Great job on resuscitating that V fib cardiac arrest and achieving sustained ROSC.
Now what? Cool them!
Whether you cool them or not could determine whether your patient goes into multisystem organ failure in the ICU or walks out of the hospital few weeks later.
What:
Targeted temperature management (TTM) to improve survival and neurological outcomes among comatose survivors of patients with cardiac arrest
Who:
Adults with out-of-hospital cardiac arrest with an initial shockable rhythm and nonshockable rhythm
Inclusion criteria (must meet all criteria)
Postcardiac arrest status (any rhythm as a cause of arrest is eligible)
ROSC < 30 minutes from EMS/code team arrival
Time at induction < 6 hours from ROSC
Comatose status (patient does not follow commands)
MAP ≥ 65 mm Hg (may include use of vasopressor drugs)
Exclusions may include
DNR advanced directive, MOLST, poor baseline status, or terminal disease
Traumatic etiology for the arrest
Active bleeding or known intracranial bleeding (relative)
Cryoglobulinemia (relative)
Pregnancy (relative; consider obstetrician/gynecologist consultation)
Recent major surgical procedure (relative)
Severe sepsis/septic shock as cause of arrest (relative)
Why:
Decreased fever-related tissue injury
Reduction in ischemic-reperfusion injury
Cerebral metabolic rate decreases by a 6-7% for every 1ºC drop in body temperature which reducing oxygen demand, preserving phosphate compounds and preventing lactate production and acidosis
Bernard, et al (2002) found an Absolute Risk Reduction (ARR) for death or severe disability of 23%, NNT was 4.5
The Hypothermia After Cardiac Arrest (HACA) Group (2002) found an ARR for unfavourable neurological outcome of 24%, and NNT of 4
How:
IV cold saline 2-3 mL/kg
Cooling vest and cooling machine- Arctic Sun
If shivering does not occur, do not use neuromuscular blockade
If paralysis employed, titrate to degree of shivering- do not need train-of-four monitoring
Sedation of choice is institution dependent (MMC CICU uses Fentanyl and Midazolam)
When:
Initiation of TTM within122 minutesof hospital admission was associated with improved survival.
Most guidelines recommend initiation within6 hours
What temperature should be targeted:
This remains controversial, with guidelines accepting a range of temperature targets from 33-36C. Available evidence shows no benefit to hypothermia (33C) compared to normothermia (36C). In the absence of evidence, targeting 36C is prudent
TTM36 is more hemodynamically stable than TTM33, which is relevant because these are often very unstable patients.
TTM36 avoids electrolytic shifts associated with raising and lowering the temperature.
Hypothermia at 33C suppresses immune function and associates with increased rates of pneumonia.
TM33 will induce bradycardia, which is dangerous in patients with underlying torsades de pointes.
References
Bernard SA et al. Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med 2002;346:557-63. PMID 11856794
Hypothermia after Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med 2002;346:549-56. PMID 11856793
Nielsen N et al. Targeted temperature management at 33 degrees C versus 36 degrees C after cardiac arrest. N Engl J Med 2013; 369: 2197-206. PMID 24237006
Stanger, Dylan, et al. "Door‐to‐targeted temperature management initiation time and outcomes in out‐of‐hospital cardiac arrest: insights from the Continuous Chest Compressions Trial." Journal of the American Heart Association 8.9 (2019): e012001.
Donnino, Michael W., et al. "Temperature management after cardiac arrest: an advisory statement by the advanced life support task force of the international liaison committee on resuscitation and the American Heart Association emergency cardiovascular care committee and the council on cardiopulmonary, critical care, Perioperative and Resuscitation." Circulation 132.25 (2015): 2448-2456.
REBEL EM
LITFL
EB Medicine
Mayo Clinic Florida TTM Guideline