Transcript ASD - EarthLink

The “NORMAL” Heart
1
Cardiac Anatomy (cross
section)
2
Cardiac anatomy (external)
3
Cardiac Auscultation
4
Cardiac Circulation
5
Cyanotic/ Acyanotic Defects
CYANOTIC
•
• Tetrology of Fallot
(TOF)
• Transposition of the
greater arteries (TGA)
•
•
•
ACYANOTIC
Atrial Septal Defect
(ASD)
Ventricular Septal
Defect (VSD)
Patent Ductus
Arteriosus (PDA)
Coarctation of the
Aorta (COA)
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ASD
7
ASD
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Atrial Septal Defect
(ASD)
An opening (hole) between the atria allowing blood from
the higher pressure left atria to enter the lower pressure
right atria.
Degree of symptoms depends on the size of the hole. A
child with a small ASD will have virtually no clinical
symptoms but will have a significant murmur (the smaller
the hole, the louder the murmur). The smaller ASD can
close spontaneously.
The child with a large ASD will exhibit s/s of CHF.
9
Repair of ASD
Repair can be performed in two ways
Open or closed heart surgery (depending on the
type of defect and age of the patient)
 A “umbrella” closure performed in the cardiac
cath lab.
A child with an unrepaired ASD does not require
SBE prophylaxis.
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VSD
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VSD
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Ventricular Septal Defect
A opening (hole) between the right and left
ventricle. VSD’s are the most common birth
defect in children. Can range from a pin point
sized hole to a large opening (virtually no septal
wall present).
Causes increased pulmonary blood flow and left to
right shunting of blood flow, this increased flow
cause increased work load on the RV
predisposing the child to CHF.
13
A VSD is normally an acyanotic defect
however
In very LARGE VSD’s ( there is
virtually no septal wall)
accompanied by significant congestive
heart failure , cyanosis can be present.
14
Assessment of the child with a
significant VSD
Child will exhibit s/s of CHF:
Tachypnea, dyspnea
Poor growth = Failure To Thrive
Decreased fluid (formula) intake
Palpable cardiac thrill
Systolic murmur at lower sternal border
15
Medical treatment of a child with a VSD
Pharmacologic management of CHF.
(Digoxin, Lasix).
Increased caloric intake to meet increased
metabolic demands (increased BMR)
High calorie infant formula, commercial infant
formula is 20kcal/oz, by adding less
water/more concentrate or formula powder it
will increase kcal/oz. Can go up to 30kcal/oz.
Synagis vaccine for RSV Sept- March
16
Surgical repair of VSD
The vast majority of small VSD’s close
spontaneously. The moderate-large will require
open heart surgery to repair.
• Age of repair depends on the degree of CHF.
The child with a VSD will require SBE prophylaxis
for life.
17
Nursing intervention (VSD)
•
Small frequent feeding of high caloric infant formula.
– Must be monitored closely to be assured formula is being mixed correctly. Infant
formula that is mixed improperly (to high a concentration) can be rapidly fatal.
– Feeding log
•
Parental education
– Medication administration
– Teach parents s/s of CHF
– Teach parents s/s infection (especially RSV Sept-March)
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If possible once-twice a week phone contact in-between visits to the
cardiologist for the infant with a moderate-large VSD.
Parental support
Provide referrals to support groups
Referrals and assistance to help with the high price of increased calorie
formula (can be as high as $400 a month)
Frequent weights (outpatient- Minimum of wkly, inpatient - daily)
Referral to EI if child is not meeting developmental milestones
18
Coarctation of Aorta
19
Coarctation of the Aorta (COA)
A localized narrowing (coarctation) of the aorta
Will cause increased pressure proximal to the defect (head and
upper extremities) and decreased pressure to distal (body and lower
extremities)
Clinical Manifestations of COA (dependant on the
degree of coarctation):
• Increased BP
• Bounding pulses in arms
• Decreased BP in lower extremities
• Decreased/Absent femoral pulses
• Cool lower extremities
20
Degree of COA
In infants with a significant COA, there can be s/s of
CHF with rapid progression to the infant being
critically ill with acidosis and hypotension. At this
stage they will require intubation and Inotropic
support until repair can be completed.
With a milder degree of coarctation, the defect might
not be diagnosed until it begins to produce
symptoms (dizziness, headache, numbness in lower
extremities, epitasis, syncope) Some children are
not diagnosed until adolescence.
