- Induced hypothermia
- Core temp of <35ᵒC
- Measure temp by nasopharyngeal, rectal or bladder route
- Side effects
- CVS
- High catecholamines initially leads to high c.o. and O₂ demand
- Further reduction in temp leads to reduced HR and reduced O₂ demand
- SVR ↑, CVP ↑, so MAP is usually maintained
- Increased PR interval, wide QRS, J wave
- VF ~ 28ᵒC, arrhythmias <30ᵒC
- Resp
- Reduced metabolism means need to reduce Vm to avoid alkalosis
- Haematological
- Acid-base
- 2 ways of interpreting samples
- Alpha stat - without correction for temp (used in CPB)
- pH stat - addition of CO₂ to normalise pH
- Infection/GI
- Impaired immune function
- Increased nosocomial infection
- Increased insulin resistance
- Low GI motility
- Pancreatitis
- Increased lactate
- Renal
- Dieresis due to reduced absorption of solute in LOH
- Clinical applications
- Cardiac arrest survivors (HACA study)
- Traumatic head injury
- Newborn Hypoxic-ischaemic encephalopathy
- Neurosurgery
- CVA
- CPB
- Hepatic encephalopathy
- ?ARDS/spinal cord protection for aortic surgery
- Techniques used
- Antipyretics
- Fans
- Ice packs
- Cold fluids
- Water filled blankets
- Forced cold air
- Intra vascular line
- Bypass
- Cooling caps
- Mechanisms of action
- Reduced CMRO₂ (~ 7%/ᵒC)
- Promote cerebral vasoconstriction
- Inhibits caspase activity
- Suppression of inflammatory cascade
- Improved ion homeostasis
- Decreased free radical formation
- CEACCP
Link:ceaccp.oxfordjournals.org/content/6/1/23.full.pdf