Chest
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Traditional measures of ARDS severity such as Pao2/Fio2 may not reliably predict clinical outcomes. The oxygenation index (OI [Fio2 × mean airway pressure × 100)/Pao2]) may more accurately reflect ARDS severity but requires arterial blood gas measurement. We hypothesized that the oxygenation saturation index (OSI [Fio2 × mean airway pressure × 100)/oxygen saturation by pulse oximetry (Spo2)]) is a reliable noninvasive surrogate for the OI that is associated with hospital mortality and ventilator-free days (VFDs) in patients with ARDS. ⋯ In patients with ARDS, the OSI was correlated with the OI. The OSI on the day of ARDS diagnosis was significantly associated with increased mortality and fewer VFDs. The findings suggest that OSI is a reliable surrogate for OI that can noninvasively provide prognostic information and assessment of ARDS severity.
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Massive pulmonary emboli can cause an abrupt onset of symptoms simultaneous with large pulmonary artery occlusions. In contrast, the temporal relationship between pulmonary vascular occlusion by smaller emboli and the development of symptoms of pulmonary infarction is unknown. We describe the time interval between embolization and the onset of clinical symptoms and signs compatible with pulmonary infarction. ⋯ The clinically silent time interval between embolization of a pulmonary artery and the onset of symptoms and signs compatible with lung infarction is 24 hours or greater.