ODR - Hyperthermias Flashcards
Define hyperpyrexia
Situation where the hypothalamic set point is raised - infection
Define hyperthermia
Elevation of body temperature due to inability to control systems to function
Imbalance between factors warming up and cooling down body
CVS effects of hyperthermia
Tachycardia, raised cardiac outpuot
Low SVR –> hypotension
Failure to resuscitate –> cold and clammy
Metabolic effects of hyperthermia
Tissue oxygen demand +++
Rise in BMR
Right shift of curve to offset –> increased O2 availability
Immune effects of hyperthermia
Temperature sensitive pathogens are compromised
Leucocyte activity increased –> increased response to infection
How does pyrexial affect critical illness
Usually sepsis.
Temp regulated by hypothalamus
Cytokines from sepsis –> arachidoic acid pathway –> heat produces by PGE2
Managment of pyrexia
1) Minimise heat gain –> environmental factors – bed clothes, heaters, etc
?limit shivering –> clonidine/dexmed
2) treat the cause –> drain collections, Abx etc
3) drugs –> paracetamol resets set point –> no mort benefit
Dantrolene when indicated
4) physical methods
Physical methods
Cooling rather than enhancing heat loss
Fan/cool air
Cold packs
Cold blankets
Bladder and abodminal irrigation
Extracorporeal methods
Purpose built methods - artic sun, cool guard
