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Pulmonary Fibrosis

Low Numbers on My Mom`s PFT



My mother is 67 and was diagnosed with IPF in March 2009. She is currently on 5 Liters while laying or sitting and 6 liters while up walking. She had a PFT this week and her lung function was 25%. How long can she survive on such a small percentage. Her leg and back hurt her from a fracture in her lower back she is in so much pain, she is taking pain meds but she sleeps all day. No one has told us what stage or how long. Please help


There are many different numbers that can be generated from pulmonary function tests. For patients with IPF, the most relevant are the forced vital capacity (FVC), total lung capacity (TLC), and diffusing capacity (DLCO). For each of these, a specific percent of predicted value can mean different things. In general, when the diffusing capacity is less than 35%, when the forced vital capacity is less than 50%, or when supplemental oxygen is required, then IPF is entering an advanced stage.

In IPF, there is not a clear-cut staging system that is used like there is with cancer or COPD. Many patients do not seem to get a little bit worse each week but may have periods when the lung disease stays relatively stable for several months then precipitously declines. It is not possible to predict how many weeks, months or years a particular person has to live with IPF, but as a general rule, most patients live an average of 3-5 years from the time of initial presentation to the doctor.

When patients require 6 liters of oxygen just to make the effort to sit up, then they have very advanced IPF, unless there are other reasons for the low oxygen level.

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Response by:

James N Allen, Jr, MD James N Allen, Jr, MD
Clinical Professor of Pulmonary, Allergy, Critical Care & Sleep Medicine
College of Medicine
The Ohio State University