Episode 48: Undifferentiated hypotension

Brandon walks Bryan through a case of new, unexplained hypotension in the ICU, with a focus on approaching shock, the use of POCUS, and risk stratifying unexplained problems.

Takeaway lessons

* Sudden changes in vital signs or other status are often due to precipitating factors, such as iatrogenic stimuli, whereas more gradual changes are often due to evolution of the underlying diseases. This is not always reliable.* Sudden changes can also be due to monitoring artifacts, such as inaccurate telemetry, problematic arterial lines, etc.* Failing arterial lines are usually damped (reduced amplitude), causing depressed systolic pressures and raised diastolics, but the MAP still tends to still be reliable.* Hypotension with a narrower pulse pressure is somewhat more suggestive of hypovolemia than vasodilation. This is not always reliable.* Point-of-care ultrasound is probably the single best tool for assessing unexplained hypotension, mainly because it can (within a few seconds) rule out most of the life-threatening, specifically treatable causes, such as cardiac tamponade, PE, cardiogenic shock, major hemorrhage, and tension pneumothorax. Distributive shock (e.g. from sepsis), while among the most common causes of hypotension in the ICU, is a diagnosis of exclusion.* A fluid bolus used diagnostically should be given fast, and all the faster if you’re not giving very much volume. Use a pressure bag and don’t leave the room.* One of the hardest acts of judgment in a clinician is to recognize whether a new finding is a “big deal” or not.