Unit 8 - Neuraxial Anesthesia Pt 2 Flashcards
(44 cards)
coagulopathic states that make neuraxial anesthesia contraindicated
- Plt < 100,000
- PT, aPTT, or bleeding time 2x normal value
- Risk epidural or spinal hematoma
why is increased ICP a potential contraindication to neuraxial anesthesia
- increased chance of brain herniation with sudden change in CSF pressure
- Sudden change in CSF pressure by passing a needle through dura
why is sepsis a relative contraindication to neuraxial anesthesia
- Introduction of contaminated blood beyond blood-brain barrier
- Worsening hypotension d/t neuraxial sympathectomy
valvular lesions with fixed SV that may make neuraxial contraindicated
- severe AS
- severe MS
- HOCM
why is difficult airway a relative contraindication to neuraxial anesthesia
- block failure may require rapid conversion to GA
- RAS depression is common and may cause sedation
- Supplementation with IV sedatives may lead to airway obstruction or collapse
why is a full stomach a relative contraindication to neuraxial anesthesia
- hypotension & brainstem hypoperfusion r/t sympathectomy can cause N/V
- Can lead to aspiration if sedated patient has full stomach
why is neuraxial anesthesia often avoided in patients with peripheral neuropathy
- theory that these patients are more susceptible to injury
- Slower to recovery from injury
Data lacking but legal word has a strong opinion
neuraxial considerations in pts with multiple sclerosis
- epidural is safe, spinal might exacerbate s/s
- if spinal would benefit pt, inform about small risk of exacerbation
why should lower dose and concentration of LA be used for neuraxial if pt has multiple sclerosis
Demyelinated fibers may be more susceptible to LA-induced neurotoxicity with spinal
neuraxial considerations in pts with spina bifida
- Increased risk for traumatic injury during needle placement depending on extend of defect
- Greatest risk: neural tube defects, tethered cord
is previous back surgery a contraindication to neuraxial
nope
is a lower back tattoo a contraindication to neuraxial
theoretical concern of introducing neurotoxic compounds into body (no data to justify)
cutting tip spinal needles
Quincke
Pitkin
pros and cons of cutting tip spinal needles
pros: requires less force
cons:
* Higher risk PDPH
* Less tactile feel
* Needle more easily deflected
* More likely to injure cauda equina
non-cutting tip spinal needles - pencil point
Sprotte
Whitacre
Pencan
rounded bevel tip spinal needle
Greene
pros of non-cutting tip spinal needles
- Lower risk PDPH
- More tactile feel
- Needle less likely to deflect
- Less likely to injure cauda equina
needle angles of epidural needles
Crawford = 0 degrees
Hustead = 15 degrees
Tuohy = 30 degrees
why is aortic stenosis a relative contraindication for neuraxial anesthesia
fixed afterload makes CO highly dependent on preload, which decreases with sympathectomy
distance from epidural space to skin in lumbar region of most adults
3-5 cm
Distance ↑ in pregnant & obese patients: skin to epidural space up to 9 cm
optimal depth of epidural catheter insertion
3-5 cm inside epidural space
consequences of epidural catheter depth too shallow vs. too deep
o Too shallow = higher incidence of inadequate analgesia (epidural failure)
o Too deep = catheter may enter epidural vein or exit through intervertebral foramen
distance from ligamentum flavum to dura
~7 mm
(can range from 2 mm – 2.5 cm)
distance from ligamentum flavum to dura
~7 mm
(can range from 2 mm – 2.5 cm)
