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ANESTHESIA ALERT
A CLOSER LOOK
Aging's Impact on Post-Op Delirium
A
ging causes changes in the central nervous system, altering structure and function, afferentation
(the way certain receptors are stimulated
and send signals from the peripheral to the
central nervous system), sleep, memory, plasticity (ability to "bounce
back") and pre-existing diseases. In addition, as organ systems' maximal
functional capabilities decline, so do functional reserve capabilities.
Given these physiological changes then, it's not surprising that age is a
risk factor for post-operative delirium. In the past decade, neuropsychologists have used the concept of a threshold theory to explain why some
elderly people are vulnerable to cognitive deterioration while others
remain cognitively intact their entire lives. The basis of the threshold theory is that an individual's brain-reserve capacity determines cognitive
changes during aging. The less brain-reserve capacity a patient has, the
lower the threshold for recovering from acute injury. Surgery stresses the
nervous system, and anesthesia's effects compound the impact. Delirium
is, therefore, the result of an acute insult in a vulnerable patient, and elderly patients are likely to be the most vulnerable. The higher the vulnerability of the patient, the less noxious the insult need be to prevent a
patient from functioning normally later. — Christopher J. Jankowski, MD
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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