Week 2: Physiological differences between paediatric population and adults Flashcards
Should we treat paediatric patients as “little adults” ?
No
Differences in neurological system
-BBB not mature until 2
-Myelinization in first year of life
-Numerous reflexes present initially
-CNS immature; nerve fibres poorly developed
How much % of brain growth is achieved in an infant’s life?
50% by 1y, 75% by 3, 90% by 6
How much %BW does a brain weight at birth?
12%; doubles by 1y, 3X by 5-6
When does blood brain barrier develop?
1 month. This is why we’re worried if a baby has a fever
Fontanelle
Suture/separation between the bones of the skull that have not yet joined
What are fontanelles covered by?
Tough membranous tissue to protect brain
When does the posterior fontanelle close?
2-3m
When are anterior fornatelle and sutures palpable?
18 months and then they close
What do we think if a patient presents with depressed or sunken fontanelles?
dehydration
What do we think if a patient has a bulging fontanelle and a screaming cat cry?
Increase in intercranial pressure
Why do we have fontanelles?
To allow the brain space to grow- as this is a period of RAPID growth
You are an RN, and are told to do a COMPLETE neurological assessment on a pediatric patient. How would you proceed?
-Fontanelles
-Reflexes
-LOC/Glasgow
-PERRLA
-Behaviour appropriate
-Bilateral strength and coordination
-Crying-what type of crying?
-Are they inconsolable?
-orientation
-Strength and coordination of suck
How long is the respiratory tract growing and changing?
12y
Upper airway differences between children and adults?
Shorter neck
Shorter trachea
Obligatory nose breathers (newborns)
Larynx and glottis higher in neck
Tongue is large relative to small nasal and oral passage
What happens as a result of the shorter and more narrow trachea?
Creates risk for obstruction
Newborns are obligatory nose breathers, talk about it.
They won’t automatically open their mouth if the nose is obstructed. This emphasizes the important of nasal patency.
What increases the newborn’s risk of aspiration?
Larynx and glottis high in the neck
What are some of the lower airway differences?
-25 million alveoli (less)
-Less lung volume
-Depend on diaphragm to breath
-CO2 not expired with they are stressed
So, what are the concerns with fewer alveoli seen in children-when do they increase?
300mil by age 8. Smaller alveoli as they aren’t fully developed, predispose them to alveolar collapse
Why do infants have greater airway resistance?
It is smaller and narrower by 15X. If anything goes wrong (i.e. swelling) their risk is far greater than in an adult
What happens when a child can’t expire CO2 properly?
metabolic acidosis
You are an RN, and you are doing a complete respiratory assessment on a child. How would you proceed?
-Auscultate
-resp rate
-WOB
-SPO2
-Rhythm
What are some ways we can tell there is WOB?
grunting, can see ribs, trash, nasal flaring, head bobbing
Wheezing
High pitched, musical, mid to late expiration
Air is squeezed or compressed in passageway
Crackles
Fine, high pitched crackle or pop. Heard on inspiration. Not cleared by coughing.
Inhaled air collides with previously deflated airways which will not pop open
Stridor
High pitched crowing sound. Originates in larynx or trachea
Obstruction from swelling or lodged foreign body
Transmitted sounds
May seem to originate in the lungs but is referred from upper airway
Observation for WOB: HARGNT
Head bobbing, accessory muscle use, retractions, grunting, nasal flaring, tracheal tug
What is the main difference between adults and paediatric patients in the CVS?
Cardiac output is rate dependent (labile) and not stroke volume dependant as seen in adults
What happens to fetal HR when they become stressed or face respiratory distress?
Tachycardia because they are labile and responding to the increased O2 demand
Why is there a Lower BP in infants?
Thought to be related to underdeveloped left ventricle
Is the radial pulse palpable ?
No
When listening to fetal heart, what is common?
A murmer
What is a way you can monitor hydration stats in fetus?
Fontanelle palpation
Cyanosis that worsens with crying
Cardiac origins
Cyanosis that improves with crying?
Pulmonary as crying increases tidal volume
What does crying increase?
pulmonary resistance to blood flow, increased right to left shunt
Central cyanosis
Inside mucous memebranes with reducedHg saturation. We are concerned about this
Acrocyanosis
Cyanosis of extremities. Normal in newborn
Peripheral cyanosis?
Extremeties, perioral. Hypothermia or decreased flow
Saliva production begins
4m
Sucking reflex present until
3-4m
From ____-____y, intestinal flora becomes morore adult like and stomach acidity _______
1-3, increases
What allows for physiologic control of bowel function? when does this happen?
Myelination of nerves in anal sphincter, 2y
Why do babies spit up?
Lower esophageal muscle tone is not fully developed until 1 month
How big is an infant small intestine?
250cm, adult is 600cm
What organ is relatively larger in infants than in adults?
LIVER, 5% compared to 2% as adults
What types of medications do we give newborns and why?
Weight based. The liver is immature at birth and inefficient at detoxifying substances and medications; the kidneys are also smaller
Is an infant prone to hypoglycaemia or hyperglycaemia?
Hypoglycemia
Do infants have more or less body water compared to adults?
More. This is why they’re more prone to fluid and electrolyte imbalances
Is gastric digestion more or less functional in infants?
Less
A toddler presents with a “pot belly” how do you proceed?
This is a normal finding and this will become flatter with age
Why are infants vulnerable to dehydration or fluid overload (GU)
Can’t concentrate or excrete urine in response to fluid status with their small bladder capacity
Bladder capacity in infants compared to adults?
15-20ml, 600-800ml
Structural variations lead to….
Funcional limitations
In the first year, the infants GU system…
-Poor fluid volume control
-Less ability to conserve water
-Prone to over/underdehydration
-Unable to excrete excessive Na, nitrogenous wastes, drug metabolites
-Cant conserve alkaline buffers or secrete hydrogen ions
-Risk for acidosis
-Lings provide little opportunity for fast removal of CO2
Output must be… how is it measure?
Weigh diaper, 1g=1ml,
1-2ml/kilo/hr
Increase the fluid requirements
Vomiting, fever, diarrhea, diabetes, burns, tachypnea, chemo
What leads to a decreased fluid requirement ?
Meningitis, CHF, renal failure, SIADH
Why are fetal ribs more flexible and compliant?
% of cartilage in ribs is higher until puberty
Are infant bones more easily fractured?
Yes because they’re soft
How much is infant muscle mass compared to adult?
25% vs. 40% in adults
Who heals faster from a bone injury-a child or an adult
Young, more osteogenic potential
Infants have lower metabolic rate, lower O2 needs, and lower calorie needs?
False. It is all higher!
why is hypothermia a greater risk in infants?
Thermoregulation in immature
What is the ratio of temperature elevation (extra breaths: 1 degree F over normal)
4:1
Who has a larger skin surface area?
Child, 2.5X more
How many resp infections/year- infants
6-9
How many resp infections by age 6/year?
4-5
Infants have a ______ response to infection
Slower
