Regional anesthesia Flashcards
what is RA
it involves the injection of LA agents around nerves in the PNS or CNS causing Reversible abolition of pain and sensation in a part of the body without loss of consciousness
what are the types of RA (2)
- Neuraxial anesthesia (Spinal anesthesia and Epidural)
- Peripheral nerve blockades
when LA are injected into the subarachnoid space what do they inhibit
nerve impulse conduction in all nerves with which it comes in contact (motor, sensory, autonomic) via sodium channel blockade.
what is the MOA of LA
LA produce anesthesia by inhibiting excitation of nerve endings or by blocking conduction in peripheral nerves by binding to and inactivating sodium channels
which nerves are affected first after injection of LA (2)
- autonomic
- sensory
what happens when autonomic fibers are blocked (2)
- vasodilation
- hypotension
what are advantages of spinal anesthesia (7)
- Avoids hazards of GA
- Rapid action
- consciousness is preserved
- Alternative to GA for certain poor risk patients
- Lesser post op confusion
- Safe and cheaper alternative
- prolonged post op analgesia
where does the spinal cord end in adults
L1
where does the spinal cord end in children
L3
what is the most dependent part in supine position
T4-T8
in the cervical area what is the first palpable spinous process
C2
the spinous process of T7 is at what level
is at the level of inferior angle of Scapula
what is at S2-S4
perineum
in the cervical area what is the most prominent spinous process
C7
- bony knob at the back of the neck
what is at T4
nipples
what is the line joining the top of the iliac crests at L4/L5
tuffiers line
what layers do you penetrate when trying to reach the subarachnoid space (9)
- Skin
- Subcutaneous fat
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum
- Dura matter
- Subdural space
- Arachnoid matter
- Subarachnoid space
what is at T6
xiphoid
what are absolute contraindications for spinal anesthesia (5)
- Inadequate drug/ equipment
- Severe hypovolemia
- Increased ICP
- Patient refusal
- Infection at puncture site
what do dermatomes help with
to know the level of your spinal anesthesia
what are indications for spinal anesthesia (2)
- Operations below lower half of body
- surgery on the lower limb, pelvis, genitals, and perineum, and most urological procedures, obstetric procedures e.g. cesarean section - Patients with systemic disease
what is at T10
umbilicus
what is found at T1-T4
cardiac accelerators fiber
- will result in bradycardia & decrease in contractility if affected