TY - JOUR
T1 - Lung inflammation persists after 27 hours of protective acute respiratory distress syndrome network strategy and is concentrated in the nondependent lung
AU - Borges, João Batista
AU - Costa, Eduardo L V
AU - Bergquist, Maria
AU - Lucchetta, Luca
AU - Widström, Charles
AU - Maripuu, Enn
AU - Suarez-Sipmann, Fernando
AU - Larsson, Anders
AU - Amato, Marcelo B P
AU - Hedenstierna, Göran
PY - 2015/5/20
Y1 - 2015/5/20
N2 - Objective: PET with [18F]fluoro-2-deoxy-d-glucose can be used to image cellular metabolism, which during lung inflammation mainly reflects neutrophil activity, allowing the study of regional lung inflammation in vivo. We aimed at studying the location and evolution of inflammation by PET imaging, relating it to morphology (CT), during the first 27 hours of application of protective-ventilation strategy as suggested by the Acute Respiratory Distress Syndrome Network, in a porcine experimental model of acute respiratory distress syndrome. Design: Prospective laboratory investigation. Setting: University animal research laboratory. Subjects: Ten piglets submitted to an experimental model of acute respiratory distress syndrome. Interventions: Lung injury was induced by lung lavages and 210 minutes of injurious mechanical ventilation using low positive end-expiratory pressure and high inspiratory pressures. During 27 hours of controlled mechanical ventilation according to Acute Respiratory Distress Syndrome Network strategy, the animals were studied with dynamic PET imaging of [18F]fluoro-2-deoxy-d-glucose at two occasions with 24-hour interval between them. Measurements and Main Results: [18F]fluoro-2-deoxy-d-glucose uptake rate was computed for the total lung, four horizontal regions from top to bottom (nondependent to dependent regions) and for voxels grouped by similar density using standard Hounsfield units classification. The global lung uptake was elevated at 3 and 27 hours, suggesting persisting inflammation. In both PET acquisitions, nondependent regions presented the highest uptake (p = 0.002 and p = 0.006). Furthermore, from 3 to 27 hours, there was a change in the distribution of regional uptake (p = 0.003), with more pronounced concentration of inflammation in nondependent regions. Additionally, the poorly aerated tissue presented the largest uptake concentration after 27 hours. Conclusions: Protective Acute Respiratory Distress Syndrome Network strategy did not attenuate global pulmonary inflammation during the first 27 hours after severe lung insult. The strategy led to a concentration of inflammatory activity in the upper lung regions and in the poorly aerated lung regions. The present findings suggest that the poorly aerated lung tissue is an important target of the perpetuation of the inflammatory process occurring during ventilation according to the Acute Respiratory Distress Syndrome Network strategy.
AB - Objective: PET with [18F]fluoro-2-deoxy-d-glucose can be used to image cellular metabolism, which during lung inflammation mainly reflects neutrophil activity, allowing the study of regional lung inflammation in vivo. We aimed at studying the location and evolution of inflammation by PET imaging, relating it to morphology (CT), during the first 27 hours of application of protective-ventilation strategy as suggested by the Acute Respiratory Distress Syndrome Network, in a porcine experimental model of acute respiratory distress syndrome. Design: Prospective laboratory investigation. Setting: University animal research laboratory. Subjects: Ten piglets submitted to an experimental model of acute respiratory distress syndrome. Interventions: Lung injury was induced by lung lavages and 210 minutes of injurious mechanical ventilation using low positive end-expiratory pressure and high inspiratory pressures. During 27 hours of controlled mechanical ventilation according to Acute Respiratory Distress Syndrome Network strategy, the animals were studied with dynamic PET imaging of [18F]fluoro-2-deoxy-d-glucose at two occasions with 24-hour interval between them. Measurements and Main Results: [18F]fluoro-2-deoxy-d-glucose uptake rate was computed for the total lung, four horizontal regions from top to bottom (nondependent to dependent regions) and for voxels grouped by similar density using standard Hounsfield units classification. The global lung uptake was elevated at 3 and 27 hours, suggesting persisting inflammation. In both PET acquisitions, nondependent regions presented the highest uptake (p = 0.002 and p = 0.006). Furthermore, from 3 to 27 hours, there was a change in the distribution of regional uptake (p = 0.003), with more pronounced concentration of inflammation in nondependent regions. Additionally, the poorly aerated tissue presented the largest uptake concentration after 27 hours. Conclusions: Protective Acute Respiratory Distress Syndrome Network strategy did not attenuate global pulmonary inflammation during the first 27 hours after severe lung insult. The strategy led to a concentration of inflammatory activity in the upper lung regions and in the poorly aerated lung regions. The present findings suggest that the poorly aerated lung tissue is an important target of the perpetuation of the inflammatory process occurring during ventilation according to the Acute Respiratory Distress Syndrome Network strategy.
KW - acute pulmonary inflammation
KW - acute respiratory distress syndrome
KW - mechanical ventilation
KW - positron emission tomography
KW - ventilator-induced lung injury
KW - [<sup>18</sup>F]fluoro-2-deoxy-D-glucose
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U2 - 10.1097/CCM.0000000000000926
DO - 10.1097/CCM.0000000000000926
M3 - Article
C2 - 25746507
AN - SCOPUS:84932161069
VL - 43
SP - e123-e132
JO - Critical Care Medicine
JF - Critical Care Medicine
SN - 0090-3493
IS - 5
ER -