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
PaO2 of the umbilical vein vs artery
vein = 30, artery = 20
vein carries oxygenated blood to baby, artery carries co2 blood to mom
Which statement regarding fetal hgb is TRUE?
A. It has a higher P50 than the adult
B. It is replaced by hgb A at 9 months of age
C. It has an increased affinity for 2,3,-DPG
D. Erythrocytes containing hemoglobin F have a shorter lifespan
D. Erythrocytes containing hemoglobin F have a shorter lifespan
70-90 days compared to hgbA - 120 days
fetal RBC lifespan compared to HgbA rbc lifespan?
fetal= 70-90 days
adult = 120 days
P50 of HgbF
compared to HgbA
why?
19mmHg
26.5mmHg
HgbF is unable to bind 2-3-DPG, explaining it’s higher affinity for o2
when does HgbA begin to replace HgbF?
when is the process completed?
start to replace at 2 months
completed by 6 months
How does a left shift in the oxyhemoglobin curve benfit the fetus?
bc it creates an oxygen partial pressure gradient across the uteroplacental membrane that facilitates the passage of o2 from mom to baby
Why does HgbF have a higher affinity for O2 (sciency stuff)
Bc HgbF has 2 alpha and 2 gamma subunits (HgbA has 2 alpha and 2 beta)
-2,3,DPG only binds to the beta subunit (and increased 2,3-DPG shifts it to the right)
-Since HgbF has 2 gamma subunits instead of beta, it cannot bind 2,3,-DPG
-Therefore there is a left shift in the curve
What is the hemoglobin at birth
When does the physiolgoic anemia occur?
17g/dL
month 2-3 (10g/dL)
–> think 23 is your bday and your always cold, 23, 2-3 months = physicologic anemia
What is the purpose of fetal hemoglobin?
It facilitate the passage of O2 from mom to baby
- gamma subnits cant bind 2-3, IPG; shifts to the left, creating a gradient
Potential complications of massive transfusion in the neonate include all of the following EXCEPT:
A. Metabolic acidosis
B. Metabolic alkalosis
C. Hypocalcemia
D. Hypokalemia
Hypokalemia
*Neonates and kids who get blood tranfusions are at a risk for hyperkalemia
3 indications for FFP
dosing
- coagulopathy
- massive transfusion
- emergent warfarin reversal
10-20mL/kg
T/F- FFP is no indicated for expansion of intravascular volume
True
Platelet transfusion is recommended for invasive procedures to maintain the platelet count above what?
50,000mm^3
Why can giving PRBCs to neonates cause hyperkalemia and cardiac arrest?
bc when RBCs are stored, the cell membrane becoems dysfunctional, allowing potassium to leak
i mean couldnt this be an issue with adults too?
What’s the goal of a PRBC transfusion
to increase oxygen-carrying capacity
Why are transfusion triggers higher for infants/neonates vs adults?
bc they have a higher o2 demand and a decreased affinity for O2 (hgbF)- so they are less likely to release o2 to metabolically active tissue
PRBC transfusion trigger in children < 4mo:
-severe CPD:
-for major surgery or moderate CPD:
dose
how much will it raise hgb?
-severe CPD: <13g/dL
-Major surgery or mod. CPD: < 10g/dL
10-15ml/kg
10ml/kg will raise hgb by 1-2g/dL
Most clinicians will follow the Transfusion Practice Guidelines of the ASA Task Force on Blood Component Therapy for children older than what?
- Transfusion is rarely indicated if Hgb > ______
- Tranasfusion is almost always indicated if Hgb < ______
- Transfusion should be considered on an individual basis if _______
- The use of a universal transfusion trigger is not recommended .
older than 4months old without signficant CPD
*by this time RBCs containing Hgb A are beggining to proliferate, they have a lower affinity for o2 and are more willing to rlease o2 to metabolically active tissue
10-15ml/kg [10ml/kg will raise hgb by 1-2g/dL]
rarely needed if > 10
almost alwasy if < 6
individual basis 6-10
dose for platlets if obtained from aphersis vs pooled platelet concentrate
a single apheresis unit = how many pooled platelet concentrates
one pooled platelet concentrate will increase platelets by how much?
