16. Post-Cardiac Arrest Care

Post-Arrest Care 

  • Optimize ventilation and oxygenation: use advanced airway and mechanical ventilation to maintain SpO2 >94% and PaCO2 no lower than 40-45mmHg (avoid CNS vasoconstriction from hypocapnea). See Critical Care: Mechanical Ventilation. 
  • Hemodynamics: treat hypotension to maintain perfusion (IV fluids, vasopressors). See Critical Care: Fluid Resuscitation and Critical Care: Initial Choice of Vasopressor in Hypotension. 
  • If not following commands, consult Neurology Critical Care immediately and consider Targeted Temperature Management (see below). 
  • Identify underlying cause: 
    • ECG: if STEMI or high suspicion of myocardial infarction, consider coronary reperfusion. 
    • Consider additional imaging as needed to identify underlying cause (e.g. CXR, bedside US, CT). 
      • Consider head imaging if unwitnessed fall before going to ICU or cath lab as this can affect ability to anti-coagulate for MI. 
    • Lab studies: ABG, CBC, electrolytes, troponin, lactate, toxicology studies, coags. 

Targeted Temperature Management following Cardiac Arrest 

Definitions: 

  • Targeted temperature management (TTM): temperature maintained <36˚C. 
  • Therapeutic hypothermia: temperature maintained between 32-34˚C. 

Overview and evidence:  

  • Indications: TTM is indicated in all post-arrest patients who are not able to follow commands immediately after ROSC. 
  • Contraindications: the only absolute contraindication for TTM is an advanced directive prohibiting invasive interventions. 
  • TTM is recommended in many circumstances that were previously thought to be relative contraindications (active bleeding, hemodynamic instability), with flexibility in the goal temperature based on clinical scenario (e.g. higher goal [close to 36] in active bleeding, hemodynamic instability, coagulopathy, sepsis, thrombolysis and lower goal [32-34] in deep coma with loss of brainstem reflexes, cerebral edema, seizures). 
    • Temperature goals should be determined in discussion with Neurology Critical Care specialists, but do not delay temperature management pending assessment. 
  • Evidence: 
    • Cochrane review of 5 studies shows therapeutic hypothermia improves survival and neurologic outcome. 
    • TTM trial (2013): no difference in mortality or neurologic function in out-of-hospital cardiac arrest between patients cooled to target temperature of 33°C vs 36°C. Suggests that avoiding hyperthermia is the critical benefit of targeted temperature management. 

Management: 

  • Hypothermia induction should commence immediately, as preparations are being made for any other procedures (cardiac catheterization, thrombolysis, etc.). 
  • Patient will need temperature-sensing Foley or esophageal probe.  
  • Options for cooling include ice packs, cooling blankets, liter bolus of chilled (4°C) IV saline, NG lavage, femoral cooling catheter. Arctic Sun or Innercool systems can also be used.  
  • Administer sedation (propofol or midazolam + fentanyl). 
  • Timing and duration: hypothermia should be maintained for 24 hours after reaching goal temperature. Patients can then be passively rewarmed to 37˚C at 0.25-0.5˚C per hour. 
  • Shivering: meperidine, magnesium sulfate, or paralytics (cisatracurium) should be added if patient begins to shiver. 

Complications:   

  • Cooling: coagulopathy, arrhythmia, hyperglycemia, and infection. 
  • Rewarming: electrolyte abnormalities, hypotension, cerebral edema, seizures. 

Prognostication 

  • Neuroprognostication is always difficult, so consult with your Neurology Critical Care specialists. 
  • Biomarkers such as neuron-specific enolase (“the troponin of the brain”) and SSEPs (somatosensory evoked potentials) can be helpful for prognostication. 
  • Absence of pupillary and corneal reflexes 72 hours post arrest is poor prognostic sign. 

 

Keywords: cooling, therapeutic hypothermia, post-arrest, cardiac arrest 

2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, Part 8: Post-Cardiac Arrest Care. Circulation 2015;132:S465-S482. 

Arrich J, Holzer M, et al. Hypothermia for neuroprotection in adults after cardiopulmonary resuscitation. 

Cochrane Database Syst Rev. 2012;9:CD004128. 

TTM Trial Investigators. Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest. N Engl J Med 2013; 369:2197-2206.