ObjectiveTo assess the efficacy of subglottic secretion drainage for preventing ventilatorassociated pneumonia.MethodsData of relevant randomized controlled trials (RCT) from January 1991 to June 2010 were collected,and data were split into two groups,namely draining group and non-draining group.Meta analysis of ventilator-associated pneumonia was carried out for finding the incidence and mortality in patients with mechanical ventilation using the methods recommended by the Cochrane Collaboration.ResultsSeven RCTs met the inclusion criteria and 1647 patients were enrolled.Subglottic secretion drainage reduced the incidence of ventilator-associated pneumonia ( OR =0.45,95％ confidence interval [CI]:0.32 - 0.63 ),primarily by reducing early-onset pneumonia.But the mortalities of ventilator associated pneumonia were not significantly different between the two groups ( OR =1.03,95％ confi dence interval [CI]:0.75 - 1.41 ).ConclusionsSubglottic secretion drainage appeared effective in preventing ventilator associated pneumonia among patients expected to require ＞48 hours of mechanical ventilation,but the mortality was unchanged.

ObjectiveTo explore the possible mechanism of Chuanxiong （Rhizoma Chuanxiong） & Tianma （Rhizoma Gastrodiae） herbal pair in treating migraines based on AMP-activated protein kinase （AMPK）/transient receptor potential A1 channel （TRPA1） pathway. MethodsForty-eight healthy male SD rats were randomly divided into control group， model group， and Chuanxiong Tianma medication group， with 16 rats in each group. The control group and model group were given 10 ml/kg of normal saline by gavage， while the Chuanxiong Tianma medication group was given 0.675 g/kg of Chuanxiong Tianma herbal pair by gavage， once daily for 8 consecutive days in both groups. Migraime model was performed before the last administration， with subcutaneous injection of 10 ml/kg of normal saline in the control group， and subcutaneous injection of 10 ml/kg of nitroglycerin in the model group and Chuanxiong Tianma medication group. The Von Frey filament was used to measure the periorbital mechanical pain threshold of rats. The enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of calcitonin gene-related peptide （CGRP） in rat serum and cerebrospinal fluid. The nitric oxide （NO） assay kit was used to determine the NO level in serum and cerebrospinal fluid. RT-PCR was usedto detect the mRNA expression levels of immediate-early genes in the trigeminal ganglion of rats （c-Fos）， CGRP， transient receptor potential V1 channel （TRPV1）， AMPK alpha subunit （PRKAA）， and TRPA1. Immunofluorescence was used to detect the number of c-Fos-positive cells in the trigeminal cervical complex （TCC） and the protein expression levels of phosphorylated AMPK （pAMPK） and TRPA1 in the trigeminal ganglion. ResultsCompared to those in the control group， the mechanical stimulation threshold and pAMPK protein expression in the model group decreased， while the levels of CGRP and NO in serum， c-Fos， CGRP， TRPV1 and TRPA1 mRNA levels in the trigeminal ganglion， TRPA1 protein expression， and the number of c-Fos-positive cells in the TCC significantly increased （P＜0.05）. Compared to those in the model group， the mechanical stimulation threshold and pAMPK protein expression in the Chuanxiong Tianma medication group significantly increased， while the levels of CGRP and NO in serum， c-Fos， CGRP， TRPV1 and TRPA1 mRNA levels in the trigeminal ganglion， TRPA1 protein expression， and the number of c-Fos-positive cells in the TCC significantly decreased （P＜0.05）. ConclusionChuanxiong Tianma herbal pair may improve migraine symptoms by regulating the AMPK/TRPA1 pathway in the trigeminal ganglion and increasing the mechanical pain threshold.