PURPOSE: This study was designed to evaluate the effects of different ventilatory strategies on the release of inflammatory mediators into the systemic circulation of anesthetized patients who had healthy lungs.
METHODS: Forty five patients undergoing open thoracic surgery were randomized to receive mechanical ventilation with either (1) Vt = 10 ml/kg on ZEEP, (2) Vt = 6 ml/kg on ZEEP, or (3) Vt = 6 ml/kg on PEEP of 10 cm H2O. Because interleukin-6 and macrophage inflammatory protein-2 are more sensitive markers of ventilation-induced cytokine release, serum and bronchoalveolar lavage samples were examined for these mediators. Cells, protein, tumor necrosis factor (TNF)-[alpha], interleukin (IL)-8, soluble intercellular adhesion molecule (sICAM)-1, IL-10, and elastase were determined in the bronchoalveolar lavage. Data were analyzed by parametric or nonparametric tests, as indicated. In all patients, an increase of proinflammatory variables was found. Concentrations were significantly smaller after OLV with Vt = 6 mL/kg on PEEP of 10 cm H2O.
RESULTS: The results of this study showed that mechanical ventilation with high VT (10 ml/kg at ZEEP) induced lung injury after 3 h compared to mechanical ventilation with a lower VT (6 ml/kg at PEEP10 cm H2O). Ventilation with Vt 6 mL/kg at PEEP10 cm H2O in comparison with Vt 10 mL/kg significantly decreased alveolar TNF-[alpha] and sICAM-1 and increased IL-10 after OLV.
CONCLUSION: OLV may promote production and release of proinflammatory substances in the alveoli of the dependent lung. Reductions of Vt and subsequently decreased peak airway pressures have significant effects on alveolar TNF, sICAM-1 and IL-10 concentrations after OLV and in the postoperative course.
CLINICAL IMPLICATIONS: Whether lung protective ventilation approaches, such as pressure-limited ventilation with sufficient PEEP and a decelerating flow pattern, further reduce lung damage during OLV remains to be studied. Enhancement of protective ventilatory stratergy even during short term ventilation.
DISCLOSURE: Abeer Sherif, No Financial Disclosure Information; No Product/Research Disclosure Information