Regional lung volume changes in children with acute respiratory distress syndrome during a derecruitment maneuver.
OBJECTIVE
Regional differences in lung volume have been described in adults with acute respiratory distress syndrome, but it remains unclear to what extent they occur in children. To quantify regional alveolar collapse that occurred during mechanical ventilation during a standardized suctioning maneuver, we evaluated regional and global relative impedance changes (relative DeltaZ) in children with acute respiratory distress syndrome using electrical impedance tomography.


METHODS
Prospective observational trial.


METHODS
A 30-bed pediatric intensive care unit.


METHODS
Six children with acute respiratory distress syndrome.


METHODS
Standardized suctioning maneuver.


RESULTS
By comparing layers from nondependent (layers 1 and 2) to dependent lung areas (layers 3 and 4), it was demonstrated that the middle layers (2 and 3) had the greatest ventilation-induced change in relative DeltaZ; layer 4 showed the least ventilation-induced change in relative DeltaZ. During suctioning, layers 1, 2, and 3 showed a negative change in relative DeltaZ, whereas layer 4 showed no significant change in relative DeltaZ. The derecruitment-induced change in relative DeltaZ representing the lung-volume loss was -9.8 (-3.0 mL/kg) during the first suctioning maneuver, -16.1 (-5.4 mL/kg) during the second, and -21.7 (-7.4 mL/kg) during the third. The ventilation-induced change in relative DeltaZ during mechanical ventilation remained unchanged after suctioning (mean change in relative DeltaZ before vs. after suctioning, 40.1 +/- 9.1 vs. 41.4 +/- 10.8; p = .30). Dynamic compliance was 11.8 +/- 6.1 mL.cm H2O before and 11.8 +/- 6.9 mL.cm H2O after the suctioning sequence (p = .90).


CONCLUSIONS
Considerable regional heterogeneity was present during ventilation and a derecruitment maneuver. Significantly lower change in relative DeltaZ in the most dependent lung regions suggests alveolar collapse during ventilation before suctioning.
Wolf
Gerhard K
GK
Division of Critical Care Medicine, Department of Anesthesia, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA. gerhard.wolf@childrens.harvard.edu
Grychtol
Bartlomiej
B
Frerichs
Inez
I
van Genderingen
Huibert R
HR
Zurakowski
David
D
Thompson
John E
JE
Arnold
John H
JH
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D017097:Electric Impedance; D006801:Humans; D008176:Lung Volume Measurements; D008991:Monitoring, Physiologic / Q000379:methods; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000503:physiopathology; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000628:therapy; D013396:Suction; D014054:Tomography / Q000379:methods*