Chapter 5 - Reional Analgesia Techniques Flashcards
Continuous infusions of AMIDES should be reduced by ____ % in infants < 6 months.
30%
- The hepatic pathways for conjugation of the amide locals are immature.
- Neonate has less capacity to metabolize Bupivicaine
- Clearance at 1 month of age is only 1/3 of adult rates
- By 9 months, clearance reaches adult rates
T/F
The greater the volume of distribution of a local anesthetic also prolongs the elimination 1/2 life.
T
- Plasma levels of Bupivicaine after administration of a 2.5 mg/kg dose in the epidural space in infants are significantly LESS than in younger children
What sites on albumin does bilirubin bind to?
Acidic sites on albumin protein
What sites on albumin does Bupivicain bind to?
Basic sites on albumin protein
By how many months of age has the clearance of bupivicaine (Amide) reached adult rates?
9 months of age
- The hepatic pathways for conjugation of the amide locals are immature.
- Neonate has less capacity to metabolize Bupivicaine
- Clearance at 1 month of age is only 1/3 of adult rates
- By 9 months, clearancereaches adult rates
Bupivicaine infusion should be limited to how long and what rate?
Limited to 48 hrs
&
0.2 mg/kg/hr
T/F
Levobupivicaine is less cardiotoxic than bupivicaine and 20% less potent
F
- 20% MORE potent
- Suitable for prolonged infusion
What agent has gained popularity as an agent for caudal analgesia?
Ropivicaine
When compared to Bupivicaine:
- Same sensory block and duration
- More rapid onset
- Less cardiotoxic
- Less motor block
T/F
Ropivicaine should not be used for penile or digit nerve blocks.
Why or Why not?
T
Vasoconstriction and ischemia have been reported
What is the treatment plan for seizures due to local toxicity?
- 100% O2
- Intubate
- Benzodiazepine (Midazolam [Versed] 0.05 - 0.2 mg/kg)
** or**
Thiopental 2 - 3 mg/kg
** or**
Propofoal 1 -2 mg/kg
Acute intravascular (IV or IO) injection of Bupivicaine may cause V-tach and difficulty restoring NSR which can result in low CO. What therapy can be implemented to elude the local anesthetic from the myocardium?
IV Intralipid 20% at 1ml/kg loading dose
followed by
1 ml/kg Q 3 to 5 min.
or
infusion of 0.25 to 0.5 ml/kg/min
A maximum total dose of 8 - 12 mL/kg is recommended
T/F
Propofol can also be used to substitute for Intralipid 20% therapy after local toxcity with acute mycardial dysfunction, but at lower doses (0.5 to 0.75 mg/kg)
F
Propofol should NEVER be substituted for Intralipid
Why may lidocaine in normal doses in children with right-to-left cardiac shunting cause toxic effects?
The normal first-pass absorption within the pulmonary circulation is bypassed
- Dose should be reduced by AT LEAST 50%
What are more reliable signs of intravascular injection of a local anesthetic with epinephrine than tachycardia?
Peaked T waves
and
ST elevation
- May be more difficult to assess and therefore is a less sensitive warning sign in children
- Epinephrine may interact with halothane and precipitate arrhythmias
- Doses of epinephrine up to 10 mcg/kg by infiltration are considered safe in children
Clonidine, at what dose, can be added to local anesthetics for use in the caudal/epidural space?
Clonidine 1 - 2 mcg/ml
- This will prolong effect for ~3 hrs
- However, has INCONSISTENT effects on the rate of elimination of the local from epidural space
- In preterm infants, apnea reported after epidural administration
- Also may contribute to postop sedation (doses >2 mcg/kg) so, undesirable in outpatients
Spinal cord may extend to as low as what level in the infant?
L3
- compared to L1 - 2 in the older child or adult
- Perform lumbar puncture at L4 - 5
The dural space extends to what level in the neonate?
S3 - 4
T/F
The volume of CSF in infants is relatively smaller than in adults
F
- Infants = 4 ml/kg
- Adults = 2 ml/kg
What are the contraindications for spinal or epidural?
- Sepsis
- Infected lumbar puncture site
- Coagulopathy
- No consent
When performing a spinal, what is the size & how do you prepare a neonatal spinal needle and syringe?
22 g or 25 g
1 in.
Measure dead space with tb syringe
- Prepare a syringe containing 0.4 to 1.0 mg/kg of 1% tetracaine mixed with equal volume of 10% dextrose
PLUS
- a volume of this mixture equal to the dead space of the needle (aprox 0.2 ml)
For thoracc/abdominal surgery in preterm infants (
1 mg/kg
1 % Tetracaine
or
0.5% or 0.75% Bupivicaine
When inserting the needle for a spinal, how should the needle face and at level should you be?
L4 -5
and
bevel facing laterally
- Inject slowly to prevent a high or total spinal
After a spinal has been provided for the infant and returned to supine position, where should the BP cuff nd pulse ox be placed?
On the lower extremity
After a spinal is provided, how long is the duration of anesthesia?
1.5 hours




