Unit 11 - Neonatal A&P Flashcards
1
Q
normal VS for a newborn
A
SBP = 70
DBP = 40
HR = 140
RR = 40-60
2
Q
normal VS for a 1year old
A
SBP = 95
DBP = 60
HR = 120
RR = 40
3
Q
normal VS for a 3 year old
A
SBP = 100
DBP = 65
HR = 100
RR = 30
4
Q
normal VS for a 12 year old
A
SBP = 110
DBP = 70
HR = 80
RR = 20
5
Q
why do neonates have a higher RR than adults
A
- much higher O2 consumption & CO2 production vs adults
- Neonate must increase alveolar ventilation accordingly - metabolically more efficient to increase RR
6
Q
primary determinant of cardiac output and systolic blood pressure in neonates
A
HR
7
Q
Vt in neonates vs. adults
A
same on a per weight basis (6 mL/kg)
8
Q
why do neonates rely on HR to maintain CO
A
The neonatal myocardium lacks the contractile elements to significantly adjust contractility or stroke volume
Non-compliant LV is sensitive to increased afterload
9
Q
what defines hypotension in a newborn
A
SBP < 60 mmHg
10
Q
what defines hypotension in a 1 yr old
A
SBP < 70 mmHg
11
Q
what defines hypotension in a child > 1 yr
A
SBP < [70 + (child’s age in years x2)] mmHg
12
Q
neonatal period
A
first 28 days of life
13
Q
infant period
A
29 days to one year
14
Q
what explains why a child becomes relatively less dependent on HR to support CO with age
A
SVR increases over time
* As the left ventricle pumps against a higher SVR, the contractile elements multiply and mature, giving the LV the ability to better adjust contractility
15
Q
why do newborns respond to stressful situations (DL, suctioning) with bradycardia
A
ANS regulation of the heart is immature at birth - SNS is less mature than the PNS
16
Q
preferred med in treating hypovolemia and bradycardia in neonates
A
epinephrine over atropine
epi has added benefit of augmenting contractility
17
Q
why are neonates generally unable to increase HR in the setting of hypovolemia
A
baroreceptor reflex is poorly developed
18
Q
how do s/s pain manifest in the neonate
A
activates SNS - tachycardia, HTN
19
Q
why is neo generally a poor choice for treating hypotension in a neonate
A
neonates can’t significantly increase contractility to overcome increased afterload
20
Q
factors that predispose neonates to intracranial hemorrhage with pain
A
pain = SNS response = tachycardia and HTN
combination of hypertension, an immature cerebral autoregulatory response, and a fragile cerebral vasculature
21
Q
babies are preferential nose breathers until what age
A
5 months
22
Q
how is an infant’s epiglottis different from an adult’s
A
infant’s is stiffer and longer
U-shaped or omega shaped
23
Q
why is a more acute angle required to visualize the glottis in infants
A
shorter neck
cephalad larynx
larger tonge
24
Q
why is sniffing position avoided in infants
A
tends to move laryngeal opening further from line of sight in DL
25
positioning an infant for DL
* Larger occiput flexes the neck when placed supine on a flat surface
* A shoulder roll helps align oral, pharyngeal, and laryngeal axes
26
why is it more difficult to displace the epiglottis of an infant during DL (vs. adult)
epiglottis is stiffer and longer
27
why is a miller blade preferred in infants
infant's tongues occupy a relatively large area of mouth
helps to lift the tongue to better expose the pediatric larynx
28
level of newborn's glottis
full term: ~C4
premature: ~C3
29
glottic opening in newborns vs. adults
adult glottis is at ~C5
newborn glottis is at ~C3-C4
higher glottic opening = more superior, cephalad, or rostral (not more anterior)
| the only time an infant's airway is more "anterior" is w neck flexion
30
why are infants at higher risk of upper airway obstruction vs. adults
tongue is closer to soft palate and more likely to obstruct
31
position of pediatric larynx
C3-C5
| adult = C5-C6
31
position of pediatric larynx
C3-C5
| adult = C5-C6
