Pharmacology pediatric anesthesia Flashcards
There is a large volume of distribution for
water soluble medications (higher TBW)
______ Vd of fat-soluble drugs occurs in pediatrics
decreased
Children have altered and reduced
protein binding- increases free fraction of medications
Children have an immature
blood brain barrier
Children have longer
half-lives (secondary to immature hepatic/renal function)
Pediatric dosing is typically based on a
per kilogram recommendation
Weight can be roughly estimated by the following:
50th percentile weight (kg)= (Age x2) + 9
<1: age (mo)/2+ 4
Regarding volume of distribution, neonates have a
proportionately higher total water content 70-75% (adult is 50-60%)
reduced % of fat
reduced amounts of lean muscle mass
-these differences result in a ECF volume of distribution proportionately HIGHER than that of an adult
There is an increased Vd of ________
water-soluble drugs (related to higher total water content)
The increased Vd of water-soluble drugs is due to
- larger initial doses of water-soluble drugs are required
- potentially delayed excretion
- succinylcholine, bupivacaine, many antibiotics
There is a decreased Vd of
fat soluble drugs (related to decreased fat & muscle mass)
With fat-soluble drugs, there is an
increased duration of action because there is less tissue mass into which the drug can distribute
-thiopental, fentanyl
Decreased Vd of fat soluble drugs is improved by age 2 related to
improved BBB
Membrane permeability is ______ in the newborn
HIGH
There is reduced total
serum protein concentrations
leading to more of the administered drug free in the plasma to exert a clinical effect (e.g. lidocaine & alfentanil)
In regards to protein binding, _______ may be needed for drugs such as barbiturates and local anesthetics
reduced dosing
Hepatic enzymes usually convert medications from a
less polar state (lipid soluble) to a more polar, water-soluble compound
in general this ability is reduced in neonates
The ability to metabolize a conjugate medication improves with
age with both increased enzyme activity and increased delivery of drugs to the liver
_________ have a prolonged elimination half-life in neonates
aminoglycosides & cephalosporins
_______ develops rapidly in first few months of life
GFR & tubular function
Renal function is______
less efficient than in adults
-incomplete glomerular development, low perfusion pressure, and inadequate osmotic load
The concentration of inhaled anesthetics in the alveoli
increase more rapidly with decreasing age: infants>children>adults
In pediatrics, the inhalation induction is
more rapid
overdose occurs quickly and is leading cause of serious complications
Excretion and recovery of inhaled anesthetics is
more rapid