Undifferentiated Shock

Today, we reviewed a case of a medically complex gentleman with a history of recurrent follicular lymphoma s/p chemo found to be hypotensive with new onset afib who was admitted to the ICU with undifferentiated shock. This prompted a fascinating discussion regarding etiology of his shock (septic vs cardiogenic).

Learnings points:

It is important to have a framework for how to think about shock. We used a common framework that divides shock into 5 main categories:

- Distributive (Septic and Non-septic)
- Cardiogenic (Cardiomyopathic, arrhythmogenic, mechanical)
- Hypovolemic (Hemorrhagic and Non-hemorrhagic)
- Obstructive (Pulmonary vascular, mechanical)
- Mixed/Unknown

A careful history and exam can be extremely helpful in differentiating which type of shock your patient has. (i.e. infectious symptoms, heart failure symptoms, trauma, bleeding, insensible losses, elevated/flat JVD, edema, cool/warm extremities, pulsus parodoxus, signs of infection, and many more)

Lastly, Dr. Mannion explored more nuanced tools for differentiating shock including mixed venous oxygen saturations. His PICO question was, "In patients with septic shock, does measurement of central venous oxygen saturation correlate with true mixed venous oxygen saturation?"

He reviewed one article published in Crit Care in 2010 by van Beest et al that found there was no agreement of mixed venous and central venous saturation in sepsis and the difference between SvO2 and ScvO2 is not fixed.