Neonatal Anatomy & Physiology Flashcards

1
Q

What are a normal set of vitals for the newborn?

A

SBP: 70
DBP: 40
HR: 140
RR: 40-60

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2
Q

What are a normal set of vitals for the 1yr old?

A

SBP: 95
DBP: 60
HR: 120
RR: 40

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3
Q

What are a normal set of vitals for the 3 year old?

A

SBP: 100
DBP: 65
HR: 100
RR: 30

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4
Q

What are a normal set of vitals for the 12 yr?

A

SBP: 110
DBP: 70
HR: 80
RR: 20

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5
Q

Why do neonates have a high alveolar ventilation compared to adults?

A

They have increased O2 consumption and carbon dioxide production.

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6
Q

What is the primary determinant of cardiac output in the neonate!?

A

Heart rate

Neonatal heart lacks the contractile elements to adjust contractility or stroke volume

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7
Q

What is hypotension defined as in the newborn?

A

< 60 mmHg

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8
Q

What is hypotension defined as in the 1 year old?

A

< 70 mmHg

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9
Q

What is hypotension defined as in a child > 1 years old?

A

70 + (child’s age x 2) mmHg

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10
Q

Why do stressful situations (DL or suctioning) cause bradycardia in the newborn?

A

SNS system is less developed. PNS system is not. PNS system takes over.

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11
Q

What is the breathing patterned of the neonate?

A

Preferential nose breather till 5 mos ~

**bilateral nasal atresia May requires emergency airway management 🚨

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12
Q

How is the tongue in the neonate compared to the tongue in the adult?

A

Tongue is larger relative to oral cavity

**this makes it more likely to obstruct airway AND DL more difficult

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13
Q

How is neck length in the neonate compared to neck length in the adult?

A

Short neck ~ more acute angle to DL

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14
Q

How is the epiglottis in the neonate compared to the epiglottis in the adult?

A

Adult: leaf or c-shaped/ floppy/ shorter

NEONATE: U SHAPED; STIFF, LONGER
***makes it more difficult to displace during DL

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15
Q

How is vocal cord position of the neonate compared to vocal cord position of the adult?

A

Adult: cords are perpendicular

Neonate: cords have ANTERIOR SLANT ~ passage of ETT may be difficult. ETT may get stuck on anterior commissure ~ also hard for nasal intubations

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16
Q

What is the laryngeal position in the adult compared to the neonate?!

A

Adult: C5-C6
Neonate: C3-C4

**Larynx is more superior, cephalad, or rostral. IT IS NOT MORE ANTERIOR!!!

Miller blade preferred.

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17
Q

What is the narrowest point in the neonatal airway compared to the adult airway?

A

Adult ~ glottic opening

Neonate ~ fixed (cricoid ring); dynamic (glottic opening!)

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18
Q

What is the Subglottic airway shape in the neonatal airway compared to the adult?

A

Adult ~ cylinder
Peds ~ funnel

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19
Q

Where is the right main stem bronchus in the neonatal airway? Where is the bronchus in the adult airway?

A

Adult: more vertical (takes off at 25 degrees)

Neonatal: LESS VERTICAL (55 degrees) ~ both bronchi take off at 55 degrees until age of 3 years.

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20
Q

What is the intubating position for the adult? What about the neonate?

A

Adult: sniffing
Peds: head ON BED with SHOULDER ROLL **+infant has large occiput

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21
Q

What is the oxygen consumption of the neonate compared to that of the adult?

A

Neonate: 6mL/kg/min

Adult: 3 mL/kg/ min

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22
Q

at what age do alveoli stop growing in number?

A

8-10 years

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23
Q

What is the neonatal alveolar ventilation?

A

130 mL/kg/min

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24
Q

Why do neonates desaturate so much faster than adults?

A

Increased ratio of alveolar ventilation relative to the size of FRC

***decreased FRC reflecting a reduced O2 reserve

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25
Q

What type of diaphragm fibers does the neonate have?

A

More type 2 (fast twitch) ~ short burst of heavy work

Less type 1 [25%] (slow twitch) ~ built for endurance

***neonates are more likely to experience resp fatigue

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26
Q

What is the risk of apnea inversely related to?

A

Inversely related to post-conceptual age (PCA)

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27
Q

Infants less than what should be admitted for 24 hr observation?

A

< 60 weeks PCA

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28
Q

Former preterm infants < than what have a greater risk of postoperative apnea than infants > what?

A

44 weeks PCA

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29
Q

What medication can decrease the risk of postoperative apnea after general anesthesia?

