Pediatric Anesthesia

Question 1

What is considered pre-term?

Answer 1

Prior to 37 weeks gestational age

Question 2

What is considered neonate?

Answer 2

1-28 days of life

Question 3

Which direction does fetal Hgb shift the oxyhemoglobin dissociation curve?

Answer 3

Left (increased O2 loading in the lungs/placenta, decreased O2 unloading at tissues)

Question 4

What is Hgb of full term neonate?

Answer 4

18-20g/dl

Question 5

At what fetal age are primitive lung buds developed from the foregut?

Answer 5

4 weeks

Question 6

At what fetal age is branching of bronchial tree complete to 28 divisions, no further formation of cartilaginous ariways?

Answer 6

16 weeks

Question 7

At what age are primitive alveoli and type II cells present; surfactant detectable; survival possible with artificial ventilation?

Answer 7

24 weeks

Question 8

What is guppy breathing?

Answer 8

Fetus makes respiratory movements in utero from 30 weeks gestation at a rate of 60/min

Question 9

What is the current view on adaptation of breathing?

Answer 9

Rhythmic breathing occurs with clamping of the umbilical cord and increasing O2 tensions from air breathing

Question 10

What is the primary event of the respiratory system transition?

Answer 10

Initiation of ventilation

Question 11

With onset of ventilation, what happens to PVR and pulmonary blood floor?

Answer 11

PVR decreases dramatically and pulmonary blood flow increases

Question 12

Since neonate and infant lungs are prone to collapse, what can be done to prevent this?

Answer 12

PEEP

Question 13

Why are neonate and infant lungs prone to collapsing?

Answer 13

1. Weak elastic recoil
2. Weak intercostal muscles
3. Intra-thoracic airways collapse during exhalation

Question 14

How do infant’s lungs not collapse all the time?

Answer 14

Infants terminate the expiratory phase of breathing before reaching their true FRC which results in intrinsic PEEP and higher FRC

Question 15

What is the most common and universal sign of respiratory distress in the infant?

Answer 15

Tachypnea

Question 16

What two things can abolish the neonates initial hyperpneic response to hypoxia?

Answer 16

Hypothermia and low levels of anesthetic gases

Question 17

What are the two phases of response to hypoxia in the neonate?

Answer 17

Initial response is hyperpnea. Secondary response in about two minutes is respiratory depression and apnea.

Question 18

What does hypoxia cause in babies?

Answer 18

PROFOUND bradycardia

Question 19

What are 6 contributing factors for apnea of infancy?

Answer 19

1. Fatigue from prolonged increased WOB.
2. Inefficient diaphragmatic contraction
3. 25% of muscle fibers in diaphragm are Type 1 fatigue resistant (adults have 55%) work horse fibers
4. increased O2 Consumption
5. Decreased FRC
6. Increased closing volume.

Question 20

In utero, how much CO goes to lungs?

Answer 20

5-10%

Question 21

How much blood is diverted away from the liver via the ductus venosus?

Answer 21

50%

Question 22

What two things cause the PDA to close?

Answer 22

Increase in PO2 and decrease in circulating prostaglandins

Question 23

When is physiologic closue/anatomic closure of PDA?

Answer 23

10-15 hours

2-3 weeks.

Question 24

Does a R-L shunt or L-R shunt re-open the PFO?

Answer 24

R-L shunt

Question 25

T/F: Before anatomic closure of the fetal shunts, nothing will cause them to open?

Answer 25

False; Right to left shunting may occur in normal neonates during coughing, bucking, straining

Question 26

What is treatment for PPHTN?

Answer 26

Hyperventilation to maintain alkalosis
Pulmonary vasodilators
Minimal handling
Avoidance of stress
Adequate ventilation and oxygenation is key

Question 27

Fetal kidneys have higher or lower RBF and GFR?

Answer 27

Lower

Question 28

Why is fetal GFR/RBF lower?

Answer 28

1. Structurally immature small size and number of glomeruli
2. Low systemic arterial pressure
3. High renal vascular resistance
4. Low permeability of glomerular capillaries

Question 29

How many weeks is considered “Full term” ?

Answer 29

37 weeks

Question 30

T/F: Neonates have matured neontal renal tubules but not a normal RAAS?

Answer 30

False; normal RAAS but abnormal renal tubules

Question 31

What does abnormal renal tubules lead to?

Answer 31

Inadequate sodium conservation

Question 32

T/F: Neonate is considered an “obligate sodium conserver”?

Answer 32

False; “obligate sodium loser”

Question 33

T/F: NS infusion in a neonate will result in dehydration

Answer 33

True

Question 34

Which method of heat loss is greatest?

Answer 34

Radiation

Question 35

What two methods can prevent radiation heat loss?

Answer 35

1. Warm operating rooms

2. Radiant lamp “french fry lights”

Question 36

Heat production is achieved by what three things?

Answer 36

1. Voluntary muscle activity
2. Involuntary muscle activity
3. Non-shivering thermogenesis.

Question 37

What is non-shivering thermogenesis?

Answer 37

Metabolism of brown fat which develops in the fetus b/t 26-30 weeks gestation. This comprises 2-6% of neonates total body weight.

Question 38

Where is brown fat located in the neonate?

Answer 38

Mediastinum b/t the scapulae, around the adrenals, and in the axilla.

Question 39

How is non-shivering thermogensis mediated?

Answer 39

Sympathetic nervous system.

Question 40

The heat produced with non-shivering thermogenesis is a product of what?

Answer 40

Fatty acid metabolism.