Neurosurgery notes/Trauma/Management of trauma/Non surgical/Temperature

Temperature

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Non surgical

Pyrexia

General

  • Core body temperature exceeding 37.5°C to 38.5°C
  • Occurs in more than 50% of TBI patients on
  • Pyrexia independently associated with worse outcome

Due to

  • Infection
  • Hypothalamic dysfunction

Management

  • Targeted temperature management (TTM): targeted normothermia or mild hypothermia (35.5– 37°C)—
    • High- quality evidence of outcome benefits following cooling to normothermia is lacking.
      • Is significant heterogeneity between studies in the
        • Timing of onset and duration of TTM,
        • Target temperature,
        • Timing and rate of rewarming.
          • Rewarming is the most dangerous phase of TTM, and must be carried out in a controlled manner (0.1– 0.25°C per hour)
          • To minimize the risk of rebound intracranial hypertension and hyperkalaemia
      • Maekawa 2015: a recent RCT failed to find a benefit of TTM over fever control alone, despite inducing TTM as soon after injury as possible, maintaining target temperature (32– 34°C) for at least 72 hours, and rewarming slowly (<1°C per day)
    • Mechachism
      • Neuroprotective actions including
        • Stabilization of the BBB,
        • ICP reduction,
        • Inhibition of inflammation and intracellular calcium overload
  • Options
    • Antipyretic medications,
    • Surface and intravascular cooling devices,
  • Adverse effects of TTM
    • Shivering
    • Abnormalities in blood glucose
    • Abnormal Electrolyte levels
    • Abnormal fluid balance

Hypothermia

Advantage (theoretical)

  • Neuroprotective effects,
  • Reduce intracranial pressure.

Disadvantage (theoretical)

  • Coagulopathy
  • Immunosuppression
  • Profound hypothermia
    • Cardiac dysrhythmia
    • Death

Two options

Prophylactic hypothermia

  • When hypothermia given early after injury and prior to intracranial pressure elevation,
  • Conflicting results.
    • Of uncertain relevance to adult traumatic brain injury (TBI), two recent high-quality paediatric trials failed to show benefit and additionally suggested harm related to prophylactic hypothermia for TBI.
    • Interest has thus shifted to exploring how specific aspects of induced hypothermia, such as the duration and depth, relate to clinical effect.
      • Gradual rewarming can mitigate the inherent risk of rebound intracranial pressure elevation
      • Localized cerebral cooling in the hopes of obtaining the desired benefits without the systemic side effects.
  • Early (within 2.5 hours), short-term (48 hours post-injury) prophylactic hypothermia is not recommended to improve outcomes in patients with diffuse injury
    • Long (5 days) vs Short (2 days ) duration cooling- Jiang, 2006
      • Better outcomes at 6 months on longer cooling
    • Selective head vs full body cooling- Lui et al 2006
      • To reduce side effect
      • GOS scores 2 years after the injury were highest in the selective brain cooling group (GOS 4 or 5, 72.7% vs. 57.1% for systemic cooling, 34.8% normothermia)
      • Rates of Pneumonia is lowest in selective head cooling
        • (22.7% vs. 38.1% for systemic cooling and 34.8% for the normothermia group
    • Paediatric
      • Beca 2015
        • N=50, hypothermia to a temperature of 32–33°C for 72 hours followed by slow rewarming at a rate compatible with maintaining ICP and CPP.
        • Very small numbers therefore could not find that hypothermia had worse outcome (Morbidity/Mortality)
      • Hutchison et al 2008
        • N=225
        • Hypothermia to a temperature of 32–33°C for 72 hours followed by slow rewarming at a rate compatible with maintaining intracranial pressure and cerebral perfusion pressure.
        • In children with severe traumatic brain injury, hypothermia therapy that is initiated within 8 hours after injury and continued for 24 hours does not improve the neurologic outcome and may increase mortality.

Therapeutic hypothermia

  • Treatment for refractory intracranial pressure elevation
  • Eurotherm trial Andrews 2015
    • Any patient with refractory intracranial pressure elevation after stage 1 treatment
    • 32-35°C
    • Tried to maintain ICP < 20mmHg
    • Hypothermia had poorer GOSE outcomes, mortality
    • Avoiding Pyrexia was beneficial
  • Watson et al Watson 2018 meta-analysis
    • Avoiding Pyrexia was beneficial
    • Avoiding fever in the control groups so as not to overestimate any benefit from using TH.
      • When controlled normothermia is used, then TH is no longer beneficial