A

Caffeine (10 mg/kg IV)

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30
Q

How does neonatal chest wall compliance and lung compliance compare to the adult?

A

Chest walk compliance : ^ d/t cartilaginous rib cage ~ flimsy

Lung compliance: decreased ~ fewer alveoli

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31
Q

What three things does a neonate do to increase their FRC?

A

Sustained tonic activity of inspiratory muscles

Narrowing of glottis during expiration

Shorter expiratory time with a faster resp rate ~ creates end-expiratory pressure

***these are abolished with general anesthesia and muscle relaxation.

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32
Q

How do the lung capacities differ in the neonate?

A

FRC: decreased
VC: decreased
TLC: decreased
RV: increased
CC: increased
Tidal volume: same

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33
Q

What is the pH of mother at term?

A

pH: 7.40

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34
Q

What is the pH of umbilical vein: placenta of fetus?

A

pH: 7.35

***REMEMBER VEIN IS OXYGENATED IN THE FETAL CIRCULATION

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35
Q

What is the pH of the umbilical artery: fetal placenta?

A

pH: 7.30

**REMEMBER THIS IS THE UN-OXYGENATED SITE IN FETAL CIRCULATION

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36
Q

What is the fetal pH at 10 mins, 1 hour and 24 hours?

A

**10 mins: 7.2

1 hour: 7.35
24 h: 7.35

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37
Q

What is the PaO2 of mother at term?

A

90

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38
Q

What is the PaO2 of umbilical vein?

A

30

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39
Q

What is the PaO2 of umbilical artery?

A

20

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40
Q

What is the PaO2 of neonate at 10 mins, 1 hr, and 24 hrs?

A

10 mins: 50
1hr: 60
24hours: 70

41
Q

What is the PaCO2 of mother at term?

A

30

42
Q

What is the PaCO2 of umbilical vein?

A

40

43
Q

What is the PaCO2 of umbilical artery?

A

50

44
Q

What is the PaCO2 of neonate at 10 mins, 1 hour, and 24 hours?

A

10 min: 50
1 hr: 30
24 hr: 30

45
Q

What is the full ABG or a newborn at 10 mins?

A

pH: 7.2
PaO2: 50
PaCO2: 50

46
Q

What stimulates the neonate to breathe rhythmically?

A

Clamping of the umbilical cord AND the acute rise in PaO2

47
Q

Before maturation (44ish weeks) hypoxemia what?

A

Depresses ventilation

48
Q

After maturation (44ish weeks) hypoxemia what?

A

Hypoxemia stimulates ventilation

49
Q

What is the P50 of fetal hemoglobin (Hgb F)?

A

19 mmHg

(Shifts curve to the LEFT) ~ this facilitates a lower O2 partial pressure (increased gradient) and creates passage of O2 from mom to fetus

50
Q

what does adult hemoglobin consist of?

A

Two alpha
Two beta chains

51
Q

What does fetal hemoglobin consist of?

A

Two alpha
Two gamma

“Gamma is a problamma!” Gamma is unable to bind 2,3 DPG ~ this explains the curve to the LEFT! Higher affinity to oxygen

52
Q

At what age is Hgb F COMPLETELY replaced by Hgb A?

A

At six months

53
Q

at what age does infants have physiologic anemia? Hgb declines to 10 g/dL?

A

3ish months > months 4 hemoglobin begins to rise

54
Q

What is the hemoglobin of a neonate at birth?

A

17 ish

55
Q

What is the P50 of hemoglobin A? (Like in the adult)

A

26.5 mmHg

56
Q

What is the transfusion trigger for a child with severe cardiopulmonary disease?
***child < 4 months

A

< 13 g/dL

57
Q

What is the transfusion trigger for a child presenting for major surgery or with a moderate cardiopulmonary disease? ***child < 4 mos

A

< 10

58
Q

What is the dose of PRBCs in the neonate?

A

10 mL/kg

***10 mL/kg will increase Hgb by 1-2 g/dL

59
Q

What is the dose of FFP in the neonate?

A

10-20 mL/kg

60
Q

What is the dose of platelets if by apheresis?

A

5 mL/kg

61
Q

What is the dose of platelets from platelet concentrate?

A

1 pack/10 kg

62
Q

A single apheresis equals how many pooled platelets?

A

6-8 pooled platelet concentrates

63
Q

How much will one pooled concentrate increase serum platelets?

A

50 x 10^9/L

64
Q

What are the main complications to massive transfusion in the neonate?

