Mechanical ventilation affects inflammatory mediators in patients undergoing cardiopulmonary bypass for cardiac surgery: a randomized clinical trial.

OBJECTIVES: 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. CONCLUSION: Mechanical ventilation might be a cofactor able to influence the inflammatory response after cardiac surgery.

Functional systolic anterior motion of the mitral valve due to accessory chordae.

Accessory mitral valve tissue is an uncommon finding, usually associated with other congenital cardiac malformations and diagnosed during childhood. We present the case of a 70-year-old patient referred to our hospital for aortic valve and ascending aorta replacement. At preoperative examination, no evidence of mitral valve structural abnormalities was detected. Anaesthesia induction was complicated by sudden haemodynamic impairment. Intraoperative transoesophageal echocardiography showed two anomalous mitral chordae. The presence of abnormal mitral tissue also allowed to assess the mechanism of unexpected haemodynamic worsening: anomalous chordae caused anterior displacement of the anterior mitral leaflet, resulting in left ventricular outflow tract obstruction and mitral regurgitation. Medical therapy was instituted and the planned surgical approach was modified according to the new anatomy observed at echocardiographic examination. A valve-sparing technique was successfully applied. This case provides a good example of the diagnostic usefulness of routine intraoperative transoesophageal echocardiography, especially when facing unexpected findings. It also shows how transoesophageal echocardiography may help guide medical and surgical treatment.