Mechanical ventilation strategies and inflammatory responses to cardiac surgery: a prospective randomized clinical trial.
OBJECTIVE
To examine whether postoperative mechanical ventilation with lower tidal volumes (V(T)) has protective effects on inflammatory responses induced by cardiopulmonary bypass (CPB) surgery in smokers and nonsmokers.


METHODS
Prospective, randomized, controlled clinical trial in the intensive care unit of a university hospital.


METHODS
We examined 44 patients (22 smokers, 22 nonsmokers) immediately after uncomplicated CPB surgery.


METHODS
Ventilation was applied for 6 h with either V(T) of either 6 or 12 ml/kg ideal body weight.


RESULTS
The time course of serum tumor necrosis factor (TNF) alpha, interleukin (IL) 6, and IL-8 determined 0, 2, 4, and 6 h after randomization did not differ significantly between the ventilatory strategies. By contrast, in bronchoalveolar lavage fluids sampled after 6 h only TNF-alpha levels were significantly higher in the high V(T) group than the low V(T) group (50+/-111 pg/ml vs. 1+/-7 pg/ml). IL-6 and IL-8 concentrations did not differ between groups. Subgroup analysis of patients with serum TNF-alpha level higher than 0 pg/ml after surgery revealed lower TNF-alpha serum levels during lower V(T) ventilation. All observed effects were small, independent of patients' history of smoking, and were not correlated with duration of ventilation and ICU stay.


CONCLUSIONS
Ventilation with lower V(T) had no or only minor effect on systemic and pulmonary inflammatory responses in patients with healthy lungs after uncomplicated CPB surgery. Our data do not suggest a clinical benefit of using low V(T) ventilation in these selected patients.
Wrigge
Hermann
H
Department of Anesthesiology and Intensive Care Medicine, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. hermann.wrigge@ukb.uni-bonn.de
Uhlig
Ulrike
U
Baumgarten
Georg
G
Menzenbach
Jan
J
Zinserling
Jörg
J
Ernst
Martin
M
Drömann
Daniel
D
Welz
Armin
A
Uhlig
Stefan
S
Putensen
Christian
C
D000368:Aged; D001026:Coronary Artery Bypass; D016207:Cytokines / Q000097:blood; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000209:etiology / Q000517:prevention & control*; D011182:Postoperative Care; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial; D012907:Smoking
D016207:Cytokines