Common Lung Microbiome Identified among Mechanically Ventilated Surgical Patients.
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ABSTRACT:
SUBMITTER: Smith AD
PROVIDER: S-EPMC5127496 | biostudies-literature | 2016
REPOSITORIES: biostudies-literature
Publications
Common Lung Microbiome Identified among Mechanically Ventilated Surgical Patients.
Smith Ashley D AD Zhang Yan Y Barber Robert C RC Minshall Christian T CT Huebinger Ryan M RM Allen Michael S MS
PloS one 20161129 11
The examination of the pulmonary microbiome in patients with non-chronic disease states has not been extensively examined. Traditional culture based screening methods are often unable to identify bacteria from bronchoalveolar lavage samples. The advancement of next-generation sequencing technologies allows for a culture-independent molecular based analysis to determine the microbial composition in the lung of this patient population. For this study, the Ion Torrent PGM system was used to assess ...[more]
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Project description:Mechanically ventilated surgical patients have a variety of bacterial flora that are often undetectable by traditional culture methods. The source of infection in many of these patients remains unclear. To address this clinical problem, the microbiome profile and host inflammatory response in bronchoalveolar lavage samples from the surgical intensive care unit were examined relative to clinical pathology diagnoses. The hypothesis was tested that clinical diagnosis of respiratory tract flora were similar to culture positive lavage samples in both microbiome and inflammatory profile. Bronchoalveolar lavage samples were collected in the surgical intensive care unit as standard of care for intubated individuals with a clinical pulmonary infection score of >6 or who were expected to be intubated for >48 hours. Cytokine analysis was conducted with the Bioplex Pro Human Th17 cytokine panel. The microbiome of the samples was sequenced for the 16S rRNA region using the Ion Torrent. Microbiome diversity analysis showed the culture-positive samples had the lowest levels of diversity and culture negative with the highest based upon the Shannon-Wiener index (culture positive: 0.77 ± 0.36, respiratory tract flora: 2.06 ± 0.73, culture negative: 3.97 ± 0.65). Culture-negative samples were not dominated by a single bacterial genera. Lavages classified as respiratory tract flora were more similar to the culture-positive in the microbiome profile. A comparison of cytokine expression between groups showed increased levels of cytokines (IFN-g, IL-17F, IL-1B, IL-31, TNF-a) in culture-positive and respiratory tract flora groups. Culture-positive samples exhibited a more robust immune response and reduced diversity of bacterial genera. Lower cytokine levels in culture-negative samples, despite a greater number of bacterial species, suggest a resident nonpathogenic bacterial community may be indicative of a normal pulmonary environment. Respiratory tract flora samples were most similar to the culture-positive samples and may warrant classification as culture-positive when considering clinical treatment.
| S-EPMC6200244 | biostudies-literature
Project description:The respiratory microbiome has been less explored than the gut microbiome. Despite the speculated importance of dysbiosis of the microbiome in ventilator-associated pneumonia (VAP) and acute respiratory distress syndrome (ARDS), only few studies have been performed in invasively ventilated ICU patients. And only the results of small cohorts have been published. An overlap exists between bacterial populations observed in the lower respiratory tract and the oropharyngeal tract. The bacterial microbiota is characterized by relatively abundant bacteria difficult to cultivate by standard methods. Under mechanical ventilation, a dysbiosis occurs with a drop overtime in diversity. During VAP development, lung dysbiosis is characterized by a shift towards a dominant bacterial pathogen (mostly Proteobacteria) whereas enrichment of gut-associated bacteria mainly Enterobacteriaceae is the specific feature discriminating ARDS patients. However, the role of this dysbiosis in VAP and ARDS pathogenesis is not yet fully understood. A more in-depth analysis of the interplay between bacteria, virus and fungi and a better understanding of the host-microbiome interaction could provide a more comprehensive view of the role of the microbiome in VAP and ARDS pathogenesis. Priority should be given to validate a consensual and robust methodology for respiratory microbiome research and to conduct longitudinal studies. A deeper understanding of microbial interplay should be a valuable guide for care of ARDS and VAP preventive/therapeutic strategies. We present a review on the current knowledge and expose perspectives and potential clinical applications of respiratory microbiome research in mechanically ventilated patients.
