the patient is not breathing in, there is a continuous pressure (EPAP) and when the patient breath in there is a higher pressure (IPAP).
PEEP stands for positive end expiratory pressure. CPAP = PEEP = EPAP
Some machines have IPAP and EPAP as the input. Other machines have PEEP and PS (pressure support) as the input. IPAP = PEEP + PS and EPAP = PEEP.
What BiPAP settings do you use for each type of respiratory failure?
Failure of oxygenation means there is a problem with taking up oxygen (ie. pulmonary edema, atelectasis). If the patient has a problem with oxygenation, PEEP/CPAP/EPAP is the key. PEEP helps maintain a continue pressure to help recruit alveoli and increase matching between ventilation and perfusion.
- BiPAP setting: PS low (5 or less); PEEP high (start with 5 and you can titrate up to 10 or more)
Failure of ventilation means there is a problem getting rid of CO2 (ie. asthma, COPD). If the patient has a problem with ventilation, IPAP is the key. A COPD or asthma patient will have auto peep due to difficulty getting air out. However, when the patient fatigues, there is even a problem getting air in, which worsens the respiratory acidosis. IPAP supports the respiratory effort when the patient is breathing in.
- BiPAP setting: PS high (start with 5 and you can titrate up to 10 or more); PEEP low (3-5 to keep the mask open)
You can start with 10/5 (IPAP/EPAP) and titrate up or down PS or PEEP depending on the type of respiratory failure.