Hypothermia Hyperthermia Dr. Stella Yiu Staff Emergency Physician S Yiu, 2012.
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Transcript of Hypothermia Hyperthermia Dr. Stella Yiu Staff Emergency Physician S Yiu, 2012.
HypothermiaHyperthermia
Dr. Stella YiuStaff Emergency Physician
S Yiu, 2012
Hypothermia: LMCC wants you to
• List causes• List illnesses that precipitate
hypothermia• Conduct neurological, CVS and resp
assessment• List and monitor investigations • Manage a hypothermic patient by
contrasting different warming methods
NORMAL TEMPERATURE: 36.5 – 37.5 CELSIUS
Causes
1.Decreased heat production
2.Increased heat loss
3.Impaired thermoregulation
1. Decreased heat production
Not enough fuel (poor nutrition, hypoglycemia)
Engine slower (hypothyroid, hypopituitarism, adrenal insufficiency)
Engine unable to produce heat (age, impaired shivering)
Photo credit: RaGardner4 and Pedro J Perrieira, , flickr creative commons
2. Increased heat loss
Immersion/exposure
2. Increased heat loss
• Vasodilation: drugs, alcohol, sepsis, toxins
2. Increased heat loss
• Skin disorders (burn, dermatitis)
• Iatrogenic (trauma bay, 3 L cold NS)
3. Impaired thermoregulation
CentralMetabolic (Cirrhosis, uremia), drugs (barbituates, TCAs), CNS (stroke, trauma, MS, Parkinson)
PeripheralSpinal cord transection,
neuropathy, DM
Physiological effects
Pacemaker cells slllllooooow
Cardiovascular: Bradycarida, arrhythmia, VF, asytole (<28)
Neurologic: depression, activity abnormal less than 33,
Examination
35-32 – Mild
Physiological adjustment
32-29– Mod
CNS: Ataxia ConfusionCVS: Brady, Afib
< 29: Severe
CNS: Coma, fixed pupilsCVS: VF, asystole
Investigations
Temp: esophageal
Lytes (HyperK)
Coag profile (DIC)
EKG
Osborn J waves
Mild: Passive Rewarming
>30 and no CVS- Surface rewarming- Warm blankets- Removal or cold, wet clothing
Severe: Arrhythmia
VF:CPR, defib,
If first defib does not work, do not defib (continue CPR) until warmed to >30
Patient not dead until warm and dead
Severe: Active rewarming
Gently handle, no CPR on frozen chest
Airway: IntubateBreathing: Warm OxygenCirculation: Warm saline (heated to 65)
Severe: Active rewarming
InhalationIntravenous
GI lavageBladder lavage
PeritonealPleural
ECMODialysis
Invasive
NOT DEAD UNTIL WARM (>30-32) AND DEAD
Hyeprthermia
Hyperthermia: LMCC wants you to
• List causes • List illnesses that predispose to
hyperthermia• Know abnormal exams of hyperthermic
patients • Select investigations • Manage hyperthermic patient by
various cooling methods• Understand how dantrolene works
CausesEnvironment (heat stroke)
Decreased heat dissipation
ObesityDrugs (anticholinergics, serotonin syndrome, sympathomimetics)Metabolic heat
Thyroid, pheochromocytomaMalignant hyperthermiaNeuroleptic malignant syndrome
Sepsis
Examination
Heat stroke
T> 40Orthostatic BP, tachycardia, tachypneaCNS: Confusion, cerebellar, cerebral edema
NMS/MH Physical
NMS (post antipsychotic) or MH (post anesthetic)
T>40, autonomic dysfunction, lead-pipe rigidityMotor: Myoclonus, dystonia, dysphagiaCNS: confusion, agitation, coma
Hyperthemia: Clinical and lab findings
CVS: CHF, pulmonary edema, CV collpase
Liver: necrosis
Rhabdomyolysis
DIC
Cooling
Evaporative:Mist + FaceIce packs
Con: shivering, cannot attach electrodes
More aggressive cooling
Tub immersionCon: Cumbersome
GI/Peritoneal lavageCon: Invasive
Cardiac bypassCon: Invasive, not readily available
STOP COOLING WHEN TEMP < 40
Dantrolene
Muscle relaxer(interferes with coupling-excitation of skeletal muscle cells)
Only effective treatment in MH