Hidden FIVC

I was about to put a PFT report I’d been reviewing in my outbox when I noticed something odd about the flow-volume loop.

Hidden FIVC_redacted 1

What I saw was that the final inspiration of the FVC maneuver had ended to the left of the initial inspiration. This means a couple of thing, first and foremost that the FIVC was larger than the FVC and that the FVC was likely underestimated because the patient hadn’t really taken a full inspiration prior to exhaling. I had already looked at the raw data for the patient’s spirometry results for other reasons but I pulled them up again to see if I had missed something.

Continue reading