2. Epidural Anesthesia/Analgesia
Local anaesthetic solutions are deposited in
the epidural space between the Dura mater
and the periosteum lining the vertebral canal.
The epidural space contains adipose tissue,
lymphatics and blood vessels. The injected
local anaesthetic solution produces analgesia
by blocking conduction at the intradural spinal
nerve roots.
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3. Wide application
Epidural block can be performed at the
sacral(caudal), lumbar, thoracic or cervical levels.
Epidural techniques are widely used for operative
anesthesia, obstetric analgesia, postoperative
pain control, and chronic pain management.
Dose judgment could be single shot, intermittent
bolus or continuous infusion or combined.
4. Epidural Anesthesia
Indication and Contraindication:
the same of spinal anaesthesia.
Additional indication is the post operative
Paine management using the epidural catheter
technique.
Complications: the same of spinal
anaesthesia, except the post dural puncture
headache.
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5. 5
Differences between Spinal and Epidural Anesthesia
Spinal anaesthesia Extradural Anaesthesia
Level: below L1/L2, where the spinal cord ends Level: at any level of the vertebral column.
Injection: subarachnoid space i.e. puncture of
the Dura mater
Injection: epidural space (between Ligamentum
flavum and dura mater) i.e without puncture of
the dura mater
Identification of the subarachnoid space: When
CSF appears
Identification of the Epidural space: Using the
Loss of Resistance technique.
Dose: 2.5- 3.5 ml bupivacaine 0.5% heavy Dose: 15- 20 ml bupivacaine 0.5%
Onset of action: rapid (2-5 min) Onset of action: slow (15-20 min)
Density of block: more dense Density of block: less dense
Hypotension: rapid Hypotension: slow
Headache: is a probably complication Headache: is not a probable.
6. Differential block:
By using relatively dilute concentrations of
local anesthetic combined with an opiate, an
epidural can block the smaller sympathetic
and sensory fibers wile sparing the larger
motor fibers.
7. Segmental block:
Due to local anesthetic is not spread readily
in CSF as spinal anesthesia, a well-defined
band of anesthesia at certain nerve roots
without those above and below blocked can
be achieved with epidural techniques.
8. 8
Epidural Anesthesia continue
Technique:
Loss of resistance technique to identify
the epidural space.
0.5% Bupivacaine (mainly) or
lidocaine (2.0%) is usually used to
produce epidural anaesthesia.
20. Advantages in conjugation
with GA
CV systems:
Blockade of cardiac sympathetic innervation
(arise atT1-T4) with dilute local anesthetic
postoperatively via a thoracic epidural
catheter can reduce myocardial ischemia in
patients with coronary artery disease.
21. Respiratory system
Thoracic or upper abdominal surgery is
associated with
1.decreased diaphragmatic function
postoperatively from decreased phrenic
nerve activity
2. decreased FRC
these can lead to atelectasis and hypoxia via
V/Q mismatch
22. Some evidence suggests that
postoperative thoracic epidural
analgesia in high-risk patients can
improve pulmonary outcome by
decreasing the incidence of
pneumonia and respiratory failure,
improving oxygenation, and
decreasing the duration of
mechanical ventilatory support
23. Metabolic and endocrine
system
Surgical trauma produces increases in ACTH,
cortisol, epinephrine, norepinephrine and
vasopressin and activate RAA system.
Neuraxial blockade can partially suppress (during
major invasive surgery) or totally block (during
lower extremity surgery) this stress response and
then reduce perioperative arrhythmias and the
incidence ischemia possibly. AT11 block can block
adrenal pathways and blunt hyperglycemia.
24. Complication of neuraxial
block
Backache
Headache
Urinary retention
Maternal fever
Transient neurologic symptoms (TNS):
back pain radiating to the legs without sensory or
motor deficits, occurring after the resolution of
spinal block and resolving spontaneously within
several days
25. High or total spinal anesthesia
Subdural injection
Cardiac arrest
Systemic toxicity
Cauda equina syndrome & other neurologic
deficits, transient or permanent
Maningitis & arachnoiditis
Epidural abscess
Spinal & Epidural hematoma