Tuesday, April 11, 2006

Pulmonary function

How would you define these pfts? The ratio is 72 (96% predicted). FEV1 63% pred and FVC 65%.
The TLC is 84% predicted and the DLCO is 44%.

7 comments - CLICK HERE to read & add your own!:

Ali said...

Just glancing at these results, you think of a restrictive pattern. The TLC value, however, is a bit high to fit into that diagnosis. If the value was just 5% less, the results might be more interpretable ( to favor restriction). I would go back and look at the raw data of the pft to verify that the results are valid. With body plethysmography, it is very difficult to obtain valid results. Furthermore, the tech doing the testing has complete discretion in deriving the FRC numbers. As you know, this directly impacts the TLC value. Thus, if the FRC is overestimated, the TLC will be falsely high. (And if the pt doesn't exhale to RV during the FVC maneuver, the ERV will be falsely low, thereby making the RV and TLC falsely high.) The point I'm trying to emphasize is that if results don't seem to fit together, you should look at the raw data to ensure that it's valid--particularily with body box maneuvers. Nitrogen washout is another story. It seems like an easy test, but it is difficult for patients to prevent room air from leaking in. Also, if there is air trapping, N2 washout may not be valid (I know this issue is debatable).

Ali said...

By the way, what did the FV Loop look like?

Baleeiro said...

Great comments by Ali. We don't know much about age, body habitus, quality of test, etc. at this point. With a low FEV1 and FVC with a normal TLC and with FEV1 proportionally lower than the FVC I would be inclined to call it a moderate obstructive defect with gas exchange abnormality. Was the RV up? Did the patient exhale for at least 6 seconds on the spiro?

Anonymous said...

FEV1 63% pred and FVC 65% - that's proportionally lower?

Anonymous said...

Yes, 63 is lower than 65.

Anonymous said...

I guess it depends on how you define proportionally then. Or rather state dis-proportionately - in comparison to the FVC that is. In this example, they are both about equally reduced from norm. Therefore, could be the early signs of a restrictive/infiltrative disorder. Could be mixed also. In obstructive diseases, FEV1 is reduced disproportionately to the FVC, and is an indicator of flow limitation. In restrictive disorders, the FEV1, FVC, and total lung volume are all reduced, and in this setting FEV1 is a measure of volume rather than flow.

Anonymous said...

2 years later 4 years later
FVC 3.48 (103%) 3.37 (101%) 3.22 (99%)
FEV1 2.98 (104%) 2.88 102%) 2.75 (100%)
FEV1/FVC % 0.86 (101%) 0.85 (102%) 0.85 (101%)
FEF 25-75% 3.48 (104%) 3.36 (102%) 3.22 (104%)
FEF 50% 4.00 (92%) 3.65 (85%) 3.55 (95%)
FEF75% 1.73 (98%) 1.67 (97%) 1.41 (87%)
FEF Max 6.3 (106%) 6.04 (102%) 5.42 (89%)
FIF Max 6.25 5.83 6.33
Expiratory Time 6.12 5.71 7.02
MVV 103 (98%) 107 (106%)
MIP -120 (120%) -120 (141%) -215 (253%)
MEP 89 (61%) 96 (64%) 116 (77%)
SVC 3.52 (104%) 3.38 (101%) 3.27 (101%)
IC 2.74 (122%) 2.92 (130%) 2.77 (134%)
ERV 0.78 (69%) 0.46 (42%) 0.5 (41%)
TGV 1.53 (55%) 2.15 (78%) 2.41 (63%)
RV 0.75 (50%) 1.69 (110%) 1.91 (124%)
TLC 4.27 (85%) 5.07 (101%) 5.18 (106%)
DLCOunc 15.74 (66%) 18.16 (76%) 15.41 (50%)
DL/VA 3.81 (80%) 4.20 (88%) 3.69 (58%)
VA 4.13 (82%) 4.32 (86%) 4.04 (82%)
Raw 1.43 (77%) 2.23 (120%) 1.78 (96%)
Gaw 0.7 (68%) 0.45 (44%) 0.56 (54%)
sGaw 0.39 (192%) 0.22 (108%) 0.23 (90%)
sRaw 2.54 (<4.76) 4.52 (<4.76) 4.3 (<4.76)