Project description:Introduction: The ideal ventilation strategy for patients with massive brain damage requires better elucidation. We hypothesized that in the presence of massive brain injury, a ventilation strategy using low (6 mL/kg) tidal volume (VT) ventilation with open lung positive end-expiratory pressure set according to the minimal static elastance of the respiratory system (LVT/OLPEEP), attenuate the impact of massive brain damage on gas-exchange, respiratory mechanics, lung histology and whole genome alterations compared with high (12 mL/kg) VT and low PEEP ventilation (HVT/LPEEP). Methods: Twenty-eight adult male Wistar rats were randomly assigned to one of four groups: 1) no brain damage (NBD) with LVT/OLPEEP; 2) NBD with HVT/LPEEP; 3) brain damage (BD) with LVT/OLPEEP; and 4) BD with HVT/LPEEP. All animals were mechanically ventilated for six hours. Brain damage was induced by an inflated balloon catheter into the epidural space. Hemodynamics was recorded and blood gas analysis was performed hourly. At the end of the experiment, respiratory system mechanics and lung histology were analysed. Whole genome analysis was performed using Affimetrix gene chips and confirmatory real-time PCR. Results: In NBD, both LVT/OLPEEP and HVT/LPEEP did not affect arterial blood gases, as well as whole genome expression changes and real-time PCR. In BD, LVT/OLPEEP, compared to HVT/LPEEP, reduced lung damage according to histology, genome analysis and real-time PCR with decreased interleukin (IL-6), cytokine-induced neutrophil chemoattractant (CINC)-1 and angiopoietin-4 expressions. LVT/OLPEEP compared to HVT/LPEEP improved overall survival. Conclusions: In BD, LVT/OLPEEP minimizes lung morpho-functional changes and inflammation compared to HVT/LPEEP. LVT/OLPEEP might represent a suitable ventilatory strategy in massive brain damage. 24 Wistar rats - lung samples, 4 groups, 1. non-braindamaged/braindead high tidal volume ventilation, 2. non-braindamaged/braindead best PEEP ventilation, 3. Braindamaged/braindead high tidal volume ventilation, 4. Braindamaged/braindead best PEEP ventilation
Project description:In the present study we seek to identify changes in lung gene expression under mechanical ventilation in uninjured as well as acutely and chronically injured lungs. A standard volume-controlled lung-protective ventilatory protocol is compared to a concept of mechanical ventilation using variable tidal volumes.
Project description:Addition of CO2 to the inspired gas can ameliorate lung injury during high tidal volume mechanical ventilation in animal models. Although some effects of hypercapnia on physiology and cell signaling have been characterized, we hypothesized that assessment of genome-wide gene expression patterns would reveal novel pathways of protection. We subjected male C57BL/6J mice to non-injurious low stretch (tidal vol = 10 mL/kg, PEEP = 2 cm H2O) or injurious high stretch (tidal volume approx 35 mL/kg, PEEP = 0 cm H2O) mechanical ventilation for 3 hours under normocapnia (FiCO2 = 0) or hypercapnia (FiCO2 = 0.12).
Project description:Interventions: routine ventilation : tidal volume of 9ml/kg and PEEP=0cmH2O;Lung protective ventilation group:tidal volume of 7ml/kg and PEEP=5cmH2O
Primary outcome(s): mechanical power
Study Design: Parallel
Project description:Gene expression profiling was performed in lung tissues from an animal model of sepsis challenged with injurious and non-injurious mechanical ventilation to unravel the molecular pathways involved in acute lung injury. Sepsis was induced in male Sprague Dawley rats by means of cecal ligation and puncture. Septic rats were randomly allocated to three distinct groups: spontaneous breathing, mechanically ventilated with high tidal volume with zero positive end expiratory pressure (PEEP) and with low tidal volume and 10 cmH2O of PEEP. Comparisons were performed against an unventilated control group.
Project description:Introduction: The ideal ventilation strategy for patients with massive brain damage requires better elucidation. We hypothesized that in the presence of massive brain injury, a ventilation strategy using low (6 mL/kg) tidal volume (VT) ventilation with open lung positive end-expiratory pressure set according to the minimal static elastance of the respiratory system (LVT/OLPEEP), attenuate the impact of massive brain damage on gas-exchange, respiratory mechanics, lung histology and whole genome alterations compared with high (12 mL/kg) VT and low PEEP ventilation (HVT/LPEEP). Methods: Twenty-eight adult male Wistar rats were randomly assigned to one of four groups: 1) no brain damage (NBD) with LVT/OLPEEP; 2) NBD with HVT/LPEEP; 3) brain damage (BD) with LVT/OLPEEP; and 4) BD with HVT/LPEEP. All animals were mechanically ventilated for six hours. Brain damage was induced by an inflated balloon catheter into the epidural space. Hemodynamics was recorded and blood gas analysis was performed hourly. At the end of the experiment, respiratory system mechanics and lung histology were analysed. Whole genome analysis was performed using Affimetrix gene chips and confirmatory real-time PCR. Results: In NBD, both LVT/OLPEEP and HVT/LPEEP did not affect arterial blood gases, as well as whole genome expression changes and real-time PCR. In BD, LVT/OLPEEP, compared to HVT/LPEEP, reduced lung damage according to histology, genome analysis and real-time PCR with decreased interleukin (IL-6), cytokine-induced neutrophil chemoattractant (CINC)-1 and angiopoietin-4 expressions. LVT/OLPEEP compared to HVT/LPEEP improved overall survival. Conclusions: In BD, LVT/OLPEEP minimizes lung morpho-functional changes and inflammation compared to HVT/LPEEP. LVT/OLPEEP might represent a suitable ventilatory strategy in massive brain damage.
