Successful resuscitation and therapeutic
hypothermia determines the best clinical outcome after a cardiac
arrest. Therapeutic hypothermia is not limited to cardiac arrest but its
been used extensively in patients with stroke, traumatic brain
injuries, during cardiac catheterization surgeries and neonatal
resuscitations. Hypothermia increases the chances of good neurological
outcome. American Heart Association’s chain of survival emphasizes the
need for post cardiac arrest care and recommends therapeutic hypothermia
during Return of Spontaneous Circulation (ROSC) management and care.
Physicians and researchers have been
using this for ages. Hippocrates recommended the use of topical cooling
to stop bleeding .In the early 1990, it was found that mild hypothermia,
even after the cardiac arrest had benefit for the brain. Peter Safar
added the word H after the A,B,C,D…. of resuscitation. The history of
inducing hypothermia began in the 1950s with elective moderate
hypothermia (28-32) of the brain for the protection and preservation of
the brain. Recently, former formula1 champion Michael Schumacher was
kept in therapeutic hypothermia after traumatic brain injury. Four
randomized control trials done among 417 patients who were successfully
resuscitated from cardiac arrest proved that, it improves neurologic
outcome.
Therapeutic hypothermia otherwise also
known as mild therapeutic hypothermia, induced hypothermia is of two
types invasive and non invasive. Invasive methods include intravascular
cooling catheters and ice cooled infusions whereas non invasive methods
include cooling pads, fans, alcohol baths, cooling blankets, ice packs,
perfluorocarbon into the nasal cavity. There are different types of
cooling which ranges from mild cooling (32-34) to severe cooling up to
28 .
AHA recommends that all unconscious
patients achieving ROSC after out-of-hospital VF cardiac arrests receive
induced hypothermia it also state that induced hypothermia may be
beneficial in non-VF arrest for out-of-hospital or in-hospital arrest.
Nursing care plays a pivotal role in
preventing irreversible brain damage and adverse outcomes after cardiac
arrest. A close and continuous monitoring of vital signs which includes
temperature, pulse, blood pressure, oxygen saturation ECG, input output
and shivering scale monitoring should be performed during the
maintenance phase of Inducing therapeutic hypothermia. Intravenous
fluids with glucose content should be avoided. Close observation s
required as patient is under analgesia and sedation. There is a high
risk for getting infection if there is any delay in wound healing,
aspiration and ventilator associated pneumonia. Fluid and electrolytes
such as potassium, magnesium phosphorous calcium should be monitored and
replaced. Other laboratory values such as haemo concentration, PT, INR,
PTT should also be checked at frequent intervals.
Re warming plays a crucial role in
Therapeutic hypothermia;warming should be done at a slow pace to prevent
complications. Rebound hyperthermia seizure, cerebral edema,
hypotension and ventricular fibrillation are other potential life
threatening complications.
A prospective cohort study of four years
conducted among 67,48 patients from 538 hospitals concluded that after
in- hospital cardiac arrest, therapeutic hypothermia was used rarely and
once initiated the target temperature was commonly not achieved. Post
cardiac arrest care is a multidisciplinary approach. Ignorance, lack of
knowledge, lesser facilities could be the reason for not initiating post
cardiac arrest care, educational modules, simulation exercises,
protocol development and continuing education can increase awareness and
can translate laboratory researches into bedside actions.
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