Page 87 - Livre électronique des RFTP 2023

P50. GRADING THE SEVERITY OF OBSTRUCTION IN
MIXED VENTILATORY DISEASE

B.BARKOUS, K.KCHAOU, C.BRIKI, S.JAMLI, S.BEN KHAMSA JAMELEDDINE.

SERVICE DE PHYSIOLOGIE ET EXPLORATIONS FONCTIONNELLES RESPIRATOIRES DE L'HOPITAL
ABDERRAHMANE MAMI ARIANA

INTRODUCTION : No consensus exists for grading the severity of an obstructive
ventilator disease (OVD) in presence of additional restriction. While the ATS/ERS
guidelines currently recommend the use of FEV1 predicted to grade the severity
of an OVD, we hypothesize that in the coexisting of restrictive ventilator disease
(RVD), the decrease in FEV1 can overestimate the degree of obstruction.

OBJECTIVE : We aimed to compare the correlation between FEV1 predicted and
adjusted FEV1 with the degree of air trapping to define which parameter is more
appropriate to grade a mixed ventilator disease (MVD).

PATIENTS AND METHODS : It was a retrospective study that included 9546
patients during 2016-2022, conducted in the department of pulmonary function
tests of Abderrahmane Mami hospital Ariana. All patients underwent total body
plethysmography and a MVD was defined when both FEV1/FVC ratio and Total
Lung Capacity (TLC) are under their lower limits of normal. These parameters were
measured: FEV1, FVC, TLC and residual volume (RV). FEV1 was adjusted for the
degree of restriction by dividing FEV1/TLC. The degree of hyperinflation was
indicated with RV/TLC ratio.

RESULTS : Of the total sample, 47 patients had MVD. Of these patients, 83% were
males. The mean age (years) was 49.55 ±20.49, mean FEV1 (%) was 40.14±15.03,
mean TLC (%) was 63.90 ± 14.20 and mean RV (%) was 90.17 ± 36.50. Patients had a
variety of lung diseases with predominance of COPD (32.6%), interstitial lung
disease (30.4%), lung cancer (15.9%) and both sarcoidosis and tuberculosis (15.2%).
The correlation between FEV1 and RV/TLC ratio was greater when using the
adjusted than the unadjusted FEV1 (r= -0.624 vs r= -0.406, p<0.01), suggesting that
the adjusted FEV1 reflected more the degree of obstruction.

CONCLUSION : Grading the severity of obstruction in MVD based on FEV1
adjusted seems to be more appropriate. Further evidence based on clinical
features using this grading method is needed.

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