Neonatal Cardiology Flashcards
CHD and perfusion (109 cards)
1
Q
General Approach to CHD
A
- pre/post ductal saturations
- Hyperoxia test
- CXR
- PEG1
- Consider need for intuabtion
2
Q
Neonates who get PGE1
A
TOF
DTGA
Tricuspid atresia
Truncus arteriosus
3
Q
Neonates who would get worse with PGE1
A
TAPVC
4
Q
TOF relies on
A
VSD and PDA
Relies on VSD and PDA because of the RVOT obstruction that can happen (Tea spell)
5
Q
Left sided obstructive lesions
A
- Hypoplastic left heart
- Coarctation of the aorta
- critical aortic stenosis
- HOCM with SAM
6
Q
Right sided obstructive lesions
A
TOF
Pulmonary atresia
(pulmonary stenosis)
7
Q
Parallel Circulation
A
D-TGA
TAPVC
Truncus Arteriosus
8
Q
BP gradient
A
difference between arms and legs suggestive of LV dysfunction or service coarctation of the aorta
9
Q
How does respiratory distress in cyanotic CHD present
A
Often no increased WOB, but hypoxemic from right to left shunt. Textbook answer is resting tachypnea
10
Q
Definition of cyanosis
A
3-5g/DL of dexoygenated hemoglobin
11
Q
Why do we perform a hyperoxia test?
A
To help distinguish cardiac and pulmonary causes of cyanosis. A hyperoxia test will not increase oxygenation greatly in CHD, but will improve in parenchymal lung disease.
can be useful in the setting without TnECHO
12
Q
Describe the physiologic bases of the hyperoxia test
A
If the child has parnchymal lung disease, saturations will increase with administration of oxygen. If the child has a cardiac shunt with right to left physiology, the hyperoxia test will not provide a sufficient increase in saturations.
In cyanotic CHD due to Right to left shunting, blood in the pulmonary veins are fully saturated with oxygen in ambient air.
Administration of higher concentration of FiO2 increases the amount of dissolved oxygen but has MINIMAL effect on oxygen tension levels because there is no effect on the deoxygenated blood that is shunting the systemic circulation
13
Q
What will happen to patients with parenchymal pulmonary disease with an hyperoxia test
A
supplemental oxygen will increase SpO2
14
Q
Formal Hyperoxia testing (using ABGs)
A
Testing is performed by measuring the PaO2 in the right radial artery (preductal) before and after administration of 100% fio2 for 10 minutes
PaO2 >150 suggests hyperoxia test suggests pulmonary disease. An increase <150suggests CHD
15
Q
informal hypoxia testing
A
an increase in the oxygen saturations <10 percent with admin of 100% fio2 suggests a pulmonary cause of cyanosis
delta of > 10 = CHD/PPHN
delta of <10 = parnchymeal lung
16
Q
Four characteristics of TOF
A
- PS
- RV hypertrophy
- over-ride of the aorta
- VSD
17
Q
Why are TOF babies cyanotic
A
If the RV obstruction or increase in PVR is significant enough to increase resistance, it will be easier for blood to cross the VSD from the RV into the LV and go out into the aorta, which becomes the path of least resistance
the right to left shunt across the VSD results in a large volume of desaturated blood entering the systemic circulation, causing cyanosis
18
Q
TOF/Tet spell treatment plan
A
- calm baby (decrease PVR)
- oxygen (pulmonary vasodilator and systemic vasoconstrictor)
- knees to chest (increase SVR by pressing on the femoral arteries)
- Prostaglandin (to maintain ductal potency and pulmonary flow pending on surgical repair)
- Morphine
- Betablocker and phenylphrine (BB to relax RVOT and phenyl to increase SVR)
19
Q
d-TGA relies on:
A
PDA/PFO or VSD
20
Q
Describe d-tga in one sentence
A
discordant lesion in which the aorta arises from the RV and the pulmonary artery arises from the LV
21
Q
Why does DTGA lead to cyanosis
A
- deoxygenated systemic venous blood goes into the RA/RV and back into the systemic circulation via the aorta
- oxygenated pulmonary venous blood to the left atrium and back to the lungs via the LV and pulmonary artery
22
Q
whats the importance of the PDA in DTGA
A
it allows oxygenated rich blood in the LV go through the pulmonary artery and through the PDA which connects in to the aorta, which them provides systemic oxygenation (not a lot but some)
23
Q
d-TGA mgmt/tx:
A
- prostaglandin to keep DA patent.
