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ANESTHESIA ALERT
To be called delirium, the cognitive or perceptual disturbance must
not be better accounted for by a pre-existing, established or evolving
dementia; rather, it should occur as a direct result of the physiological
consequences of an acute insult (that is, surgery). Delirium after emergence from anesthesia can result in events such as IV catheter
removal, injuries to the patient or staff, and increased time in PACU.
Delirium can be expected in the 24 to 72 hours immediately post-op.
Emergence delirium may predict longer-term post-operative delirium
and, in some populations, may actually predict long-term functional
decline. However, the relationship between post-op delirium and
dementia is unclear.
Some postulated mechanisms of delirium that may be in place
include decreased oxidative metabolism in the central nervous system, decreased presence of neurotransmitters, increased cortisol or
other inflammatory mediator levels and embolic phenomena, along
with genetic predisposition and effects of medications.
Predicting risk
Increasing age and duration of anesthesia, subsequent operations,
post-operative infection and respiratory complications are risk factors
for early post-op delirium. Other predictors include alcohol abuse,
low physical function, major electrolyte and glucose abnormalities,
vision impairment (<20/70), a previous history of illness, long-term
anti-depressant treatment and BUN-to-creatinine ratio ≥18:1.
J A N U A R Y 2013 | O U T PAT I E N T S U R G E R Y M A G A Z I N E O N L I N E
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