Respiratory care
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High-frequency jet ventilation (HFJV) is primarily used in neonates but may also have a role in the treatment of infants with congenital heart disease and severe respiratory failure. We hypothesized that HFJV would result in improved gas exchange in these infants. ⋯ HFJV was associated with a decrease in [Formula: see text] and an increase in pH in infants with congenital heart disease who remained on HFJV 4 to 6 h after initiation.
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The use of high-frequency oscillatory ventilation (HFOV) is backed by sound physiologic rationale, but clinical data on the elective use of HFOV have been largely disappointing. Nonetheless, HFOV is still occasionally used as a rescue mode in patients with severe hypoxemia. The evidence that supports this practice is sparse. ⋯ Our study did not support utilization of HFOV as a "last-ditch" rescue measure in subjects with respiratory failure. The delayed timing of HFOV initiation and its detrimental hemodynamic effects are among the potential reasons for the high mortality rate.
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The role of end-expiratory lung volume (EELV) during a spontaneous breathing trial (SBT) in patients who were tracheostomized and on prolonged mechanical ventilation is unclear. This study aimed to assess EELV during a 60-min SBT and its correlation with weaning success. ⋯ The change in EELV during a 60-min SBT may be of prognostic value for liberation from prolonged mechanical ventilation in patients who had a tracheostomy. Our findings suggest a model to understand the underlying mechanism of failure of liberation from mechanical ventilation in these patients.
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The ventilatory ratio (VR) is a simple index of ventilatory efficiency and dead space. Because increased dead space and high ventilatory demands impose a limitation to unassisted ventilation, and may predispose patients to injurious strong efforts during assisted ventilation, evaluation of the VR could provide helpful information during weaning. We hypothesize that there is a threshold of VR associated with tolerance of unassisted breathing. ⋯ Successful liberation from assisted ventilation was associated with a VR < 2. A VR > 2 was associated with longer duration of weaning. The VR could be used as an additional tool to facilitate the decision-making process during weaning.
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The generation of excessive inspiratory muscle pressure (Pmus) during assisted mechanical ventilation in patients with respiratory failure may result in acute respiratory muscle injury and/or fatigue, and exacerbate ventilator-induced lung injury. A readily available noninvasive surrogate measure of Pmus may help in titrating both mechanical ventilation and sedation to minimize these risks. This bench study explored the feasibility and accuracy of using a ventilator's expiratory pause hold function to measure Pmus across multiple operators. ⋯ The expiratory pause maneuver generally provided reproducible, stable approximations of Δ Pmus across ventilators and ventilator settings, and a range of simulated effort. Technique standardization produced relatively consistent results across multiple operators. The expiratory pause maneuver seemed feasible for general use in monitoring inspiratory effort during assisted mechanical ventilation.