Neuraxial blocks 4 Flashcards
Relative or absolute contraindications to neuraxial anesthesia include
coagulopathy
increased ICP
sepsis
infection at the puncture site
severe hypovolemia
valve lesions with fixed stroke volume
scoliosis, arthritis, spinal fusion, and osteoporosis
difficult airway
full stomach
peripheral neuropathy
multiple sclerosis
Describe lab values which would preclude spinal anesthesia.
platelet count <100,000
PT, aPTT, or bleeding time twice the normal value
Coagulopathy increases the risk of
spinal or epidural hematoma
In terms of spinal anesthesia, increased intracranial pressure increases the risk of
brain herniation with a sudden change in CSF pressure
Examples of valve lesions with fixed stroke volume that may preclude spinal anesthesia include
severe aortic stenosis, severe mitral stenosis, or hypertrophic cardiomyopathy
Things that are not contraindications to spinal anesthesia include:
pre-existing back pain
previous back surgery
lower back tattoo
Depending on the extent of the defect, patients with spina bifida are at increased risk for ______ with neuraxial anesthesia
traumatic injury during needle placement
Patients that are at greatest risk for traumatic injury from neuraxial technique with spina bifida include those with
severe neural tube defects or a tethered cord
If you perform spinal anesthesia on a patient with multiple sclerosis, it is important to understand that demyelinated fibers may be
more susceptible to local anesthetic-induced neurotoxicity- it’s best to use a lower dose and concentration of LA
A full stomach may be a contraindication to neuraxial anesthesia because
hypotension (and brainstem hypoperfusion) related to the sympathectomy can cause nausea and vomiting which could lead to pulmonary aspiration
Peripheral neuropathy may be a contraindication to neuraxial technique because
there is theory that these patients are more susceptible to injury and they are also slower to recover from it
Cutting tip spinal needles include
Quincke or the Pitkin
What is a benefit of a cutting tip spinal needle?
requires less force
A concern with using a cutting spinal needle includes
higher incidence of post-dural puncture headache
Non-cutting pencil point tips include
Sprotte or Whitacre
(lower incidence of PDPH but require more force to insert)
If you’re using a spinal needle that is 22g or smaller, the risk of needle deflection is minimized by
placing an introducer needle into the interspinous ligament
Types of epidural needles include
Crawford, Hustead, and Tuohy (most common)
The ___________ of the Tuohy needle minimizes the risk of dural puncture
30-degree curvature and the blunt tip
The optimal depth of catheter insertion into the epidural space is
3-5 cm inside
An epidural catheter that is too shallow results in
higher incidence of inadequate analgesia (epidural failure)
An epidural catheter that is too deep results in
the catheter may enter an epidural vein or exit through an intervertebral foramen
Describe why you should never withdraw the catheter through the needle
the needle could sheer the catheter and leave fragments inside the patient
The Green needle is considered to be a
non-cutting, rounded bevel tip needle
Pros of using the pencil point tip spinal needle include
lower risk of PDPH, more tactile feel, needle less likely to deflect, less likely to injure the cauda equina
Epidural needles differ by the amount of
curvature at the needle tip
A Crawford epidural needle has a _____ degree tip
0
A Hustead epidural needle has a ______ degree tip
15 degree
A Tuohy epidural needle has a __________ degree tip
30 degrees
notice the needle angle increases in alphabetical order
A 22 pound child requires a caudal anesthetic. How many milliliters of 0.2% ropivacaine should be administered to achieve a T10 sensory blockade?
10 mL
For a T10 sensory block you should administer 1 mL/kg
The caudal approach is most commonly used in the
pediatric patients
The caudal approach is useful for procedures requiring up to a
T10 sensory block
Absolute contraindications to caudal anesthesia include
spina bifida, meningomyelocele of the sacrum, and meningitis
The ________ of the local anesthetic solution determines the height of a caudal block.
volume
Correct needle placement of caudal anesthesia is confirmed by
feeling a pop as the needle passes through the sacrococcygeal ligament to enter the epidural space.
You should not use _________ for loss of resistance in children because of
air; risk of air embolism
Why is caudal anesthesia infrequently used in adolescence and adulthood?
sacral anatomy is more difficult to identify
a lumbar approach to the epidural space is easier to perform and equally effective
Relative contraindications to caudal anesthesia include
pilonidal cyst, abnormal superficial landmarks, hydrocephalus, intracranial tumor, progressive degenerative neuropathy
Describe the positioning for performing caudal anesthesia
prone- small roll placed under the iliac crests with the legs in the frog position
lateral- flex the hips and make sure the top leg is flexed more than the bottom leg (Simm’s position)
Describe the landmarks needed for caudal anesthesia
use the posterior superior iliac spines and the sacral hiatus as landmarks
envision an equilateral triangle with the apex of the triangle at the sacral hiatus
Describe needle type and degree of insertion for caudal anesthesia.
22 or 25 gauge needle or 20 gauge IV catheter with bevel up at a 45 degree angle
Resistance to injection with caudal anesthesia suggests that the needle tip is in
the subperiosteal area
The patient may experience ______________ with caudal anesthesia
a feeling of fullness in the sacrum before the block sets up - this is normal
________ provides analgesia that is equal to epidural opioids when administered with caudal anesthesia
clonidine 1 mcg/kg
Describe the pediatric and adult dosing of a caudal block with the desired height block at the sacral level
peds: 0.5 mL/kg
adult: 12-15 mL
Describe the pediatric and adult dosing of caudal anesthesia with the desired height of the block to be sacral to low thoracic (~T10)
peds: 1 mL/kg
adult: 20-30 mL
Describe the pediatric and adult dosing of caudal anesthesia with the desired height of the block to be sacral to mid thoracic
peds: 1.25 mL/kg
adult: N/A
Common pediatric procedures where caudal anesthesia is useful include:
circumcision, hypospadias repair, anal surgery, inguinal herniorrhaphy, low thoracic surgery
