Person:

Kacmarek, Robert

Background: Although much has evolved in our understanding of the pathogenesis and factors affecting outcome of patients with acute respiratory distress syndrome (ARDS), still there is no specific pharmacologic treatment for ARDS. Several clinical trials have evaluated the utility of corticoids but none of them has demonstrated a definitive benefit due to small sample sizes, selection bias, patient heterogeneity, and time of initiation of treatment or duration of therapy. We postulated that adjunctive treatment of persistent ARDS with intravenous dexamethasone might change the pulmonary and systemic inflammatory response and thereby reduce morbidity, leading to a decrease in duration of mechanical ventilation and a decrease in mortality. Methods/design This is a prospective, multicenter, randomized, controlled trial in 314 patients with persistent moderate/severe ARDS. Persistent ARDS is defined as maintaining a PaO2/FiO2 ≤ 200 mmHg on PEEP ≥ 10 cmH2O and FiO2 ≥ 0.5 after 24 hours of routine intensive care. Eligible patients will be randomly allocated to two arms: (i) conventional treatment without dexamethasone, (ii) conventional treatment plus dexamethasone. Patients in the dexamethasone group will be treated with a daily dose of 20 mg iv from day 1 to day 5, and 10 mg iv from day 6 to day 10. Primary outcome is the number of ventilator-free days, defined as days alive and free from mechanical ventilation at day 28 after intubation. Secondary outcome is all-cause mortality at day 60 after enrollment. Discussion This study will be the largest randomized controlled clinical trial to assess the role of dexamethasone in patients with persistent ARDS. Trial registration Registered on 21 November 2012 as DEXA-ARDS at ClinicalTrials.gov website (NCT01731795). Electronic supplementary material The online version of this article (doi:10.1186/s13063-016-1456-4) contains supplementary material, which is available to authorized users.

ABSTRACT Background: Ventilatory strategy and specifically positive end-expiratory pressure (PEEP) can modulate the inflammatory response and pulmonary-to-systemic translocation of lipopolysaccharide (LPS). Both inflammation and ventilatory pattern may modify brain activation, possibly worsening the patient's outcome and resulting in cognitive sequelae. Methods: We prospectively studied Sprague–Dawley rats randomly assigned to undergo 3 h mechanical ventilation with 7 mL/kg tidal ventilation and either 2 cmH2O or 7 cmH2O PEEP after intratracheal instillation of LPS or saline. Healthy nonventilated rats served as baseline. We analyzed lung mechanics, gas exchange, lung and plasma cytokine levels, lung apoptotic cells, and lung neutrophil infiltration. To evaluate brain neuronal activation, we counted c-Fos immunopositive cells in the retrosplenial cortex (RS), thalamus, supraoptic nucleus (SON), nucleus of the solitary tract (NTS), paraventricular nucleus (PVN), and central amygdala (CeA). Results: LPS increased lung neutrophilic infiltration, lung and systemic MCP-1 levels, and neuronal activation in the CeA and NTS. LPS-instilled rats receiving 7 cmH2O PEEP had less lung and systemic inflammation and more c-Fos-immunopositive cells in the RS, SON, and thalamus than those receiving 2 cmH2O PEEP. Applying 7 cmH2O PEEP increased neuronal activation in the CeA and NTS in saline-instilled rats, but not in LPS-instilled rats. Conclusions: Moderate PEEP prevented lung and systemic inflammation secondary to intratracheal LPS instillation. PEEP also modified the neuronal activation pattern in the RS, SON, and thalamus. The relevance of these differential brain c-Fos expression patterns in neurocognitive outcomes should be explored.