As noninvasive ventilation grows in popularity, new research examines when the therapy works, and when clinicians should be cautious.
As noninvasive ventilation (NIV) has grown in popularity as a treatment for patients with hypoxemia, a new review of the latest scientific literature shows it can be a meaningful strategy for a number of conditions, including acute exacerbation of chronic obstructive pulmonary disease (COPD) and cardiogenic pulmonary edema.
NIV treatment modalities include nasal cannula, simple masks, and continuous positive airway pressure (CPAP), among others. Its popularity can be tied in part to its patient-friendliness, the authors said.
“Compared with invasive ventilation, NIV is more comfortable while preserving the patient’s airway defense mechanism,” they wrote. “Moreover, complications directly related to intubation and mechanical ventilation can be avoided, such as aspiration, trauma to surrounding structures, barotrauma, [and] ventilator-associated pneumonia.”
Popowicz and Leonard began by explaining some of the different categories of NIV devices, after which they outlined clinical uses of these tools.
For instance, NIV can be used in postsurgical extubation to prevent or treat postextubation. The investigators noted that between 20% and 40% of patients who are intubated will require reintubation, and with reintubation comes an increased risk of mortality. High-flow nasal cannula (HFNC), CPAP, and bilevel positive airway pressure (BPAP) can all be used in such scenarios.
The authors said one study found patients who received NIV immediately following extubation had lower rates of respiratory failure compared with a control group given Venturi masks.
In trauma cases, the authors said there is a lack of consensus about the use of NIV, except for general agreement that certain patients—such as those with facial deformities or upper airway obstructions—are inappropriate candidates for NIV.
There is more robust research, however, when it comes to treating COPD with NIV. The authors explained that patients with chronic COPD have compensatory mechanisms, but those mechanisms diminish during acute exacerbations.
“Respirations are compromised as increased respiratory rate leads to low tidal volumes, which increases respiratory acidosis and induces increased energy expenditure and fatigue,” they noted.
NIV can help by providing external positive end-expiratory pressure, offsetting the effects of the exacerbation, the authors said. However, the benefit has only been seen in acidotic patients. It was poorly tolerated in patients who were minimally acidotic, they added.
Popowicz and Leonard said the use of NIV in patients with acute respiratory distress syndrome (ARDS) remains controversial. Some research has shown that early NIV application in patients with mild ARDS might reduce the need for intubation, although the current guidelines of the European Respiratory Society and the American Thoracic Society do not include a recommendation for patients with ARDS, due to insufficient data.
On the other hand, the investigators said NIV has clear benefits in patients with cardiogenic pulmonary edema. Data show NIV can decrease systemic venous return and left ventricular after-load in patients. Guidelines suggest bilevel NIV or CPAP for patients with acute respiratory failure associated with pulmonary edemas, the authors noted.
Finally, the authors addressed the COVID-19 pandemic. They wrote that early research has suggested NIV can play a helpful role for many patients, although they also cautioned that the use of such equipment can also theoretically lead to transmission risk.
Popowicz P and Leonard K. Noninvasive ventilation and oxygenation strategies. Surg Clin North Am. Published online November 18, 2021. doi:10.1016/j.suc.2021.09.012