32
at what point does the pediatric larynx descend to C4
~1 year old
33
age pediatric larynx achieves adult position
by 5-6 yrs old
34
narrowest region of pediatric airway
dynamic = vocal cords
fixed = cricoid ring
35
changes in bronchi in children
up to 3 years of age, both bronchi take off at 55 degrees off the midline
36
situations that increase risk of cricoid edema in pediatric airways
* an ETT that is too large
* multiple intubation attempts
* prolonged intubation
* frequent head positioning while intubated
37
why do neonates require a comparatively higher alveolar ventilation to sustain normal arterial gas tensions vs. adults
Because the neonatal alveolar surface area is only 1/3 of the adult and basal oxygen consumption is 2 - 3 times that of the adult
38
when do distal saccules of the lung start to develop
24-28 wga
39
O2 consumption of neonate vs adult
neonate = 6-9 mL/**kg**/min
adult = 3.5 mL/**kg**/min
40
alveolar ventilation of a neonate vs adult
neonates = 130 mL/kg/min
adult = 60 mL/kg/min
41
FRC in neonates
slightly reduced
| 30 mL/kg vs. 34 mL/kg in adults
42
FRC in neonates
slightly reduced
| 30 mL/kg vs. 34 mL/kg in adults
43
why do neonates rapidly desaturate during hypoventilation or apnea
neonate's relatively higher oxygen consumption will quickly exhaust the oxygen reserve contained in the FRC
also decreased FRC
44
why do neonates rapidly desaturate during hypoventilation or apnea
neonate's relatively higher oxygen consumption will quickly exhaust the oxygen reserve contained in the FRC
also decreased FRC
45
why do neonates experience a faster inhalation induction vs. adults
Increased ratio of alveolar ventilation relative to the size of the FRC
46
primary muscle of inspiration
diaphragm
47
types of muscle fibers in diaphragm and intercostals
type 1 = slow-twitch, endurance
type 2 = fast-twitch, bursts of heavy work (tire easily)
48
predominant type of diaphragm muscle fibers in neonates
25% type 1
75% type 2
49
why are neonates at risk for resp fatigue and failure
The neonatal diaphragm only has 25% type 1 fibers (adults have 55%)
50
age that should be admitted for apnea monitoring after surgery
< 60 weeks PCA
| post conceptual age
51
age that should be admitted for apnea monitoring after surgery
< 60 weeks PCA
| post conceptual age
52
meds to reduce risk of postop apnea
caffeine 10 mg/kg
theophylline (higher risk toxicity)
53
lung and chest wall compliance in neonates vs adults
* decreased lung compliance d/t fewer alveoli
* increased chest wall compliance d/t cartilaginous ribcage
54
lung volumes that are decreased in neonates
FRC
VC
TLC
55
lung volumes that are increased in neonates
RV
CC
56
3 processes that support a neonate's FRC
* Sustained tonic activity of inspiratory muscles
* Narrowing of glottis during expiration
* Shorter expiratory time with a faster respiratory rate creates end-expiratory
pressure
57
why do neonates have increased WOB
a function of increased airway resistance (particularly in small airways)
58
ABG from umbilical vein
pH = 7.35
PaO2 = 30
PaCO2 = 40
59
ABG from umbilical artery
pH = 7.3
PaO2 = 20
PaCO2 = 50
60
ABG of mother at term
pH = 7.4
PaO2 = 90
PaCO2 = 30
61
ABG of newborn 10 min after delivery
pH = 7.2
PaO2 = 50
PaCO2 = 50
62
ABG of a newborn 1 hr after delivery
pH = 7.35
PaO2 = 60
PaCO2 = 30
63
ABG of a newborn 24 hrs after delivery
pH = 7.35
PaO2 = 70
PaCO2 = 30
64
supplies oxygen to fetus in utero
umbilical vein
65
what causes a newborn to breathe rhythmically after birth
Clamping of the umbilical cord
acute rise in PaO2 promotes continuous breathing
66
when do neonates develop a relatively normal FRC
in the first 20 minutes of life
67
why do neonates hyperventilate during the first hour of extrauterine life
likely due to its poor buffering capacity and compensation for nonvolatile acids in the blood
| After this time, the pH and PaCO2 stabilize
68
why do neonates hyperventilate during the first hour of extrauterine life
likely due to its poor buffering capacity and compensation for nonvolatile acids in the blood
| After this time, the pH and PaCO2 stabilize
69
when does neonatal respiratory control mature
42 - 44 weeks post-conceptional age
70
when does neonatal respiratory control mature
42 - 44 weeks post-conceptional age
71
how does hypoxemia affect neonates before and after respiratory control matures
* Before maturation: hypoxemia depresses ventilation
* After maturation: hypoxemia stimulates ventilation
72
P50 of fetal Hgb
19 mmHg
73
how does fetal Hgb affect the oxyhgb dissociation curve
shifts to the left
74
how does the low P50 of fetal Hgb benefit the fetus
creating an oxygen partial pressure gradient across the uteroplacental membrane that facilitates the passage of O2 from mother to fetus
75
composition of Hgb A vs Hgb F
Hgb A = 2 alpha and 2 beta chains
Hgb F = 2 alpha and 2 gamma chains
76
explains why Hgb F has a higher affinity for oxygen
does not bind 2,3-DPG since it has 2 gamma chains instead of 2 beta
| the binding site fo 2,3-DPG is only on the beta chain
77
how does 2,3-DPG affect oxyhgb dissociation curve
right shift
78
lifespan of fetal RBCs
70-90 days
79
hgb at birth
17 g/dL
80
how long does it take for Hgb A to replace Hgb F
6 months - P50 at this time same as adult (26.5)
## Footnote
in 1st 2 months, erythrocytes containing Hgb F are replaced by those that produce Hgb A
81
what age is assoc with physiologic anemia in newborns
2-3 months
Hgb ~ 10 g/dL
82
age Hct begins to rise
4 months
| erythropoesis increases, hgb concentrtation rises
83
age Hct begins to rise
4 months
| erythropoesis increases, hgb concentrtation rises
84
when does P50 reach adult level
4-6 months old
85
RBC transfusion trigger < 4 mo
< 13 g/dL with severe cardiopulmonary disease
< 10 mg/dL in child presenting for major surgery or moderate cardiopulmonary disease
86
10 mL/kg of PRBCs will increase Hgb by ___
1-2 g/dL
87
PRCB transfusion practice guidelines for > 4 mo
- Transfusion is rarely indicated if Hgb > 10 g/dL
- Transfusion is almost always indicated if Hgb < 6 g/dL
- Transfusion should be considered on a need's basis if Hgb is 6 - 10 g/dL
- The use of a universal transfusion trigger is not recommended
88
indications for neonatal FFP admin
* Emergency reversal of warfarin
* Correction of coagulopathic bleeding with increased PT or PTT
* Correction of coagulopathic bleeding if > 1 blood volume has been replaced and coagulation studies are not easily obtained
89
indications for plt admin in neonates
Recommended for invasive procedures to maintain the platelet count above 50,000
90
indications for plt admin in neonates
Recommended for invasive procedures to maintain the platelet count above 50,000
91
platelet transfusion dose if obtained from apheresis
5 mL/kg
92
neonatal platelet transfusion dose from pooled plt concentrate
1 pack/10 kg
93
single aphresis plt unit = ____ pooled concentrations
6-8
94
5 complications of massive transfusion in the neonate
1. metabolic alkalosis or acidosis
2. hypothermia
3. hyperglycemia
4. hypocalcemia
5. hyperkalemia
95
P50 of hgb A
26.5 mmHg
96
purpose of fetal Hgb
facilitates passage of O2 from mother to fetus
97
Hgb F is compeltely replaced by Hgb A by what age
6 months old
98
why can giving neonates PRBCs cause hyperkalemia and cardiac arrest
When RBCs are stored, the cell membrane becomes dysfunctional, which allows potassium to leak into the supernatant
99
cause of graft vs host disease from PRBC transfusion in neonate
donor leukocytes attack recipient bone marrow
leads to pancytopenia, fever, hepatitis, diarrhea
100
prevention of graft v host disease from PRBC transfusion in neonates
