IMM 27 and 28: Pediatrics Flashcards
What is gestational age (GA)?
time from the first day of the mother’s last menstrual period to the day of birth
What is post-natal age (PNA)?
chronological age – time from birth
What is post-menstrual age (PMA)?
gestational age (GA) + post-natal age (PNA)
- usually used up to 44 weeks
What is corrected age (CA) or corrected gestational age (CGA)?
chronological age - number of weeks born before 40 weeks of gestation
- used only for children up to 3 years old who were born pre-term
How old are premature newborns?
< 38 weeks GA
How old are term newborns?
> or equal to 38 weeks GA
How old are neonates?
0-28 days PNA
How old are infants?
1-24 months
How old are young children?
2-6 years
How old are children?
6-12 years
How old are adolescents?
12-19 years
What is the weight at 10 days?
lose 5-10% of birth weight
What is the weight at 14 days?
back to birth weight, then gain 25-30 g/day
What is the weight at 3 months?
gain ~500 g/month (15 g/day
What is the weight at 4-6 months?
2x birth weight
What is the weight at 12 months?
3x birth weight
What is the weight at > 2 years?
gain ~2.25 kg per year
What children are included in WHO Growth Charts?
- healthy, term, singleton
- no health, environmental, economic constraints on growth
- willing to follow health and feeding recommendations
- non-smoking mother
- breastfed: (a) exclusive or predominant breastfeeding for ≥ 4 months, (b) introduction of complementary foods between 4-6 months, (c) partial breastfeeding to be continued ≥ 12 months
- routine pediatric health care visits & immunization
What are the strengths of WHO Growth Charts?
growth standard vs. growth reference
- prescriptive, based on healthy children
- best portrayal of physiological growth (growth standard)
- consistent with current nutrition recommendations
- establish breastfed child as model for growth: CDC charts (50% breastfed at all; ~30% breastfed ≥ 3 mo), WHO charts (75% breastfed ≥ 4 mo; 68% partially breastfed ≥ 12 mo)
What is the HR, SBP, and RR of newborns?
- HR: 120-150
- SBP: 60-70
- RR: 30-60
What is the HR, SBP, and RR of 6 month olds?
- HR: 120-140
- SBP: 65-120
- RR: 25-35
What is the HR, SBP, and RR of 1 year olds?
- HR: 120-140
- SBP: 70-120
- RR: 20-30
What is the HR, SBP, and RR of 5 year olds?
- HR: 90-110
- SBP: 80-125
- RR: 20-25
What is the HR, SBP, and RR of 15 year olds?
- HR: 60-90
- SBP: 110-130
- RR: 12-16
What parts of the brain are developed at birth?
all major structures of the brain and cranial nerves
- blood brain barrier
- myelination
Myelination
- CNS continues to myelinate during 1st year of life
- at 1 year, all major nerve tracts are myelinated
Describe brain growth from birth.
- birth brain weighs: 350-450 g
- adult brain weighs:1.3-1.4 kg
- 1st year of life brain triples in size
- 2.5 years brain weighs 0.9-1 kg (75% of adult)
- 6 years brain weighs 1.2-1.3 kg (90% of adult)
Describe the head.
large and weighs more than body
What happens to cranial sutures?
use at 16-18 months
What are the developmental milestones of neurological function?
- motor function – gross motor skills, fine motor skills
- language/speech
- cognitive – following commands, learning, problem solving, remembering
- social – connecting and having relationships with others, cooperating, responding to feelings of others
Pulmonary
- limited capacity to increase tidal volume – rib position, rib movement on inspiration (up vs. up and out)
- chest compliance
- respiratory muscles – fewer type 1 fibres, small airway muscles not completely developed (response to beta-2 agonists)
How do alveoli and airways change after 8 years old?
- up to 8 years old: alveoli increase in number and size
- after 8 years: growth in size of alveoli and airways
- alveolar epithelium and endothelium continue to develop until 10-12 years of life
How does oxygen consumption change from neonates to adults?
neonate oxygen consumption is 2x greater than adults
Airway
all conducting airways are present at birth
- number does not change
- branching pattern does not change
- airways increase in size and length as growth occurs
Respiration
- diaphragm is chief muscle of respiration until around 6 years old
- abdominal distension or decreased compliance results in decreased ventilation
- limited capacity to increase tidal volume, rib position, rib movement on inspiration (up vs. up and out)
Describe the work of breathing of neonates vs. adults.
neonate 3x greater than adult
What type of breathers are infants?
obligate nasal breathers
- breathe and eat
What does a small reduction in airway radius (mucus, edema, inflammation) result in?
increased resistance to airflow, therefore increased respiratory distress
What is cardiac output?
CO = HR x SV
Describe cardiac output in neonates and infants.
