Alveolar recruitment in combination with sufficient positive end-expiratory pressure increases oxygenation and lung aeration in patients with severe chest trauma.
OBJECTIVE
Investigation of oxygenation and lung aeration during mechanical ventilation according to the open lung concept in patients with acute lung injury or acute respiratory distress syndrome.


METHODS
Retrospective analysis.


METHODS
Surgical intensive care unit of a university hospital.


METHODS
We retrospectively identified 17 patients with acute lung injury/acute respiratory distress syndrome due to pulmonary contusion who had thoracic helical computed tomography scans before and after ventilation with the open lung concept.


METHODS
Baseline ventilation consisted of low tidal volumes (< or =6 mL/kg) and positive end-expiratory pressure (PEEP; 5-17 cm H2O). We briefly applied high inspiratory pressures for opening up collapsed alveoli. External PEEP and intrinsic PEEP were combined to keep recruited lung units open. We generated intrinsic PEEP by pressure-cycled high-frequency inverse ratio ventilation (80 min, inspiratory/expiratory ratio 2:1) and maintained our ventilatory strategy for 24 hrs. Then, after reducing total PEEP by decreasing respiratory rate, Pao2/Fio2 ratio was reevaluated. If it remained >300 mm Hg, weaning was started. If not, previous ventilator settings were resumed for another 24 hrs after recruiting the lungs once again.


RESULTS
Physiologic variables and ventilator settings were obtained from routine charts. Data from computed tomography before and after the open lung concept were analyzed for volumetric quantification of lung aeration and collapse. All results are presented as median and range. During baseline ventilation, PEEP was 10 (range, 5-17) cm H2O and after recruitment 21 (range, 18-26) cm H2O. Opening pressures were 65 (range, 50-80) cm H2O. After recruitment, Pao2/Fio2 ratio was higher in all patients. Total lung volume increased from 2915 (range, 1952-4941) to 4247 (range, 2285-6355) mL and normally aerated volume from 1742 (range, 774-2941) to 2971 (range, 1270-5232) mL. Atelectasis decreased significantly from 604 (range, 147-1538) to 106 (range, 0-736) mL. Hyperinflation increased significantly from 5 (range, 0-188) to 62 (range, 1-424) mL, whereas poor aeration did not change substantially from 649 (range, 302-1292) to 757 (range, 350-1613) mL. No hemodynamic problems occurred.


CONCLUSIONS
Lung recruitment increased arterial oxygenation, normally aerated lung volume, and total lung volume while decreasing the amount of collapsed tissue. These results indicate that the open lung concept is a reasonable mode of ventilation for patients with severe chest trauma.
Schreiter
Dierk
D
Surgical Intensive Care Unit, Department of Surgery, University Hospital Leipzig, Leipzig, Germany. dschr@medizin.uni-leipzig.de
Reske
Andreas
A
Stichert
Bastian
B
Seiwerts
Matthias
M
Bohm
Stephan H
SH
Kloeppel
Rainer
R
Josten
Christoph
C
D000293:Adolescent; D000328:Adult; D003131:Combined Modality Therapy; D003288:Contusions / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D003422:Critical Care / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology; D055370:Lung Injury; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011175:Positive-Pressure Respiration / Q000379:methods*; D011650:Pulmonary Alveoli / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001261:Pulmonary Atelectasis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D013898:Thoracic Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D010100:Oxygen