FEV1/FVC? FEV1/FEV6?

Prof Dr Nurhayat YILDIRIM İÜ Cerrahpaşa Medical Faculty Departement of Pulmonary Disease

• Tiffenau and Pinelli published first results recording forced expiration manoeuvres in 1947.

• Tiffenau defined the ratio between the FEV1 and VC in 1949.

Yernault JC. ERJ 1997 ;10:2704-2710.

• Forced expiration manoeuvres time depandes on patient’s ability to cooperate.

• It is a fact that the performance of the technician effects the spirometry.

• Slow and not forced VC measurement is always greater than forced VC measurement.

• IVC > EVC > FVC• IVC manoeuvre requires extra

measurement.• (E)VC > FVC

• Gas volume exhaled (FVC) during the forced expiration time, is closest to that exhaled during slow expiration (VC).

• FEV1/FVC < FEV1/VC

FEV1/FVC is the

GOLD STANDARTat defining

an obstruction.

End of test criteria

• The volume-time curve shows no change in volume (<0.025 L) for ≥1 s, and the subject hastried to exhale for ≥ 3 s in children aged < 10 yrs and for ≥ 6 s in subjects aged > 10 yrs.

• The subject cannot or should not continue futher exhalation.

Miller MR. ERJ 2005;26:319-338.

• The difrences between the FVC and FEV1 values of two tests had to be less than 200 mL.

ATS. AJRCCM 1995;152:1107-1136

• •

FVC? FEV6?

• Glindmeyer has found that 6.64 s was sufficient to obtain 99% of FVC for spirograms with FEV1/FVC as low as 50%.

Glinmeyer HW. ARRD 1987;136:449-452.

COPD

COPD

Second(s)

• •

• In severely obstructed patients, the total exhalation may last up to 20 s.

• Using FEV1/FEV6 ratio as an alternative to FEV1/FVC may reduce the sensitivity of detection of obstructive lung disease in the diagnosis of airway obstruction

Swanney MP. AJRCCM 2000;162:917-919.

• In severely obstructed patients, the total exhalation may last for up to 20 s.

• Using FEV1/FEV6 ratio as an alternative to FEV1/FVC may reduce the sensitivity of detection of obstructive lung disease in the diagnosis of airway obstruction.

Swanney MP. AJRCCM 2000;162:917-919.

• Flow after 6 seconds of forced expiration, coming from more diseaed lung ünits with the longest time constants, was most meaningful and should not be ignored.

Hansen JE. ERJ 2006

FVC > FEV6

FEV1/FVC < FEV1/FEV6

FEV1/FVC? FEV1/FEV6?

Prof Dr Nurhayat YILDIRIM İÜ Cerrahpaşa Medical Faculty Departement of Pulmonary Disease

• •

• The difrences between the FVC and FEV1 values of two tests had to be less than 200 mL.

ATS. AJRCCM 1995;152:1107-1136

Hansen JE. ERJ 2006

DemirT. Respir Med 2005;99:103-106.

FEV1/FVC < %70 KOAH is the criteria in obstruction

diagnosis.Studies that recommend FEV6

value instead of FVC, find useful the FEV1/FEV6 <

%73 ratio as the obstruction criteria.

The new cutoff value for FEV1/FEV6

• When the cutoff value is 73% the sensitivity is 94.4% and the specificity 93.3%

• When the cutoff değeri 76% the sensitivity is %76 and the specificity 100%.

Vandevoorde J. Chest 2005;127:1560-1564.

FEV1/FVC vs FEV1/FEV6

Author Sens Spes PPD NPD Case• Swanney 95 97.4 98.6 91.1 337• Vandevoo 94 93.1 89.8 96 11676• Akpınar- El 92 98 92 98 1139 13152• Hansen 76.7 98.2 90.3 95.2 66.2 99.4 91.2 96.5 22571• Demir 86 100 100 92.2 5114• Ulubay 78.3 100 100 89.9 1509• Başyiğit 82.1 99.4 98.9 90.4 570• Fidan 70.1 100 4672 34 416 11865

VC > FVC > FEV6

FEV1/VC < FEV1/FVC < FEV1/FEV6

FEV1/VC < FEV1/FVC < LLN

Hansen JE. ERJ 2006;

Hansen JE. ERJ 2006;

Akpınar-Elçi M. ERJ 2006;27:374-377.

Akpınar-Elçi M. ERJ 2006;27:374-377.

Demir T. Respir Med 2005;99:103-106.

Demir T. Respir Med 2005;99:103-106.

Demir T. Respir Med 2005;99:103-106.

Demir T. Respir Med 2005;99:103-106.

Demir T. Respir Med 2005;99:103-106.

• By replacing FVC with FEV6 and using the proper referance equations, the sensitivity of the FEV6 method was 0.94, which means that 6% of the subjects would be classified as healthy, eventhough they were ill.

Akpınar-Elçi M. ERJ 2006;27:374-377. Pedersen OF. ERJ 2006;27:345-347.