Intercomparison of recruitment maneuver efficacy in three models of acute lung injury.
OBJECTIVE
To compare the relative efficacy of three forms of recruitment maneuvers in diverse models of acute lung injury characterized by differing pathoanatomy.


METHODS
We compared three recruiting maneuver (RM) techniques at three levels of post-RM positive end-expiratory pressure in three distinct porcine models of acute lung injury: oleic acid injury; injury induced purely by the mechanical stress of high-tidal airway pressures; and pneumococcal pneumonia.


METHODS
Laboratory in a clinical research facility.


METHODS
Twenty-eight anesthetized mixed-breed pigs (23.8 +/- 2.6 kg).


METHODS
The RM techniques tested were sustained inflation, extended sigh or incremental positive end-expiratory pressure, and pressure-controlled ventilation.


METHODS
Oxygenation and end-expiratory lung volume.


RESULTS
The post-RM positive end-expiratory pressure level was the major determinant of post-maneuver PaO2, independent of the RM technique. The pressure-controlled ventilation RM caused a lasting increase of PaO2 in the ventilator-induced lung injury model, but in oleic acid injury and pneumococcal pneumonia, there were no sustained oxygenation differences for any RM technique (sustained inflation, incremental positive end-expiratory pressure, or pressure-controlled ventilation) that differed from raising positive end-expiratory pressure without RM.


CONCLUSIONS
Recruitment by pressure-controlled ventilation is equivalent or superior to sustained inflation, with the same peak pressure in all tested models of acute lung injury, despite its lower mean airway pressure and reduced risk for hemodynamic compromise. Although RM may improve PaO2 in certain injury settings when traditional tidal volumes are used, sustained improvement depends on the post-RM positive end-expiratory pressure value.
Lim
Sung-Chul
SC
Department of Pulmonary/Critical Care Medicine, Regions Hospital, University of Minnesota, St. Paul, MN, USA.
Adams
Alexander B
AB
Simonson
Dana A
DA
Dries
David J
DJ
Broccard
Alain F
AF
Hotchkiss
John R
JR
Marini
John J
JJ
D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D008170:Lung Compliance; D008176:Lung Volume Measurements; D019301:Oleic Acid; D011018:Pneumonia, Pneumococcal; D011175:Positive-Pressure Respiration / Q000379:methods*; D011336:Probability; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000502:physiology*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013552:Swine
D019301:Oleic Acid