Congenital Heart Disease Flashcards
Some of the most common signs to suggest a congenital heart disease?
Shortness of breath Increased work of breathing Tachypnea Cyanosis Shock Diaphoresis with feeding Dehydration
What questions do you want to ask mom when considering possibility of CHD?
Where was the child born? What do the parents already know? What information do they have? Have procedures already been done? What is normal for baby?
What physical exams should be done for suspected CHD?
Sick kid exam: ABC’s
Liver size: hints at CHF
Femoral pulses: coarctation
What are some of the first diagnostic tests done at bedside for CHD?
Pulse ox on right arm and left leg looking for discrepancy
Hyperoxia test with 100% non-rebreather
What is the treatment for all CHD patients? What is the dose and side effect?
PGE1 0.05–0.1 mcg/kg/min load then maintenance at 0.01 mcg/kg/min
Causes apnea in 10%–20% and may require intubation before transfer
Don’t hesitate to give PGE1 if CHD is suspected
Which of the CHD does not respond to PGE1?
TAPVR
What are the 3 major presentations of CHD?
Cyanosis, Shock, CHF
What are the CHD’s that cause CHF?
These lead to increased blood to the lungs
Coarctation, VSD, AS, AV canal
What exam findings suggest CHF?
Large liver, rales in the lungs, dehydration
4 week-old infant presents in respiratory distress. Lungs with rales and you note a large liver. What is the treatment?
PGE1
4 week-old infant presents in respiratory distress. Lungs with rales and you note a large liver. Mom says he has a pulmonary artery band. He is hypotensive. What do you do?
Start PGE 1
Consider giving a pressor:
Dopamine, Milrinone, Digoxin
Explain the dose dependent function of dopamine
Receptors D —> B —> A
Dopamine then Beta then Alpha effects
How does milrinone work?
PDE inhibitor leading to vasodilation and also + inotropy but without chronotropy
Good for CHF patients because of the inotropy and the vasodilation
What are the cyanotic CHD’s?
Five T's, or numbers 1–5 Truncus Transposition Tricuspid Tetralogy TAPVR
3Wk infant presents cyanotic, gray, hypotensive, hypoxic, breathing rapidly. What is first intervention and what to do if abnormal?
Hyperoxia test
Give PGE 1!
Kid has Hx of a corrective operation for CHD and presents with acute decompensation. What are two things to think of when treating this kid?
Dehydration and Thrombosis
Sometimes shunts are placed that have passive flow. Correcting dehydration and optimizing hemodynamics can sometimes fix the problem
Shunts can clot and Heparin at times must be considered
tPA can also be considered in critical situations
Describe how ductal dependent lesions can be affected by changes in flow caused by dehydration.
Flow across ductus is determined by pressure gradient between aorta and the pulmonary artery. When PVR drops, flow can reverse and divert away from the PA into the aorta and bypass the lungs leading to hypoxia. This will be corrected, not by more O2, but by increasing the PVR (maybe with a pressor, or just with hydration) and reverse the flow back into the PA and to the lungs
Describe how ductal dependent lesions can worsen clinically with increased supplemental O2, or decreased CO2, or alkalosis?
Flow across ductus is passive and dependent on pressure gradient between aorta and PA
They have chronic PHTN that is reversed when given O2, or hyperventilated causing decreased CO2 and alkalosis which will increase pulmonary flow and cause hypotension and shock
It may be necessary to hypoventilate and allow hypoxia in order to restore normal systemic flow of blood
What are three cardiac conditions where change in flow can cause issues between pulmonary and systemic circulation?
Ductal dependent lesions, Truncus, and Tetralogy
Describe change in flow in truncus arteriosis and how this changes with different insults
Blood flow to lungs and systemic is with the same pressure. If resistance in the lungs or the system change then flow to both will change.
Septic shock will decrease PVR and flow to the lungs will suffer and a pressor would be needed to correct the balance.