| S-EPMC7871139 | biostudies-literature
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| S-EPMC4313225 | biostudies-literature
Project description:Objective: Compare the duration of mechanical ventilation between patients receiving sedation with continuous infusions of propofol alone or combination with the use of dexmedetomidine and propofol. Design: Retrospective, propensity matched (1:1) cohort study, employing eight variables chosen a priori for matching. Timing of exposure to dexmedetomidine initiation was incorporated into a matching algorithm. Setting: Level 1, university-based, 32-bed, adult, mixed trauma and surgical intensive care unit (SICU). Continuous sedation was delivered according to a protocol methodology with daily sedation vacation and spontaneous breathing trials. Choice of sedation agent was physician directed. Patients: Between 2010 and 2014, 149 SICU patients receiving mechanical ventilation for >24 h received dexmedetomidine with propofol. Propensity matching resulted in 143 pair cohorts. Interventions: Dexmedetomidine with propofol or propofol alone. Measurements and Main Results: There was no statistical difference in SICU length of stay (LOS), with a median absolute difference of 5.3 h for propofol alone group (p = 0.43). The SICU mortality was not statistically different (RR = 1.002, p = 0.88). Examining a 14-day period post-treatment with dexmedetomidine, on any given day (excluding days 1 and 14), dexmedetomidine with propofol-treated patients had a 0.5% to 22.5% greater likelihood of being delirious (CAM-ICU positive). In addition, dexmedetomidine with propofol-treated patients had a 4.5% to 18.8% higher likelihood of being above the target sedation score (more agitated) compared to propofol-alone patients. Conclusions: In this propensity matched cohort study, adjunct use of dexmedetomidine to propofol did not show a statistically significant reduction with respect to mechanical ventilation (MV) duration, SICU LOS, or SICU mortality, despite a trend toward receiving fewer hours of propofol. There was no evidence that dexmedetomidine with propofol improved sedation scores or reduced delirium.
| S-EPMC6164835 | biostudies-other
Project description:BACKGROUND:Atelectasis is a common finding in mechanically ventilated children with healthy lungs. This lung collapse cannot be overcome using standard levels of positive end-expiratory pressure (PEEP) and thus for only individualized lung recruitment maneuvers lead to satisfactory therapeutic results. In this short communication, we demonstrate by lung ultrasound images (LUS) the effect of a postural recruitment maneuver (P-RM, i.e., a ventilatory strategy aimed at reaerating atelectasis by changing body position under constant ventilation). RESULTS:Data was collected in the operating room of the Hospital Privado de Comunidad, Mar del Plata, Argentina. Three anesthetized children undergoing mechanical ventilation at constant settings were sequentially subjected to the following two maneuvers: (1) PEEP trial in the supine position PEEP was increased to 10 cmH2O for 3 min and then decreased to back to baseline. (2) P-RM patient position was changed from supine to the left and then to the right lateral position for 90 s each before returning to supine. The total P-RM procedure took approximately 3 min. LUS in the supine position showed similar atelectasis before and after the PEEP trial. Contrarily, atelectasis disappeared in the non-dependent lung when patients were placed in the lateral positions. Both lungs remained atelectasis free even after returning to the supine position. CONCLUSIONS:We provide LUS images that illustrate the concept and effects of postural recruitment in children. This maneuver has the advantage of achieving recruitment effects without the need to elevate airways pressures.
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Project description:RationaleMechanical ventilation with O₂-rich gas (MV-O₂) offers life-saving treatment for respiratory failure, but also promotes lung injury. We previously reported that MV-O2 of newborn mice increased lung elastase activity, causing elastin degradation and redistribution of elastic fibers from septal tips to alveolar walls. These changes were associated with transforming growth factor (TGF)-β activation and increased apoptosis leading to defective alveolarization and lung growth arrest, as seen in neonatal chronic lung disease.ObjectivesTo determine if intratracheal treatment of newborn mice with the serine elastase inhibitor elafin would prevent MV-O₂-induced lung elastin degradation and the ensuing cascade of events causing lung growth arrest.MethodsFive-day-old mice were treated via tracheotomy with recombinant human elafin or vehicle (lactated-Ringer solution), followed by MV with 40% O₂ for 8-24 hours; control animals breathed 40% O₂ without MV. At study's end, lungs were harvested to assess key variables noted below.Measurements and main resultsMV-O₂ of vehicle-treated pups increased lung elastase and matrix metalloproteinase-9 activity when compared with unventilated control animals, causing elastin degradation (urine desmosine doubled), TGF-β activation (pSmad-2 tripled), and apoptosis (cleaved-caspase-3 increased 10-fold). Quantitative lung histology showed larger and fewer alveoli, greater inflammation, and scattered elastic fibers. Elafin blocked these MV-O₂-induced changes.ConclusionsIntratracheal elafin, by blocking lung protease activity, prevented MV-O₂-induced elastin degradation, TGF-β activation, apoptosis, and dispersion of matrix elastin, and attenuated lung structural abnormalities noted in vehicle-treated mice after 24 hours of MV-O₂. These findings suggest that elastin breakdown contributes to defective lung growth in response to MV-O₂ and might be targeted therapeutically to prevent MV-O₂-induced lung injury.
