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)
What is the paramedic approach good for?
Good for calcified intraspinous ligament or difficult positioning
The needle will pass through 1 ligament during the paramedium approach, which one
Ligamentum Flavum
How is the needle inserted for paramedium approach?
1 cm lateral and 1 cm inferior to space
Angle needle medially and cephelad
If lamina contacted, walk off bone
If a patient receives a spinal, what must they do before being discharged?
Must void prior to discharge
Complications from spinal
Neurologic Injury
- 03% occurance (1:240,000)
- Needle introduction to nerve or cord
- Spinal cord ischemia
- Bacterial contamination
- Hematoma
Complications from spinal
Cauda Equina Syndrome
Microcatheters
5% lido, repeated dosing
Complications from spinal
Arachnoiditis
Infection Myelograms from oil based dyes Blood Neuro irritant Surgical interventions Intrathecal steriods Trauma
Complications from spinal
Meningitis
Bacterial or aseptic
Use Strict sterile technique
Complications from spinal
Postdural puncture headache
- up to __% incidence
- what makes it worse/better
25%
Worse when head up, relief when supine
Non-invasive treatment for PDPH
Fluids Caffeine (500mg 1-2 doses) Bed rest Analgesics Sumatriptan
May take up to 1-6 weeks to resolve
Invasive treatment for PDPH
Epidural Blood Patch
Mainstay of invasive treatment
1st effective up to 64% OB and 95% non-OB
2nd effective up to 90%
Complications from spinal
Spinal Hematoma
Why is this important to diagnose?
What increased the risk?
This is a MEDICAL EMERGENCY
- Neurologic symptoms
- Immediate neuro consult and MRI
Incidence 0.00063%
Anticoagulation, increased age, female, hx of GI bleed, length of therapy
Complications from spinal
High Spinal
Monitor and treat appropriately
Airway and Pressor support
Complications from spinal
CV collapse
What is the 1st S/S?
Bradycardia usually 1st
Treat aggressively
Absolute contraindications to epidurals
patient refusal
uncorrected hypovolemia
increased ICP
infection at site
Relative contraindications to epidurals
coagulopathy
fixed cardiac defect
anatomic abnormalities
unstable neurologic disease
Controversial contraindications to epidurals
inability to communicate, tattoos, complicated surgery with major blood loss
Where is the epidural placed?
Usually at L2-L4
When can you use adult levels for epidural placement?
after age 8
Physiologic effects spinal to spinal
Above T4
Below T4
Above T4
T1-T4 cardiac sympathetic fibers
Profound hypotension and bradycardia
Below T4
Vasomotor tone controlled by T5-L1
Decreased venous return, and subsequent decreased CO
If pt has respiratory arrest after epidural, what was it most likely from?
likely due to sympathectomy and brain and brainstem ischemia
What is the key factor effecting epidural coverage
Volume**
Adults: 1-2 mL for each level to be blocked
Lumbar gets more spread cephalad than caudal
Thoracic even spread up and down
How does concentration effect coverage for epidural?
Lower – sensory
Higher – may get motor
Is position a factor for epidural spread?
NO
How does age effect coverage for epidural?
Inreased age = decreased dose
How does height effect coverage for epidural?
<5’2” use 1mL per level
>5’2” increase by 0.1mL for each 2 inches
How does pregnancy and obesity effect coverage?
Decreased dose
Epidural vein engorgement and increased adipose tissue
What is average onset time for epidural
10-20 min
What are the approaches for epidural placement
Median
Paramedian start 1.5-2cm laterally
Taylor
What are the 2 techniques for IDing epidural space
Loss of resistance (LOR)
Hanging drop
Explain LOR technique
Place needle & stylet through supraspinous ligament and into intraspinous ligament
Remove stylet and attach syringe with air or fluid
Always secure needle against patient
2 ways to proceed
1: Alternate very slow advancement and tapping pressure to plunger of syringe until LOR
2: Advance needle with continuous pressure on plunger until LOR
Explain hanging drop technique
Needle placed as before
Small amount of fluid placed in needle hub
Needle advanced until Epidural space encountered
Drop will suck into needle
Used mostly for Thoracic
For a caudal block, how is the sacral hiatus ID’d?
ID’d by Sacral Cornu
What angle is the needle inserted at for a caudal?
Needle inserted at 45 degree angle
During a caudal, there is a distinct “snap” or “pop” when through which membrane?
sacrococcygeal membrane
Once through the sacrococcygeal membrane, what are the next steps
Lower angle to 160 degrees
Advance :
Adults no more than 1.5 cm
Children no more than 0.5 cm
Aspirate for blood or CSF
Insert catheter or inject
After IDing the epidural space with the needle, what are the next steps?
- Note depth on needle
- Place catheter through needle
- Mark for end of needle and resistance
- Advance catheter 5-7 cm more
- Remove needle over catheter
- Withdrawal catheter until 3-5 cm remain in epidural space
- Attach end to catheter
- Aspirate for blood or CSF
- Dressing – clear occlusive
- Test Dose
(3 mL of 1.5% Lido with 15mcg epi)
What should you NEVER do when placing an epidural catheter?
NEVER WITHDRAW CATHETER THROUGH NEEDLE***
What should you always do before dosing an epidural?
ALWAYS ASPIRATE PRIOR TO INJECTION
What is the dosing for Lumbar Thoracic Caudal Continuous infusion
Lumbar:
1-2 mL per segment
Give in 5 mL increments q 3-5 min
Thoracic:
0.7 mL per segment
3-6 mL q 30 min
Caudal:
3 mL per segment
Continuous infusion:
4-15 mL/hr (Individualize)
With an epidural, what should be done if you have a unilateral block?
Pull catheter back
Unaffected side down
Redose
Replace
With an epidural, what should be done if you have an inadequate block?
Raise head & redose with higher concentration
Add fentanyl or give 50 mcg
With an epidural, what should be done if there is questionable quality and pt needs to go to OR?
In OR remove catheter
Do CSE with new catheter placement
With an epidural, what should be done if you have a dissipating block?
Requires more or doesn’t last
Check for intravascular placement
Rebolus with higher concentration & increase rate
Add opiod
What is the incidence of back pain with epidurals?
What is the treatment?
20-30% incidence
Usually self limiting
NSAIDS, Tylenol, Heat
PDPH is more common in what group and after what accidentally happens?
Most common in younger female
Usually expected after wet tap
If inadvertent subdural injection, when will you see it?
Delayed response 10-15 minutes
Get ready for High spinal
(hallmark - high but patchy block)
If inadvertent subarachnoid injection, when will you see it?
Fast high spinal
What are they symptoms and treatment for men
Non-positional headache, fever, lethargy, confusion and classic nuchal rigidity
Emergent antibiotic therapy
Head CT, lumbar puncture, neuro consult
Arachnoiditis
Also thought to be from adherence of ____
tissue pulling