If PHTN is suddenly decreased by giving too much O2, then systemic shock can develop and iatrogenic hypoxia and hypercapnea are needed to restore systemic blood flow
Describe the flow patterns in tetralogy of fallot
Flow here is opposite to truncus
There is resistance to RV outflow and a VSD pushing blood to the systemic side. Blood gets to the lungs by ductus. There is at baseline too much blood going to the system and not to the lungs. These kids get in trouble when they are worked up and breath fast leading to increased systemic flow and decreased pulmonary flow. Squatting increases PVR which aids in pushing blood back to the lungs for oxygeniation.
What are some interventions to reverse a Tet spell?
Knees to chest to increase PVR
Phenylephrine
Esmolol to dilate pulmonary outflow
Morphine to relax the kid and the RV outflow tract which spasms, leading to the spell
What labs are helpful in kids with CHD and why?
O2 sat compared to their baseline
pH, lactate, H/H
If pH and lactate are normal, then the kid is likely at their baseline
Elevated H/H indicate a chronic condition
CHD kids have an increased risk of what catastrophic condition that often isn’t thought of in kids?
Stroke because of the abnormal flow patterns and the communication between left and right side of the heart
When to suspect CHD?
<6 weeks of age Born at home Cyanosis, shock, or CHF Lethargy AMS Poor feeding Dehydration Tachypnea Respiratory distress Hypotension Hypoxemia
How to confirm CHD in ED?
Pulse Ox tests, pulses, hyperoxia test, Echo
You suspect CHD based on history and exam, what next?
Consider:
Supplemental O2, small fluid boluses, PGE 1, intubation, pressors, echo, CARDS CONSULT!
What does it mean if there is an O2 sat difference or a BP difference between the RUE and the LLE?
It indicates a ductal dependent lesion, not just coarctation!
What kids should for sure be given PGE 1?
Fail hyperoxia test (on O2 for at least 10 minutes and there is minimal change in SpO2)
There is a difference between RUE and LLE pulse ox and BP
How long to Prostaglandins take to work?
Should start seeing a response in 15–20 minutes
What is the other name for PGE 1?
Alprostadil
When is apnea most commonly seen with alprostadil?
In kids less than 2kg and in the first hour of infusion
How is alprostadil dosed?
Initial infusion rate of 0.05–0.1 mcg.kg/min until desired effect is seen: in systemic restricted conditions, will see improvement in BP and pH; in pulmonary restricted flow will see improvement in O2
What are causes of acyanotic shock? Treatment?
Coarctation
PGE 1
What are causes of acyanotic CHF? Treatment?
PDA, ASD, AVSD, VSD
These are open passages for blood flow leading to too much flow to the lungs
Treatment is PPV, diuretics, ACE inhibitors, PDE III inhibitors
Some of these are caused by the Ductus not closing when it should so PGE 1 is not helpful or needed, but might not cause any harm in undifferentiated patient?
With higher hemoglobin concentrations, is cyanosis easier or harder to recognize?
Apparently it is EASIER to recognize with higher hemoglobin concentrations
How does a PDA respond to supplemental O2?
Cyanotic kids with a PDA may have persistent PHTN that is causing too much blood to bypass the lungs from a PDA. Giving O2 dilates the pulmonary vasculature leading to more blood going to the lungs and improvement of their hypoxemia.
What three causes should come to mind when evaluating a hypoxemic kid?
1) Intra-pulmonary shunting
2) Intra-cardiac shunting
3) Hemoglobin issue
This is why the hyperoxia test is done, to differentiate between 1 and 2
What is the most common congenital defect?
Congenital heart defects
What percentage of CHD kids survive into adulthood?
90%
Though there are many causes of congenital cardiac emergencies, the majority are caused by?
Ductal dependent lesions and therefore PGE 1 is reasonable to try in the undifferentiated patient and should not be delayed for ECHO confirmation
