Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SBM Resp JXC > 2013-09-09 Neonatal Physio; SIDS > Flashcards

2013-09-09 Neonatal Physio; SIDS Flashcards

1
Q

Discuss the basic concepts of fetal respiration.

A

Deoxygenated blood from the fetus —umbilical arteries—>placenta—>fingers of the chorion—>dip into the intervillous space (blood bath) of the placenta—>umbilical veins—>DV—>IVC—>RA—>PFO—>LA—>LV—>Aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Descrive the anatomical and physio development of the pulm vasc

A
  • -pre-acinar (pre-resp) branching pattern complete by 16 weeks
  • -Airways develop alongside arteries
  • -at first, arteries have small lumens and relatively thick SMM layer in media
  • *chronic fetal stress can further increase the thickness of the SMM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is mechanism behind ∆s in PVR?

A

Morphological Changes Occur in three stages: 1) Rapid Adaptation, 2) Structural Stabilization, 3) Growth

1) Rapid Adaptation
- -endothelial cells in both alveolar (w/in 30 mins) and resp unit arteries (w/in 24 hrs) thin out, making a wider lumen w/ decr PVR

2) Structural Adaptaption
- -Wall thickness of arterial walls —> adult by 3 mos
- -SMM cells deposit stabilizing c.t. around themselves

3) Growth
- -blah over it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe some of the problems assoc’d w/ a failure to go thru a nl transition.

A

PFC - persistence of the fetal circulation

PDA - patent ductus arteriosus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe some of the problems assoc’d w/ PFC.

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe some of the problems assoc’d w/ PDA.

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the double Bohr effect?

A

The Bohr effect describes the effect that pH and pCO2 have on the binding affinity of Hb. Since there are two systems of circulation coming together in the placenta, the Bohr effect is happening twice. Thus the name.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is 2,3-DPG and what is its effect on Hb?

A

2,3-diphosphoglycerate

Decreases the affinity of dHbA for O2. (Does not bind with high affinity to HbF.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is fetal CaO2 different from pregnant woman different from non-pregnant person.

A

Fetal CaO2: incr, and is >mom at term because 1) incr [Hgb] and has HbF > HbA.

Mom CaO2: decreased carrying capacity compared w/ non-pregnant b/c decr [Hgb], incr plasma vol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does fetal SaO2 compare to mom?

A

Fetal: ~75%
Mom: ~98%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Draw out fetal circulation.

A

See page 3 of notes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the fetal shunts and where are they?

A

DV - ductus venosus: allows oxygenated blood in umbilical vein to bypass the liver

FO - foramen ovale: allows oxy’d blood in the RA to shunt over to the LA bypassing the lungs

DA - ductus arteriosus: allows blood that made it through the RA —> RV —> pulm art to shunt into the aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What factors ∆ PVR in fetus?

A

PVR = pulmonary vascular resistance

Vasoconstrict caused by:
a) physical (fluid in lung)
b) decr O2 and pH
c) leukotrienes
d) TxA2
(? Endotholin A, PDGF, PAF, AA metabolites)
Vasodilation caused by:
a) incr O2 and pH
b) NO
c) PGI2 (prostacyclin)
(?ET_B activation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does fetus regulate DA?

A

PGE2 (prostaglandin E2) = major dilator

  • -Made in placenta, cleared in fetal lung
  • *THEREFORE NO NSAIDS IN PREGNANCY

ET-1 (endotholin 1) = major constrictor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does NEOnate regulate DA?

A

O2 major factor for closing DA after birth

  • -Ca2+ mediated
  • -also incr ET-1 which overwhelms, PGE2 and NO
  • -PGE2 is also lost when placenta is gone and there’s decr in PGE2 receptors in DA wall @ term

–decr flow and later reversed flow thru DA also may responsible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Draw transitions Fetal—>Transitional—>Neonatal circulation

A

See diagram on notes pg. 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe some of the causes of perinatal asphyxia

A

MATERNAL: utero-placental insufficiency

  • -chronic HTN
  • -preg-induced HTN (PIH) = pre-eclampsia 50% decr in intervillous perfusion =(
  • -maternal renal, CV dzs
  • -uterine anomalies
  • -maternal fever (no hot tubs)
  • -placental abruption

FETAL

  • -CV (e.g. SVT)
  • -hydrops fetalis (fetal edema of any cause)
  • -polyhydramnios
  • -infection

IATROGENIC

  • -regional anesthetic hypoperfusion
  • -uncorrected supine positioning
  • -β-blockade
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the course of perinatal asphyxia?

