Apex- Neonate A&P Flashcards
Each vital sign is consistent with the term newbord EXCEPT:
-HR 140
-RR 40
-SBP 90
-DBP 40
SBP 90
Normal SBP in the newborn is ~ 70mmHg
When is a baby considered a “neonate” compared to an infant?
neonate = 1st 28 days of life
infant = day 29 - 1 year
fill in chart
What is the primary determinant of blood pressure in the neonate?
HR
Newbord: What is considered:
Hypotension:
Normotensive:
Hypertensive:
Hypotensive < 60
Normotensive 70
Hypertensive > 80
Is phenylepherine a good or bad choice for neonates?
why or why not
no bc neonates have a poorly compliant venticle so they cant significantly increase contractility to overcome an elevated afterload
*increasing the HR is the best way to support BP
Is it better to increase the RR or TV for a neonate?
why?
RR - bc its metabolically more efficient since neonates consume twice as much oxygen and produce twice as much co2 than the adult
*explains why newbords have a high respiratory rate, yet tidal volume is the same as the adult on a per weight bases (6ml/kg)
why do neonates respond to laryngoscopy with bradycardia?
bc autonomic regulation of the heart is immature at birth, with the SNS being less mature than the PNS, so the PNS takes over in times of stress
What is hypotension defined as in the:
-newborn
-less than 1yo
-older than 1yo
newborn < 60
1yo < 70
oldert than 1yo= < [70+ (age in yrs x 2)]
What would you want your BP above for a 3yo?
> 76
[70+ (age in yrs x 2)]
Why is it that when the neonate gets older, they become relatively less depedent on HR to support cardiac output?
bc SVR is low in the neonate , but overtime the SVR increases and the LV has to pump agaisnt higher SVRs whigh lead to growth and development of the contractile elements of the LV.
What is the normal tidal volume (ml/kg) in the neonate
6ml/kg
What is the primary determinant of SBP in the neonate?
HR
poor LV contractility, so cant increase SV- more reliant on Hr
Hypotension in a 5yo would be what
<80
[70+ (age in yrs x 2)]
What are some ways the pediatric ariway differs from the adult?
8 key points
- preferential nose breathers
- larger tongue relative to the volume of the mouth
- shorter neck
- “U” or “omega” shaped epiglottis that is longer and stiffer
- Vocal cords with an anterior slant
- Larynx at C3-4
- Subglottic airway is funnel shaped
- Right and left mainstem bronchi take off at 55 degrees
What is the narrowest region of the pediatric airway?
Dependes
Narrowest fixed region = cricoid
Narrowest dyamic region = vocal cords
How do you position for DL in the infant and why?
a roll under the shoulders bc their big ass heads flex their neck
No Sniffing (for) babies!
glottis in the adult vs full term newborn
adult = C5
full term newborn = C4
premature newborn = C3
is the newborn glottic opening anterior?
no - it is more cephalad/rostral (C4 compared to C5 in the adult)
think adults cant handle C4 but newborns can - idk
Why is a straight blade (miller) preferred in newborns?
bc the combination of the larger tongue and more cephelad larynx results in a more acute angle between the oral and laryngeal axis’s
-a straight blade can better help lift the tongue to expose the larynx
Shape of adult vs infant epiglottis
2 characteristics of each
adult = C-shaped: short and floppy (dick)
infant = Omega shaped: longer and stiffer (just gettin started)
T/F- the infant vocal cords slant anteriorly
true
Narrowest region in the adult airway?
vs kids
why do we care?
the laryngeal inlet (glottis)
(cylinder shaped, whereas the infant is funnel shaped so gets smaller as your go down; cricoid = smallest fixed region, VC = smallest dynamic region)
bc the narrowest region of the airway determines the maximum ETT size that the airway can accomodate
How to the bronchi take of in infant vs adult?
What age does the transition occur?
infant (up to 3yo) - both take off at 55 degrees
adult:
-left 25 degree
-right 45 degree
During an inhalation induction, a neonate begins to desaturate shortly after removal of the facemask. Which statement bEST explains why the neonate desaturated so quickly?
A. decreased TV to dead space ratio
B. O2 consumption is 3mL/kg/min
C. Increased alveolar ventilation to FRC ratio
D. Patient is experiencing MH
C. increased alveolar ventilation to FRC ratio
O2 consumption of adult vs neonate
adult = 3ml/kg/min
infant = 6ml/kg/min
bc the neonate has a higher ratio of alveolar ventilation relative to the size of their FRC, the o2 supply contained within the FRC is quickly depleted
T/F- neonates desat so quickly mainly due to a decrease in FRC
False - the neonates high o2 consumption (twice that of a dult) will quickly exhaust the o2 reserve in the FRC (slighlty decreased) leading to rapid desaturation
6ml/kg/min o2 consumption (adult = 3)
Why do neonates have a faster inhalational induction?
due to fast turnover of the FRC (o2 consumption double that of an adult [6ml/kg/min]), allows for a quicker development of anesthetic partial pressure inside the alveoli leading to a faster induction
the 3 main respiratory/venilation differences in the adult vs neonate
neonates have a
- increased o2 consumption to support metabolic demand
- increased alveolar ventilation to increase o2 supply
- slighly decreased FRC reflecting a decreased o2 reserve
- 6-9ml/kg/min vs 3.5ml/kg/min (6/3) [3x 2 =6]
- 120ml/kg/min vs 60ml/kg/min (120/60) [60 x 2 = 120]
- 30ml/kg vs 34ml/kg
Does the neonate have more type 1 or type 2 muscle fibers in the diaphragm?
why does thsi matter?
more type 2!
type 2 fibers = fast twitch fibers; ype 1 = slow twitch fibers
bc of this, neonates a re more likely to experience respiratory fatigue
Type 1 fibers are dendurance fibers
T/F- neonates have the same amount of dead space on a per weight basis
what is it?
true
2ml/kg
What is the primary muscle of inspiration?
diaphragm
patients less than how many weeks post-conceptual age should be admitted for 24-hr observation with an apnea monitr?
what can they give the baby to decrease the risk of postop apnea after GA?
<60 weeks PCA
caffeine (10mg/kg IV)
*does not take the place of postop admission with monitoring
theophylline = alternative but higher risk of toxicity
Describe type 1 vs type 2 muscle fibers
type 1 muslce fibers are slow-twitch fibers that are built for endurance
type 2 muscle fibers are fast-twitch and are built for short bursts of heavy work and tire easily
In the neonate, what % of respiratory muscle are type-1 fibers
adult?
25%
compared to 55% in the adult
How do lung compliance and chest wall compliance differ in the newborn?
lower lung compliance due to fewere alveoli
higher chest wall compliance due to a ribcage mostly made of cartlidge (less structural support, flimsy, easily to displace)
Increased/Decreased or no change in the neonate comapred to the adult:
Vital capacity
decreased
Increased/Decreased or no change in the neonate comapred to the adult:
Residual volume
increased
Increased/Decreased or no change in the neonate comapred to the adult:
closing capacity
increased
when colosing capacity overlaps with TV, the neonate is at risk for VQ mismatching in favor of shunting
Increased/Decreased or no change in the neonate comapred to the adult:
tidal volume
no change
6ml/kg
Increased/Decreased or no change in the neonate comapred to the adult:
TLC
decreased
During laminar flow, resistance is (directly/inversely) proportional to the radius raised two what power
what law
significance in neonates
inversely, to the 4th power
pousielles
smaller airway diameter = increased airway resistance
Select the data that MOST accurately depicts a normal umbilical artery blood gas:
A. pH 7.20/ PaO2 50/ PaCO2 = 50
B. pH = 7.30/ O2 20/ CO2 50
C. pH 7.35/ O2 30/ CO2 40
D. pH = 7.4/ O2 90/ CO2 30
B. pH = 7.30/ O2 20/ CO2 50
umbilica arteries return deoxygenated blood from the fetus to the placenta, so it makes sense that the blood has a low PaO2 and a higher PaCO2
umbilical vein(s) (#) supply what kind of blood and where
umbilicar artery(s) (#) supply what kind of blood and where
1 umbilical vein- supplies o2 from moms placenta to baby
2 umbilical arteries return co2 rich blood from baby to moms placenta
The newborn comes into the world slighlty acidoditic (ph ~ what)
when does arterial pH stablize at 7.35?
7.20
stablizes in 1 hour
Respiratory control doesnt mature until how many weeks post conceptional age?
why does this matter
42-44 weeks
prior to this, hypoxemia inhibits ventilation
label
What action stimulates the newborn to breathe rhythmically?
what promotes continuous breathing?
clamping of the umbilical cord
the acute rise in PaO2
*hypoxemia causes apnea
T/F- the acute rise in PaCO2 after clamping the umbilicar cord is what promotes continous breathing
false- the acute rise in PaO2
Why do babies hyperventilate during the first hour of life?
likely due to poor buffering capcity and to compensate for nonvalatile acids in the blood
How does hypoxemia impact ventilation in the newborn?
it depresses ventilation
What is the reference arterial pH in a 1-day old child?
7.35