Mechanical ventilation affects inflammatory mediators in patients undergoing cardiopulmonary bypass for cardiac surgery: a randomized clinical trial.
OBJECTIVE
Respiratory support for patients recovering from cardiopulmonary bypass and cardiac surgery uses large tidal volumes and a minimal level of positive end-expiratory pressure. Recent data indicate that these ventilator settings might cause pulmonary and systemic inflammation in patients with acute lung injury. We examined the hypothesis that high tidal volumes and low levels of positive end-expiratory pressure might worsen the inflammatory response associated to cardiopulmonary bypass.


METHODS
Forty patients undergoing elective coronary artery bypass were randomized to be ventilated after cardiopulmonary bypass disconnection with high tidal volume/low positive end-expiratory pressure (10-12 mL/kg and 2-3 cm H2O, respectively) or low tidal volume/high positive end-expiratory pressure (8 mL/kg and 10 cm H2O, respectively). Interleukin 6 and interleukin 8 levels were measured in the bronchoalveolar lavage fluid and plasma. Samples were taken before sternotomy (time 0), immediately after cardiopulmonary bypass separation (time 1), and after 6 hours of mechanical ventilation (time 2).


RESULTS
Interleukin 6 and interleukin 8 levels in the bronchoalveolar lavage fluid and plasma significantly increased at time 1 in both groups but further increased at time 2 only in patients ventilated with high tidal volume/low positive end-expiratory pressure. Interleukin 6 and interleukin 8 levels in the bronchoalveolar lavage fluid and in the plasma at time 2 were higher with high tidal volume/low positive end-expiratory pressure than with low tidal volume/high positive end-expiratory pressure.


CONCLUSIONS
Mechanical ventilation might be a cofactor able to influence the inflammatory response after cardiac surgery.
Zupancich
Enrico
E
Servizio di Anestesia e Rianimazione, Azienda Ospedaliera Cardiologico G.M. Lancisi, Ancona, Italy.
Paparella
Domenico
D
Turani
Franco
F
Munch
Christopher
C
Rossi
Alessandra
A
Massaccesi
Simone
S
Ranieri
V Marco
VM
D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000276:immunology; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods; D005260:Female; D006801:Humans; D018836:Inflammation Mediators; D015850:Interleukin-6 / Q000032:analysis / Q000276:immunology*; D016209:Interleukin-8 / Q000032:analysis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000009:adverse effects / Q000379:methods; D012121:Respiration, Artificial / Q000009:adverse effects* / Q000379:methods; D013990:Tidal Volume / Q000276:immunology
D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8