Description

• Noninvasive ventilation (NIV) is a method of delivering oxygen via a positive pressure mask for patients experiencing dyspnea and respiratory failure
• NIV can benefit virtually any patient experiencing these symptoms and it may obviate the need for endotracheal intubation. In some patient populations, there is a mortality benefit from NIV, especially when given early in the patient's clinical course

• NIV mask configurations: While most EDs use full face mask NIV, other options available include nasal-only masks, cephalic masks that cover the entire front of the face, and NIV helmets. This chapter will focus on full face mask NIV as it is the most common configuration in most U.S. EDs
• NIV basic modes: Continuous positive pressure (CPAP) and bilevel positive pressure (BiPAP)*
  • CPAP provides a fixed pressure support throughout the respiratory cycle
  • BiPAP provides a baseline pressure during expiration and between breaths with an increase in pressure during the inspiratory cycle
  • Regardless of mode, NIV improves work of breathing by physiologic stenting of small airways in the lung. This decreases the degree of atelectasis at the level of the alveoli
  • In patients with acute cardiogenic pulmonary edema (ACPE), the common misbelief is that NIV works by forcing fluid out of the lungs. However, the actual mechanism is NIV increases intra-thoracic pressure which decreases both preload and afterload
  • Note: The term “BiPAP” is a proprietary trademark for a ventilation mode made by a particular device manufacturer. However, it is ubiquitously used to indicate bi-level NIV