A
  • -circ to brain myocardium and adrenal maintained or incr’d
  • -causes vasoconstriction in lungs which is good for fetus but BAD for neonate

(also constricts skin, liver, kidney, GI tract)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a term infant?

A

40 weeks
(now avg is 39 wks b/c of elective c-sections and inductions)

GROSSSSSS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do you Dx perinatal hypoxia due to decreased pulm blood flow?

A
  • -cyanosis/pallor
  • -low SaO2 on room air which improves w/ 100% O2 (Hyperoxia test)
  • -tachypnea, scaphoid abd, heart murmur, abnormal CXR
21
Q

What are four categories of problems that could cause decreased pulm blood flow?

A

1) decreased size of pulm vasc bed
2) f(X)al obstruction
3) pulm vasc constrict
4) pulm venous HTN

22
Q

DDx for decreased size of pulm vasc bed?

A 
congenital pulm hypoplasia
2° pulm hypoplasia
--diaphragmatic hernia
--oligo/an-hydramnios
--absent fetal breathing (neurologic)
--congen chylo- (accumulation of lymphatic fluid in the pleural space) or hydro-thorax
23
Q

DDx for f(x)al obstruction?

A

polycythemia (incr viscosity)

24
Q

DDx for pulm vasc constriction?

A
  • -perinatal asphyxia
  • -pulm parenchymal dz (RDS, pneumonia)
  • -persistence of fetal circ syndrome (PFC)
25
Q

DDx for pulm venous HTN?

A
  • -pulmonary venous, LA or mitral obstruction
  • -LV failure 2° to congen heart dz
  • -transient LV dysfunction
26
Q

If very low PaO2 from birth doesn’t improve with 100% O2, assume…

A

…congenital cardiac dz until proven otherwise

Order a STAT Echo

27
Q

Tx for PFC?

A

Persistant Fetal Circ causes:
–hypoxia, hypercarbia and acidosis

TX: sedation, vent, iNO, QUIET

28
Q

Clinical presentation of baby w/ PDA?

A

premie w/ RDS that doesn’t respond to mech vent

  • -wide pulse pressure (PP = SBP - DBP)
  • -bounding periph pulses
  • -“hyperactive pericordium”
  • -murmur
  • -CXR show pulm edema, cardiomegaly

Order Echo

29
Q

Prevent an tx a PDA

A

prevent w/ steroids to mom prenatally (betamethasone)

tx: indomethacin or ibuprofen or surgery

30
Q

What is periodic breathing?

A

“PB” is that crazy breathing patter babies do that’s very rapid and shows up as a quick oscillating wave on the monitor.

31
Q

Stupid question: which is worse for a baby: bradycardia or hypoxia?

A

bradycardia

32
Q

Compare neonatal and adult ventilatory responses to increased pCO2.

  • -How does hypoxia affect them?
  • -How about sleep?
A

ADULT
linear relationship between pACO2 and ventilation increases that is very sensitive to small changes in pO2
–hypoxia makes even more sensitive

NEONATE
linear relationship between pACO2 and ventilation increases that is NOT very sensitive (shallow slope) to small ∆s in pO2.
–even less sensitive when asleep
–hypoxia? (doesn’t say)

33
Q

Compare and contrast the degree of neuronal connectivity in the respiratory pattern generator between adults and neonates.
–What consequences does this have for neonates.

A

neonates have far fewer connections when compared to adult’s impressive connectivity and redundancy
–leaves neonate more dependent on external stimuli/CO2/hypoxia to ensure rhythmic stability

34
Q

Compare neonatal and adult ventilatory responses to hypoxia.

A

Both have non-linear and not very sensitive responses to hypoxia.

  • -even less sensitive to hypoxia if the pACO2 is low.
  • -especially week hypoxic drive in preemies
35
Q

An experiment was performed in which the minute ventilation was measured for 5 minutes in a full-term, healthy infant at 2 days of age breathing room air (21% oxygen) and then measured for an additional 5 minutes while the infant was breathing 15% oxygen.

  1. After 1 minute of breathing 15% oxygen, would you expect the minute ventilation to be increased, decreased, or unchanged from that observed while breathing room air?
A

The more mature the baby, the more it will increase.