- balloon atrial septostomy
- material switch operations (ASO) is standard for surgical repair for DTGA
24
Q
define Truncus arteriosus
A
there is a common arterial trunk. the lack of wall development also impairs the creation of separate aortic and pulmonary valves, resulting in the single truncal valve associated with TA
25
Physiology of Truncus arterisosus
main concern is developing HF 2nd to left tor right shunting.
in the new born, with TA, PVR is initially high, with relatively little left tor right shunting at birth. The amount of flow into the pulmonary arteries is relatively normal and is almost equal to the systemic cardiac output.
over the first several weeks of life, the PVR drops and left to right shunting increases to the point of heart failure.
26
Truncus arteriosus
| mgmt
1. Alprostadil (PGE1)
2. diuretic therapy
3. inotropy
4. angiotensin blockade
5. NIPPV
27
Tricuspid Atresia definition
is a cyanotic CHD lesion that is characterized by congenital agenesis or absence of the TV resilient in NO direct communication between right atrium and RV
28
In Tricuspid atresia the exit of blood from the RA is
through the PFO or ASD. this obligatory right to left shunt is necessary for survival as it allows deoxygenated systemic blood to enter the LA and subsequently the LV
29
Tricuspid atresia mgmt
1. Alprostadil (PGE1) to maintain an adequate patent ductus arteriosus
2. intubation, mech vent, inotropic support prn
3. surgical mgmt - the goal of staged single ventricle palliation is to ensure adequate pulmonary and systemic BF
30
What is total anomalous pulmonary venous connection- TAPVC
- The TAPVC is a cyanotic CHD in which all four pulmonary veins fail to make their normal connection into the left atrium
the result is drainage of all pulmonary venous return into the systemic venous circulation
31
Physiology of TAPVC
1. venous mixing
- the entire oxygenated pulmonary venous return mixes with deoxygenated blood from the systemic venous system
- because both the RA and RV receive so much volume, they dilate and fail
2. Pulmonary venous congestion
- in partially obstructed forms of TAPVC there is significant obstruction of the pulmonary venous return to the heart. pulmonary venous pressures rises and the high pressure is transmitted back to the lung vasculature resulting in progressive interstitial and alveolar edema
32
obstructed TAPVC
generally present as critical ill and will die without immediate surgical correction.
33
unobstructed TAPVC physiology and when does it present with cyanosis
unobstructed lesions may only have subtle cyanosis immediately after birth. after the immediate new born period symptoms are related to pulmonary edema. overtime this results in RV hypertrophy and failure
34
mgmt of TAPVC
1. supplemental oxygen
2. mech vent
3. inotropic support
4. dont give alprostadil
5. needs ecmo for refractory shock
35
d-TGA relise on
PDA
36
Tricuspid Atresia relies on
PFO/ASD
37
Truncus arteriosus relies on
VSD/PDA
38
TOF cxr
boot shaped
39
dTGA cxr
Egg on a string
40
TAPVC CXR
pulmonary edema
41
how much more does Fetal Hgb retain oxygen than that of an adult
1.34 (adult) 1.37 fetal
42
MAP should equal
GA, but pressure doesn't equal flow. still have to look at SBP/DBP readings and correlate clinically
43
Factors contributing to Low systolic BP
```
low pulmonary BF
impaired filling
structural/rhtyhm
myocardial injury
failed adapation
vasoconstriction
```
44
Common causes of low diastolic BP
vasodilation
| hypovolemia
45
common causes of preterm hemodynamic instability
- failed adaption to transition
- PDA
- Sepsis/NEC
- Low pulmonary BF (PPHN, high mean airway pressures)
Cardiogenic Shock
- congenital heart
- PPHN
Hypovolemic Shock
- Hemorrhagic (
- Non-hemorrhagic (insensible losses)
Obstructive
-tension pneumothorax
Distributive
-Sepsis
46
Common causes of HD instability in the term infant
- HIE --> Acidotic environment
- Pulmonary HTN (RV failure)
- sepsis
- CHD
47
Hydrocortison is useful in neonates because
the neonate doesn't have the endogenous ability to secrete cortisol the same as an adult is able to
48
Dobutamine dose
2-10mcg/kg/min usually for anytime you want inotropy. Dont have to worry as much about the vasodilator effects that you do with adults, but its still there
49
cardiogenic shock inotropes in neonate
dobutamine and then maybe milirone for inotropy.
