ANS Pathophysiology Flashcards
What determines HR in patients who have had a heart transplant?
The intrinsic rate of the SA node (100-120 bpm)
What determines cardiac output in patients who have had a heart transplant?
Preload; HR is fixed and CO = SV x HR
Drugs that can increase HR in patients who have had a heart transplant
Drugs that directly stimulate SA node:
Epinephrine
Isoproterenol
Glucagon
Drugs that will not increase HR in patients who have had a heart transplant
Indirect- acting drugs:
Atropine
Glycopyrrolate
Ephedrine
Effect on recipient heart: Digitalis
Normal increase in contractility
Minimal effect on AV node
Effect on recipient heart: atropine
None
Effect on recipient heart: epinephrine
Increased inotropy
Increased chronotropy
Effect on recipient heart: norepinephrine
Increased inotropy
Increased chronotropy
Effect on recipient heart: isoproterenol
Normal increase in inotropy
Normal increase in chronotropy
Effect on recipient heart: qunidine
No vagolytic effect
Effect on recipient heart: verapamil
AV block
Effect on recipient heart: nifedipine
No reflex tachycardia
Effect on recipient heart: hydralazine
No reflex tachycardia
Effect on recipient heart: beta blocker
Increased antagonist effect
What reflex is preserved in the transplanted heart?
Bainbridge reflex (d/t SA node stretch response)
Most common cause of cardiac denervation in non-cardiac surgery patients
Diabetes
Neuroendocrine tumors that arise from neural crest cells
Paragangliomas
What is the difference between paragangliomas and pheochromocytomas?
Paragangliomas exist in extra-adrenal locations and rarely secrete vasoactive substances
Common sites of paraganliomas
Neuroendocrine tissues surrounding the aorta or within the lung
Head and neck near carotid artery, glossopharygeal nerve, jugular vein, and middle ear
Most common vasoactive substance paragangliomas secrete
Norepinephrine
Anesthetic concern for paraganglioma that has invaded the IJ
Air embolism
Anesthetic concern for paragangliomas of glossopharyngeal, vagus, or hypoglossal nerves
Airway obstruction, swallowing impairment –> aspiration
Degeneration and dysfunction of diverse CNS structures (basal ganlia, cerebellar cortex, locus coeruleus, pyramidal tracts, and vagal motor nuclei)
Multiple system atrophy
Signs and symptoms of multiple system atrophy with autonomic dysfunction
Urinary retention
Bowel dysfunction
Impotence
Postural hypotension
Sluggish pupillary reflexes
Control of breathing may be abnormal
Failure of baroreceptor reflexes
