Pediatric Principles Flashcards
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
What is the Mosteller Formula?
BSA (m2) = [height (cm) x weight (kg)]/3600
-squared
What should the total daily dose of a pediatric medication not exceed?
total daily dose of a medication should not exceed adult maximums
-caution in overweight children
-few exceptions: vancomycin, ABX in CF
What are some considerations to keep in mind regarding oral administration in pediatrics?
can they swallow?
-tablets, capsules
ketogenic diet?
-syrups
palatability? volume?
-solutions
How can palatability of oral medications be improved in pediatric patients?
may need to mask the medication taste
-chocolate/strawberry syrup - coats tongue
-peanut butter - coats tongue
-applesauce - masks flavor, medium for mixing
-ice cream - cold minimizes flavor, numbs taste buds
What is the risk with flavoring agents?
ruining the flavor for the kid
What are some tips for oral administration in pediatrics?
do not administer the liquid straight back into the throat
slowly introduce the medication to the rear cheek
always use standardized measuring syringes or cups
-NOT household table/tea spoons
30 minute rule for vomiting
taste/flavouring
What is the 30 minute rule?
if the med is given, child throws up < 30 min after admin, can dose again
-do not repeat if dose thrown up a 2nd time
if med is given, child throws up > 30 min after admin, DO NOT repeat the dose
What is the Aliquot Method?
making a larger volume and using a portion of the dose
What are considerations to keep in mind when using the Aliquot Method?
final volume must be a volume the child can tolerate
is the final volume easily measurable?
is the tablet readily dissolvable in solution?
What is an important consideration to keep in mind when providing a drug by tube?
will the medication plug the tube?
What are the different types of parenteral access lines in pediatrics?
peripheral IV
central IV
-peripherally inserted central catheter (PICC)
-broviac catheter
-umbilical catheter (neonates only)
intraosseous catheters
What are the different types of tubes?
nasogastric
-most similar to taking a drug orally
nasojejunal
-past the duodenum, some drugs may not be absorbed the same
gastric/jejunal
-long term, surgically implanted
What are the two ways to calculate total daily fluid requirements?
formula method
-per 24 hours
4/2/1 method
-hourly
How do you calculate the formula method?
100 ml for each of the first 10 kg +
50 ml for each kg 11-20 +
20 ml for each additional kg above 20
How do you calculate the 4/2/1 rule?
4 ml/kg each of the first 10 kg +
2 ml/kg for kg 11-20 +
1 ml/kg for each additional kg above 20
Which fluid is used empirically for fluid replacement?
D5W/NS for all children 1 month CGA to 18 years old
Which patients do we avoid D5W/NS in?
renal or cardiac disease
diabetic ketoacidosis
severe burns
underlying conditions that affect electrolyte regulation
What is required for blood pressure assessment in pediatrics?
age
sex
height
How is “high” or “low” blood pressure based in pediatrics?
based on evaluation against published tables
How is hypertension classified in pediatrics?
hypertension is generally classified as either SBP or DBP greater than 95th percentileH
How is height percentile determined?
must plot height, based on age and sex
Describe rectal temperature.
reference standard for core temp
gold standard of measurement but invasive
Describe axillary temperature.
lower than rectal
preferred in neutropenic patients, children who cant coordinate oral temp
Describe oral temperature.
0.6 C lower than rectal
generally preferred in children who can coordinate
Describe tympanic temperature.
close to core
limit use when temp has clinical implications
Describe infrared temperature.
can have significant variability +/- core temperature
should not dictate clinical decision making
What is a normal temperature in children?
standard “normal” is 37.2 C - with variation within a day of 0.5 C
-morning nadir, late-afternoon/early-evening peak
True or false: older children and adults have a higher temperature vs neonates and infants
false
neonates and infants have higher temp vs older children and adults
-higher surface-area to body-weight ratio
-higher metabolic rate
What is the general consensus regarding tetracycline use in pediatrics?
relatively contraindicated in < 8 years old
-recent publications support short-term use (< 21 days) when clinical benefits outweigh harms
Why do we generally avoid tetracyclines in kids < 8?
tetracycline chelates with calcium to form tetracycline-calcium complexes which deposit into developing bones and teeth
What is the general consensus regarding fluoroquinolone use in pediatrics?
not recommended for use by Health Canada and FDA
Why do we generally avoid fluoroquinolones in pediatrics?
risk of arthropathy
-juvenile animal data showing AE on cartilage development
-appears to be a small absolute risk increase in MS AEs
-severe arthropathies necessitates avoiding unless necessary
When might fluoroquinolones be used in pediatrics?
potential use when it is reasonable alternative to parenteral therapy
-limited use to when no safe and effective alternative exists
Which pediatric patients is SMX/TMP contraindicated in?
less than 2 months of age
Why is SMX/TMP contraindicated in infants less than 2 months of age?
sulfa antibiotic displaces bilirubin from protein binding sites –> hyperbilirubinemia and kernicterus
What is kernicterus?
permanent brain damage resulting from hyperbilirubinemia in blood
-can result in cerebral palsy, hearing loss, problems with vision, growth, and intellectual disabilities
What is high dose amoxicillin often used for?
90 mg/kg/day often used to overcome streptococcus pneumoniae resistance
-addition of clavulin broadens antimicrobial coverage
What dose of clavulanate is associated with excessive diarrhea?
doses greater than 8 mg/kg/day
What might be seen to achieve high-dose amoxicillin without giving high-dose clavulanate?
two different amoxicillin prescriptions
-to achieve a 14:1 ratio
Should ASA be used in kids for fever or pain?
do not use as an anti-pyretic or analgesic in children
What is ASA associated with in kids?
Reye Syndrome in patients < 18 using ASA, particularly after viral illness (flu, chickenpox)
What are some indications for ASA in kids?
often used for cardiac conditions in pediatrics
-Kawasaki disease
-post-operative congenital heart repair prophylaxis
-rheumatic fever
