Lung inhomogeneities, inflation and [18F]FDG uptake rate in ards

  • M Cressoni
  • D Chiumello
  • M Brioni
  • I Algieri
  • M Gotti
  • K Nikolla
  • D Massari
  • A Cammaroto
  • A Colombo
  • P Cadringher
  • E Carlesso
  • L Gattinoni
Open Access
Poster presentation
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Keywords

Lung Volume Normal Lung Lung Parenchyma Stress Raiser Actual Classification 

Introduction

In ARDS lung parenchyma presents great variability in inflation, lung inhomogeneities and [18F]FDG uptake. In fact, inflation progressively decreases along the sternum-vertebral axis[1] leading to further inhomogeneities that may act as “stress raiser”.[2] That can activate a local inflammatory response leading to edema.

Objectives

We aimed to examine the voxel by voxel relationship between [18F]FDG uptake and inhomogeneity according to the actual classification of ARDS.

Methods

20 ARDS patients underwent a PET-CT scan at 10 cmH2O. [18F]FDG uptake was determined with the graphical Patlak approach[3] voxel by voxel. Lung inhomogeneities were determined by measuring the gas/tissue ratio in two contiguous lung regions. We defined inhomogeneities the fraction of lung volume whose inhomogeneities were greater than 1.61.[4]

Results

5 patients presented mild, 12 moderate and 3 severe ARDS. In mild and moderate ARDS a consistent lung fraction is homogeneous with a high [18F]FDG metabolic activity (53 ± 14% and 53 ± 20%). Inhomogeneous lung fraction with a higher [18F]FDG uptake increases from mild to severe (12 ± 3%, 16 ± 9% and 27 ± 11%). On the other hand, the homogeneous parenchyma with normal [18F]FDG uptake decreases in worse ARDS (33 ± 14%, 26 ± 20% and 5 ± 9%).

Conclusions

Our findings indicate that the actual classification of ARDS from mild to severe reflects the underlying pathophysiology. In fact, while a similar sized homogeneous and inflamed/metabolically more active compartment is present in all the ARDS patients, in mild ARDS it is associated with a consistent fraction of normal lung while in severe ARDS is primarily associated with inhomogeneous, inflamed/metabolically more active lung tissue.

References

  1. 1.
    Gattinoni L: Intensive Care Med. 2005, 31 (6): 776-84. 10.1007/s00134-005-2627-z.PubMedCrossRefGoogle Scholar
  2. 2.
    Mead J: J Appl Physiol. 1970, 28 (5): 596-608.PubMedGoogle Scholar
  3. 3.
    Patlak CS: J Cereb Blood Flow Metab. 1983, 3 (1): 1-7. 10.1038/jcbfm.1983.1.PubMedCrossRefGoogle Scholar
  4. 4.
    Cressoni M: Am J Respir Crit Care Med. 2013Google Scholar

Copyright information

© Cressoni et al.; 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Authors and Affiliations

  • M Cressoni
    • 1
  • D Chiumello
    • 2
  • M Brioni
    • 1
  • I Algieri
    • 1
  • M Gotti
    • 1
  • K Nikolla
    • 1
  • D Massari
    • 1
  • A Cammaroto
    • 1
  • A Colombo
    • 1
  • P Cadringher
    • 1
  • E Carlesso
    • 1
  • L Gattinoni
    • 1
    • 2
  1. 1.Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore PoliclinicoUniversità degli Studi di MilanoMilanItaly
  2. 2.Dipartimento di Anestesia, Rianimazione ed Emergenza UrgenzaFondazione IRCCS Ca' Granda-Ospedale Maggiore PoliclinicoMilanItaly

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