apheresis = 5mL/kg
pooled = 1packed/10kg
6-8 pooled platelet concentrates
1 pooled platlet will increase by 50,000 (i think)
How much plaelets would you give an infant who ways 20kg
2 pooled packs
1pack/10kg
Why is mass transfusion associated with:
-Alkalosis
Bc the liver metabolizes citrate to bicarbonate
Why is mass transfusion associated with:
-Hypothermia
Transfusion of cold blood
Why is mass transfusion associated with:
Hyperglycemia
due to the dextrose additive to stored blood
Why is mass transfusion associated with:
Hypocalcemia
bc calcium binds to citrate
Why is mass transfusion associated with:
hyperkalemia
how to prevent it
due to the administration of older blood
-when RBCs are stored, the cell membrane becomes dysfunction, allowing potassium to leak
administer washed or fresh cells that are < 7 days old
What is Graft-vs-host disease
(rare but devastating)- what does it lead to (4)
what can we do to prevent it that would be especially benificial in immunocompromised patients?
when donor leukocytes attack recipient bone marrow
fever, hepatitis, diarrhea, pancytopenia
Give irradiated blood - gamma radiation destroys donor leukocytes
What is the transfusion trigger for a 2-month old child with severe CPD?
<13
At what age shoud you follow the Transfusion Practice Guidelines of the ASA Task force on a Blood Component in a healthy child?
4months and older
What is hte dose range of FFP in a 20-kg pt?
200-400mls
(10-20ml/kg)
What is the dose for pooled platelets in a 7yo?
1 pack/10kg
a 3kg term neonate requires emergency ex lap for NEC. Her preop hct is 50%. What is the maximum allowable blood loss to maintain a hct of 40%?
A. 40mL
B. 55mL
C. 70mL
D. 85mL
B. 55mL
EBVV for a term neonate = 80-90ml/kg
EBV X [(Hcg starting-Hct target)/Hct starting)]
What 4 things do you need to ask yourself when someone asks you how much blood should you transfuse for a neonate/kid?
- What is the normal H&H for the age
- What is the estimated BV
- What’s the transfusion trigger
- How much blood can be lost before the trigger is reached?
Label
Normal H&H for adult female vs male
female = 12-16 & 35-45
male = 14-18 & 40-50
Label
The newborns kidney tends to:
A. excrete sodium
B. Reabsorb sodium
C. Reabsorb water
D. Reabsorb glucose
why
A. Salt wasters!!
due to an immature concentrating mechanism
for the same reason it partially lacks the ability to retain water and glucose
T/F- the neonate has decreased perfusion pressure compaired to the adult
True
T/F the neonate has a higher GFR than the adult
false -it’s immature
T/F - neonates have low insensible losses
from what?
false! high insensible losses
highest from evaporation- most signficant source of water loss
T/F - neonates have low insensible losses
from what?
false! high insensible losses
highest from evaporation- most signficant source of water loss
what is the most signficant source of water loss in the neonate?
evaporation
how long does the neonate lose sodium for?
a few days
When does GFR reach adult levels?
What about renal tubular function
b/t 8-24 months
2 years
Why is most of the neonates high insensible losses lost rhough evaporation?
bc the surface area to body weight ratio is 4x higher than the adult
+ their skin is immature, thinner, and more permeable to water
Total body water for a premature neonate is approximately:
A. 65%
B. 75%
C. 85%
D. 95%
C. 85% (80-90%)
Which is lowest at birthweight and increases with age - ECF or ICF?
ICF
Signs of dehydration in the neonate (5)
- sunken anterior fontanel
- weight loss
- lethargy
- dry mucous membranes
- increased hematocrit
label
What would the hourly mainteance fluid be for a 15kg child?
50mls
calculating 3rd space loss:
minimal surgical trauma:
moderate:
major:
minimal 3-4
moderate 5-6
major 7-10
Ratio of blood replacement for:
crystalloid, colloid, blood
crystalloid 3:1
colloid 1:1
blood 1:1
when do signs of hypoglycemia manifest in the newborn?
<40mg/dL
treatment of hypoglycemia in the newborn
what if seizures are present?
2ml/kg of 10% dextrose
double the dose to provide adequate substrate to the brain.
After bolus, D10 infusion at 8mg/kg/min to maintain serum glucose > 40
A 2-week old neonate will be expected to demonstrate all of the following EXCEPT a/an:
A. increased free fraction of highly protein bound drugs
B. Faster circulation time
C. Larger volume of distribution for water-soluble drugs
D. Shorter duration of action for lipid-soluble drugs
D. Shorter DOA for lipid-soluble drugs
-neonates have more TBW and lower fat/muscle
-drugs that require fat for redistribution and termination of effect have a LONGER DOA, not shorter
Do neonates require higher or lower doses of water-soluble drugs to achieve a given plasma concentration?
