Lung recruitment and lung volume maintenance: a strategy for improving oxygenation and preventing lung injury during both conventional mechanical ventilation and high-frequency oscillation.
OBJECTIVE
To determine whether using a small tidal volume (5 ml/kg) ventilation following sustained inflation with positive endexpiratory pressure (PEEP) set above the critical closing pressure (CCP) allows oxygenation equally well and induces as little lung damage as high-frequency oscillation following sustained inflation with a continuous distending pressure (CDP) slightly above the CCP of the lung.


METHODS
Twelve surfactant-depleted adult New Zealand rabbits were ventilated for 4 h after being randomly assigned to one of two groups: group 1, conventional mechanical ventilation, tidal volume 5 ml/kg, sustained inflation followed by PEEP > CCP; group 2, high-frequency oscillation, sustained inflation followed by CDP > CCP.


RESULTS
In both groups oxygenation improved substantially after sustained inflation (P < 0.05) and remained stable over 4 h of ventilation without any differences between the groups. Histologically, both groups showed only little airway injury to bronchioles, alveolar ducts, and alveolar airspace, with no difference between the two groups. Myeloperoxidase content in homogenized lung tissue, as a marker of leukocyte infiltration, was equivalent in the two groups.


CONCLUSIONS
We conclude that a volume recruitment strategy during small tidal volume ventilation and maintaining lung volumes above lung closing is as protective as that of high-frequency oscillation at similar lung volumes in this model of lung injury
Rimensberger
P C
PC
Department of Pediatric Intensive Care, Hôpital des Enfants, University Hospital of Geneva, Switzerland. Peter.Rimensberger@hcuge.ch
Pache
J C
JC
McKerlie
C
C
Frndova
H
H
Cox
P N
PN
D000818:Animals; D006612:High-Frequency Ventilation / Q000009:adverse effects / Q000379:methods*; D007385:Intermittent Positive-Pressure Ventilation / Q000009:adverse effects / Q000379:methods*; D008168:Lung / Q000473:pathology; D009195:Peroxidase / Q000378:metabolism; D011659:Pulmonary Gas Exchange; D011817:Rabbits; D011897:Random Allocation; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000517:prevention & control*; D015656:Respiratory Mechanics; D013990:Tidal Volume
D009195:Peroxidase