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Assessment of bronchial obstruction and its reversibility by shape indexes of the flow-volume loop in asthmatic children
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  • Amaury Berrier,
  • Angelica Tiotiu,
  • Claude Bonabel,
  • Phi linh Nguyen Thi,
  • David Richard,
  • Silvia Demoulin-Alexikova,
  • Cyril Schweitzer,
  • Iulia Ioan
Amaury Berrier
CHRU de Nancy
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Angelica Tiotiu
CHRU de Nancy
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Claude Bonabel
CHRU Nancy
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Phi linh Nguyen Thi
CHRU Nancy
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David Richard
CHRU Nancy
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Silvia Demoulin-Alexikova
CHRU Nancy
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Cyril Schweitzer
Centre Hospitalier Régional Universitaire de Nancy
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Iulia Ioan
CHRU Nancy
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Abstract

Asthma assessment by spirometry is challenging in children as forced expiratory volume in one second (FEV1) is frequently normal at baseline. Bronchodilator (BD) reversibility testing may reinforce asthma diagnosis but FEV1 sensitivity in children is controversial. Ventilation inhomogeneity, an early sign of airway obstruction, is described by the upward concavity of the descending limb of the forced expiratory flow-volume loop (FVL)s, not detected by FEV1. The aim was to test the diagnosis ability of FVL shape indexes as β-angle and forced expiratory flow at 50% of the forced vital capacity (FEF50)/peak expiratory flow (PEF) ratio, to identify asthmatics from healthy children in comparison to “usual” spirometric parameters. Seventy-two asthmatic children and twenty-nine controls aged 8 to 11 years were prospectively included. Children performed forced spirometry at baseline and after BD inhalation. Parameters were expressed at baseline as z-scores and BD reversibility as percentage of change reported to baseline value (Δ%). Receiver operating characteristic curves were generated and sensitivity and specificity at respective thresholds reported. Asthmatics presented significantly smaller zβ-angle, zFEF50/PEF and zFEV1 (p≤0.04) and higher BD reversibility, significant for Δ%FEF50/PEF (p=0.02) with no difference for Δ%FEV1. zβ-angle and zFEF50/PEF exhibited better sensitivity (0.58, respectively 0.60) than zFEV1 (0.50), and similar specificity (0.72). Δ%β-angle showed higher sensitivity compared to Δ%FEV1 (0.72 vs 0.42), but low specificity (0.52 vs 0.86). Quantitative and qualitative assessment of FVL by adding shape indexes to spirometry interpretation may improve the ability to detect an airway obstruction, FEV1 reflecting more proximal while shape indexes peripheral bronchial obstruction.

Peer review status:IN REVISION

24 Aug 2020Submitted to Pediatric Pulmonology
25 Aug 2020Assigned to Editor
25 Aug 2020Submission Checks Completed
29 Aug 2020Reviewer(s) Assigned
19 Sep 2020Review(s) Completed, Editorial Evaluation Pending
20 Sep 2020Editorial Decision: Revise Major