A

Alkalosis > citrate metabolism to bicarb
Hypothermia > transfusion of cold blood
Hyperglycemia > d/t dextrose additive
Hypocalcemia > bind if Ca by citrate
Hyperkalemia > admin of older blood

65
Q

How can the risk of hyperkalemia following massive transfusion be reduced for the neonate?

A

Washed or fresh cells (< 7 days old)

66
Q

What is the dose for pooled platelets in a child?

A

1 pack/10kg

67
Q

What is the normal Hgb in the newborn?

A

17ish

68
Q

What is the normal Hgb in the 3 month old?

A

12ish

69
Q

What is the normal Hgb in the 6 month-1 year old?

A

12 ish

70
Q

What is the normal hemoglobin in the adult female?

A

14 ish

71
Q

What is the normal hemoglobin in the adult male?

A

16isb

72
Q

How does the neonatal kidney compare to the adult kidney?

A

Decreased:

Perfusion pressure
GFR
Diluting/contesting abilities

73
Q

Why is meticulous fluid management so important in the neonate?

A

They do a poor job of conserving water
BUT also they are unable to excrete large volumes of water

***in addition, they have a HIgH insensible loss. They lose most of the body water through evaporation d/t surface area to body weight ratio (4x higher than the adult)

74
Q

What is a neonate when think of solutes and the kidney?

A

Obligate sodium loser

(In addition to glucose too)

75
Q

When does GFR reach adult levels?

A

8-24 months!!!

76
Q

When does tubular function achieve FULL concentrating ability?

A

2 years

77
Q

What is the TBW%, ECF and ICF in the premature infant?

A

TBW% ~ 85
ECF: 60
ICF: 25

78
Q

What is the TBW%, ECF and ICF in the neonate infant?

A

TBW: 75
ECF: 40
ICF: 35

79
Q

What is the TBW%, ECF and ICF in the child/adult?

A

TBW: 60
ECF: 20
ICF: 40

80
Q

What does a higher ICF volume (in child and adults NOT neonates) do?

A

Provides a volume reserve

81
Q

What are some signs of dehydration in the neonate?

A

Sunken anterior frontanel
Weight loss > 10% (this is normal in 1st wk)
Irritability
Dry mucus membranes
Decreased skin turgor
Increased hematocrit

82
Q

What type of children/infants are at risk for developing hypoglycemia?

A

Premature
Low gestational weight
< 48 hours of age
Newborns of DM mommas
Children with DM
Children who receive glucose based parenteral nutrition

83
Q

What is the average BBG in which signs of hypoglycemia will show in the neonate?

A

40 mg/dL

84
Q

What does treatment of hypoglycemia include?

A

IV 10% Dextrose (2 mL/kg) bolus

Followed by 8 mg/kg/min titrates to maintain serum glucose > 40

85
Q

Because neonates have a night total percentage of body water….?

A

They require higher doses of water-soluble drugs to achieve a given plasma concentration

86
Q

Because neonates have a faster cardiac output….?

A

Drugs are delivered and removed from the rest of the body at a faster rate

87
Q

Because neonates have a lower concentration of proteins…?

A

Neonates will experience increased free drug levels and have a higher risk of toxicity

88
Q

Because neonates have a higher total body water and lower % of fat and muscle, drugs that require fat for redistribution and termination…..?

A

Will have a longer duration of action

89
Q

At what age are adult value of hepatic metabolism reached?

A

1 year

90
Q

Why do neonates have a higher sensitivity to sedative-hypnotics?

A

Immature BBB

91
Q

At what age is the MAC for Sevo highest?

A

About 3 months (3.2)

92
Q

How does the MAC requirements go in the neonate/child? From least to most

A

Premature < neonate < infant < 3 month old INFANT (highest)

6 mos -12 years is higher than the adult, but lower than 3 months (2.5)

93
Q

Why is the dose of non-depolarizing muscle relaxants the same as an adult in a neonate but a dose of depolarizing NMB is increased?

A

Combo of increased ECF volume and increased sensitivity to nondepolarizers is a wash ~ equal

BUT the increased ECF and SAME sensitivity to sux requires a higher dose

94
Q

In children less than 5, sux can cause what?!

A

Bradycardia and asystole

Preoperative atropine may help.

95
Q

If a child experiences cardiac arrest following Sux, what should be assumed?

A

Hyperkalemia

🚨 calcium is the first line treatment!!!

96
Q

What is the IM dose of sux in neonates/infants?

A

5mg/kg

97
Q

What is the IM dose of sux in children?

A

4 mg/kg

98
Q

What is the ONLY non-depolarizer that can be given in IM route?

A

Rocuronium

Dose: 1mg/kg (<1 yr) and 1.8 mg/kg (>1 yr)