To the Editor: The randomized controlled trial by Dr Taccone and colleagues1 studied prone positioning in patients with acute respiratory distress syndrome (ARDS). The article raises questions about cardiovascular alterations and treatment of sepsis in study patients.
Shock and hemodynamic instability make prone positioning more difficult and potentially less safe. Furthermore, hemodynamic alterations and vasoactive agents (such as α- and β-adrenergic agents used clinically, including norepinephrine, dopamine, and dobutamine) can change perfusion distribution in the lung, alter gas exchange, and worsen oxygenation. Thus, over time a patient could move out of a state of being ineligible for the trial, and could also move from a classification of moderate to severe hypoxemia, with no change in the underlying ARDS pathology.
Furthermore, it is likely that more patients in the severe hypoxemia group had hemodynamic instability. Previous trials of prone positioning found that 75.9% of supine-positioned and 70.7% of prone-positioned patients had vasopressor or inotropic support,2 that 35% of supine-positioned and 29% of prone-positioned patients had cardiovascular dysfunction,3 and that the mean number of days of vasopressor infusion was 6.35 days (supine group) and 5.43 days (prone group) or was not reported.4 Thus, cardiovascular alterations and need for cardiovascular support have been common in patients in previous randomized controlled trials of prone positioning in patients with ARDS.
Accordingly, it would be valuable to know the cardiovascular characteristics and support given (eg, heart rate, mean arterial pressure, central venous pressure, and use of inotropic and vasopressor agents) for the supine vs prone group (and moderate vs severe hypoxemia subgroups) at baseline and over time. In addition, approximately 59% of patients had pneumonia and 5% had sepsis, so 64% could have been managed using Surviving Sepsis Campaign guidelines,5 which (if not balanced between groups) could have altered outcomes. Therefore it would also be valuable to have information about activated protein C levels, as well as the use of early antibiotics, early goal-directed therapy, corticosteroids, and intensive insulin, in each group at baseline and over time.
Financial Disclosures: Dr Russell reported being an inventor on a patent application for the use of vasopressin in septic shock that the University of British Columbia has submitted; having received consulting fees from Ferring and Sirius Genomics; having received grants from Novartis, Ferring, and Eli Lilly; having received speaking honoraria from Eli Lilly; and holding stock in Sirius Genomics, which has submitted patents owned by the University of British Columbia and licensed to Sirius Genomics related to the genetics of vasopressin and activated protein C.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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