irradiated blood
101
hgb & hct in newborn
Hgb 14-20 g/dL
Hcg 45-65%
102
Hgb & Hct in 3 month old
Hgb 10-14 g/dL
Hct 31-41 %
103
hgb & hct in 6-12 month old
Hgb 11-15 g/dL
Hct 33-42%
104
hgb & hct in 6-12 month old
Hgb 11-15 g/dL
Hct 33-42%
105
Hgb & Hct in adult female
hgb 12-16 g/dL
hct 37-47%
106
hgb & hct in adult male
hgb 14-18 g/dL
hct 42-50%
107
dose range for FFP
10-20 mL/kg
108
EBV of premature neonate
90-100 mL/kg
109
EBV of term neonate
80-90 mL/kg
110
EBV of infant
75-80 mL/kg
111
EBV of 1 year old
70-75 mL/kg
112
kidneys at birth vs. adult
immature at birth
* decreased perfusion pressure
* decreased GFR
* decreased diluting and concentrating ability
113
why are neonates intolerant of fluid swings
poor job conserving water - intolerant of fluid restriction
unable to excrete large volumes of water - don't do well with overload
114
how do neonates lose most of their water
through evaporation
| surface area to body weight ratio that is four times higher than the adu
115
how do neonates lose most of their water
through evaporation
## Footnote
surface area to body weight ratio that is four times higher than the adu
116
why do neonates lose most of their body water through evaporation (via skin)
* surface area to body weight ratio that is four times higher than the adult
* immature skin is thinner and more permeable to water
117
how long does it take for GFR to reach adult levels
8-24 months old
118
when does renal tubular function achieve full concentrating ability
~ 2 years of age
119
TBW in a premature neonate vs term neonate
preterm = 85%
term = 75%
120
why are neonates oligate sodium losers at birth
kidneys have an immature concentrating mechanism
121
when is TBW highest
at birth
| decreases with age
122
when is TBW highest
at birth
| decreases with age
123
when is ECF highest
at birth
| decreases with age
124
when is ECF highest
at birth
| decreases with age
125
when is ICF highest
lowest at birth and increases with age
126
in what age groups is ECF > ICF
neonates (premature and term)
127
when does TBW approximate adult values
by 1 yr old
128
4:2:1 rule for fluid replacement
first 0-10 kg = 4 mL/kg/hr
next 10-20 mg add 2 mL/kg/hr
> 20 kg add 1 mL/kg/hr to previous total
129
fluid replacement for third space losses
* Minimal surgical trauma = 3 - 4 mL/kg/hr
* Moderate surgical trauma = 5 - 6 mL/kg/hr
* Major surgical trauma = 7 - 10 mL/kg/hr
| As a general rule, third-space loss is not included in the first hour of
129
fluid replacement for third space losses
* Minimal surgical trauma = 3 - 4 mL/kg/hr
* Moderate surgical trauma = 5 - 6 mL/kg/hr
* Major surgical trauma = 7 - 10 mL/kg/hr
| As a general rule, third-space loss is not included in the first hour
130
when should glucose-containing fluids be used in neonates
reserved for infants and children at risk of developing hypoglycemia
* Prematurity
* < 48 hours of age
* Small for gestational age
* Newborns of diabetic mothers
* DM & received insulin on the day of surgery
* TPN dependent
131
at what glucose level do s/s hypoglycemia develop when < 72 hours old
30-40 mg/dL
132
at what glucose level do s/s hypoglycemia develop when > 72 hours old
< 40 mg/dL
133
treating neonatal hypoglycemia
IV 10% dextrose (2 mL/kg)
4 mL/kg if seizures present
after bolus, D10 gtt at 8 mg/kg/hr to maintain serum glucose > 40
134
CO in the newborn
200 mL/kg/min
135
why do neonates have a faster circulation time vs adults
increased CO (200 mL/kg/min)
136
MAC of sevo in a 3 month old
3.2%
137
why are neonates more sensitive to sedative-hypnotics
An immature BBB allows passage of drugs that would otherwise not be able to enter the brain
138
when do babies reach adult values of drug biotransformation
by 1 yr old
139
when is normal GFR achieved
8-24 months of age
140
