Shortness of breath: Flow Volume Loop

In this video from Medcram, Dr. Seheult discusses a shortness of breath case. This case involves a 30-year-old woman who had been in a motor vehicle accident and had been hospitalized and intubated one month prior to coming to see a pulmonologist.  After she was discharged from the hospital she noted that she was having progressive shortness of breath. Her primary care provider had initially prescribed her albuterol, but she did not improve with this so she was referred to a pulmonologist. The pulmonologist ordered pulmonary function testing which includes a flow volume loop.

What is a flow volume loop?

So what exactly is a flow volume loop? In the picture that is illustrated on the video, a flow volume loop is characterized by flow on the Y-axis and volume on the X-axis. In the initial volume loop testing, a patient is asked to inhale as much air as they can. Once they can no longer inhale any additional air, they are asked to blow out the air as quickly as they can.

The patient in this case underwent a flow volume loop and the result was completely abnormal compared to a normal flow volume loop. She was noted to have reduction in the flow of air with inhalation and exhalation. She was diagnosed with a fixed airway obstruction. There are very few causes of this, but given her history it was related most likely to her previous history of intubation with a resulting subglottic stenosis.

What was found on bronchoscopy?

The patient on bronchoscopy essentially had a tiny opening past her vocal cords in an area that should be wide open. She was breathing literally through a tiny 3-4 mm hole opening. This most likely happened because when she was intubated, the tip of the endotracheal tube caused an irritation where it was located which caused increased granulation tissue which resulted in narrowing of that airway.  She was taken to the operating room and this was able to be corrected.

For further information on pulmonary function testing, Medcram has a new course that is available called Pulmonary Function Test Explained Clearly.



Pulmonary Function Test (PFT) Explained Clearly (MedCram) |…

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