What is included in supportive therapy during targeted temperature management (TTM)?

Updated: Jul 26, 2019
  • Author: Alex Koyfman, MD; Chief Editor: Karlheinz Peter, MD, PhD  more...
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Answer

Answer

Note the following:

  • A mean arterial pressure (MAP) goal of more than 80 mm Hg is preferred from a cerebral perfusion standpoint. Hypertension is potentially additive to the neuroprotection of hypothermia. Norepinephrine can be used, beginning at 0.01 mcg/kg/min and titrated to a MAP greater than 80 mm Hg. The treating team should determine the MAP goal, balancing the cardiac safety with the theoretical advantage of higher cerebral perfusion pressures. Often, blood pressure remains elevated during hypothermia as a result of peripheral vasoconstriction. Hypotension is a concern during the warming phase.

  • Practice standard neuroprotective strategies such as placing the head of the bed at 30º. [5]

  • Monitor the patient for dysrhythmia (most commonly bradycardia) associated with hypothermia. If life-threatening dysrhythmia arises and persists, or hemodynamic instability or bleeding develops, then active cooling should be discontinued and the patient rewarmed. An electrographic (ECG) Osbourne or camel wave may be present when cooling. Heart rate less than 40 bpm is frequent and is not a cause for concern in the absence of other evidence of hemodynamic instability.

  • Hematologic testing recommendations include a complete blood cell (CBC) count, chemistry panel, troponin level, arterial blood gas (ABG) level, and partial thromboplastin time (PTT) at 0 hours. Hypothermia commonly causes hypokalemia, which may be exacerbated by insulin administration. Conversely, when patients are rewarmed, potassium exits cells, and hyperkalemia may occur. Repeat measurements of glucose, potassium, and ABG are needed every 6 hours. Unexplained increases in serum amylase and lipase levels have been observed during hypothermic therapy and appear to have limited clinical significance.

  • Potassium values less than 3.5 mEq/L should be treated while the patient is being cooled. Potassium administration should be stopped once rewarming begins.

  • Elevated serum glucose level is deleterious to the injured brain. Tight glycemic control should be maintained, although a specific range is not recommended by the American Heart Association (AHA). [2]

  • Normocarbia is advised, with the partial pressure of carbon dioxide (PaCO2) and end-tidal carbon dioxide (CO2) in the reference range (35-45 mm Hg for PaCO2; 30-40 mm Hg for end tidal CO2).

  • Avoid fever following targeted temperature management (TTM), as any elevated temperature is associated with worse neurologic outcome.

  • Avoid hypoxia, with administration of oxygen saturation above 94%. However, hyperoxia is also harmful.

  • Skin care should be checked every 2-6 hours for thermal injury caused by cold blankets.

  • Regularly check the patient’s temperature with a secondary temperature monitoring device when cooling.

  • Do not provide nutrition to the patient during the initiation, maintenance, or rewarming phases of the therapy.


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