Relationship between microaspiration and ventilator-associated events: A post-hoc analysis of a randomized controlled trial.

OBJECTIVE: The relationship between ventilator-associated events (VAE) and microaspiration in intubated patients has not be studied. The objective of this study was to evaluate the relationship between abundant microaspiration of oropharyngeal secretions or gastric contents and the incidence of VAE. PATIENTS AND METHODS: This was a post hoc analysis of the BESTCUFF study, which was a multicenter, cluster randomized, cross-over, controlled, open-label trial in adult patients ventilated for over 48 h. All tracheal aspirates were sampled for 48 h following enrollment, with quantitative measurement of pepsin and alpha-amylase. VAE were identified using National Healthcare Safety Network criteria, based on PEEP or FiO2 variations compared to stable parameters in previous days. The primary objective was to assess the relationship between abundant global microaspiration and the incidence of VAE, adjusted for pre-specified confounding factors (sex, SAPS II score and Glasgow coma scale). RESULTS: 261 patients were included, of which 31 (11.9%) developed VAE, with an overall median age of 65 (interquartile range 52-74), a majority of male patients (164, 62.8%), a median SAPS II score of 50 [40-61], a median SOFA score of 8 [5-11], and acute respiratory failure as main reason for ICU admission (117, 44.8%).The incidence of VAE was not significantly associated with abundant global microaspiration (adjusted cause-specific hazard ratio (cHR): 1.55 [0.46-5.17), abundant gastric microaspiration (adjusted cHR: 1.24 [0.61-2.53), or with abundant oropharyngeal microaspiration (adjusted HR: 1.07 [0.47-2.42]). CONCLUSIONS: Our results suggest no significant association between abundant global, gastric or oropharyngeal microaspiration and the incidence of VAE. IMPLICATIONS FOR CLINICAL PRACTICE: This study underscores that measuring microaspiration in intubated critically ill patients might not be useful to predict the diagnosis of VAE or to evaluate interventions aiming at preventing these complications.

Identification of insulin-sensitizing molecules acting by disrupting the interaction between the Insulin Receptor and Grb14.

Metabolic diseases are characterized by a decreased action of insulin. During the course of the disease, usual treatments frequently fail and patients are finally submitted to insulinotherapy. There is thus a need for innovative therapeutic strategies to improve insulin action. Growth factor receptor-bound protein 14 (Grb14) is a molecular adapter that specifically binds to the activated insulin receptor (IR) and inhibits its tyrosine kinase activity. Molecules disrupting Grb14-IR binding are therefore potential insulin-sensitizing agents. We used Structure-Based Virtual Ligand Screening to generate a list of 1000 molecules predicted to hinder Grb14-IR binding. Using an acellular bioluminescence resonance energy transfer (BRET) assay, we identified, out of these 1000 molecules, 3 compounds that inhibited Grb14-IR interaction. Their inhibitory effect on insulin-induced Grb14-IR interaction was confirmed in co-immunoprecipitation experiments. The more efficient molecule (C8) was further characterized. C8 increased downstream Ras-Raf and PI3-kinase insulin signaling, as shown by BRET experiments in living cells. Moreover, C8 regulated the expression of insulin target genes in mouse primary hepatocytes. These results indicate that C8, by reducing Grb14-IR interaction, increases insulin signalling. The use of C8 as a lead compound should allow for the development of new molecules of potential therapeutic interest for the treatment of diabetes.

Impact of tapered-cuff tracheal tube on microaspiration of gastric contents in intubated critically ill patients: a multicenter cluster-randomized cross-over controlled trial.

PURPOSE: Studies on the impact of tapered-cuff tracheal tubes on rates of microaspiration and ventilator-associated pneumonia (VAP) in intubated patients have reported conflicting results. The aim of this study was to determine the influence of this shape of tracheal cuff on abundant microaspiration of gastric contents in critically ill patients. METHODS: All patients intubated in the intensive care unit (ICU) and requiring mechanical ventilation for at least 48 h were eligible for this multicenter cluster-randomized controlled cross-over open-label study. The primary outcome was abundant microaspiration of gastric contents, defined by the presence of pepsin at significant level in >30% of tracheal aspirates. Quantitative measurement of pepsin and salivary amylase was performed in all tracheal aspirates during the 48 h following enrollment. RESULTS: A total of 326 patients were enrolled in the ten participating ICUs (162 in the PVC tapered-cuff group and 164 in the standard-cuff group). Patient characteristics were similar in the two study groups. The proportion of patients with abundant microaspiration of gastric contents was 53.5% in the tapered-cuff and 51.0% in the standard-cuff group (odds ratio 1.14, 95% CI 0.72-1.82). While abundant microaspiration of oropharyngeal secretions was not significantly different (77.4 vs 68.6%, p = 0.095), the proportion of patients with tracheobronchial colonization was significantly lower (29.6 vs 43.3%, p = 0.01) in the tapered-cuff than in the standard-cuff group. No significant difference between the two groups was found for other secondary outcomes, including ventilator-associated events and VAP. CONCLUSIONS: This trial showed no significant impact of tapered-cuff tracheal tubes on abundant microaspiration of gastric contents. TRIAL REGISTRATION: ClinicalTrials.gov, number NCT01948635.

Impact of tracheal cuff shape on microaspiration of gastric contents in intubated critically ill patients: study protocol for a randomized controlled trial.

BACKGROUND: Ventilator-associated pneumonia (VAP) is the most common infection in intubated critically ill patients. Microaspiration of the contaminated gastric and oropharyngeal secretions is the main mechanism involved in the pathophysiology of VAP. Tracheal cuff plays an important role in stopping the progression of contaminated secretions into the lower respiratory tract. Previous in vitro studies suggested that conical cuff shape might be helpful in improving tracheal sealing. However, clinical studies found conflicting results. The aim of this study is to determine the impact of conical tracheal cuff shape on the microaspiration of gastric contents in critically ill patients. METHODS/DESIGN: This prospective cluster randomized controlled crossover open-label trial is currently being conducted in ten French intensive care units (ICUs). Patients are allocated to intubation with a polyvinyl chloride (PVC) standard (barrel)-shaped or a PVC conical-shaped tracheal tube. The primary objective is to determine the impact of the conical shaped tracheal cuff on abundant microaspiration of gastric contents. Secondary outcomes include the incidence of microaspiration of oropharyngeal secretions, tracheobronchial colonization, VAP and ventilator-associated events. Abundant microaspiration is defined as the presence of pepsin at significant level (>200 ng/ml) in at least 30 % of the tracheal aspirates. Pepsin and amylase are quantitatively measured in all tracheal aspirates during the 48 h following inclusion. Quantitative tracheal aspirate culture is performed at inclusion and twice weekly. We plan to recruit 312 patients in the participating ICUs. DISCUSSION: BEST Cuff is the first randomized controlled study evaluating the impact of PVC tracheal-cuff shape on gastric microaspirations in patients receiving invasive mechanical ventilation. Enrollment began in June 2014 and is expected to end in October 2015. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01948635 (registered 31 August 2013).