Critical care : the official journal of the Critical Care Forum
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Comparative Study
Comparison of three methods of extravascular lung water volume measurement in patients after cardiac surgery.
Measurement of extravascular lung water (EVLW) by using the lithium-thermal (Li-thermal) and single-thermal indicator dilution methods was compared with the indocyanine green-thermal (ICG-thermal) method in humans. ⋯ The principal finding of this study was that the prototype Li-thermal method did not provide reliable measurements of EVLW volume when compared with the ICG-thermal reference technique. Although minimal bias was associated with the single-thermal method, limits of agreement were approximately 45% of the normal value of EVLW volume. The Li-thermal method performed very poorly because of the overestimation of mean indicator transit time by using an external lithium ion electrode. These findings suggest that the assessment of lung water content by lithium-indicator dilution is not sufficiently reliable for clinical use in individual patients.
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Ventilator-associated pneumonia (VAP) is a common cause of morbidity, antibiotic use, increased length of stay and, possibly, increased mortality in ICU patients. Colonization of the oropharyngeal cavity with potentially pathogenic micro-organisms is instrumental in the pathogenesis of VAP, and selective oropharyngeal decontamination (SOD) with antibiotics (AB-SOD) or antiseptics, such as chlorhexidine gluconate (CHX-SOD), has been associated with reduced incidences of VAP. ⋯ CHX-SOD was associated with a reduction in Staphylococcus aureus colonization, but the study was underpowered to demonstrate a reduction in VAP incidence. We urgently need well-designed and adequately powered studies to evaluate the potential benefits of CHX-SOD on patient outcome in ICUs.
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Physiological determinants of weaning success and failure are usually studied in ventilator-supported patients, comparing those who failed a trial of spontaneous breathing with those who tolerated such a trial and were successfully extubated. A major limitation of these studies was that the two groups may be not comparable concerning the severity of the underlying disease and the presence of comorbidities. In this physiological study, we assessed the determinants of weaning success in patients acting as their own control, once they are eventually liberated from the ventilator. ⋯ The recovery of an inadequate inspiratory muscle force could be the major determinant of 'late' weaning success, since this allows the patients to breathe far below the diaphragm fatigue threshold.
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Extracorporeal lung-supporting procedures open the possibility of staying within widely accepted margins of 'protective' mechanical ventilation (tidal volume of less than 6 mL per kg of predicted ideal body weight and plateau pressure of less than 30 cm H2O) in most any case of respiratory failure or even of further reducing ventilator settings while still providing adequate gas exchange. There is evidence that, at least in some patients, a further reduction in tidal volumes might be beneficial. ⋯ In addition, a simple reduction of the tidal volume will certainly not be the right answer. If extracorporeal support largely influences gas exchange, the 'optimal' tidal volume/positive end-expiratory pressure ratio keeping stress and strain low and avoiding alveolar derecruitment will still have to be individually defined.
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Comment
Searching for an ideal hemodynamic marker to predict short-term outcome in cardiogenic shock.
Cardiogenic shock is a lethal condition. Physicians are searching for hemodynamic markers which could help risk-stratification of patients in this picture. Torgersen and coworkers present an hourly time integral of the cardiac power index and cardiac index drops to predict outcomes in the setting of cardiogenic shock. Continuous monitoring of hemodynamic markers may have a role in prediction of outcomes.