Non-Invasive Ventilation with CPAP and BiPAP

Basic Differences

BiPAP provides two pressure levels, making it more effective for patients with hypercapnic respiratory failure and those who cannot tolerate high CPAP pressures, according to the American Thoracic Society 1, 2
CPAP delivers a single constant pressure throughout the respiratory cycle, primarily used to correct hypoxemia by recruiting underventilated lung areas and improving oxygenation, as recommended by the American College of Chest Physicians 1
BiPAP provides two distinct pressure levels: IPAP (higher pressure during inspiration) and EPAP (lower pressure during expiration), as described by the European Respiratory Society 1, 2

CPAP maintains a constant positive pressure throughout the breathing cycle, recruits collapsed alveoli, unloads inspiratory muscles, and offsets intrinsic PEEP in COPD patients, as stated by the American Thoracic Society 1
BiPAP combines pressure support with CPAP principles, provides ventilatory assistance during inspiration, recruits underventilated lung, and offsets intrinsic PEEP, according to the European Respiratory Society 2

CPAP is preferred for cardiogenic pulmonary edema patients who remain hypoxic despite maximal medical treatment, chest wall trauma patients who remain hypoxic despite adequate regional anesthesia and high flow oxygen, and diffuse pneumonia with hypoxemia, as recommended by the American College of Chest Physicians 3
BiPAP is preferred for acute exacerbations of COPD with respiratory acidosis, patients who develop hypercapnia during CPAP treatment for pneumonia, and weaning patients from invasive ventilation when conventional strategies fail, according to the American Thoracic Society 3

BiPAP ventilators are simpler to use, cheaper, and more flexible than other ventilator types, and have been used in the majority of randomized controlled trials of NIV, as stated by the European Respiratory Society 3
Both CPAP and BiPAP are contraindicated in patients after recent facial or upper airway surgery, with facial abnormalities, fixed upper airway obstruction, or who are vomiting, as recommended by the American College of Chest Physicians 3

Rebreathing can occur with BiPAP if exhaust ports become occluded, and normal EPAP levels may not completely eliminate rebreathing during BiPAP, especially with increased respiratory frequency, as described by the European Respiratory Society 2