What is Noninvasive Ventilation?

How CPAP and BiPAP can treat COPD

CPAP machine, a form of noninvasive ventilation
What is noninvasive ventilation and when may it be used with COPD?. :nicolesy/E+/Getty Images

What is Noninvasive Ventilation?

Noninvasive ventilation is an alternative to invasive, mechanical ventilation for patients who have chronic respiratory insufficiency or respiratory failure and can no longer breathe adequately on their own.

Also known as Noninvasive Positive Pressure Ventilation (NIPPV), noninvasive ventilation assists a person in taking a full breath and helps to maintain an adequate oxygen supply to the body.

NIPPV provides ventilatory support to a patient through the upper airways. It enhances the breathing process by giving the patient a mixture of air and oxygen from a flow generator through a tightly fitted facial or nasal mask. Since the lungs are, in a way, held open by the positive pressure, it is easier to get oxygen down into the tiny alveoli where the exchange of oxygen and carbon dioxide take place.

How is Noninvasive Ventilation Used in COPD?

Patients with chronic obstructive pulmonary disease, or COPD, are sometimes prescribed noninvasive ventilation, such as CPAP (continuous positive airway pressure) or BiPAP (bilevel positive airway pressure), during exacerbations to help them breathe.

Typically associated with sleep apnea treatment, both CPAP and BiPAP deliver pressurized oxygen through an aim mask to the patient’s airways. The pressure prevents the throat muscles from collapsing and restricting airflow.

CPAP machines are set to a single level of pressure that remains constant throughout the night, whereas BiPAP has two pressure levels, one for inhaling and one for exhaling.

How Effective is Noninvasive Ventilation in COPD?

A 2014 research paper published in the Lancet found NIPPV improved survival rates in people with COPD.

The yearlong randomized multicenter, multinational study found patients with COPD who received noninvasive ventilation had a 36 percent lower risk of mortality.

Other studies show NIPPV used during acute COPD exacerbations reduce the need for endotracheal intubation, are associated with a lower rate of treatment failure and shorter hospital stays.

In addition, a 2016 study found that long term NIPPV may result improvements in arterial blood gasses (ABGs),  lung function, and health-related quality of life. In general, these improvements were much better with high intensity noninvasive ventilation (using the highest possible inspiratory pressure) than with low intensity NIPPV.

When is Noninvasive Ventilation Recommended?

In patients with COPD who are experiencing hypercapnic respiratory failure due to an acute COPD exacerbation, noninvasive positive pressure ventilation can be used in place of endotracheal intubation in select patients.

Your doctor may recommend NIPPV for you if you have moderate to severe dyspnea,(the sensation of shortness of breath), tachypnea (a rapid respiratory rate) and hypercarbia (an elevated carbon dioxide level in the blood), with a pH between 7.25 and 7.35.

People should not be treated with NIPPV instead of mechanical ventilation if they are medically unstable because of hypotension (low blood pressure), sepsis (a severe generalized infection that can lead to shock), hypoxia (a deficiency in oxygen in the tissues of your body) or other life-threatening systemic illness, have a worsening mental status, or are coping with excessive secretions which put them at a higher risk of aspiration.

Unlike invasive ventilation, which requires monitoring in the intensive care unit (ICU), noninvasive ventilation can frequently be performed in the general hospital ward, provide the staff is appropriately trained in its use.

CPAP vs BiPAP

Both CPAP and BiPAP deliver pressurized oxygen through a mask, though CPAP is set at a single constant measure whereas BiPAP has two settings, one for inspiration and one for expiration.

BiPAP is used more often for people with COPD since it is easier to exhale against a lower pressure. BiPAP also allows for adjustments in time.

Bottom Line on Noninvasive Ventilation

Noninvasive ventilation is not appropriate for every person and is not always successful. Only your doctor can determine if you are a candidate for noninvasive ventilation.

That said, studies showing both the reduced need for endotracheal intubation and improved survival rates for people with COPD who are candidates for NIPPV is very encouraging. In addition, when looking at long term use of noninvasive ventilation with COPD, changes such as an improvement in blood gasses and lung function, as well as a better quality of life have recently been noted, particularly with high flow NIPPV.

Sources:

Altintas, N. Update: Non-Invasive Positive Pressure Ventilation in Chronic Respiratory Failure Due to COPD. COPD. 2016. 13(1):1110-21.

Kasper, Dennis, Anthony Fauci, Stephen Hauser, Dan Longo, and J. Jameson. Harrison's Principles of Internal Medicine. New York: McGraw-Hill Education, 2015. Print.

Kohnlein, T., Windisch, W., Kohler, D. et al. Non-Invasive Positive Pressure Ventilation for the Treatment of Severe Stable Chronic Obstructive Pulmonary Disease: A Prospective, Multicentre, Randomised, Controlled Clinical Trial. The Lancet. Respiratory Medicine. 2014. 2(9):698-705.

Windisch, W., Storre, J., and T. Kohnlein. Nocturnal Non-Invasive Positive Pressure Ventilation for COPD. Expert Reviews of Respiratory Medicine. 2015. 9(3):295-308.

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