Resp Care
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The rapid-shallow-breathing index (RSBI) is widely used to evaluate mechanically ventilated patients for weaning and extubation, but it is determined in different clinical centers in a variety of ways, under conditions that are not always comparable. We hypothesized that the value of RSBI may be significantly influenced by common variations in measurement conditions and technique. ⋯ RSBI can be significantly affected by the level of ventilator support, but is relatively unaffected by both the technique used to determine the breathing pattern and the time of day at which it is measured.
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Randomized Controlled Trial
The addition of mechanical insufflation/exsufflation shortens airway-clearance sessions in neuromuscular patients with chest infection.
Mechanical insufflation/exsufflation (in-exsufflation) increases peak cough flow and may improve sputum clearance. No studies have compared current respiratory physiotherapy practice (manual percussion, shaking, and assisted cough) plus mechanical in-exsufflation to current physiotherapy practice without in-exsufflation in noninvasive-ventilation (NIV) dependent neuromuscular patients with an acute respiratory-tract infection. We hypothesized that airway clearance in these patients would be more effective with in-exsufflation, compared to without in-exsufflation. ⋯ This is a short-term study of the use of in-exsufflation as a supplement to standard NIV plus physiotherapy in a small group of patients with neuromuscular disease. The addition of mechanical in-exsufflation shortened airway-clearance sessions. The device appeared to be safe and well tolerated, and may provide additional benefit to patients with neuromuscular disease and upper-respiratory-tract infection; further studies are indicated.
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Comparative Study
Comparison of semi-quantitative endotracheal aspirates to quantitative non-bronchoscopic bronchoalveolar lavage in diagnosing ventilator-associated pneumonia.
Current strategies for diagnosing ventilator-associated pneumonia (VAP) favor the use of quantitative methods; however, semi-quantitative cultures of endotracheal aspirates are still commonly used. ⋯ Semi-quantitative cultures of endotracheal aspirate are poorly concordant with quantitative cultures obtained via non-bronchoscopic BAL. Although the performance of endotracheal aspirate improves when antibiotic treatment is considered, guiding therapy on the basis of semi-quantitative cultures may still result in failure to identify potentially multiple-drug-resistant pathogens, and would also tend to promote excessive antibiotic usage. Our data support the use of quantitative cultures in diagnosing VAP.
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Adaptive pressure control is a mode of mechanical ventilation where inflation pressure is adjusted by the ventilator to achieve a target tidal volume (VT). This means that as patient effort increases, inflation pressure is reduced, which may or may not be clinically appropriate. The purpose of this study was to evaluate the relationship between ventilator work output and patient effort in adaptive pressure control. ⋯ Adaptive-pressure-control algorithms differ between ventilators in their response to increasing patient effort. Notably, some ventilators allow the patient to assume all of the WOB, and some provide a minimum level of WOB regardless of patient effort.
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Patients with obstructive airway conditions, including chronic obstructive pulmonary disease (COPD), use nebulizers for drug delivery. Tidal breathing patterns employed by patients during nebulized drug delivery may vary. It is unclear whether different breathing patterns affect the emitted quantity of nebulized drug. This in vitro study evaluated whether different tidal breathing patterns that encompass a range that could be observed in COPD patients influence the emitted amount of nebulized arformoterol. ⋯ These breath-simulation experiments suggest that only about 20% of the nominal 15-microg arformoterol dose was emitted from the nebulizer apparatus with each of the 4 tidal breathing patterns studied, and that a longer inspiratory phase was associated with greater inhaled dose.