Effect of mechanical ventilation under intubation on respiratory tract change of bacterial count and alteration of bacterial flora.

Background: The most common 'second strike' in mechanically ventilated patients is a pulmonary infection caused by the ease with which bacteria can invade and colonize the lungs due to mechanical ventilation. At the same time, metastasis of lower airway microbiota may have significant implications in developing intubation mechanical ventilation lung inflammation. Thus, we establish a rat model of tracheal intubation with mechanical ventilation and explore the effects of mechanical ventilation on lung injury and microbiological changes in rats. To provide a reference for preventing and treating bacterial flora imbalance and pulmonary infection injury caused by mechanical ventilation of tracheal intubation. Methods: Sprague-Dawley rats were randomly divided into Control, Mechanical ventilation under intubation (1, 3, 6 h) groups, and Spontaneously breathing under intubation (1, 3, 6 h). Lung histopathological injury scores were evaluated. 16SrDNA sequencing was performed to explore respiratory microbiota changes, especially, changes of bacterial count and alteration of bacterial flora. Results: Compared to groups C and SV, critical pathological changes in pulmonary lesions occurred in the MV group after 6 h (p < 0.05). The Alpha diversity and Beta diversity of lower respiratory tract microbiota in MV6, SV6, and C groups were statistically significant (p < 0.05). The main dominant bacterial phyla in the respiratory tract of rats were Proteobacteria, Firmicutes, Bacteroidetes, and Cyanobacteria. Acinetobacter radioresistens in group C was significant, Megaonas in group MV6 was significantly increased, and Parvibacter in group SV6 was significantly increased. Anaerobic, biofilm formation, and Gram-negative bacteria-related functional genes were altered during mechanical ventilation with endotracheal intubation. Conclusion: Mechanical ventilation under intubation may cause dysregulation of lower respiratory microbiota in rats.

Full-dose pemetrexed plus cisplatin combined with concurrent thoracic radiotherapy for previously untreated advanced nonsquamous non-small cell lung cancer.

Compared with other platinum-based doublet chemotherapy, pemetrexed plus platinum is more effective and tolerable as the first-line treatment for nonsquamous non-small cell lung cancer (NSCLC). Thus, we examined the feasibility of using thoracic radiotherapy combined with concurrent full-dose pemetrexed as the first-line treatment for advanced nonsquamous NSCLC patients. From January 2009 to July 2012, 41 patients with stage IIIB or IV nonsquamous NSCLC were treated with full-dose pemetrexed plus cisplatin as the first-line chemotherapy combined with concurrent thoracic radiotherapy, with or without radiotherapy for metastases. The status of mutations in the epidermal growth factor receptor was unknown before the treatment, and no tyrosine-kinase inhibitor and cytotoxic drug maintenance therapy were administered to the patients after the chemotherapy. The median follow-up duration was 26.3 months (range, 5.8-57.5 months). Twenty-one patients had stage IIIB disease (19 with stage N3-IIIB). Of the 20 patients with stage IV disease, 16 had oligometastases (≤5) and four had polymetastases. The median number of chemotherapy cycles was 4. The median radiation dose was 60 Gy. Thirty-six patients received radical doses of radiotherapy. Toxicities were highly tolerated. The median progression-free survival was 12 months and the median overall survival was 32 months. The 1-, 2-, and 3-year overall survival rates were 87.5, 67.1, and 43.4%, respectively. As the first-line treatment for selected patients with advanced nonsquamous NSCLC, thoracic radiotherapy combined with concurrent full-dose pemetrexed plus cisplatin was safe and highly tolerable. In addition, the survival rate was encouraging. Prospective clinical trials are needed to verify the results.