Spinals and Epidurals Flashcards
What are the types of needles
Pencil (better feel, less trauma)
Cutting (place longitudinal)
Name the 4 spinal needles
Quincke (medium cutting)
Pinkin (cutting)
Sprotte (pencil point)
Whitacre (pencil point)
Pencan (pencil point)
Greene (noncutting rounded bevel)
Name the 3 epidural needles
Crawford (0 degrees)
Hustead (15 degrees)
Touhy (30 degrees)
What does a stylet in the needle do?
Prevents introduction of dermal cells
can lead to dermoid spinal cord tumor
What are the needle sizes?
22-27 gauge
90-145mm
ABSOLUTE contraindications to a spinal
PATIENT REFUSAL Lack of Cooperation Uncorrected coagulopathies Infection at the site of block Hypovolemia Indeterminate neurologic disease Increased ICP
Relative contraindications to a spinal
Infection distinct from site of injection
Unknown duration of surgery
Uptake and spread from subarachnoid space depends on
Concentration of LA in CSF
Surface area of nerve tissue exposed
Lipid content of nerve tissue
Blood flow to nerve tissue
Distribution of LA depends on
Baricity
Position
Dose
The level of spread depends on
Baricity Position Dose Site of injection Age? Speed of injection Volume Concentration
Specific gravity of CSF
0.002-0.009
Define baricity
the density of a LA relative to CSF
Define Isobaric
Baricity similar to CSF
LA will remain in place
Saline added
Define hyperbaric
Baricity higher than CSF
LA will sink
Dextrose added to increase baricity
Define hypobaric
Baricity lower that CSF
LA will rise
Water added to reduce baricity
Systemic effects of Neuraxial anesthesia:
Liver and Kidneys
if MAP maintained, no changes
Systemic effects of Neuraxial anesthesia
Cadiovascular
Sympathectomy - vasodilation of arterial and venous capacitant vessels (venous predominantly). Reduction in venous return, CO and BP
Volume load with 15ml/kg
Bradycardia from block of cardiac accelerators (T1-T4) and Bezold-Jarish reflex)
Systemic effects of Neuraxial anesthesia
Respiratory
Little effect with normal lung physiology
Accessory muscle function reduced (imprint of inspiratory & expiratory and ability to cough)
Major effect with high spinal
Loss of proprioceptive input = dyspnea feeling (maintain reassurance, if they can talk, they can breath)
Systemic effects of Neuraxial anesthesia
GI
Sympathetic innervation from T6-L2
- Increased secretions
- Sphincters relax
- Bowel constricts
Nausea and Vomiting about 20%
- Atropine to treat after high spinal
Systemic effects of Neuraxial anesthesia
CNS
Reduced sensory input from the reticular activating system (RAS) can lead to drowsiness
Which LA is NOT approved for spinal
2-Chloroprocaine
Which LA are approved for spinals
Lidocaine
Tetracaine
Bupivacaine
What is the spinal inset/duration/dose for Lidocaine
Onset: 3-5 min
Duration: 60-90 min
Dose: 25-50 mg
What is the spinal onset/duration/dose for Tetracaine
Onset: 3-6 min
Duration: 70-180 min
Dose: 5-20mg
What is the spinal onset/duration/dose for Bupivacaine
Onset: 5-8 min
Duration: 90-150 min
Dose: 5-20 mg
When you ID the iliac crest for spinal placement, what level are you at?
L4-L5
When doing a midline approach,
Needle angle degree…
Resistance at all layer, but mostly at..
Remove stylet and check for flow, if no what..
After free flowing CSF, attach syringe and..
Slightly cephalad 10-15 degrees
Ligamentum flavus (will feel a pop when thru)
Rotate needle (may be up against something)
Aspirate, inject slow (0.5 ml/sec)
Complications during spinal placement:
Bone contacted
Withdraw needle and stylet to skin and redirect
Complications during spinal placement:
Paresthesia
Stop advancing
Remove stylet and check for CSF
Complications during spinal placement:
Blood
Not usually a problem unless excessive
Reattempt
Complications during spinal placement:
Position
May use table to alter block during first few minutes
When placing a spinal needle via midline approach, what structures do you meet (in order)
Skin Subcutaneous Supraspinous Ligament Intraspinous Ligament Ligamentum Flavum (epidural space) Dura mater (subdural space) Arachnoid mater (subarachnoid space- spinal placement)