Resp Care
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Critically ill patients requiring mechanical ventilation are frequently subjected to long periods of physical inactivity, leading to skeletal muscle atrophy and muscle weakness. Disuse muscle atrophy is the result of complex mechanisms, including altered protein turnover and disturbed redox signaling. These ICU-acquired complications are associated with longer duration of mechanical ventilation, prolonged ICU and hospital stays, and poorer functional status at hospital discharge. ⋯ Physical rehabilitation, when started at the onset of mechanical ventilation, has been associated with shorter periods of mechanical ventilation, decreased ICU and hospital stay, and improved physical function at hospital discharge. This review summarizes the impact of both physical inactivity and mechanical ventilation on skeletal and diaphragmatic muscles structure and function. Also reviewed is the growing evidence demonstrating the feasibility and safety of early physical rehabilitation interventions for mechanically ventilated patients, as well as their benefit on patient outcomes.
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In recent years, there has been increasing interest in the use of noninvasive ventilation (NIV) in the post-extubation period to shorten the length of invasive ventilation, to prevent extubation failure, and to rescue a failed extubation. The purpose of this review is to summarize the evidence related to the use of NIV in these settings. NIV can be used to allow earlier extubation in selected patients who do not successfully complete a spontaneous breathing trial (SBT). ⋯ In this setting, NIV is indicated only in patients with hypercapnic respiratory failure. Reintubation should not be delayed if NIV is not immediately successful in reversing the post-extubation respiratory failure. Evidence does not support routine use of NIV post-extubation.
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The ventilator discontinuation process is an essential component of overall ventilator management. Undue delay leads to excess stay, iatrogenic lung injury, unnecessary sedation, and even higher mortality. On the other hand, premature withdrawal can lead to muscle fatigue, dangerous gas exchange impairment, loss of airway protection, and also a higher mortality. ⋯ More recent developments have focused on the utility of computer decision support to guide these processes and the importance of linking sedation reduction protocols to ventilator discontinuation protocols. These guidelines are standing the test of time, and practice patterns are evolving in accordance with them. Nevertheless, there is still room for improvement and need for further clinical studies, especially in the patient requiring prolonged mechanical ventilation.
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Recently, advanced therapies for pulmonary arterial hypertension have become available, and have been effective in reducing pulmonary vascular resistance and symptoms in patients with Eisenmenger syndrome, previously thought to be inoperable. This review summarizes the current knowledge on the pathophysiology and treatment of Eisenmenger syndrome. ⋯ With continued improvements in the diagnosis, preoperative management, refinement of surgical techniques and intra- and postoperative management strategies, the patients with Eisenmenger syndrome selected using a diagnostic-treatment-and-repair strategy are operable with safety and efficacy in the current era with advanced pulmonary arterial hypertension therapy. Future directions of Eisenmenger syndrome may be the combination of reversal of pulmonary vascular remodeling and correction.
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Review
Reflections on pediatric high-frequency oscillatory ventilation from a physiologic perspective.
Mechanical ventilation using low tidal volumes has become universally accepted to prevent ventilator-induced lung injury. High-frequency oscillatory ventilation (HFOV) allows pulmonary gas exchange using very small tidal volume (1-2 mL/kg) with concomitant decreased risk of atelectrauma. However, its use in pediatric critical care varies between only 3% and 30% of all ventilated children. This might be explained by the fact that the beneficial effect of HFOV on patient outcome has not been ascertained. ⋯ Gas exchange is determined by the frequency and the oscillatory power setting, controlling the magnitude of the membrane displacement. Experimental work as well as preliminary human data have shown that it is possible to achieve the smallest tidal volume with concomitant adequate gas exchange when oscillating at high frequency and high fixed power setting. Future studies are needed to validate these novel approaches and to evaluate their effect on patient outcome.