HIGHER - they are big bags of water, it’ll be diluted so you have to give more
Cardiac output of a newborn in ml/kg/min
200ml/kg/min
Some things to consider regarding kinetics and dynamics and dosing drugs i nthe newborn (7)
- Higher MAC
- immature BBB
- immature hepatic function
- immature renal function
- higher cardiac output (faster circ time)
- higher Vd of water-soluble drugs
- Low plasma protein (immature liver, liver makes albumin)
when is hepatic function that of an adult?
1yo
Neonates have a reduction in glucuronyl transferase. What two implications does this present?
- they cant conjugate bilirubin
- nor metabolize acetaminophen as well
glucuronyl transfersase helps conjugate bilirubin and metabolize tylenol
At what age does MAC peak
how is this different with sevo?
2-3 months! (dilutional anemia - random)
Sevo:
0-6 months - MAC highest @ 3.2%
6mo-12yo - MAC lower, but still higher than adult (2.5)
MAC of sevo for 6mo up to 12yo
when is the MAC of sevo the highest? what age and %
2.5%
0-6mo - 3.2%
Why are neonates more sensitive to sedative-hypnotics?
bc of an immature BBB
Anesthetic considerations for the administration of NMBs in the neonate include:
A. Avoidance of sux
B. a longer DOA of sux
C. a large dose of sux
D. a larger dose of sux and NDMRs
C. larger dose of sux
combo of increased ECF and normal sensitivity of sux requires an increased dose of 2mg/kg
*the black box warning on sux assoc w hyperkalemia with undiagnosed muscular dystrophy in kids under 8 is present; howerver, it still remians a suitable option for RSI, anticipated difficult airway, laryngospasm, or other airway emergencies
-te dose for nondepolarizers is the same for neonates and adults on a per kg basis
Dose of sux for kids- IV
IM? (neonates and infants vs older kids)
why
2mg/kg
older kids = 4mg/kg, infants + neonates 5mg/kg
increased TBW (ECF) + normal sensitivity to sux
T/F duration of sux is similar between neonates and adults
true
*
t/f- the dose of nondepolarizers is the same for neonates and adults on a per kg basis
true
Recovery from neuromuscular blockade includes a TOF > what and a maximum inspiratory force (MIF) less than what? (ex)
TOF > 90%
MIF < -25cm H20 (ex. -30cm H20)
3 subjective data that seem to correlate with adequate recovery from NMB in the neonate
- grimacing
- elbow and hip flexion
- bringing knees to chest
The neonatal NMJ is immature. When compared to adults, the NMJ is more sensitive to what and equally sensitive to what (NMBs)
more sensitive to NDMRs
equally sesnitive to sux
In kids less than what age, sux may cause bradycardia or asystole
when is this most likely to occur
how to prevent?
kids < 5yo
after repeat administration (but can occur after 1st dose)
Pretreatment with Atropine 0.02mg/kg IV
What would you do if your kid goes into cardiac arrest immediately following sux?
IV calcium
What is the only nondepolarizer than can be given IM
dose (<1yo vs >1yo)
onset
Roc
<1yo = 1mg/kg, >1yo = 1.8mg/kg
3-4 minutes
T/F- Vec is considered a long-acting NMB in the pediatric population
True- metabolized by the liver with active metabolites that may increase the DOA in this population
(compared to roc which is also metabolized by the liver but has no active metabolites)
0.1-0.15mg/kg
Neostigmine dose - peak effect in how many mins
Edrophonium dose - peak effect in how many mins
which is associated with less muscarinic s/e’s ?
which anticholinergic pairs with each
neostigmine 0.05mg-0.07mg/kg) - peak in 10 mins
edrophonium 1mg/kg- peak in 2 mins
edrophonium less muscarinic s/e’s
atropine with edrophonium and glyco with neostigmine
Why do neonates require a higher dose of sux compared to an adult?
neonates have higher TBW which offset the degree of NMJ immaturity
calulate the mainance dose for a 2.5kg neonate
10ml/hr
4 x 2.5 = 10ml
What is the PO2 when fental hemoglobin is 50% saturated by oxygen?
19
What is the o2 consumption in a 3kg neonate?
18ml o2/min
6ml/kg/min
A 1-month old, 4kg patient is presenting for major surugery. What volume of packed cells is needed to increase the hgb concentration from 8-10
30mls, 60mls, 120mls, 90mls
60mls
10ml/kg will raise it by 1-2
kid weighs 4kg and we need to increase by 2g
need to administer between 40-80ml of PRBCs
Which vital signs represent abnormal findings in a newborn (select 2)
- HR of 90
- SBP of 60
- RR of 50
- DBP 40
HR 90 ( should be 140)
SBP 60 (should be 70)
