Critical care : the official journal of the Critical Care Forum
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Comparative Study Clinical Trial
Intra- and inter-individual variation of BIS-index and Entropy during controlled sedation with midazolam/remifentanil and dexmedetomidine/remifentanil in healthy volunteers: an interventional study.
We studied intra-individual and inter-individual variability of two online sedation monitors, BIS and Entropy, in volunteers under sedation. ⋯ The large intra-individual and inter-individual variability of BIS and Entropy values in sedated volunteers makes the determination of sedation levels by processed electroencephalogram (EEG) variables impossible. Reports in the literature which draw conclusions based on processed EEG variables obtained from sedated intensive care unit (ICU) patients may be inaccurate due to this variability.
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Septic patients may require anaesthesia for surgery or to facilitate endotracheal intubation for respiratory failure. These patients frequently start with a deranged haemodynamic state, including vasodilation with hypotension, and cardiomyopathy, making induction of anaesthesia a potentially hazardous task. ⋯ Before induction, the physician should understand the haemodynamic state (especially using echocardiography), should restore cardiovascular reserve with inotropes and vasopressors, and should induce anaesthesia with the smallest dose of the safest drug. In the previous issue of Critical Care, Zausig and colleagues show that propofol may not be the safest choice of induction agent in septic patients.
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Blood glucose levels and insulin resistance in critically ill patients on admission to intensive care units (ICUs) have been identified as factors influencing mortality. The pathogenesis of insulin resistance (IR) in critically ill patients is complex and not fully understood. Resistin is a hormone mainly derived from macrophages in humans and from adipose tissue in rodents, which regulates glucose metabolism and insulin sensitivity. In non-critically ill patients, resistin was found to be related to impaired glucose tolerance, insulin resistance, metabolic syndrome, obesity and type 2 diabetes. Therefore, resistin might represent a link between inflammation, acute phase response and insulin resistance in critically ill patients. We aimed to examine the correlation of serum resistin concentrations to parameters of inflammation, organ function, metabolism, disease severity and survival in critically ill patients. ⋯ Serum resistin concentrations are elevated in acute inflammation due to sepsis or systemic inflammatory response syndrome (SIRS). The close correlation with other acute phase proteins suggests a predominant, clinically relevant resistin release from macrophages in ICU patients. Moreover, resistin could potentially serve as a prognostic biomarker in non-sepsis critically ill patients.
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Multicenter Study
Association of arterial blood pressure and vasopressor load with septic shock mortality: a post hoc analysis of a multicenter trial.
It is unclear to which level mean arterial blood pressure (MAP) should be increased during septic shock in order to improve outcome. In this study we investigated the association between MAP values of 70 mmHg or higher, vasopressor load, 28-day mortality and disease-related events in septic shock. ⋯ MAP levels of 70 mmHg or higher do not appear to be associated with improved survival in septic shock. Elevating MAP >70 mmHg by augmenting vasopressor dosages may increase mortality. Future trials are needed to identify the lowest acceptable MAP level to ensure tissue perfusion and avoid unnecessary high catecholamine infusions.
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Comparative Study
Changes in skeletal muscle oxygenation during exercise measured by near-infrared spectroscopy on ascent to altitude.
We sought to quantify changes in skeletal muscle oxygenation during exercise using near-infrared spectroscopy (NIRS) in healthy volunteers ascending to high altitude. ⋯ In most individuals, NIRS can be used to measure exercising skeletal muscle oxygenation in the field. During exercise the patterns of absolute oxygenation are broadly similar at altitude and SL. Following prolonged adaptation to altitude, the rate of muscle desaturation is more rapid than observed at SL but less so in those exposed to extreme hypoxia above 5,300 m.