36
Q

An experiment was performed in which the minute ventilation was measured for 5 minutes in a full-term, healthy infant at 2 days of age breathing room air (21% oxygen) and then measured for an additional 5 minutes while the infant was breathing 15% oxygen.

  1. What would you expect the change in minute ventilation to be after 5 minutes of 15% oxygen breathing?
  2. How would the adult ventilatory response to 15% oxygen breathing differ from that in this full-term 2-day-old newborn?
A

It will decrease because of biphasic response to hypoxia which says RR will increase in the first few minutes of hypoxia (or plateau in the case of a preemie) and then begin to decrease.

This is true of both kiddos and adults, but neonates will lower their RR to below their original baseline while adult while lower it to a point that is still above the original (i.e. pre-hypoxic) RR.

37
Q

An experiment was performed in which the minute ventilation was measured for 5 minutes in a full-term, healthy infant at 2 days of age breathing room air (21% oxygen) and then measured for an additional 5 minutes while the infant was breathing 15% oxygen.

  1. What would you expect to observe if the experiment were repeated at 3 to 4 weeks of age in this same infant?
A

The decrease in RR during the biphasic response to hypoxia will be less dramatic than with a younger neonate (i.e. more like that of an adult).

38
Q

An experiment was performed in which the minute ventilation was measured for 5 minutes in a full-term, healthy infant at 2 days of age breathing room air (21% oxygen) and then measured for an additional 5 minutes while the infant was breathing 15% oxygen.

  1. What would you expect to observe if this experiment were performed in a 24-week-gestation infant at 2 days of age? At 3 to 4 weeks to age? At 6-8 weeks of age?
A

A 24 wk GA infant’s biphasic response would be of a plateau’d RR (vs. an increased RR as compared with a term infant or an adult) followed by a very dramatic decrease in RR after just 1 minute to a rate less than 1/2 the original RR.

With increasing age the first half of the biphasic response would look more adult (i.e. the RR would increase) and the decrease would be less dramatic.

39
Q

Random Fact: What is %FIO2 on a transcontinental flight?

A

~18% O2

40
Q

How does hypoxia affect the ventilatory response to CO2?

A

It blunts it

41
Q

Why does having a smaller FRC make hypoxia in situations of decreased RR worse?

A
  • If one has little lungs/smallFRC,changes in ventilation cause large changes in PAO2 and PACO2 – the small reservoir is easily emptied and filled -not stable.
  • If one has big lungs/largeFRC, the FRC acts as a reserve (like thermal inertia) and slows rate of change and reduces amplitude of gas changes.
42
Q

Sum Up: What factors contribute to oscillatory breathing patterns and apnea in premature infants?

A 
• immature wiring
• Decreased responsiveness to CO2
• Biphasic Ventilatory response to hypoxia
• LowFRC
• Easily collapsible upper airway
• Issues with‘loop gain’–unstable system
^^NOT SURE WHAT THAT MEANS
43
Q

What is the gold standard therapy for PB and apnea in infants?

A

PB = periodic breathing

  • -caffeine
  • -CPAP
  • -O2 to prevent hypoxia (not too high!)
  • -tactile stimulation
  • -Time until brain matures
44
Q

Define asphyxia

A

Asphyxiaisanysituationinwhichthereisa decrease in oxygen (O2) and an increase in carbon dioxide (CO2) in the body.
– If you stop breathing
– If your mouth, nose, or airway becomes obstructed.
– If you “rebreath” (imagine an infant face down in soft bedding).

45
Q

Define suffocation

A

a form of asphyxia

46
Q

Define entrapment

A

Entrapment is when an infant is “trapped” in a

situation that produces asphyxia.

47
Q

Define Strangulation

A

Strangulation is when bed clothes or other material is wrapped around the neck, blocking the airway causing asphyxia.

48
Q

What are the A Level Recommendations to parents to prevent PB/apnea/SIDS/SUID?

A 
back to sleep
firm sleep surface
no soft objects or loose bedding in crib
regular prenatal care
no smoke exposure during preg or after
breastfeed
room share w/o bed sharing
pacifier at nap time and bedtime
avoid overheating
do not use at-home cardio-resp monitor
avoid EtOH before and after birth

SBM Resp JXC (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions