R1iv: Physiological Consequences of Hyperthermia

Define:

Hyperthermia = when core body temperature exceeds tight regulatory control by thermoregulation (Core Body Temp > 37.5°C)

Heat Stroke = severe hyperthermia (Core Body Temp > 40.6°C )dry skin, loss of consciousness)

Physiological Consequences

CNS

  • Altered conscious levels
  • Delerium, lethargy, coma, seizures
  • NaCl depletion 2 sweating (at maximum 2L/hr)

CVS

  • ↑CO, ↑HR, ↓SVR
  • QT prolongation
  • ST segment changes
  • Myocardial infarction
  • Hypotension 2 volume depletion & VD

METABOLIC

  • ↑BMR
  • ↑O2 consumption
  • Lactic acidosis
  • Resp Alkalosis

RESP

  • Respiratory failure/ ARDS due to systemic inflammation

RENAL

  • Renal failure
  • Rhabdomyolysis
  • Myoglobin induced ATN

GI

  • Severe electrolyte derangement
  • LFT derangement
  • Acute hepatitis 2 splanchnic blood flow diversion

HAEM

  • DIC
  • Coagulopathy

IMMUNE

  • Diversion of blood flow away from gut
  • Bacterial translocation
  • Cytokine release

Pharmacological Consequences

A

  • ↑drug absoption due to blood diversion

M

  • ↓drug metabolism secondary to blood flow diversion and altered enzyme denaturation

E

  • ↓drug clearance