Observational StudyCerebral Oxygenation and Neurological Outcomes FOllowing CriticAL Illness-2

Inclusion

1. Adults ≥ 18 years old
2. Admitted to a critical care unit requiring one or more of the following:

(a) Respiratory failure requiring invasive mechanical ventilation with an expected duration >24 hours (b) Shock of any etiology. Shock is defined by the need for one of the following vasopressors/inotropes: (i) Dopamine ≥7.5 mcg/kg/min (ii) Dobutamine ≥5 mcg/kg/min (iii) Norepinephrine ≥5 mcg/min (iv) Phenylephrine ≥75 mcg/min (v) Epinephrine at any dose (vi) Milrinone at any dose (if used in conjunction with another agent) (vii) Vasopressin ≥0.03 u/min(if used in conjunction with another agent)

Exclusion:

1. Admission to the ICU > 24 hours
2. Life expectancy <24 hours
3. Admitting diagnosis that affects the central nervous system
4. Any reason that the subject may not be able to participate in the follow up assessments (i.e. limb amputation, paresis, neuromuscular disorders)