NBME Step 2 CK Form 7 Acute respiratory distress syndrome (NBME Answers)

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Patient with severe pancreatitis who develops hypoxia, hypotension with elevated right-sided pressures and normal left-sided pressures and a severely increased A-a gradient, most consistent with acute respiratory distress syndrome
PAO2 = (713 x 0.6) – (PaCO2/0.8) = 428 – (38/0.8) = 428 – 48 = 380 >> 12 –> Increased A-a gradient
Congestive heart failure –> Decreased cardiac index and increased PCWP
Causes of ARDS: Sepsis, aspiration, pneumonia, trauma, pancreatitis

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usmile1 His A-a gradient is 24.5; not 380. PAO2 = 150 - (38/0.8) = 102 102 - 78 = 24.5 +1

niboonsh where did the 713 even come from? +

niboonsh ohhh they where trying to use the FIO2 instead of 150. I did the calculation and got that same number of 380. When do we use the standard 150 versus plugging in the fio2? +