What are Hyperinflated Lungs and What Causes It?

Hyperinflation of the lungs occurs when damage to the lung tissue results in lungs that become less elastic.^[1] When the lungs lose their elasticity, the expulsion of air becomes difficult and it gets trapped inside the lungs.  Hyperinflation can also occur when patients begin to inhale before they’ve fully exhaled. Consequently, air gets trapped within the lungs with each successive breath causing them to overinflate.²

Patients with chronic obstructive pulmonary disease (COPD) often have some degree of hyperinflation of the lungs which can produce significant, detrimental effects on breathing.^[2] In COPD, the lungs can be hyperinflated at rest (static hyperinflation) and/or during exercise (dynamic hyperinflation) when breathing requirements are increased and exhalation time is shortened.

Consequences of Lung Hyperinflation

Hyperinflation of the lungs contributes to the following consequences in COPD:

• Shortness of breath
• Exercise intolerance
• Impaired muscle function
• Heart dysfunction
• Reduced physical activity levels

Diagnosis of Lung Hyperinflation

A chest X-ray is the most common tool used to diagnose hyperinflation of the lungs. In some cases, however, the lungs may appear hyperinflated on a chest X-ray for reasons that have nothing to do with lung function. If your chest X-ray shows hyperinflation and the reasons for this aren’t clear, your primary health care provider may order additional testing.^[3]

Treatments that Reduce Lung Hyperinflation

Patients with COPD are unable to fully exhale all their air which contributes to lung hyperinflation. Treatment approaches that allow faster exhalation or prolong the time available for exhalation will allow for fuller exhalation which will decrease lung hyperinflation and improve exercise tolerance.

The following therapies have been used to treat lung hyperinflation in COPD:

• Pursed lip breathing – pursed lip breathing reduces lung hyperinflation and improves exercise tolerance, breathing patterns and oxygen saturation levels in COPD patients during high intensity exercise.^[4]
• Exercise training – exercise training has been shown to reduce lung hyperinflation and improve exercise tolerance in COPD.
• Oxygen therapy – a number of studies have shown that study participants who received oxygen, when compared to study participants on room air, showed consistent reductions in lung hyperinflation during exercise.
• Bronchodilators – long-acting bronchodilators have been shown to reduce lung hyperinflation both at rest and during exercise in patients with moderate to severe COPD.^[5]
• Lung Volume Reduction Surgery (LVRS) – LVRS is a very dramatic method of reducing lung hyperinflation. It is an operation that removes the worst affected areas of your lungs so the healthier parts can work better. The operation can help relieve breathlessness, increase the ability to exercise and improve quality of life. LVRS is not for everyone. Patients only qualify for LVRS by meeting very strict criteria.

_{[1] M. Eichinger et. al. “Lung hyperinflation: foe or friend”? European Respiratory Journal Oct 2008, 32 (4) 1113-1116; DOI: 10.1183/09031936.00118807.}

_{[2] Gary T. Ferguson “Why Does the Lung Hyperinflate?” Proceedings of the American Thoracic Society, Vol. 3, No. 2 (2006), pp. 176-179.}

_{[3] Mayo Clinic. “A recent chest X-ray showed that I have hyperinflated lungs. What could cause this”? November 14, 2014.}

_{[4] Cabral, L.F., et. al. “Pursed lip breathing improves exercise tolerance in COPD: a randomized crossover study”. Eur J Phys Rehabil Med. 2015 Feb;51(1):79-88. Epub 2014 Apr 2.}

_{[5] O’Donnell, DE. “Hyperinflation, dyspnea, and exercise intolerance in chronic obstructive pulmonary disease”. Proc Am Thorac Soc. 2006 Apr;3(2):180-4.}

By Deborah Leader RN, BSN, PHN