Annals of the American Thoracic Society
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Multicenter Study
Donor Lung Sequence Number and Survival after Lung Transplantation in the United States.
In the United States, an algorithm known as the "match-run" creates an ordered ranking of potential recipients for available lung allografts. A potential recipient's match-run position, or "sequence number," is available to the transplant center when contacted with a lung offer. Lung offers with higher sequence numbers may be interpreted as a crowd-sourced evaluation of poor organ quality, though the association between the sequence number at which a lung is accepted and its recipient's post-transplant outcomes is unclear. ⋯ Acceptance of a donor lung offer at a later point in the match-run was associated with measurable indicators of organ quality, but not with clinically meaningful differences in post-transplant mortality or graft failure.
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Multicenter Study Observational Study
Prospective Assessment of the Feasibility of a Trial of Low-Tidal Volume Ventilation for Patients with Acute Respiratory Failure.
Low-tidal volume ventilation (LTVV; 6 ml/kg) benefits patients with acute respiratory distress syndrome and may aid those with other causes of respiratory failure. Current early ventilation practices are poorly defined. ⋯ Use of initial tidal volumes less than 8 ml/kg predicted body weight was common at hospitals participating in the National Heart, Lung, and Blood Institute Prevention and Early Treatment of Acute Lung Injury (PETAL) Network. After considering the size and budgetary requirement for a cluster-randomized trial of LTVV versus usual care in acute respiratory failure, the PETAL Network deemed the proposed trial infeasible. A rapid observational study and simulations to model anticipated power may help better design trials.
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Volume capnography provides a noninvasive and continuous display of the fractional concentration or partial pressure of expired carbon dioxide versus exhaled volume. Derived measurements and calculations include the end-tidal, mean alveolar, and mixed expired carbon dioxide partial pressure (Pco2); the volume of CO2 exhaled per breath and per minute; the airway, alveolar, and physiologic dead space volume; the physiologic dead space to tidal volume ratio; and expired minute ventilation, dead space ventilation, and alveolar ventilation. Thus, volume capnography provides a wealth of information about both respiratory and cardiovascular function, and it has many potential applications in critically ill patients. The effective use of volume capnography, however, requires a thorough understanding of its underlying physiological principles and the meaning and significance of derived measurements and calculations.