Targeted temperature management refers to temperature management after cardiac arrest where there was decreased or paused blood flow to the brain in an attempt to preserve neurological tissue/function. Indications
Patients not following commands or showing purposeful movements following resuscitation from cardiac arrest should have their temperature managed.
Although there are not true contraindications, here are some commonly recommended institutional indications
Post cardiac arrest (any cause)
Time < 6 hours from ROSC
Patient is comatose
MAP >=65 (with or without pressors)
Timing: As soon as possible (certainly within first couple hours) and for a duration of 48 hours.
Proposed Mechanism:
Decreasing the brain's oxygen demand (metabolic demand dec. up to 7% for every degree celcius)
Reducing the production of neurotransmitters (glutamate) and free radicals
Maintaining cell wall function
Methods:
Intravenous infusion of 30 mL/kgof cold (4°C [39°F]) isotonic saline, using a pressure bag to increase the rate of administration, reduces the core temperature by >2°C per hour
o However may cause pulmonary edema (at recommended 30ml/kg)
Proper sedation
Cold water blankets
Ice packs (groin, axilla)
Ice Bath
Other invasive: bladder, peritoneal fluid lavage; ecmo, etc.
Target:
2010 AHA guidelines recommend 32-34*C, however more recent trials show similar outcomes reducing temperature to 36*is just as effective.
o However comparison between trials shows more fevers at the temperature target, and more fever following cardiac arrest is linked to higher mortality.
Per up to date 36*C for uncomplicated and 33°C for at least 24 hours when coma is deep (loss of motor response or brainstem reflexes)
Monitoring:
Remember minute ventilation requirements, decrease as body temperature falls and therefore a blood gas should be obtained at target temperature or every few hours (also some machines don’t correct for hypothermia – institution specific).
Post cardiac arrest patients should have routines labs including coagulation studies and hypoglycemia and hyperglycemia should be avoided.
Length of cooling is institutional specific, however most recommendations say 48 hours before rewarming.
o Of note, over 24 hours may be linked to increase risk of infection and other adverse events.
Sources:
Bray JE, Stub D, Bloom JE, Segan L, Mitra B, Smith K, Finn J, Bernard S
Resuscitation. 2017;113:39. Epub 2017 Jan 31.
Nielsen, Niklas, et al. “Targeted temperature management at 33 C versus 36 C after cardiac arrest.”
New England Journal of Medicine 369.23 (2013): 2197-2206. PMID: 24237006; Altmetric
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