• ≥ 16 years of age

• Refractory hypotension documented within 48 hours prior to enrollment requiring the institution and ongoing use of vasopressor agents (phenylephrine, norepinephrine, vasopressin, epinephrine, midodrine or dopamine \>5 mcg/kg/min) at enrollment. Refractory hypotension is defined as a systolic blood pressure (SBP) less than 90 mmHg, or SBP less than 30 mmHg below baseline, or a mean arterial blood pressure less than 65 mmHg, despite adequate fluid resuscitation

• Capacity to initiate plasma exchange with 48 hours of vasopressor initiation.

• At least 1 other new organ dysfunction (in addition to refractory hypotension), defined by the following at the time of enrollment:

‣ Creatinine ≥1.5x the known baseline creatinine within 7 days, or ≥ 26.5 µmol/l increase in 48 hours,

⁃ Need for invasive mechanical ventilation or a P/F ratio \<250

⁃ Platelets \<100 x109/L, or a drop of 50 x109/L in the 3 days prior to enrollment

⁃ Arterial pH \< 7.30 or base deficit \> 5 mmol/L in association with a lactate \>/= to 3.0 mmol/L

∙ 45\. Known or suspected infection