50
distributive shock warm pressor choice
levophed, vasopressin, dopamine, epi
51
distributive cold shock pressors
dobutamine, epi
52
indicators of poor CVS health
- tachycardia
- systolic hypotension
- diastolic hypotension
- increased CRT
- Pallor/cyanosis
- deceased LOC
- Decreased UO
- Elevated lactate
- metabolic acidosis
- low scvo2
53
distributive shock causes in neonates
- sepsis
- sepsis
- sepsis
- NEC
- iatrogenic
- hydrops
- liver failure
- adrenal insufficiency
54
Functional and anatomical clousure of the PDA occurs when
Functional : first few hours of life (10-15)
| Anatomical: 2-3 weeks after delivery
55
proper placement of a UVC is through the
ductus venous. If it goes into the portal veins it could cause a hematoma.
56
if the DV fails to close after birth, it is deemed a
patent ductus venosus, and thus an intrahepatic portosystemic shunt (PSS).
57
Describe why the preductual sat is > than the post ductal sat with failure to transition
The RV pumps deoxygenated blood up the pulmonary trunk, into the PDA and into the systemic circulation - which is typically after the first one or two branches off the aorta. The LA receives oxygenated blood from the pulmonary circulation, which goes into the LV which pumps it though the aorta and out of the first branch of the aorta to the right hand (preductual) providing it with oxygenated hemoglobin.
58
Non-cyanotic cardiac conditions
ASD
VSD
PDA
Obstruction to flow: PS, AS, Coarc
59
How are ASD's treated
Often with interventionists, not often surgery anymore
60
Which way does BF in VSD/ASD typically
left to right (non-cyanotic)
61
When do PDAs typically close in term babies 👶 (anatomically)
2-5 days of life
62
When do tet spells typically develop
4-6months of age
63
Clinical signs of coarc
- deminishing/abscent femoral pulses
- BP gradient in arms
- 90% have systolic HTN of upper extremities
- pulse discrepancies of R and L arm
64
Adverse effects of PGE
Cutaneous Flush
Hyperthermia
Apnea
Hypotension
65
How does PGE improves oxygenation
Improved oxygenation comes not only from reestablishment of PDA but also from pulmonary vasodilation which reduces PVR and promotes pulmonary BF
66
When doing a 4 limb BP what are the main things to look for and be suspicious of
1. SBP
- be suspicious with a difference >10mmHg
- be very, very suspicious with >20mmHg
67
What are cyanotic CHD
Lesions that allow circulation of deoxygenated blood in the systemic circulation via intracardiac or extracardiac shunting
68
What are ductal-dependent lesions
Lesions which are dependent upon a PDA to supply the pulmonary or systemic BF, or to allow mixing between parallel circulations
69
Whats the importance of a PDA in right heart obstructions
The PDA is necessary to supply BF to the lungs
70
In critical left heart lesions, whats the importance of a PDA
The PDA supplies systemic circulation
71
Whats the importance of a PDA in parallel circulation
The PDA allows bidirectional flow, allowing for mixing between oxygenated and deoxygenated circuits
72
RF for CHD
- Prematurity
- Family hx
- Genetic syndromes and extra cardiac abnormalities
- Maternal Factors (GDM, connective tissue disorders)
- Fertliity treatment
- in utero infection
73
Closure of PDA in the first few days of life can precipitate profound cyanosis.... how??
In patients with critically obstructive right heart lesions (PS, pulmonary atresia w/ VSD) pulmonary blood flow is supplied retrograde from the aorta via the PDA (kinda like coronary vessels).
Therefore, progressively severe cyanosis occurs as the ductus closes and BF to the lungs decreases.
74
How does closing of the PDA cause cyanosis and cardiogenic shock in the context of LEFT cardiac lesions
Post-ductal saturations will be lower because of right to left shunting through the PDA. However, upon closure of the ductus, systemic circulation is compromised, resulting in cardiogenic shock and cyanosis.
75
Why do patients with parallel circulation depend upon a PDA
They relain on an PDA and ASD/VSD for mixing of oxygenated and deoxygenated blood. With closure in the absence of an adequate ASD profound cyanosis occurs.
76
What is differential cyanosis
In differential cyanosis, the preductal sat is > post-ductal sat. The upper extremities are pink and perfused and the lower half is cyanotic.
This can occur with PPHN, COA, interrupted arch, or critical aortic stenosis. In these lesions, the flow of deoxygenated blood through the PDA supplies the lower half of the body and oxygenated blood from the left heart supplies the upper body via the vessels proximal to the PDA.
77
In critical RIGHT HEART obstruction, the PDA is necessary to supply the
Lungs
78
In critical left heart obstruction the PDA is dependent to supply
the systemic circulation.