21
Surgical Repair of COA
Can be achieved in 2 ways:
– Balloon angioplasty of the coarcted area, done in the
cardiac cath lab. A balloon catheter is threaded up to
the are of the coarctation and opened in the coarcted
area, in some cases just ballooning the area will work,
in others a stent is needed to keep the aorta open.
The potential for a re-COA is possible requiring a
additional procedure.
– Surgical repair (closed heart repair, no
cardiopulmonary bypass is required). A resection and
end to end anastamsois of the aorta is performed.
A child with a COA will require SBE prophylaxis for life.
22
PDA
23
Fetal circulation
24
Patent Ductus Arterious (PDA)
The failure of the fetal ductus arterious (the artery connecting the
pulmonary artery and the aorta) to close within the first few weeks of
life. In utero the PDA allows the blood to pass between the aorta and
pulmonary artery by passing the lungs, it normally closes within the
first 72 hrs -1 week after birth.
Depending on how large the PDA is, when a large ductus stays open
(patent), systemic BP becomes greater than pulmonary BP and the
additional blood begins to shunt from the aorta across the ductus to
the pulmonary artery, this is a left to right shunt.
This shunt through the pulmonary artery through the lungs increases
the workload of the left side of the heart and RV, which increases
pulmonary vascular congestion and pulmonary vascular resistance
which may cause increased right ventricular pressure and RV
hypertrophy.
25
Treatment for PDA
There are 3 treatments available to close the ductus:
 Infusion of Indometicin (a prostaglandin inhibitor).
 Surgical closure (closed heart) procedure is called a
PDA ligation. Done via thoractomy.
 Coil occlusion, a coil (spring like object) is inserted via a
cardiac cath procedure and threaded to the level of the
PDA, this coil occludes the PDA (and blood flow). It is
successful with the small-moderate PDA.
The child with a PDA will need SBE prophylaxis for one
year after the duct is successfully closed.
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Tetrology of Fallot- TOF
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TOF
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Tetrology of Fallot
Four defects
• Pulmonic valve stenosis
• Right Ventricular Hypertrophy (right
ventricle wall is large and thick)
• Ventricular Septal Defect (VSD)
• Overriding Aorta (extends down to the
level of the VSD)
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TOF
• Four defects are present:
–
–
–
–
Pulmonic Stenosis (stenosis of the pulmonary valve)
Right ventricular hypertrophy (RV wall is thick)
Ventricular Septal Defect (VSD)
Overriding Aorta (aorta is at the level of the VSD)
These four defects combine to allow blood flow to
bypass the lungs and enter the left side of the heart
(and sending unoxygentated blood to the systemic
circulation), this is called a Right to Left shunt.
30
TET SPELL
They are hypercyanotic spells when there is an
increase in the right to left shunting of blood
(less oxygenated blood is getting to systemic
circulation).
TET spells can be precipitated by:
• Crying
• Cold
• Defecation
• Feedings
31
Treatment for TET Spells
• Older unrepaired child will assume a
squatting position (to decrease perfusion
to lower extremities) This is rarely seen in the US, most
children are repaired.
• Put child in knee chest position to increase
blood flow to upper extremities
• IV Administration of Morphine sulfate
• Administration of oxygen
32
Assessment of a child with
unrepaired TOF
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Clubbing of fingers/toes
Polycythemia (excess # of RBC’s)
Metabolic acidosis
Poor growth – FTT
Exercise- activity intolerance
Systolic murmur in pulmonic region
Cyanosis
O2 saturations as low as 50%
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Treatment and Surgical Repair of TOF
Degree of clinical manifestations and symptoms
will depend on the degree of pulmonic stenosis.
• For the child born with significant PS (the child born cyanotic) :
– Oxygen administration
– Correction of Metabolic acidosis
– Immediate infusion of Prostaglandin E1 to keep PDA open to
allow for mixing of blood.
– Palliative surgery to improve oxygenation :Blalock taussig shunt
or balloon septostomy to allow for mixing of blood
– TET repair : closing of VSD, Resection or repair of pulmonary
valve. Done anywhere from ages 6 months – 18 months
depending on the degree of PS.
– Requires open-heart surgery (cardiopulmonary bypass)
– Child with TOF will require SBE prophylaxis for life.
34
Transposition of the Greater
Arteries - TGA
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Transposition of the greater
arteries/vessels (TGA)
• The greater vessels (aorta and pulmonary
artery) positions are switched.
• The pulmonary artery leaves from the left
ventricle and the aorta leaves from the
right ventricle. (normal heart :aorta from the
left ventricle with oxygenated blood going to
systemic circulation, pulmonary artery from the
right ventricle with unoxygentated blood going to
the lungs)
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TGA
• There must be an additional defect PDA , PFO or VSD to allow for
the mixing of unoxygentated and oxygenated blood or the neonate
will not receive any oxygenated blood into circulation.
• This child is born cyanotic and needs immediate intervention to
sustain life.
• The patency of the PDA must be maintained with an infusion of
Prostaglandin E1.
• TGA is a ductal dependant defect – if the PDA closes the child will
have severe hypoxia (O2 sats can be as low as 20%) severe
cyanosis and acidosis. Death will follow very quickly.
• The birth of a child with known or suspected TGA is a true medical
emergency.
37
Treatment (at birth) for TGA
• IV access
• Intubation and mechanical ventilation
• Infusion of PGE 1 at 0.1mg/kg/min to
maintain patency of PDA
• Pharmacologic paralysis and sedation
• Correction of metabolic acidosis
• Transfer to NICU with Pediatric cardiology
services
38
Surgical treatment for TGA
• Emergency procedure if child is too unstable for
repair, if duct is closing and OR is not ready or
surgery can not be performed immediately.
• An artificial opening is made between the atria
via a balloon septostomy (balloon catheter is
threaded up to the atria and a hole is made) this
is performed in the cardiac cath lab. It will allow
the mixing of oxygenated and unoxygentated
blood.
39
Arterial Switch for TGA
• Should be done within the first few days (in rare cases
weeks) after birth.
– The aorta and pulmonary artery are resected at the level of the
valves and reimplanted to their proper anatomical position.
– Coronary arteries must also be resected.
• During the post operative period (first 24 hours) the child
is critically ill with the potential for :leaking around the
multiple suture sites, arrhythmia's , hemorrhage and LV
dysfunction.
• After the initial postoperative period (with no significant
complications ) there is a very good prognosis.
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Mitral Valve Prolapse (MVP)
41
SBE prophylaxis
• Current recommendation is Amoxicillin po
50mg/kg x1, 30mins prior to procedure
• Recommendations change every couple
years – check frequently
42
Congestive Heart Failure
In CHD, CHF is usually caused by:
 L to R shunting with increased pulmonary blood flow (large septal defects, both ASD &
VSD)
 Obstructive defects which impeded blood flow form the left ventricle (aortic stenosis)
 Mixed defects: depending on the degree of mixing and pulmonary blood flow. CHF
and cyanosis may occur together (TOF, TGA).
One sided heart failure (as seen in adults) is rare in children, failure of one ventricle will
almost always lead to failure of the other.
Increased preload,
decreased myocardial contraction,
increased after load =
impaired myocardial function
CHF
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Clinical Manifestations of CHF in
children
• Earliest s/s: tachycardia at rest HR >160
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Digoxin
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Pharmacologic classification:
Cardiac glycoside
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Therapeutic classification:
Antiarrhytmic , inotropic
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Indications:
CHF, Atrial fibrillation, A flutter
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Inotropic action:
Increase force & velocity of
myocardial contractions. In pts
with CHF it increases
contractile force and boosts
cardiac output, improves systolic
emptying. Depresses the SA node
and prolongs conduction to the AV
node.
•
How supplied:
Pediatric Elixir
Pediatric IV:
50mcg/ml
0.1mcg/ml
45
Special considerations for the use of Digoxin in the
pediatric patient
• Children have a poorly defined range of therapeutic levels, toxicity
does not occur at the same levels that are considered toxic in the
adult. Unless it is thought that a child is dig toxic, levels are not
routinely done.
• Children must use the same brand consistently.
• Safety/accidental ingestions: Must be kept in a place that is
physically impossible for a child to get to. A overdose of Digoxin will
cause severe hypokalemia and rapid death (in some cases before it
is even known that the child has taken it).
• Treatment of overdose: Digibind, emesis induction, gastric lavage,
administration of activated charcoal.
• Metabolism:
In hepatic system AND GUT.
• Excretion:
In renal system, dose must be adjusted in
renal failure.
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Total Digitalizing Dose (TDD)
When starting Digoxin in a pediatric patient, children must be digitalized which means
to give their loading dose in 3 doses, 8 hours apart
AGE
PO
IV
Full term 30mcg/kg
20mcg/kg
infant
1 month - 40 -50mcg/kg 20-30mcg/kg
2 years
2-10years 30 - 40mcg/kg 20-30mcg/kg
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TDD
1st dose = ½ of TDD
2nd dose = ¼ of TDD, 8 hours after the first
dose. EKG must be done before
the 3rd dose.
3rd dose = ¼ of TDD, 8 hours after the 2nd
dose.
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Digoxin Maintenance Doses
AGE
PO
IV
Full term infant
8 -10mck/kg
1month2 years
2 – 10 years
Children under
10 years.
10 -12 mcg/kg 1.5 - 9mcg/kg
Children over
10 years
QD
8 -10mcg/kg
2 divided
doses q12h.
6 - 8 mcg/kg
6 - 8 mcg/kg
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Adverse reactions of Digoxin
CNS
• Fatigue
• Muscle weakness
• Agitation
• Hallucinations
• Headache
• Dizziness
Cardiovascular
• Arrhythmias
•
Conduction disturbances: with or without AV block, PVC’s that may lead to increase ins severity of CHF.
EENT
• Yellow – green halo’s around visual images (hard to assess in pediatric pts)
• Blurred vision
• Light flashes
• Photophobia
GI
• Anorexia
• N/V/D
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Signs of Digoxin toxicity in children
– Nausea
– Vomiting
– Anorexia (refusal to eat)
– Bradycardia
– Arrhythmia's
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Nursing considerations in Digoxin
administration
• Prescribed dose and amount drawn up in
syringe must be verified with another
pediatric RN before administration. (even
if this is not the policy in your institution).
• During digitalizing dosing closely monitor
HR and BP.
• Assess K+ levels and urine output before
administering.
• Assess HR before administration.
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Patient/Parent teaching
• Safety: drug must be inaccessible to ALL children, an overdose will
kill a child before it is even known that they took it.
• Provide parent with detailed written instructions to take home.
• Provide parent with a chart for administration (like a med sheet used
in the hospital customized for their at home use) so they can check
off when it was given.
• Provide parent with phone number of poison control (if possible give
them stickers for phone) 1-800-222-1222 or 212-POISONS
• Provide parent with adequate supply of appropriate sized syringes
(needles removed) . Insurance will not pay for syringes if it is a n
oral medication.
• Do not administer with food/liquid .
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Patient/Parent teaching
• If child vomits after dose DO NOT repeat. Give
next dose as scheduled, if child vomits the 2nd
dose, advise parent to call the cardiologist.
• If a dose is missed and it is less than 4 hours
since scheduled time dose can be given and the
2nd dose given at regular time. If more than 4
hours has lapsed, hold that dose and resume
with next scheduled dose.
• If 2 or more consecutive doses are missed,
advise parent to call the cardiologist – NEVER
increase or double up on dose.
54
Patient/Parent teaching
• If child has concurrent illness (V/D high fever
advise parent to call cardiologist fro further
instructions).
• If child goes to a baby sitter or day care, try to
schedule doses so they are at home for
administration. If this is not possible - DO NOT
(under any circumstance) give child care
provider the bottle of Digoxin -give individual
doses drawn up in a syringe.
• Drug must be given in a TB 1cc or 3cc syringe,
never use dropper provided in bottle or any
other measuring device.
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Sample Digoxin Calculation
Infant (2 month old) with a large VSD has congestive heart failure.
Order:
Digoxin maintenance dose : 0.05mg, po,q12h
Childs weight:
8 lbs
Pediatric dosing parameters:
child: 1 mth-2 years: 0.01mg- 0.02 mg/kg in 2 divided dose
Drug available:
Pediatric elixir: 0.05 mg/1ml
Question:
1. What is the dose parameter according to the child's weight?
2. How many milligrams would the child receive per day?
3. How many milliliters would the child receive per dose?
4. Is the dose within safe dosing parameters?
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Calculations
1) Convert child's weight in lbs to kg 8lbs divided by 2.2 = 3.6kg
Calculate safe drug parameters: 0.01mg/kg/day x 3.6 kg = 0.36 mg/day
0.02mg/day x 3.6kg= 0.72mg/day
0.36-0.72 mg/day
2) How many milligrams would the child receive per day?
0.1mg
3) How many milliters would the child receive with each dose?
order is for 0.05mg q12 hours
Drug available is 0.05mg/ml
Child would receive 1 ml per dose
4) Is dose within safe parameters ? NO
The order is for 0.05 mg/q12 hours = 0.1 mg/day
Safe dose range for this pt is 0.36mg/day – 0.72mg/day
Order is MORE THAN safe dose
Do not give - notify MD ASAP
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Prostaglandin E 1 (Prostin VR
Pediatric)
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