Critical care : the official journal of the Critical Care Forum
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Sepsis-associated encephalopathy (SAE) is a state of acute brain dysfunction in response to a systemic infection. We propose that systemic inflammation during sepsis causes increased adhesion of leukocytes to the brain microvasculature, resulting in blood-brain barrier dysfunction. Thus, our objectives were to measure inflammatory analytes in plasma of severe sepsis patients to create an experimental cytokine mixture (CM), and to use this CM to investigate the activation and interactions of polymorphonuclear leukocytes (PMN) and human cerebrovascular endothelial cells (hCMEC/D3) in vitro. ⋯ Human SSCM up-regulates PMN pro-adhesive phenotype and promotes PMN adhesion to cerebrovascular endothelial cells through a β2-integrin-ICAM-1-dependent mechanism. PMN adhesion to the brain microvasculature may contribute to SAE.
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We previously showed in animals that the ratio of inspired tidal volume (Vtinsp) to inspiratory peak electrical activity of the diaphragm (EAdipk) can be used to quantify the respective patient and ventilator breath contributions (PVBCs) during neurally adjusted ventilatory assist (NAVA). The PVBC index has not been tested clinically. ⋯ This clinical study confirms previous experimental results showing that the PVBC(2) predicts the contribution of the inspiratory muscles versus that of the ventilator during NAVA, when differences in effort (EAdi) between non-assisted and assisted breaths are limited. PVBC could help to quantify and standardize the adjustment of the level of assist, and hence reduce the risks of excessive ventilatory assist in patients.
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Observational Study
Skeletal muscle oxygenation in severe trauma patients during haemorrhagic shock resuscitation.
Early alterations in tissue oxygenation may worsen patient outcome following traumatic haemorrhagic shock. We hypothesized that muscle oxygenation measured using near-infrared spectroscopy (NIRS) on admission could be associated with subsequent change in the SOFA score after resuscitation. ⋯ Differences in StO2 parameters on admission of traumatic haemorrhagic shock were found between patients who had an improvement in organ failure in the first 72 hours and those who had unchanged or worse conditions. The use of NIRS to guide the initial management of trauma patients with haemorrhagic shock warrants further investigations.
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Clinical Trial
Neurally adjusted ventilatory assist and proportional assist ventilation both improve patient-ventilator interaction.
The objective was to compare the impact of three assistance levels of different modes of mechanical ventilation; neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV), and pressure support ventilation (PSV) on major features of patient-ventilator interaction. ⋯ PAV and NAVA both prevent overdistention, improve neuromechanical coupling, restore the variability of the breathing pattern, and decrease patient-ventilator asynchrony in fairly similar ways compared with PSV. Further studies are needed to evaluate the possible clinical benefits of NAVA and PAV on clinical outcomes.
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Medical practice is rooted in our dependence on the best available evidence from incremental scientific experimentation and rigorous clinical trials. Progress toward determining the true worth of ongoing practice or suggested innovations can be glacially slow when we insist on following the stepwise scientific pathway, and a prevailing but imperfect paradigm often proves difficult to challenge. ⋯ Our intent was to stimulate insightful thinking and free interchange, and perhaps to point in new directions toward lines of innovative theory and improved care of the critically ill. In what follows, a brief background outlines the rationale for each novel and deliberately provocative unconfirmed idea endorsed by the presenter.