Resp Care
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Multicenter Study Comparative Study
Spirometric correlates of dyspnea improvement among emergency department patients with chronic obstructive pulmonary disease exacerbation.
To examine whether change in slow vital capacity (SVC) correlates to dyspnea improvement during emergency department (ED) treatment of chronic obstructive pulmonary disease (COPD) exacerbation. ⋯ Increase in SVC significantly correlated with dyspnea improvement among ED patients with moderate-to-severe COPD exacerbation. Change in SVC merits consideration when evaluating therapeutic response during COPD exacerbation.
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Randomized Controlled Trial Comparative Study
Patient comfort during pressure support and volume controlled-continuous mandatory ventilation.
Pressure-support ventilation (PSV) is more comfortable than volume controlled-continuous mandatory ventilation (VC-CMV) in acute hypercapnic respiratory failure, in patients undergoing noninvasive ventilation. Physiologic measurements of patient status have been compared in PSV and VC-CMV in endotracheally intubated patients, but patient perception of comfort has not been measured in this population. ⋯ On average the patients felt more comfortable during PSV than during VC-CMV or PRVC, so PSV may be the preferred mode for awake intubated patients.
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Anatomic dead space (also called airway or tracheal dead space) is the part of the tidal volume that does not participate in gas exchange. Some contemporary ventilation protocols, such as the Acute Respiratory Distress Syndrome Network protocol, call for smaller tidal volumes than were traditionally delivered. With smaller tidal volumes, the percentage of each delivered breath that is wasted in the anatomic dead space is greater than it is with larger tidal volumes. Many respiratory and medical textbooks state that anatomic dead space can be estimated from the patient's weight by assuming there is approximately 1 mL of dead space for every pound of body weight. With a volumetric capnography monitor that measures on-airway flow and CO2, the anatomic dead space can be automatically and directly measured with the Fowler method, in which dead space equals the exhaled volume up to the point when CO2 rises above a threshold. ⋯ It appears that the anatomic dead space estimate methods were sufficient when used (as originally intended) together with other assumptions to identify a starting point in a ventilation algorithm, but the poor agreement between an individual patient's measured and estimated anatomic dead space contradicts the assumption that dead space can be predicted from actual or ideal weight alone.
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Comparative Study
Comparison of a 10-breaths-per-minute versus a 2-breaths-per-minute strategy during cardiopulmonary resuscitation in a porcine model of cardiac arrest.
Hyperventilation during cardiopulmonary resuscitation (CPR) is harmful. ⋯ Contrary to our initial hypothesis, during the first 5 min of CPR, 2 breaths/min resulted in significantly lower carotid blood flow and brain-tissue oxygen tension than did 10 breaths/min. Subsequent addition of an impedance threshold device significantly enhanced carotid flow and brain-tissue oxygen tension, especially in the 10-breaths/min group.
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Editorial Comment
Hands-only cardiopulmonary resuscitation: is it really dangerous?