SEARCH RESULTS FOR: Neuraxial-anesthesia

Neuraxial anesthesia

Neuraxial anesthesia: Mechanism of action and complications Spinal anesthesia
Epidural anesthesia
Anesthetic injected into epidural space (surrounding spinal cord)
Blood vessel punctured
Blood accumulates in epidural space
Epidural hematoma
Inhibits motor nerve conduction (least sensitive nerve fibers to anesthetics)
     Anesthetic injected into cerebrospinal fluid (CSF) in the subarachnoid space
Punctured dura mater Cerebrospinal fluid leak Decrease cerebrospinal fluid pressure Vasodilation of cerebral blood vessels Post-dural puncture headache
Inhibits sympathetic nerve conduction (most sensitive nerve fibers to anesthetics)
Anesthetics diffuse across axon membranes & blocks voltage-gated sodium channel in nerve fibers
↓ Sodium ion flow into neuron
Nerve fibers unable to depolarize & reach threshold to trigger action potential
                 Inhibits sensory nerve conduction
              Cardiac sympathetic nerve fibers inhibited
↓ Norepinephrine release
Unopposed parasympathetic (rest and digest) activity
Parasympathetic nerves release acetylcholine (Ach)
ACh binds to muscarinic receptors on smooth muscle
↑ Peristalsis
↑ Bowel motility
C-fibre nerve fibers (unmyelinated) inhibited
Loss of pain & temperature sensation
A-delta nerve fibers (thinly myelinated) inhibited
Loss of pinprick, pain & temperature sensation
A-beta nerve fibers (myelinated) inhibited
Loss of vibration, touch & pressure sensation
A-alpha nerve fibers (heavily myelinated) inhibited
Loss of proprioception
Phrenic nerve fibers inhibited
Diaphragm paralysis
Impaired diaphragm contraction
Apnea (temporary cessation of breathing)
Loss of motor function
           ↓ Cardiac pacemaker activity
Bradycardia
(slow heart rate)
Inhibits smooth muscle tone of blood vessels
↓ Systemic vascular resistance
Authors: Shiva Ivaturi Reviewers: Run Xuan (Karen) Zeng, Luiza Radu, Julia Haber* *MD at time of publication
         Vasodilation
Hypotension
 Legend:
 Pathophysiology
 Mechanism
Sign/Symptom/Lab Finding
 Complications
 Published Feb 24, 2025 on www.thecalgaryguide.com