Critically evaluate the role of therapeutic hypothermia in the critically ill patient.
Proven role:
1) cardiac arrest – out of hospital VF arrest improved neurological outcome and survival
32-34C
2) Control of intracranial hypertension – Improves ICP, but no reduction in mortality
Areas under investigation
1) Stroke patients
2) Perinatal asphyxia
Practical issues:
a) difficulty in achieving hypothermia rapidly
b) shivering and the need for relaxants which can delay neurological assessment c) Not proven for non-vf arrests
d) Not proven for in-hospital arrests
e) Hypothermia can cause diuresis with attendant electrolyte disorders
f) Risk of arrhythmias
g) Risk of infection
In general, therapeutic hypothermia in cardiac arrest and the physiology of hypothermia overall are discussed elsewhere. This question also asks about the extended indications for therapeutic hypothermia, which are generally not very well known (being exotic and enjoying only very patchy support from the ICU senior medical community).
In late 2015, this question would be interpreted very differently, and would likely attract a slightly different answer from the candidates. A good example might resemble the college answer to Question 9 from the first paper of 2015. The discussion section for that SAQ is reproduced below, as the two questions are virtually identical, and a 2006-specific answer would be of no interest to the modern candidates.
Rationale for therapeutic hypothermia:
Advantages of therapeutic hypothermia
Well-accepted indications:
Evidence for use in cardiac arrest:
Evidence for use in traumatic brain injury
Extended indications:
Therapeutic hypothermia in cooling of a hyperthermic patient
Therapeutic hypothermia for subarachnoid haemorrhage
Therapeutic hypothermia for super-refractory status epilepticus
Therapeutic hypothermia for severe sepsis
Therapeutic hypothermia for meningitis
Therapeutic hypothermia for neonatal asphyxia
Therapeutic hypothermia for stroke
Therapeutic hypothermia for acute hepatic encephalopathy
Therapeutic hypothermia in ARDS :
Intraoperative therapeutic hypothermia
Suspended animation for delayed resuscitation
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