Pediatric Anesthesia pt1.2 Flashcards
Opposing factors regarding NMBD distribution leads to what effect? (prolonged NACh-R opening, larger Vd for water-soluble drugs)
unpredictable response
Neonate nicotinic cholinergic receptors are affected how?
stay open for a lot longer than normal
How do GABA receptors differ in a neonate from an adult?
Neonates have about 1/3 GABA receptors as adults
Overall differences in pediatric pharmacology effects include:
- TBW composition differences
- Immature metabolic pathways
- reduced protein binding
- immature BBB
- Reduced GFR
- Immature receptor responses
Respiratory differences in pediatrics that can affect the effects of inhalational agents include:
- Smaller FRC
- Increased Vm
How do the effects of inhalational agents differ in neonates?
- Rapid equilibration
- Rapid induction and recovery
- More/faster CV side effects
How do shunts affect the uptake of inhalational agents?
- Left to right shunts: increase in uptake
- Right to left shunts: decrease in uptake (slower induction)
How does MAC differ from a neonate to an infant to an adult?
- Neonates (0-30days): lower MAC
- Infants(1-6mo): Higher MAC
- Adults: MAC lowers as age progresses
except for sevo
When does MAC of inhalational agents typically peak at its highest level?
Infants 2-3months
How does the MAC of Sevoflurane (ultane) differ from the MAC values of other volatile agents?
Sevo peaks earlier:
- Highest at 0days - 6 months (3.2%)
- 6mo - 12 years: MAC lowers but still higher than adult (2.5%)
What is the preferred agent for inhalational induction?
Sevoflurane (ultane)
- rapid onset
- least pungent volatile
Why is nitrous sometimes used with sevoflurane for inhalational induction in pediatrics?
2nd gas effect: increase the uptake of sevoflurane and allow for a more rapid onset (in theory)
What is the primary downside of using Nitrous?
- increased risk of PONV in adults
Why do infants and children generally have a rapid uptake and equilibrium from inhalation agents?
- greater Vm
- higher ratio of TV:FRC (from greater metabolic rate)
- Higher cardiac output
In the neonate, what causes a greater percentage of blood flow to the vessel-rich groups?
decreased distribution of adipose tissue and decreased muscle mass (less redistribution)
Why are myocardial depressant effects exaggerated from inhalational agents?
Structural and functional immaturity of the pediatric heart
What distributional effects are characterized with the use of IV anesthetics in pediatrics?
- higher cardiac output to vessel-rich tissues
- prolonged DOA
- prolonged CNS effects
lower redistribution to vessel poor groups
Increased metabolic rate and volume of distribution leads to what effects on the propofol dose requirements?
- requires larger dosages
How do the dosage requirements for the ED50 of propofol vary with different age groups?
- 1-6 mo: 3 mg/kg
- 1-12yr: 1.3 - 1.6 mg/kg
- 10-16yr: 2.4 mg/kg
What ketamine induction dose is typically required for children?
- Larger dose
- 1-2 mg/kg
neonates may need reduced dose
What effect from ketamine should warrant caution from the provider?
- ketamine can increase secretions and children have highly reactive airways ⇉ laryngospasm risk
- give ketamine with an antisialogogue
Why is use of etomidate limited in children?
- Concerns with anaphylactoid reactions
- adrenal suppression
dose relatively unchanged 0.3 mg/kg and does offer minimal CV suppression
What route and dose of precedex can beneficially be used in kids?
Intranasal for premedication
- 1-2 mcg/kg
- 30-40 min for peak effect
- minimal respiratory depression
- Decreased emergence delirium/agitation
Why might precedex be avoided?
- High dose may prolong recovery phase and lead to slower turnover times
What dose of morphine is commonly used for pediatrics?
0.05 - 0.1 mg/kg
may reduce for neonates
What downsides are there for use of morphine in kids?
- respiratory depression
- Neonates are more sensitive to effects (clearance is decreased)
- possible histamine release
Why is codeine not typically used in pediatrics?
Black box warning and unpredictable metabolism
What dose of fentanyl is typically used in pediatrics?
0.5 - 2 mcg/kg
What benefits does fentanyl offer?
- greater hemodynamic stability
- rapid onset
- short DOA
What side effect is a cause for concern in use of remifentanil in children?
Can cause bradycardia
Pediatric patients are often ____ sensitive to NDNMBs and _____ sensitive to DNMBs
Pediatric patients are often more sensitive to NDNMBs and equally sensitive to DNMBs
Is succinylcholine water-soluble or lipid-soluble?
Highly water soluble
What effects does the solubility of succinylcholine contribute to in the neonate?
- Highly water-soluble leading to rapid redistribution into ECF (increased ECF in neonates)
- leads to requiring 2x the IV dose (2mg/kg) in infants
children only require 1mg/kg
What is the IM dose of succinylcholine used in neonates and infants?
- Neonates/infants: 5 mg/kg
- > 6months: 4 mg/kg
What main side effect can occur with succinylcholine, especially in children <5yr old?
Bradycardia
SCh usually given with atropine or glycopyrrolate
What black box warning comes with succinylcholine administration?
cardiac arrest and hyperkalemia
avoid with duchennes MD
What is the only NDNMB that can be given intramuscularly?
Rocuronium (zemuron)
Why is the duration of succinylcholine often prolonged in neonates?
reduced pseudocholinesterase
_____ may follow the first dose of succinylcholine and becomes more common after repeated doses?
Cardiac arrest
Why is train of four and twitches hard to assess in neonates and infants? What is typically assessed instead?
- Lack of surface area for prongs
- Assess clinical signs instead: grimacing, elbow/hip flexion, knees to chest…
What drugs are typically administered for reversal of paralytics in neonates?
- Neostigmine (0.05-0.07 mg/kg) (given with atropine or glyco)
- Sugammadex (2-4 mg/kg)
Sugammadex not FDA approved for children under 2
What significant side effects can occur with administration of sugammadex?
can cause Bradycardia and HoTN if large dose administered rapidly
Anesthetic considerations for the administration of neuromuscular blockers in the neonate include:
- avoid succinylcholine
- longer duration of action of succinylcholine
- larger dose of succinylcholine
- larger dose of NDNMBs
Larger dose of succinylcholine
and longer DOA of succinylcholine?