- ↑ heart rate is the most efficient means of ↑ CO
- less preload reserve
- relatively fixed SV – limited ability to stretch ventricle, noncompliant and poorly developed left ventricle
Cardiovascular
Parasympathetic System
fully formed shortly after birth
Cardiovascular
Sympathetic System
incomplete
- increased vagal responses
Cardiovascular
Cardiac Dysrhythmias
- SVT
- bradycardia
- same causes as in adults, except also: congenital heart disease, asphyxia (resulting in hypoxic injury)
Cardiovascular
Cardiac Contraction
- neonates have immature sarcomeres
- are calcium dependent for contractility
Cardiovascular
Calcium Chloride
used as a vasopressor
Cardiovascular
What do we need to be cautious about?
calcium channel blockers in neonates
Physiological Differences in Myocardium of Neonate vs. Adult
CO
- neonate: HR dependent
- adult: SV and HR dependent
Physiological Differences in Myocardium of Neonate vs. Adult
Contractility
- neonate: reduced
- adult: normal
Physiological Differences in Myocardium of Neonate vs. Adult
Starling Response
- neonate: limited
- adult: normal
Physiological Differences in Myocardium of Neonate vs. Adult
Compliance
- neonate: reduced
- adult: normal
Physiological Differences in Myocardium of Neonate vs. Adult
Afterload Compensation
- neonate: limited
- adult: effective
Physiological Differences in Myocardium of Neonate vs. Adult
Ventricular Interdependence
- neonate: high
- adult: relatively low
Blood Volume of Infants vs. Adults
- infants: 80-90 mL/kg
- adults: 65-70 mL/kg
Circulation
- blood volume relatively larger
- absolute volume smaller
- relatively small volumes of blood – significant blood loss (laboratory testing, bleeding)
Describe gastric acid production in infancy.
- decreased in infancy
- adult levels by approximately 2 years of age
Describe gastric pH at birth and after.
- at birth: 6-8
- 24 hours after birth: 1-2
- after: increases 4-7
Describe motility compared to adults.
- irregular, different peristaltic pattern than adults
- gastric emptying irregular & erratic until 6-8 months old
Gastrointestinal
- infants feed frequently
- infant diet consists of breast milk and/or formula for first 6 months
- infants have delayed gastric emptying
- nutrients in stomach majority of time between feedings
- increased rates of gastroesophageal reflux disease
- by school age, no difference between adult and child
Kidney
- at birth, adult complement of nephrons
- at birth, 50% of renal cortex
- tubular length and glomerular size increase with age
- renal blood flow is 5-10% CO at birth, and 25% CO by 2-4 years of age
Renal Function
- decreased at birth – linear development after > 34 weeks PMA
- GFR increases in first 2 weeks of life
- tubular secretion: 6-8 months
- tubular reabsorption matures by 1-2 years
- decreased ability to concentrate urine – decrease urea, increase tubular length, insensitivity to ADH
Urine Output
- neonates: 2-4 mL/kg/h
- infants and children: 1-2 mL/kg/h
- adolescents and adults: 0.5-1 mL/kg/h
What is normal creatinine (SCr) and urea in newborns?
- SCr: 26-90
- urea: 1-9
What is normal creatinine (SCr) and urea in infants?
- SCr: 17-35
- urea: 1.4-4
What is normal creatinine (SCr) and urea in children?
- SCr: 25-62
- urea: 1.8-6
What is normal creatinine (SCr) and urea in adolescent males?
- SCr: 50-106
- urea: 2.5-6.5
What is normal creatinine (SCr) and urea in adolescent females?
- SCr: 44-97
- urea: 2.8-7.5
How GFR estimated under 2 years old?
Schwartz Equation
How GFR estimated at 2 years old or greater?
modified Schwartz Equation
What is normal creatinine clearance (GFR) for age 2-8 days?
17-60
What is normal creatinine clearance (GFR) for age 4-28 days?
26-68
What is normal creatinine clearance (GFR) for age 30-90 days?
30-86
What is normal creatinine clearance (GFR) for age 1-6 months?
39-114
What is normal creatinine clearance (GFR) for age 6-12 months?
49-157
What is normal creatinine clearance (GFR) for age 12-24 months?
62-191
What is normal creatinine clearance (GFR) for age 2-12 years?
89-165
Metabolic: Thermoregulation
- ↑ body surface area (BSA)
- ↓ fat stores
- poor ability to thermoregulate
- infant cannot shiver to generate heat – need warmers, bundling
Metabolic: Blood Glucose
- hypoglycemia
- neonates: decreased glycogen stores, decreased body fat, high metabolic needs
Neonatal and Pediatric Pharmacodynamics
What can development affect?
can alter the response to a drug
- effectiveness
- toxicity
Neonatal and Pediatric Pharmacodynamics
less well understood than pharmacokinetics
Pediatric Pharmacodynamics
Morphine
- pre-term neonates may have less analgesia
- neonates more sensitive to respiratory depression
Pediatric Pharmacodynamics
Midazolam
neonates may be more sensitive
Pediatric Pharmacodynamics
Valproic Acid
risk of liver toxicity higher in < 2 years old
Why should acetylsalicylic acid (ASA) be avoided in children?
- risk of Reye’s Syndrome in children and
adolescents taking ASA while having a
viral infection - acute non-inflammatory encephalopathy
with fatty liver failure – serious condition: swelling in liver and brain, resulting in behaviour changes, seizures, death
What factors place pediatric patients at increased risk of medication errors?
watch lecture
What are some factors to consider in selecting a medication for a child?
watch lecture
