Lung computed tomography during a lung recruitment maneuver in patients with acute lung injury.
OBJECTIVE
To assess the acute effect of a lung recruitment maneuver (LRM) on lung morphology in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS).


METHODS
Ten patients with ALI/ARDS on mechanical ventilation.


METHODS
Prospective clinical study.


METHODS
Computed tomography (CT) scan facility in a teaching hospital.


METHODS
An LRM performed by stepwise increases in positive end-expiratory pressure (PEEP) of up to 30-40 cm H(2)O. Lung basal CT sections were taken at end-expiration (patients 1 to 5), and at end-expiration and end-inspiration (patients 6 to 10). Arterial blood gases and static compliance (C(st)) were measured before, during and after the LRM.


RESULTS
Poorly aerated and non-aerated tissue at PEEP 10 cm H(2)O accounted for 60.0+/-29.1% of lung parenchyma, while only 1.1+/-1.8% was hyperinflated. Increasing PEEP to 20 and 30 cm H(2)O, compared to PEEP 10 cm H(2)O, decreased poorly aerated and non-aerated tissue by 16.2+/-28.0% and 33.4+/-13.8%, respectively ( p<0.05). This was associated with an increase in PaO(2) and a decrease in total static compliance. Inspiration increased alveolar recruitment at all PEEP levels. Hyperinflated tissue increased up to 2.9+/-4.0% with PEEP 30 cm H(2)O, and to a lesser degree with inspiration. No barotrauma or severe hypotension occurred.


CONCLUSIONS
Lung recruitment maneuvers improve oxygenation by expanding collapsed alveoli without inducing too much hyperinflation in ALI/ARDS patients. An LRM during the CT scan gives morphologic and functional information that could be useful in setting ventilatory parameters.
Bugedo
Guillermo
G
Departamentos de Anestesiología y Radiología, Pontificia Universidad Católica de Chile, Santiago, Chile. bugedo@med.puc.cl
Bruhn
Alejandro
A
Hernández
Glenn
G
Rojas
Gonzalo
G
Varela
Cristián
C
Tapia
Juan Carlos
JC
Castillo
Luis
L
D000328:Adult; D000368:Aged; D000403:Airway Resistance; D001784:Blood Gas Analysis; D002985:Clinical Protocols; D005260:Female; D006801:Humans; D008170:Lung Compliance; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000503:physiopathology; D015641:Radiography, Interventional / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics; D013990:Tidal Volume; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome