Congenital Heart Defects Flashcards

1
Q

inciting factors to CHD

A

Acidosis, sepsis, hypothermia, hypoxia, hypercarbia: force fetal circulation to persist after birth

Most neonates who are critically ill from CHD have one or more of these inciting factors

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2
Q

Most congenital heart defects are the result of _____

A

genetic predisposition and environmental factors

Environmental factors: drugs, viral infection, maternal diabetes, maternal alcohol abuse

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3
Q

Normal Pressure in Right Atrium and Right Ventricle in newborns vs. children

A

RA (newborn): 0-4 mmHg
RA (child): 3-6 mmHg

RV (newborn): 65-80/0-6 mmHg
RV (child): 20-30/3-6 mmHg

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4
Q

Normal Pressure in Pulmonary Artery and Pulmonary Vein in newborns vs. children

A

Pulmonary Artery (newborn): 65-80/35-50 mmHg
Pulmonary Artery (child): 20-30/8-12 mmHg

Pulmonary Vein (newborn): 6-9 mmHg
Pulmonary Vein (child): 6-8 mmHg

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5
Q

Normal Pressure in Left Atrium and Left Ventricle in newborns vs. children

A

Left Atrium (newborn): 3-6 mmHg
Left Atrium (child): 6-8 mmHg

Left Ventricle (newborn): 65-80/0-6 mmHg
Left Ventricle (child): 90-120/6-12 mmHg

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6
Q

Normal Pressure in aorta newborns vs. children

A

Newborn: 65-80/45-60 mmHg
Child: 90-120/50-60 mmHg

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7
Q

PA wedge = ____

A

pulm venous pressure= LA if no obstruction

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8
Q

What decreases pulmonary vascular resistance?

A

Hypocapnia
Pulmonary vasodilator (nitric oxide)

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9
Q

What increases SVR?

A

sympathetic stimulation
vasoconstrictor
hypothermia

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10
Q

What increases pulmonary vascular resistance?

A

hypoxemia
hypercapnia
high hematocrit
positive pressure ventilation
metabolic acidosis
alpha-adrenergic stimulation

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11
Q

What decreases SVR?

A

vasodilators
spinal and epidural anesthesia
deep general anesthesia
hyperthermia

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12
Q

What is the normal PVR to SVR ratio?

A

1:10-1:20

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13
Q

If SVR increases relative to PVR then ___ happens

A

pulm BF increases resulting in decrease systemic BF

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14
Q

If PVR increases relative to SVR then ___ happens

A

pulm BF decreases resulting in increase in systemic BF

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15
Q

What condition(s) are associated with increased pulmonary blood flow?

A
  • atrial septal defect
  • ventricular septal defect
  • patent ductus arteriosus
  • atrioventricular canal

(all of which are acyanotic lesions)

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16
Q

What condition(s) are associated with obstruction to blood flow from ventricles?

A

coarctation of aorta

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17
Q

What condition(s) are associated with decreased pulmonary blood flow?

A

Tetralogy of Fallot

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18
Q

What condition(s) are associated with mixed blood flow?

A

Transposition of Great Arteries
Hypoplastic Left Heart Syndrome

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19
Q

What are lesions that increase pulmonary blood flow?

A

Acyanotic Lesions:
-Atrial Septal Defect (ASD)
-Ventricular Septal Defect (VSD)
-Patent Ductus Arteriosus (PDA)
-Atrioventricular Canal Defect

Cyanotic Lesions:
-Transposition of the Great Arteries (TGA)

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20
Q

Atrial Septal Defect is a communication between ___.

What kind of shunt is it?

A

the LA and RA due to a defect in the intra-atrial septum

L to R shunt

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21
Q

ASDs are classified by ____.

A

location

Ostium secundum – comprise 80% of ASDs
Ostium Primum- 15 % of ASD’s

Surgical Therapy:
Primary, patched, or device closure
Anesthesia Management:
Inhalation induction tolerated well

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22
Q

Ventricular Septal Defect (VSD) allows communication between ____.
?Types

A

RV and LV

Types:
Subpulmonary or supracristal defects
Membranous or perimembranous defects- approximately 80% of all VSDs
Muscular defects

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23
Q

With VSD, what impacts the size of the defect?

A

Size of the defect = magnitude of shunting
Small= restrictive
Large=non-restrictive

Shunt depends on PVR to SVR ratio
Normally, VSD produce L -> R shunt
If PVR to SVR ratio is higher then near normal pulmonary BF resulting in R -> L shunt (Eisenmenger syndrome)

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24
Q

Surgical Treatment of VSD

A

Surgical Therapy
Large VSDs are corrected early in childhood
Device, patch, or stitch closure

Post-op risk of EKG changes secondary to edema or sutures (Complete heart block, junctional, junctional ectopic tachycardia (JET))

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25
Patent Ductus Arteriosus connects _____. What kind of shunt is it?
the main pulmonary trunk with the proximal descending aorta 10 % of all congenital heart defects Girls > boys L to R shunt PVR:SVR ratio dependent when PDA is large
26
Treatment of Patent Ductus Arteriosus
Indomethacin infusion Closure in catheterization lab Surgical Therapy Ligation via left thoracotomy or video-assisted thorascopic surgery First closure of PDA done at BCH with Robert Gross (surgeon) and Betty Lank (nurse anesthetist) in 1938 **At risk for injuring recurrent laryngeal nerve
27
Atrioventricular Canal Defect is communication between ____.
all four chambers as well as abnormalities of mitral and tricuspid valves
28
Partial Atrioventricular Canal Defect
ASD with AV valve rings are complete and separate
29
Transitional Atrioventricular Canal Defect
partial fusion of endocardial cushions with variable AV valve abnormalities
30
Complete Atrioventricular Canal Defect
incomplete AV valve rings, ASD, VSD
31
Surgical Therapy for Atrioventricular Canal Defect
Septation of common AV valve tissue to make 2 separate tricuspid and mitral valve Closure of ASD Closure of VSD
32
Anesthesia Management for ASD VSD AVC and PDA
Maintain HR, contractility, and preload to maintain CO Airway Management and immediate control of ventilation Avoid decreases in PVR:SVR ratio Avoid decreases in PVR or increase in SVR A decrease in PVR results in increase pulmonary BF so will need increase in CO to maintain systemic BF Avoid large increases in PVR:SVR ratio (an increase may result in R to L shunt)
33
How does anesthesia management change if a R to L shunt exists?
Decrease PVR via ventilatory changes Maintain or increase SVR Avoid Air-in-line
34
Premeds and Maintenance for ASD VSD AVC and PDA
0.5 – 1 mg/kg Midazolam PO +/- 3 -5 mg/kg Ketamine PO 0.05-0.1 mg/kg Midazolam IM + 3-5 mg/kg Ketamine IM “Gentle” Inhalation induction tolerated well Maintenance on Isoflurane Inotropic choice is Dopamine (3-10 mcg/kg/min)
35
Anesthesia Management for Non-cardiac surgery - ASD, VSD, AVC, PDA
Heavy premedication to reduce need for high concentration inhaled agent for induction Airway management by a skilled provider Control of ventilation to maintain PaCO2 35-40mmHg Fentanyl IV 1-2 mcg/kg IV Rocuronium standard intubating dose 0.6 mg/kg IV If preload is of concern: bolus with 5-10 mL/kg NS; albumin 5% 10-20 mL/kg If contractility is of concern: Dopamine infusion Consider 2nd IV line If afterload is of concern: Manage PVR:SVR ratio with inotropic support and ventilatory control
36
Transposition of Great Arteries is ______.
concordance of the atrioventricular connections associated with discordance of the ventriculoarterial connections
37
More info on Transposition of Great Arteries Clinical Presentation?
The most common type is D-TGA Pulmonary and systemic circulation are in parallel Clinical presentation: Larger size and weight at birth Dyspnea and cyanosis Progressive hypoxemia Congestive heart failure-HR, Increase RR, Increase in WOB Metabolic Acidosis- lack of O2 cause tissues to have less O2
38
Dextro-TGA
Aorta emerges from RV Pulmonary Artery emerges from LV Hole or defect in ventricular septum Hole or defect in atrial septum Patent ductus arteriosus
39
Levo-TGA
Congenitally corrected transposition Aorta and Pulmonary Artery are switched Ventricles are switched with their corresponding AV valves
40
Management of Transposition of the Great Arteries
Continue Prostaglandin E1 infusion to maintain patency of DA Decrease PVR, but maintain SVR Atrial septostomy (Balloon or surgical) Repair within the first days to weeks of life Atrial Switch- atrial venous baffle created Mustard or Senning Arterial Switch- Ao/PA transposed, coronaries reimplanted Rastelli Procedure- VSD closed, baffle created to connect LV to Ao, RV/PA conduit
41
Lesions that Decrease Pulmonary Blood Flow
*Tetralogy of Fallot* Pulmonary Atresia/(IVS) Pulmonary Stenosis Tricuspid Atresia Ebstein’s Anomaly
42
Tetralogy of Fallot (TOF) is characterized by which 4 distinct defects?
1. PS, 2. RV Hypertrophy, 3. Large VSD, 4. Overriding Aorta
43
fixed and dynamic components of TOF
Fixed: pulmonary stenosis Dynamic: is found subvalvular produced by variations in the caliber of the RV infundibulum Together this creates severe RVOTO- R to L shunt
44
Management of Tetralogy of Fallot
Heavy premedication PO or IM 0.5 – 1 mg/kg Midazolam PO +/- 3 -5 mg/kg Ketamine PO 0.05-0.1 mg/kg Midazolam IM + 3-5 mg/kg Ketamine IM After heavy premedication, gentle inhalation induction is tolerated Airway Management and immediate control of ventilation Maintain HR, keep PVR down, and SVR up; avoid severe R to L shunt No air-in-line
45
Treatment for Tetralogy of Fallot
Palliative systemic to pulmonary arterial shunt: Waterston and Potts, Central shunt, Blalock-Taussig shunt Definitive repair: Resection of hypertrophied RVOT to enlarge OT, closure of VSD
46
Blalock-Taussig Shunt
Proximal end of SCA is sewn to the side of the PA Classic or Modified approach Inaccurate BP on shunt arm!! (put BP cuff on opposite arm. If cuff on same side as shunt it will be inaccurately low)
47
Blalock-Taussig Shunt
O2 sats 70-80% Avoid dehydration-volume support Low FIO2, RA if possible Too much pulm BF leads to decreased CO
48
Treatment for hypoxic Tet Spells
Administer 100% O2 Knees to chest position Morphine (0.05-0.1 mg/kg) IV Crystalloid 15-30 mL/kg to enhance preload Sodium Bicarb (1-2mEq/kg) to treat severe metabolic acidosis 𝛼−𝑎𝑑𝑟𝑒𝑛𝑒𝑟𝑔𝑖𝑐𝑠: Phenylephrine (5-10 𝜇𝑔 /kg) bolus or (2-5 𝜇𝑔 /kg/min) infusion 𝛽−𝑎𝑑𝑟𝑒𝑛𝑒𝑟𝑔𝑖𝑐𝑠: Contraindicated as increasing contractility will narrow the stenosis Propanolol (0.1mg/kg) – may reduce infundibular spasm and slowing HR may improve preload ECMO
49
Lesions Obstructing Systemic Blood Flow
Coarctation Hypoplastic Left Heart Syndrome (HLHS) Interrupted Aortic Arch Aortic Stenosis
50
Coarctation of the Aorta is _____
a focal narrowing of the aorta Represents 6-8% of congenital heart defects More commonly found in males and most common lesions in patients with Turner syndrome Produces LV pressure overload and decreased in lower body perfusion
51
Clinical Signs of Coarctation of the Aorta in Neonates
Severe congestive heart failure Weak or absent lower extremity pulses 4 extremity BP gradient CXR shows increased pulmonary vascular markings, cardiomegaly
52
Clinical Signs of Coarctation of the Aorta in Older Children
Usually asymptomatic Weak pulses in lower extremity Pain or weakness in legs with exercise Hypertension CXR: LV hypertrophy, rib notching
53
Treatment for Coarctation of the Aorta
Surgical Repair End to end repair Patch Aorto-plasty
54
Goals for management of Coarctation of the Aorta
Maintain HR, contractility, preload to maintain CO If there is ASD or VSD, avoid reduction in PVR:SVR ratio Avoid increases in SVR A-line in the R arm
55
Management of a sick neonate with coarctation of the aorta
PGE1 (0.05-0.1 𝜇g/kg/min) infusion to reestablish ductal patency Mechanical Ventilatory and inotropic support Diuretic Treatment of metabolic acidosis May suffer transient renal and hepatic dysfunction
56
Postop Consideration for Coarctation of the Aorta
Cross- clamping risk Risk for NEC Spinal cord ischemia Recurrent coarctation (10-30% risk) Re-operation Balloon dilation in cath lab
57
Hypoplastic Left Heart Syndrome is characterized by ____
an underdeveloped LV and very small Aorta
58
Survival of Hypoplastic Left Heart Syndrome is dependent on ____
R to L shunt through PDA for adequate perfusion L to R shunt at atrial level for adequate saturation: restrictive ASD Distal Ao arch flow occurs via the PDA. Proximal Ao BF and coronary BF occur by retrograde filling of a tiny ascending Aorta via PDA- this puts HLHS at high risk for myocardial ischemia. PGE1-PDA patency is life saving
59
During HLHS repair, what are the 3 main goals?
1. reliable source of pulmonary blood flow, 2. unobstructed delivery of pulmonary venous blood to systemic ventricle, 3. unobstructed path from systemic ventricle to aorta
60
Surgical Repair of Hypoplastic Left Heart Syndrome
Surgical Repair 3 Stage Palliation Stage 1 Norwood or Sano- within 1st week of life Stage 2 bi-directional Glenn (SVC end to side anastomosis to branch PA)- 3-6 months of life Stage 3 Fontan – 2-3 years of age Heart Transplantation
61
Staged Repair for HLHS
HLHS Initial Repair involving atrial septectomy, Damus-Kaye-Stansel (DKS) anastomosis of main PA to Ascending Ao, homograft augmentation of aortic arch, r-modified Blalock-Taussig shunt (BTS), to supply pulmonary BF Initial Repair involving atrial septectomy, DKS, homograft augmentation of aortic arch, RV to PA conduit to supply pulm BF Superior cavopulmonary shunt (bidirectional Glenn) Fontan procedure
62
Bi-directional Glenn
SVC is removed from heart and connected end to side to the Right pulmonary artery, which is in continuity with the Left pulmonary artery. The main PA has been separated from the heart and oversewn.
63
Fenestrated Fontan
with baffle containing fenestration inside RA to connect IVC with RPA with previous BiD Glenn shunt
64
Extracardiac Fontan
connects IVC to RPA with previous BiD Glenn shunt
65
HLHS initial management
Provide prostaglandin infusion to maintain PDA patency Decrease FIO2 delivery: Additional oxygen is not used since it tends to promote more blood flow to the lungs Possible Intubation- target PaO2 40-45 mmHg and SaO2 of 70-80% Need adequate CO to provide systemic oxygen delivery- ability to recruit stroke volume with preload is limited d/t volume overloaded single ventricle and increasing HR in ischemic prone heart is not advisable. Dopamine 3-5 𝜇𝑔 /kg/min
66
HLHS staged repair
Stage 1 75 % survival rate Stage 2 90 % survival rate Fontan – dysrhythmias, limited activity due to poor oxygenation, may develop liver and kidney dysfunction