when is normal tubular function achieved
age 2
141
dosing highly-protein bound drugs in infants
Before 6 mo, there are lower concentrations of albumin and alpha-1 acid glycoprotein, so for drugs that are usually highly protein-bound, the neonate will experience increased free drug levels and have a higher risk of toxicity
142
dosing water solube drugs in neonates
Neonates have a higher percentage of total body water, (higher Vd) so they require higher doses of water-soluble drugs to achieve a given plasma concentration
143
dosing drugs that require fat for redistribution in neonates
Neonates have a higher percentage of TBW and a lower percentage of fat and muscle mass. Drugs that require fat for redistribution and termination of effect have a longer duration of action
144
MAC changes in infancy
* Neonate (0 - 30 days): MAC is lower than the infant
* Premature: MAC is lower than the neonate
* Infant 1 - 6 months: MAC is higher than the adult
* Infant 2 - 3 months: MAC peaks at its highest level
145
MAC changes with age in infancy
* Neonate (0 - 30 days): MAC is lower than the infant
* Premature: MAC is lower than the neonate
* Infant 1 - 6 months: MAC is higher than the adult
* Infant 2 - 3 months: MAC peaks at its highest level
146
MAC of sevo in 6mo-12 yr old
2.5%
147
dosing succinylcholine in neonates
2 mg/kg
## Footnote
combination of an increased ECF and normal sensitivity to succinylcholine necessitates a higher dose
148
dosing succinylcholine in neonates
2 mg/kg
## Footnote
combination of an increased ECF and normal sensitivity to succinylcholine necessitates a higher dose
149
NMB that can cause HTN in neonates
pancuronium
150
black box warning on succinylcholine
warns of hyperkalemia (risk of cardiac arrest) associated with undiagnosed muscular dystrophy in children under 8 years old
151
first line treatment when child experiences cardiac arrest following succs admin
IV calcium is the first-line treatment
## Footnote
anytime a child experiences cardiac arrest following succinylcholine, hyperkalemia should be assumed until proven otherwise
152
dosing IM succinylcholine
* The dose for neonates and infants is 5 mg/kg
* Older children should receive 4 mg/kg
153
dosing neostigmine in neonates
0.05-0.07 mg/kg
154
dosing edrophonium in neonates
1 mg/kg
155
maximum inspiratory force (MIF) that predicts adequate NMB recovery in peds
less than -25 cm HO (e.g., - 30)
156
most common metabolic disturbance in newborns
hypoglycemia
157
children at risk of developing hypoglycemia
1. premature
2. SGA
3. < 48 hours old
4. newborns of diabetic mothers
5. diabetics who received insulin DOS
6. TPN dependent
158
neonate's UOP in the first week of life
< 1 mL/kg/day
159
Compared to the adult, what 3 kidney functions are lower in the neonate?
1. Renal perfusion pressure
2. Glomerular fitration rate
3. Diluting & concentrating ability
160
how do neonates lose most body water
evaporation
161
Why is so much body fluid lost through the skin of neonates?
* Surface area to body weight ratio is four times higher than the adult.
* Immature skin is thinner and more permeable to water.
162
why are neonates intolerant of both fluid restriction and overload
**restriction**: poor job of conserving water
**overload**: unable to excrete large volumes of water
163
neonates are obligate ____ losers in the first few days of life
sodium
164
consequences of glycosuria in the neonate
osmotic diuresis
dehydration
increased serum osmolarity (can cause ICH)
165
why does the erythrocyte transfusion trigger vary with age
depends on how much Hgb F the child has
166
167
In what age groups is ECF greater than ICF?
* premature neonates
* term neonates
168
What is the PO2 When fetal hemoglobin is 50% saturated by oxygen?
19 mmHg
169
10 mL/kg PRBCs estimated to increase Hgb by ___
1-2 g/dL