Project description:Scientific knowledge on the subjects: Injurious mechanical ventilation amplifies acute lung injury in a heterogeneous and regional fashion but the molecular mechanisms underlying regional lung injury and the protective effects of prone positioning are unclear. Regionally injurious ventilation is associated with discrete differential lung transcriptomic changes. Ventilating in the prone, compared with the supine position abrogates regional injury by depressing MKP-1. Adult rats were ventilated with high (18 mL/Kg, PEEP 0) tidal volume (Vt) in supine or prone position. Non ventilated rats were used as controls. Dorsal-caudal lung mRNA was analyzed by microarray.
Project description:Postoperative Pulmonary Complications (PPC) are very common. It severely affects postoperative recovery, particularly in the abdominal surgery. Patients with laparoscopic resection of colorectal cancer generally have a higher age and decreased lung function reserve. At the same time, they prone to developing atelectasis due to the effects of pneumoperitoneum pressure. Therefore, they are a high-risk group of respiratory insufficiency and PPC.
Mechanical ventilation with a low tidal volume is a routine in clinic nowadays. However, this conventional strategy will also result in atelectasis formation. Therefore, it may deteriorate the vulnerable lung function of patients undergoing laparoscopic resection of colorectal cancer. Patients with Acute Lung Injury or Acute Respiratory Distress Syndrome (ALI/ARDS) could benefit from the "open lung approach", including the use of positive end-expiratory pressure (PEEP) and recruitment maneuvers (RMs). Whether a lung protective mechanical ventilation strategy with medium levels of PEEP and repeated RMs, the "open lung approach", protects against respiratory insufficiency and PPC during laparoscopic resection of colorectal cancer is uncertain. The present study aims at comparing the effects of "open lung approach" mechanical ventilation strategy and conventional mechanical ventilation strategy in PPC, extra-pulmonary complications, length of hospital stay, biomarkers of lung injury and changes of respiratory function in patients undergoing general anesthesia for laparoscopic resection of colorectal cancer.
Project description:We have previously demonstrated that pre-B-cell colony enhancing factor (PBEF) ais a biomarker in sepsis and sepsis-induced acute lung injury (ALI) with genetic variants conferring ALI susceptibility118. In the current study, we explored the mechanistic participation of PBEF in ALI and ventilator-induced associated lung injury (VIALI). Initial in vitro studies and demonstrated rhPBEF aas a direct rat neutrophil chemotactic factor in vitro producing marked in vivo increases in BAL leukocytes (PMNs) in vivo following (intratracheal injection (,IT) in C57B6 mice. These latter changes were accompanied by increased BAL levels of the PMN chemoattractants (, KC and MIP2), and modest changes in lung vascular and but were not associated with significant increasesin alveolar permeability. We next explored the potential synergism between rhPBEF administration (IT) and a mechanical ventilation model of modest VILI lung injury (4 hours, 30 ml/kg tidal volume). We and observed dramatic synergistic increases in BAL PMNs, and both BAL protein and cytokine levels (IL-6, TNF-?, KC). Gene expression profiling Microarray analysis further supported a major role for PBEF in the induction of gene modules associated with ALI and VALI (NFkB pathway, leukocyte extravasation, apoptosis, toll receptor signaling). Finally, we exposed wild type and heterozygous PBEF+/- mice (targeted deletion of a single PBEF allele deletion) to a model of severe VILImechanical ventilation-induced lung injury (4 hours, 40 ml/kg tidal volume). PBEF+/- mice were significantly protected from VIALI-associated increases in BAL protein and BAL IL-6 levels and exhibited significantly reduced expression of ALI-associated gene expression modules. Together, these results indicate that PBEF is a key inflammatory mediator intimately involved in both the development and severity of ventilator-induced ALI. Experiment Overall Design: animals were treated by PBS, rhPBEF (IT administration), VILI (4 hours, 30 ml/kg tidal volume), or both.
Project description:Children have a lower incidence and mortality from acute lung injury than adults, and infections are the most common event associated with acute lung injury (ALI). To study the effects of age on susceptibility to ALI, we investigated the responses to microbial products combined with mechanical ventilation in juvenile (21 day) and adult (16 week-old) mice. We hypothesized that the increased incidence and severity of lung injury associated with increasing age is due in large part to acquired changes in the way in which inflammatory responses are activated in the lungs in response to microbial products and mechanical ventilation. Juvenile (21 day) and adult (16 week) C57BL/6 mice were treated with an aerosol of E. coli 0111:B4 lipopolysaccharide (LPS) (20 mL of 0.1 mg/mL) for 30 minutes in a sealed aerosol chamber, immediately followed by mechanical ventilation (LPS+MV) using tidal volume = 15 mL/kg, rate = 80 breaths/min, FiO2 = 30% and positive end expiratory pressure = 2 cm H2O for the duration of the study period time = 2 hours. Comparison groups included mice treated with LPS or mechanical ventilation (MV) alone, and untreated age-matched controls. There were N = 4 animals per group except the juvenile mice treated with MV alone and LPS+MV where there were N = 3. Each sample was an individual animal, therefore there were 30 samples. Mice treated with LPS alone were placed into a sealed aerosol chamber as stated above, and then allowed to breath spontaneously with free access to food and water for the duration of the study period time = 2 hours. Mice treated with MV alone were treated with the mechanical ventilation protocol stated above for the duration of the study period time = 2 hours. At the end of the study period, the mice were euthanized, and the lungs were immediately removed and placed into RNAlater (Ambion, Austin, TX) for at least 24 hr prior to isolation of total lung mRNA.