Patho of hypothermia
- exposure to cold stimulus
- peripheral vasoconstriction, increased catecholamine release, increased BMR
- sympathetic nervous system initiates increased HR, BP, RR
- as temp reduces, shivering initiated to increase activity of muscles to generate heat and increase CBT
- after initial increase temp continues to fall
- CBT below 33 - ECG changes
- rapid recline in CBT, reduction in HR, BP, RR, TV, ph
- fluid shift from intravascular to interstitial space
- progressive bradycardia and possible further ECG cahnges. CBT 20 - cardiac and resp arrest
Hypothermia management
dry pt, remove from cold environment
cut away wet clothing, insulate with blankets
do not rub or massage skin
heat packs only on chest and abdo to prevent afterdrop
gentle handling
position supine or lateral
o2
warmed saline 10ml/kg (max 40ml/kg) only if temp over 37
Hyperthermia patho
- high body temp
- hypothalamus responds
- initiates body cooling mechanisms
- sympathetic innervation (vasodilation, decreased muscle tone, increased sweat production, increased RR, increased CO)
- if core temp continues to rise
- thermoregulatory centre can fail
- cell death, multi-organ failure
Management of hyperthermia
BGL, PSA (dehydration)
cooling techniques until less than 38
remove from heat source and ensure airflow
tepid water using spray bottle
saline 20ml/kg - if temp over 40 use cool fluid
Heat stress definition
mild end of spectrum, cramping, discomfort, malaise, syncope
Heat exhaustion definition
core temp over 37 but less than 40, fluid and electrolyte imbalances
Heat stroke definition
severe end of hypertheria, core temp over 40, CNS dysfunction
can be exertional or classic
