The Pittsburgh Cardiac Arrest Category (PCAC) is a validated illness severity tool that is highly predictive of survival and functional outcome at hospital discharge. This score is based on the motor and brainstem subscales of the Full Outline of Unresponsiveness (FOUR) score, and cardiovascular and respiratory subscales of the Sequential Organ Failure Assessment (SOFA) score. Illness severity ranges from: PCAC I, awake and following commands; PCAC II, comatose without cardiopulmonary failure; PCAC III, comatose with cardiopulmonary failure (severe hypotension and/or hypoxemia); and PCAC IV, severe coma with loss of some brainstem reflexes regardless of cardiopulmonary status. Survival decreases in a stepwise fashion. PCAC I patients have 80% survival, with mortality mostly due to underlying cardiac arrest etiology and comorbidities. PCAC IV patients have 10% survival, 5% good neurological and functional recovery, and deaths are generally due to severity of brain injury.
Clinicians should use extreme caution when there are confounding variables that may affect physical examination findings. Acidosis, hypotension, hypoxemia, intoxicants such as prescription or recreational drugs, or pre‐existing conditions can cloud the initial examination.
Assessing PCAC within the first 6 h after return of spontaneous circulation allows initial resuscitative efforts to correct confounders such as profound acidosis or shock and allows some reconstitution of neuronal energetics and function. As multisystem organ failure is addressed, the neurological assessment may improve such that an initial PCAC IV may regain some motor function or brainstem reflexes and be re‐categorized as a less severely injured classification. We perform neurological assessments on admission to the emergency department then typically again after procedures and diagnostics such as central venous lines, arterial lines, chest radiography, or computed tomography (CT) imaging are performed.
Approach to neurological injury stratification review