Dexmedetomidine reduces ventilator-induced lung injury via ERK1/2 pathway activation.

Mechanical ventilation (MV) can contribute to ventilator­induced lung injury (VILI); dexmedetomidine (Dex) treatment attenuates MV­related pulmonary inflammation, but the mechanisms remain unclear. Therefore, the present study aimed to explore the protective effect and the possible molecular mechanisms of Dex in a VILI rodent model. Adult male Sprague­Dawley rats were randomly assigned to one of seven groups (n=24 rats/group). Rats were euthanized after 4 h of continuous MV, and pathological changes, lung wet/dry (W/D) weight ratio, the levels of inflammatory cytokines (IL­1ß, TNF­α and IL­6) in the bronchoalveolar lavage fluid (BALF), and the expression levels of Bcl­2 homologous antagonist/killer (Bak), Bcl­2, pro­caspase­3, cleaved caspase­3 and the phosphorylation of ERK1/2 in the lung tissues were measured. Propidium iodide uptake and TUNEL staining were used to detect epithelial cell death. The Dex pretreatment group exhibited fewer pathological changes, lower W/D ratios and lower expression levels of inflammatory cytokines in BALF compared with the VILI group. Dex significantly attenuated the ratio of Bak/Bcl­2, cleaved caspase­3 expression levels and epithelial cell death, and increased the expression of phosphorylated ERK1/2. The protective effects of Dex could be partially reversed by PD98059, which is a mitogen­activated protein kinase (upstream of ERK1/2) inhibitor. Overall, dexmedetomidine was found to reduce the inflammatory response and epithelial cell death caused by VILI, via the activation of the ERK1/2 signaling pathway.

Effects of bronchial blockers on one-lung ventilation in general anesthesia: A randomized controlled trail.

BACKGROUND: Double-lumen bronchial tubes (DLBT) and bronchial blockers (BB) are commonly used in the anesthesia for clinical thoracic surgery. But there are few systematic clinical comparisons between them. In this study, the effects of BB and DLBT on one-lung ventilation (OLV) are studied. METHODS: The 200 patients with thoracic tuberculosis undergoing thoracic surgery, were randomly assigned to group A (DLBT) and group B (BB). Intubation time, hemodynamic changes (mean arterial pressure [MAP], heart rate [HR]), and arterial blood gas indicators (arterial partial pressure of carbon dioxide [PaCO2], arterial partial pressure of oxygen [PaO2], airway plateau pressure [Pplat], and airway peak pressure [Ppeak]) at 4 time points were recorded. Complications such as hoarseness, pulmonary infection, pharyngalgia, and surgical success rate were also evaluated postoperatively. RESULTS: Intubation times were shorter in group B. Both MAP and HR in group A were significantly higher 1 minute after intubation than before, but also higher than those in group B. PaO2 levels were lower in both groups during (OLV) than immediately after anesthesia and after two-lung ventilation (TLV), with PaO2 being lower after 60 minutes of OLV than after 20 minutes of OLV. Furthermore, at both points during OLV, PaO2 was lower in group A than in group B. No significant differences in PaCO2 were found between the 2 groups. Ppeak and Pplat were increased in both groups during OLV, with both being higher in group A than in group B. The incidence of postoperative hoarseness, pulmonary infection, and pharyngalgia were lower in group B. There was no significant difference in the success rate of operation between the 2 groups. CONCLUSIONS: Compare with using DLBT, implementation of BB in general anesthesia has less impact on hemodynamics, PaO2 and airway pressures, and achieves lower incidence of postoperative complication.