Can the tomographic aspect characteristics of patients presenting with acute respiratory distress syndrome predict improvement in oxygenation-related response to the prone position?
BACKGROUND
In some patients with acute respiratory distress syndrome, the prone position is able to improve oxygenation, whereas in others it is not. It could be hypothesized that the more opacities that are present in dependent regions of the lung when the patient is in the supine position, the better the improvement in oxygenation is observed when the patients are turned prone. Therefore, we conducted a prospective study to identify computed tomographic scan aspects that could accurately predict who will respond to the prone position.


METHODS
We included 46 patients with acute respiratory distress syndrome (31 responders and 15 nonresponders). Computed tomographic scan was performed in the 6-h period preceding prone position. Blood gas analyses were performed before and at the end of the first 6-h period of prone position.


RESULTS
Arterial oxygen partial pressure/fraction of inspired oxygen increased from 117 +/- 42 (mean +/- SD) in the supine position to 200 +/- 76 mmHg in the prone position (P < 0.001). There were 31 responders and 15 nonresponders. There was a vertebral predominance of the opacities (P < 0.0001). However, there was no difference between responders and nonresponders. When only the amount of consolidated lung located under the heart was evaluated, there was more consolidated tissue under the heart relative to total lung area in nonresponders than in responders (P = 0.01).


CONCLUSIONS
There are no distinctive morphologic features in the pattern of lung disease measured by computed tomographic scanning performed with the patient in the supine position that can predict response to the prone position.
Papazian
Laurent
L
Polyvalent Intenstive Care Unit, Hôpital Sainte-Marguerite, Marseille, France. lpapazian@mail.ap-hm.fr
Paladini
Marie-Héléne
MH
Bregeon
Fabienne
F
Thirion
Xavier
X
Durieux
Olivier
O
Gainnier
Marc
M
Huiart
Laetitia
L
Agostini
Serge
S
Auffray
Jean-Pierre
JP
D000368:Aged; D001784:Blood Gas Analysis; D005260:Female; D006321:Heart / Q000503:physiopathology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D011237:Predictive Value of Tests; D016684:Prone Position / Q000502:physiology*; D011446:Prospective Studies; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging* / Q000628:therapy*; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D010100:Oxygen