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Project description:IntroductionStudies indicate that mechanically ventilated patients develop significant diaphragm muscle weakness, but the etiology of weakness and its clinical impact remain incompletely understood. We assessed diaphragm strength in mechanically ventilated medical ICU patients, correlated the development of diaphragm weakness with multiple clinical parameters, and examined the relationship between the level of diaphragm weakness and patient outcomes.MethodsTransdiaphragmatic twitch pressure (PdiTw) in response to bilateral magnetic stimulation of the phrenic nerves was measured. Diaphragm weakness was correlated with the presence of infection, blood urea nitrogen, albumin, and glucose levels. The relationship of diaphragm strength to patient outcomes, including mortality and the duration of mechanical ventilation for successfully weaned patients, was also assessed.ResultsWe found that infection is a major risk factor for diaphragm weakness in mechanically ventilated medical ICU patients. Outcomes for patients with severe diaphragm weakness (PdiTw<10 cmH2O) were poor, with a markedly increased mortality (49%) compared to patients with PdiTw?10 cmH2O (7% mortality, P=0.022). In addition, survivors with PdiTw<10 cmH2O required a significantly longer duration of mechanical ventilation (12.3±1.7 days) than those with PdiTw?10 cmH2O (5.5±2.0 days, P=0.016).ConclusionsInfection is a major cause of severe diaphragm weakness in mechanically ventilated patients. Moreover, diaphragm weakness is an important determinant of poor outcomes in this patient population.
| S-EPMC3840677 | biostudies-literature
Project description:BackgroundTracheostomy is used for patients who require prolonged mechanical ventilation. Extensive research has described the provision and optimal timing of tracheostomy, but very little describes tracheostomy utilization in low- and middle-income countries, particularly in sub-Saharan Africa.MethodsThis prospective cohort study describes patients admitted to the intensive care unit (ICU) of a tertiary hospital in Malawi who received tracheostomy versus those who did not, with a primary outcome of hospital mortality. We performed subgroup analysis of patients with severe head injuries.ResultsThe analysis included 451 patients admitted to the study ICU between September 2016 and July 2018. Overall hospital mortality was 40% for patients who received tracheostomy and 63% for patients who did not. Logistic regression modeling revealed an odds ratio (OR) of 0.34 (95% CI 0.18-0.64) for hospital mortality among patients who received tracheostomy versus those who did not (p < 0.001). Standardized mortality ratio weighting revealed an odds ratio of 0.81 (95% CI 0.65-0.99, p < 0.001) for hospital death among patients who received tracheostomy versus those who did not. In the subgroup excluding severe head injury, both ICU (50%) and hospital mortality (75%) were higher overall, but hospital mortality was not more common for patients with tracheostomy versus without (OR 1.28, 95% CI 0.94-1.74, p = 0.104).ConclusionsTracheostomy is not associated with hospital mortality in a Malawi ICU cohort, but these results are affected by the presence of head injury. Research may focus on home tracheostomy care given the lack of hospital discharge options for patients in austere settings.
| S-EPMC8171994 | biostudies-literature
Project description:ObjectivesThe determinants of decisions to limit life support (withholding or withdrawal) in ventilated stroke patients have been evaluated mainly for patients with intracranial hemorrhages. We aimed to evaluate the frequency of life support limitations in ventilated ischemic and hemorrhagic stroke patients compared with a nonbrain-injured population and to determine factors associated with such decisions.DesignMulticenter prospective French observational study.SettingFourteen ICUs of the French OutcomeRea network.PatientsFrom 2005 to 2016, we included stroke patients and nonbrain-injured patients requiring invasive ventilation within 24 hours of ICU admission.InterventionNone.Measurements and main resultsWe identified 373 stroke patients (ischemic, n = 167 [45%]; hemorrhagic, n = 206 [55%]) and 5,683 nonbrain-injured patients. Decisions to limit life support were taken in 41% of ischemic stroke cases (vs nonbrain-injured patients, subdistribution hazard ratio, 3.59 [95% CI, 2.78-4.65]) and in 33% of hemorrhagic stroke cases (vs nonbrain-injured patients, subdistribution hazard ratio, 3.9 [95% CI, 2.97-5.11]). Time from ICU admission to the first limitation was longer in ischemic than in hemorrhagic stroke (5 [3-9] vs 2 d [1-6] d; p < 0.01). Limitation of life support preceded ICU death in 70% of ischemic strokes and 45% of hemorrhagic strokes (p < 0.01). Life support limitations in ischemic stroke were increased by a vertebrobasilar location (vs anterior circulation, subdistribution hazard ratio, 1.61 [95% CI, 1.01-2.59]) and a prestroke modified Rankin score greater than 2 (2.38 [1.27-4.55]). In hemorrhagic stroke, an age greater than 70 years (2.29 [1.43-3.69]) and a Glasgow Coma Scale score less than 8 (2.15 [1.08-4.3]) were associated with an increased risk of limitation, whereas a higher nonneurologic admission Sequential Organ Failure Assessment score was associated with a reduced risk (per point, 0.89 [0.82-0.97]).ConclusionsIn ventilated stroke patients, decisions to limit life support are more than three times more frequent than in nonbrain-injured patients, with different timing and associated risk factors between ischemic and hemorrhagic strokes.
| S-EPMC7901798 | biostudies-literature