Treating pneumonia with noninvasive ventilation (NIV)

In the prior chapter we talked about two very common causes of respiratory failure—pulmonary edema and acute exacerbations of chronic obstructive pulmonary disease (AECOPD). But what about the most common cause of respiratory failure treated in the hospital setting—pneumonia? Can we use noninvasive ventilation (NIV) in patients with pneumonia?

You probably think that NIV must be able to replicate many of the findings of other respiratory diseases. You’d think it could reduce intubations and improve length of stay by decreasing the need for invasive ventilation.

You’d be right about one thing: there has been great interest in using NIV for patients with pneumonia to avoid many of the complications of invasive mechanical ventilation. Unfortunately, the evidence for using NIV in patients with pneumonia has produced some mixed results that has left many questions unanswered.

Failure rates as high as 50% have been demonstrated when trying to use NIV to treat pneumonias of varying severity. And when you come across studies that demonstrate lower rates of intubation with NIV in pneumonia, you’ll find these studies primarily included patients who had less severe pneumonia and had good response to initial medical therapy.

Trying to identify which patients are at higher risk of failure may lead to better success rates—by avoiding NIV in those patients at risk of failure and utilizing NIV in patients with characteristics that may be amenable to treatment.

There are three key factors that could predict failure:

1. Size of pneumonia (measured in number of quadrants involved on the x-ray)
2. Severity of patient illness (measured in one study using an APACHE score)
3. Presence of shock requiring treatment with vasopressors (e.g., norepinephrine)

Just know that failure rates are higher in pneumonia than in other disease states (such as chronic obstructive pulmonary disease [COPD] and acute cardiogenic pulmonary edema [ACPE]) and these patients should be monitored closely.

Patients without properly functioning immune systems, such as those with the human immunodeficiency virus (HIV), those on chemotherapy, or those taking immunosuppressive medications, have high rates of complications when invasive mechanical ventilation has been used to treat pneumonia. The use of NIV in these patients—to potentially avoid these complications—has been the focus of much research.

Early investigations into the use of NIV for patients with immunosuppression showed improved measures of oxygenation, decreased rates of intubation, and improved mortality figures. More contemporary studies failed to demonstrate this benefit, but they did not demonstrate any increase in complications.

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