Noninvasive Ventilation Clinical Guide

There are two main methods of noninvasive ventilation (NIV)—continuous positive airway pressure (CPAP) and bilevel positive airway pressure (we'll call it BPAP, but sometimes it's also called BiPAP). Both systems use the same equipment, and both deliver oxygen at a positive pressure. However, as the name suggests, CPAP provides one continuous positive pressure, which is the same when the patient breathes in as when the patient breathes out. In contrast, BPAP provides a higher pressure when the patient breathes in and a lower pressure when the patient breathes out. In both cases, the rate of respiration (the number of times the patient breathes in and out in a minute) is determined by the patient, not by the machine. In contrast, when mechanical ventilation with an endotracheal tube and ventilator is used, the patient’s breathing rate is generally determined by the machine.

In a normal, healthy patient, breathing usually occurs under negative pressure. However, the positive air pressure delivered with noninvasive ventilation (NIV) results in some physiological changes in both the respiratory system and circulatory system, which makes it a useful therapy for treating some specific diseases and conditions. As you probably know, NIV results in improved oxygenation and ventilation for the patient. But did you also know that NIV enhances pulmonary physiology, and reduces both afterload and preload? 

Noninvasive ventilation (NIV) is traditionally used to treat pulmonary edema (fluid in the lungs), acute exacerbations of chronic obstructive pulmonary disease (AECOPD), and obstructive sleep apnea (which is often treated at home with bedside devices).

In addition to the more traditional applications of noninvasive ventilation, or NIV, (e.g., obstructive sleep apnea [OSA], pulmonary edema, and chronic obstructive pulmonary disease [COPD]), NIV may also be useful in treating some patients with pneumonia, asthma, acute respiratory distress syndrome (ARDS), and even altered mental status.

Short term use of noninvasive ventilation (NIV) may also be useful to increase oxygen levels before inserting an endotracheal tube (a process known as preoxygenation), to help prevent a patient who has recently had an endotracheal tube removed from needing to be reintubated, and to help relieve breathing difficulties in patients who are receiving palliative (end-of-life) care.

Even though noninvasive ventilation (NIV) is, as its name suggests, not as invasive as other forms of respiratory support (e.g., mechanical ventilation), not all patients adjust well to its use. But, there are some tips and tricks you can use—about mask selection, initiation, and titration—to get even the most NIV-averse patient to comply, so they can reap the benefits.

High-flow nasal cannula (HFNC, or nasal high flow [NHF]) is not technically a form of noninvasive ventilation (NIV), but it does share some similarities to NIV and can be used as an alternative therapy in some situations. This procedure provides a high flow of oxygen through a specialized nasal cannula without the use of positive air pressure.

What's the status of using noninvasive ventilation (NIV) for patients with COVID-19? In this article we summarize the main concerns for both staff and patients, highlight a special case where NIV may be beneficial, and outline a 5-step procedure for safely using NIV should you need it!