Alveolar recruitment assessed by positron emission tomography during experimental acute lung injury.
OBJECTIVE
To compare changes in aerated lung volumes measured by positron emission tomography (PET) and inflation volume-pressure curve (V-P) of the respiratory system, and to evaluate the reliability of PET to assess alveolar recruitment.


METHODS
Experimental study in six anesthetized and mechanically ventilated pigs in a PET facility in an experimental university laboratory.


METHODS
Lung injury was induced by oleic acid. Animals were randomly studied in four conditions: PEEP 0cmH(2)O (ZEEP) in supine position (SP), PEEP 10cmH(2)O in SP, ZEEP in prone position (PP) and PEEP in PP, each applied for 30min.


RESULTS
With PET aerated lung volume was obtained from pulmonary density analysis using transmission scan (VA(trans)) and from nitrogen-13 kinetics on emission scan (VA(em)). Changes in VA(trans) and VA(em) were computed as the difference in aerated volume between conditions. VA(trans) and VA(em) did not differ between SP and PP, on either ZEEP or PEEP, suggesting no modification in relaxation volume of the respiratory system induced by posture. Changes in VA(trans) or VA(em) were significantly correlated with changes in aerated volume assessed from superimposed V-P curves (R (2)=0.74 and 0.75, respectively). Alveolar recruitment assessed by PET was significantly correlated with both PaO(2) (R (2)=0.61) and PaCO(2) (R (2)=0.40) variations induced by PEEP.


CONCLUSIONS
PET is a new reliable tool of scientific interest to image lung volume and alveolar recruitment during acute lung injury.
Richard
Jean-Christophe
JC
Service de Réanimation Médicale et d'Assistance Respiratoire, Hôpital de la Croix Rousse, 93 Grande Rue de la Croix Rousse, 69004, Lyon, France.
Le Bars
Didier
D
Costes
Nicolas
N
Bregeon
Fabienne
F
Tourvieille
Christian
C
Lavenne
Franck
F
Janier
Marc
M
Gimenez
Gérard
G
Guerin
Claude
C
D000818:Animals; D008176:Lung Volume Measurements; D019301:Oleic Acid; D011175:Positive-Pressure Respiration; D049268:Positron-Emission Tomography; D011187:Posture; D001261:Pulmonary Atelectasis / Q000517:prevention & control*; D011659:Pulmonary Gas Exchange; D011897:Random Allocation; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging* / Q000628:therapy*; D012129:Respiratory Function Tests / Q000379:methods*; D013552:Swine
D019301:Oleic Acid