Postresectional pulmonary oxidative stress in lung cancer patients. The role of one-lung ventilation.

ABSTRACT

OBJECTIVE: The authors conducted a prospective analysis in order to investigate through lipid peroxidation metabolites the generation of oxygen free radicals after one-lung ventilation (OLV). METHODS: From 2001 to 2003, 212 patients were prospectively studied for lung reexpansion/reperfusion injury. They were classified in six groups. Group A, non-OLV lobectomy group; B, OLV pneumonectomy group; C-E, OLV lobectomy of 60, 90, and 120 min duration, respectively; F, normal subjects as baseline group. Preoperative, intraoperative and postoperative strict blood sampling protocol was followed. Malondialdehyde (MDA) plasma levels were measured. The recorded values were analyzed and statistically compared between groups and within each one. RESULTS: Comparison of groups C-E (OLV) to all other documented significant (P<0.001) increase of MDA levels during lung reexpansion and for the following 12h. The magnitude of oxidative stress was related to OLV duration (group E>D>C, all P<0.001). The removal of cancer-associated parenchyma led to MDA level decrease postoperatively (P<0.001) especially after pneumonectomy (A vs. B, P<0.001). CONCLUSIONS: (1) Lung reexpansion provoked severe oxidative stress. (2) The degree of the amount of generated oxygen free radicals was associated to the duration of OLV. (3) Patients with lung cancer had a higher production of oxygen free radicals than normal population. (4)Tumor resection removes a large oxidative burden from the organism. (5) Mechanical ventilation and surgical trauma are weak free radical generators. (6) Manipulated lung tissue is also a source of oxygen free radicals, not only intraoperatively but also for several hours later.