Respiratory Support Devices

Mechanisms of Action and Clinical Indications

BiPAP delivers two different pressure levels: higher inspiratory positive airway pressure (IPAP) and lower expiratory positive airway pressure (EPAP), providing pressure support to augment tidal volume, and can be delivered in different modes, including spontaneous, spontaneous-timed, and timed, according to the American Academy of Sleep Medicine 1, 2
BiPAP is preferred for hypercapnic respiratory failure, such as COPD exacerbations, and is useful in neuromuscular diseases or ICU-associated muscle weakness, as stated by the American College of Chest Physicians 3, 6
HFNC delivers high flow rates of heated and humidified oxygen-air mixture, creating a washout effect in the upper airways, reducing anatomical dead space, and provides modest positive end-expiratory pressure (PEEP) effect, as recommended by the European Respiratory Society 3, 4, 5
HFNC is recommended for acute hypoxemic respiratory failure and is suggested over NIV, including BiPAP, in patients with acute hypoxemic respiratory failure, according to the European Respiratory Society 4, 7

BiPAP typically achieves higher PaO2/FiO2 ratios compared to HFNC, but HFNC results in better patient comfort and tolerance, as reported by the European Respiratory Society 3, 5
HFNC may reduce intubation compared to NIV, including BiPAP, with a risk ratio of 0.84, as stated by the European Respiratory Society 5

For hypoxemic respiratory failure, start with HFNC if available, and monitor response within 1-2 hours, as recommended by the European Respiratory Society 4, 5, 7, 8
For hypercapnic respiratory failure, BiPAP is the preferred initial therapy, and consider BiPAP in ST mode if there's concern for respiratory muscle fatigue, according to the American Academy of Sleep Medicine and the European Respiratory Society 1, 3, 8