Critical care : the official journal of the Critical Care Forum
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Comparative Study Clinical Trial Controlled Clinical Trial
Helium-oxygen mixture does not improve gas exchange in mechanically ventilated children with bronchiolitis.
STATEMENT OF Varying concentrations of helium-oxygen (heliox) mixtures were evaluated in mechanically ventilated children with bronchiolitis. We hypothesized that, with an increase in the helium:oxygen ratio, and therefore a decrease in gas density, ventilation and oxygenation would improve in children with bronchiolitis. Ten patients, aged 1-9 months, were mechanically ventilated in synchronized intermittent mandatory ventilation (SIMV) mode with the following gas mixtures delivered at 15-min intervals: 50%/50% nitrogen/oxygen, 50%/50% heliox, 60%/40% heliox, 70%/30% heliox, and return to 50%/50% nitrogen/oxygen. The use of different heliox mixtures compared with 50%/50% nitrogen/oxygen in mechanically ventilated children with bronchiolitis did not result in a significant or noticeable decrease in ventilation or oxygenation.
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Cost is a key concern in fluid management. Relatively few data are available that address the comparative total costs of care between different fluid management regimens in particular clinical indications. Relevant costs of fluid-associated morbidity and mortality, including those incurred after intensive care unit or hospital discharge, also need to be considered in evaluating the cost-benefit ratios of administered fluids. Rigorously designed pharmacoeconomic studies are needed to delineate the costs and benefits of various approaches to fluid management.
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Review
Fluid balance and colloid osmotic pressure in acute respiratory failure: emerging clinical evidence.
Available evidence suggests that both hydrostatic and osmotic forces are important in the development of acute respiratory distress syndrome (ARDS) or, more broadly, acute lung injury (ALI). More than 80% of ARDS patients in a large-scale randomized controlled trial (RCT) exhibited, at least intermittently, pulmonary artery wedge pressures (PAWP) above 18 mmHg. Retrospective analyses have shown that PAWP elevation is associated with increased mortality. ⋯ These results provide evidence that combined therapy with furosemide and albumin is effective in augmenting serum albumin and STP levels, promoting weight loss, and improving oxygenation and longer-term hemodynamic stability. Although mortality did not differ between groups, the RCT showed a trend toward reduced duration of mechanical ventilation and length of stay in the intensive care unit in patients receiving furosemide + albumin. The findings of the RCT further highlight the importance of both hydrostatic and osmotic forces in hypoxemic respiratory failure, a subject that requires further investigation.
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Comparative Study
Emergency airway management by intensive care unit nurses with the intubating laryngeal mask airway and the laryngeal tube.
When using the laryngeal tube and the intubating laryngeal mask airway (ILMA), the medium-size (maximum volume 1100 ml) versus adult (maximum volume 1500 ml) self-inflating bags resulted in significantly lower lung tidal volumes. No gastric inflation occurred when using both devices with either ventilation bag. The newly developed medium-size self-inflating bag may be an option to further reduce the risk of gastric inflation while maintaining sufficient lung ventilation. Both the ILMA and laryngeal tube proved to be valid alternatives for emergency airway management in the experimental model used.
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Physiological background concerning mechanics of the respiratory system, techniques of measurement and clinical implications of pressure-volume curve measurement in mechanically ventilated patients are discussed in the present review. The significance of lower and upper inflection points, the assessment of positive end-expiratory pressure (PEEP)-induced alveolar recruitment and overdistension and rationale for optimizing ventilatory settings in patients with acute lung injury are presented. Evidence suggests that the continuous flow method is a simple and reliable technique for measuring pressure-volume curves at the bedside. In patients with acute respiratory failure, determination of lower and upper inflection points and measurement of respiratory compliance should become a part of the routine assessment of lung injury severity, allowing a bedside monitoring of the evolution of the lung disease and an optimization of mechanical ventilation.