79
In parallel circulation, the PDA provides
Bidirectional flow that allows mixing between oxygenated and deoxygenated circuits.
80
Infants with these lesions may present with cardiogenic shock as the ductus arterosis closes and systemic perfusion decrease
Left heart issues.
- hypolastic left heart syndrome
- critical aortic valve stenosis
- critical coractation of the aorta
- interrupted aorta
81
Whats differenital cyanosis
Differenital cyanosis is when the upper half of the body is pink and the lower is cyanotic
This can occur in patients with COA or PPHN
In these lesions, deoxygenated blood from the PDA supply the lower half of the body and the upper is supplied from oxygenated rich blood that flows through the first two branches of the aorta before it mixes with the PDA deoxygenated blood.
82
What is reversed differential cyanosis
Is a rare finding that may occur in patients with TGA associated with COA or PPHN
In these infants, oxygenation is higher in the lower extremities than the upper extremities. As most oxygenated blood flow is pumped by the LV out to the pulmonary artery and this across the PDA.
83
How high should the SBP go up after eGA 23 weeks
2mmHg q week
84
For each week beyond eGA SBP should increase by 2mmHg and MAP continues with GA while DBP continues to be _____
half of SBP
85
What should the SBP/DBP and MAP of a 23 weeker be
SBP 30/15 with MAP of 23
86
What should the SBP/DBP and MAP be of a 28 weeker
MAP 28
| SBP 38/19
87
What should the SBP/DBP and MAP be for a 30 weeker
MAP 30
| 44/22
88
What should the MAP/SBP/DBP of a 38 weeker be
MAP 38
| 68/34
89
Common causes of HD instability for low pulmonary BF
RV dysfunction
Might Mean airway pressure
PPHN
90
Common causes of HD instability for impaired filling
HOCM w SAM
Tamponade
T. Pneumo
91
Common causes of HD instability for structural/Rhythm
CHD
| SVT/VT
92
Common causes of HD instability in the setting of vasoconstriction
Cold septic shock
Exogenous
Vasopressors
93
What does the SBP tell you
Force exerted on the vessel wall during systole
94
What does diastolic pressure tell you
Resting pressure of blood on the vessel
95
What does MAP tell you
Time-weighted average of pressure valves in large systemic arteries during cardiac cycle
96
What is Denervation Hypersensitivity
The finding that myocardial adrenoreceptors show a pattern of "denervation hypersensitivity" in which small concentrations achieve maximal stimulation.
As
gestational age increase, more innervation occurs.
97
HD significant PDA results in
Progressive volume of the LV output being diverted from systemic to pulmonary circulation.
98
What creates a HD significant PDA
Though ductal size is a contributing factor, a primary determinant of flow between systems is the difference in pressure between the chambers of either side.
99
Therapeutic goals in neonates with oxygenation failure and compromised HD include:
Reduction of PVR and augmentation of RV systolic function.
100
Describe RV failure in the setting of PPHN
PPHN is a failure of normal decline in PVR after birth. Low PBF leads to poor left heart filling and therefore low LVO despite normal LV systolic performance
The RV is exposed to high afterload which contributes to wall stress and is associated with increased myocardial oxygen demand which is not met by supply due to changes in RCA flow
High RV systolic pressure reduces RCA systolic flow and low systolic systemic BP leads to a decline in RCA diastolic flow
This leads to RV myocardial ischemia which causes progressive RV dilation and dysfunction and may further reduce PBF.
101
Approach to diastolic hypotension in neonate
initial therapy is crystalloid (10-20ml/kg to max 60ml/klg) followed by early pressor such dopamine
102
The three shunts of fetal circulation
ductus venous
forman ovale
ductus arteriosus
103
What are the two right to left shunts of fetal circulation
FO
| DA
104
When does the DV functionally start to close?
closes soon after clamping and structurally over days to weeks
105
How does the FO close?
Oxygen is a pulmonary vasodilator, which decrease PVR. Which increases pulmonary BF, which means more return to the LA from the pulmonary arteries, which increase LA pressure > RA pressure so the FO flap closes
106
During transition, the PVR _______ to or at below _____ and the ____ to left shunting decreases
During transition, the PVR decreases to or at below SVR and the right to left shunting decreases
107
What happens when you clamp the cord
Clamping the cord causes SVR to increase, your left atrial pressure goes up and the FO closes
Then a breath takes place which decreases PVR more and then DA slowly closes
108
How long can it take for SVD babies to obtain full FRC at 30ml/kg?
2-3 hours
109
How long can it take C-section babies to obtain full FRC at 30ml/kg?
5-6 hours
