Pediatric Principles Flashcards
(66 cards)
What is gestational age?
time from conception until birth
What is postnatal age?
chronological age since birth
What is post-conceptual age?
age since conception
-PCA = GA + PNA
List the different age categories.
premature neonate: < 37 weeks GA
full term neonate: neonate born 37-41 +6/7 weeks GA
neonate:
-full term: up to 28 days PNA
-premature: PCA is < 42-46 weeks
infant: 1 month to < 1 year of age
child: 1 year to 12 years of age
adolescent: 13 years to < 18 years of age
adult: 18 years of age and older
What are the differences in gastric pH in pediatric patients?
higher pH earlier in life
-absorption of acid labile compounds is increased
-absorption of weak acids is decreased
What are the differences in gastric motility in pediatric patients?
gastric motility increases with age (normalizes at ~ 4 months of age)
-increased time for gastric emptying and decreased intestinal motility in first months of life
-slower drug absorption and longer Tmax in neonates and young infants vs older infants and children
What are the differences in topical absorption in pediatric patients?
increased topical absorption in infants/neonates
What are the differences in skeletal muscle blood flow in pediatric patients?
reduced skeletal muscle blood flow and inefficient muscular contractions in neonates
higher density skeletal-muscle capillaries in infants compared to older children
-altered absorption in subcutaneous and IM drug absorption
What is the saying regarding babies and water?
babies are like little sacs of water filled with organs
How does TBW change throughout life?
lots at birth and then decreases over time
-fetus 94%
-preterm neonate 85%
-term neonate 78%
-adults 60%
What is the impact of TBW on Vd in pediatrics?
neonates + infants have very large extracellular total body fluid
-higher Vd of hydrophilic drugs (e.g. gentamicin)
What are the differences in plasma proteins in pediatrics?
decreased circulating albumin and alpha-1-acid glycoprotein
-increased unbound (free) fraction of drug
What are the differences in circulating endogenous products in pediatrics?
higher amount of endogenous products (i.e. unconjugated bilirubin, free fatty acids)
-displaces drugs from binding sites
What is the difference in drug metabolizing enzymes in pediatrics?
delayed maturation in drug metabolizing enzymes in neonates and infants vs older children
-more conservative dosing if hepatically metabolized
What is the difference in tubular secretion in pediatrics?
tubular secretion is immature in neonates/infants
What is the difference in glomerular filtration in pediatrics?
really low at birth, increased with age
-rapid increase in 1st two weeks of life
-reaches adult values at 8-12 months of age
Which drugs are impacted by the changes in renal clearance in pediatric patients?
drug with primarily renal clearance
-ex: vancomycin, aminoglycosides
Which equation is used to calculate CrCl in pediatrics?
bedside Schwartz
What is the equation for bedside Schwartz?
eCrCl = k x ht (cm) / SCr (mg/dL)
OR
eCrCl = ( k x ht (cm) / SCr (umol/L) ) x 88
k = 0.413
What are some considerations to keep in mind when using the Schwartz equation?
it is only an estimate
-clinical picture and trends remain crucial when evaluating
validated mostly in CKD pts, up to moderate CKD
-eGFR 15-75 ml/min
study limitations:
-rapidly changing SCr
-infants < 1 yr
-obesity
-malnutrition
-muscle wasting
What are the normal SCr ranges across different age groups?
cord: 53-106 umol/L
newborn: 27-88 umol/L
infant: 18-35 umol/L
child: 27-62 umol/L
adolescent: 44-88 umol/L
adult male: 80-115 umol/L
adult female: 53-97 umol/L
What are pediatric doses generally based on?
generally based on body weight
-check: mg/kg/day or mg/kg/dose
When is BSA used for dosing?
chemotherapy and some biologics
Which equation is used for BSA?
Mosteller Formula