Temperature Flashcards
What is heat stroke?
Defined as elevated core body temp >40.5C with associated neurological compromise
Non-exertional (classic) usually occurs at the extremes of age or in those with significant medical co-morbidities who spend extended time in an area with elevated temp (ie locked in a car)
Exertional usually occurs in young fit and healthy adults doing vigorous exercise in areas of high heat
What are the risk factors for death in heat stroke?
Any evidence of other end organ damage ie anuria, coma, CVS collapse, DIC
What are the risk factors for developing heat stroke?
Extremes of age
Pregnancy
Decreased mobility
Morbid obesity
Significant medical co-morbidities
ETOH or illicit drug use
Dehydration
Anticholinergis, anti-diuretics, topiramate
What are the differentials for hyperthermia?
Environmental
- heat stroke (exertional or not)
Infectious
- meningoencephalitis
- Severe sepsis
- Falciparum malaria
- Tetanus
- Typhoid fever
Neurologic
- Hypothalamic stroke
- Bleed
- Status epilepticus
Endocrine
- Thyroid storm
- Pheochromocytoma
- DKA
Oncologic
- Lymphoma/leukaemia
Tox
- Malignant hyperthermia
- Serotonin syndrome
- Neuroleptic malignant syndrome
- Sympathomimetics
- Anticholinergics
- Salicylate poisoning
- Alcohol/GHB withdrawal
What is the most common heart rhythm with hypothermia <32C?
- Slow AF if alive
- VF if arrested
What is the most common neurological sign in heat stroke?
- The cerebellum is the most vulnerable part of the brain
- Often present with ataxia
- However any neurological symptoms/signs can occur
- Often have seizures during the cooling process
What are the differentials for hypothermia?
Increased heat loss
- Environment
- Induced vasodilation (drugs, alcohol, toxins, sepsis)
- Burns/trauma
Iatrogenic
- Cold infusions
- RRT/ECMO
- Emergent deliveries
Endocrine
- Hypoadrenal/pituitarism/thyroid
- Malnutrition/hypothiamine
- Hypoglycaemia
Neuromuscular
- Extremes of age
- Impaired shivering
- Inactivity
- movement disorders (ie spinal cord injuries, cerebral palsy)
CNS
- Hypothalamic disorders
- SAH, CVA
- Parkinsons
- MS
- Anorexia
Drugs
- beta blockers, CNS depressants
Others
- Sepsis, Uraemia, pancreatitis
How do the symptoms and signs of hypothermia change with severity?
What are the different severity gradings for hypothermia?
Temperature based
- Cold stress 35-37C
- Mild 32-35C
- Moderate 28-32
- Severe <28C
Swiss staging system
HT 1- Mild 32-35, shivering, normal mentation
HT 2- moderate 28-32, no shivering, has altered mental status
HT 3- Severe, unconscious, 24-28C
HT 4- Apparent death, 13.7-24C but possibility of revival
HT 5- Complete death, 9-13.6C
How does ACLS change with hypothermia?
- Prepare for extended periods of CPR >90mins
- Early consideration for ECMO CPR
- If < 30C then up to 3 shocks for VF, but after this no shocks until >30C
- No drugs until >30C
- Between 30-35C double the dosing interval for drugs
- Do prolonged pulse checks or use Echo/doppler to assess for pulse
- Moving patients <32C may precipitate VF
