Nursing Process in Action · Children's Nursing

Year 2

Congenital Heart Disease: A Year 2 Deep Dive

Duct-dependent circulation, cyanotic vs acyanotic categories, coarctation, transposition, Tetralogy of Fallot spells, and HLHS — the CHD detail that builds on first-year cardiovascular basics.

← New to heart anatomy and fetal circulation? Start with the Year 1 Cardiovascular System guide first.

Children's nursing · Year 2 · The Nurse Lab

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Student note

Duct-dependent means a baby's circulation relies on the ductus arteriosus staying open. Prostin is the prostaglandin infusion used to keep it open. Cyanotic means low-oxygen blood is reaching the body (visible blue tinge). Acyanotic means the main problem is shunting or obstruction, often without obvious cyanosis at first. A tet spell (TOF spell) is a sudden drop in pulmonary blood flow in Tetralogy of Fallot.

Mindset

Cardiac is "plumbing + electrics." Plumbing = flow, valves, vessels, pressure. Electrics = rhythm and conduction.

Duct-dependent rule

If the duct closes and nothing bridges the gap, flow can fail suddenly – classic day 2–3 collapse pattern.

Cyanotic vs acyanotic

Cyanotic = oxygenation problem is visible. Acyanotic = shunting/obstruction, may not look blue at first.

Tet spell response

Knees-to-chest, calm the child, high-flow oxygen, escalate urgently.

Duct-Dependent Circulation

Why can a baby with CHD collapse suddenly in the first days of life?

What duct-dependent means

The baby needs the ductus arteriosus to stay open
It is bridging a structural problem elsewhere
If it closes, pulmonary or systemic flow can fall suddenly
Prostin (prostaglandin) keeps the duct open medically

Pre-ductal saturations

Taken from the right hand
Reflects blood reaching the brain and upper body
Sits before the ductal mixing point

Post-ductal saturations

Taken from a foot
Reflects blood reaching the lower body
Sits after ductal-level mixing

Why the difference matters

A significant pre/post gap can suggest ductal shunting
May suggest pulmonary hypertension or duct-dependent flow
Always interpret alongside the full clinical picture
Escalate a significant difference

Red flags

Sudden collapse in the first days of lifeLarge pre/post-ductal saturation gap

Clinical pearl

Many neonatal CHD emergencies are really "the duct closed and nothing is bridging the gap anymore." This is why some babies who look fine on day 1 deteriorate sharply on day 2–3 as the ductus arteriosus naturally closes.

Cyanotic vs Acyanotic: Four Groups

How does the lecture actually sort congenital heart disease?

Cyanotic – decreased pulmonary flow

Tetralogy of Fallot, tricuspid atresia
Not enough blood reaches the lungs to oxygenate

Cyanotic – mixed blood flow

TGA, TAPVD, HLHS, truncus arteriosus
Oxygenated and deoxygenated blood mix or circulate abnormally

Acyanotic – left-to-right shunt

VSD, ASD, AVSD, PDA
Blood moves high-pressure left → right, raising pulmonary flow

Acyanotic – obstruction

Pulmonary/aortic stenosis or atresia, coarctation
Flow out of the ventricles or through a major vessel is restricted

Clinical pearl

Cyanotic = the oxygenation problem is visible because low-oxygen blood reaches the body. Acyanotic = there may be no obvious blue tinge at first, but the heart can still be under real strain from shunting or obstruction.

Coarctation & Transposition

One is an obstruction problem, one is a plumbing problem – how do you tell them apart?

Coarctation – the question to ask

"Can blood get past the narrowing to the lower body?"
Do four-limb blood pressures if concerned
Weak/absent femoral pulses, cool lower limbs
Poor gut perfusion raises NEC risk

Coarctation – management

Often needs Prostin if duct-dependent, then surgical repair
Post-op: BP monitoring, pain control (high BP stresses the repair)
Watch limb perfusion and gut perfusion/NEC risk

TGA – why mixing is lifesaving

Aorta and pulmonary artery are switched
Creates two parallel circuits that never meet
Without mixing, oxygenated blood cannot reach the body

TGA – how mixing happens

Via PDA, ASD, or VSD
Balloon atrial septostomy if needed
Two separate circuits + no mixing = rapid deterioration

Red flags

Weak or absent femoral pulsesUpper/lower limb BP differenceRapid deterioration in suspected TGA

Clinical pearl

Coarctation is a "can blood get past?" problem. TGA is a "does blood ever meet?" problem. Keeping that distinction clear stops the two conditions blurring together in revision.

Tetralogy of Fallot & TOF Spells

What are the four features, and what actually happens in a tet spell?

The classic four

Pulmonary stenosis – less blood reaches the lungs
VSD – hole allowing right/left ventricle mixing
Overriding aorta – sits over the VSD, receives mixed blood
Right ventricular hypertrophy – RV thickens against obstruction

What triggers a tet spell

Pulmonary blood flow suddenly falls
Often when the child is upset, crying, or agitated
Child becomes very blue, distressed, and unwell

Emergency response

High-flow oxygen – a pulmonary vasodilator
Knees-to-chest positioning
Keep the child calm; escalate urgently
Morphine may be prescribed in some cases

Why knees-to-chest works

Increases systemic vascular resistance
Makes it harder for blood to flow out to the body
Pushes more blood towards the lungs instead

Red flags

Sudden severe cyanosis with agitationChild becoming increasingly distressed and blue

Clinical pearl

A tet spell is one of the few paediatric cardiac emergencies with an immediate physical first-aid response you can start before any drug: knees-to-chest, calm the child, high-flow oxygen, escalate.

Hypoplastic Left Heart Syndrome

How does a baby survive when the left side of the heart barely functions?

What HLHS is

Severely underdeveloped left ventricle
Mitral and/or aortic valve problems
Very small/underdeveloped aorta
The right ventricle has to support the whole circulation

Keeping the baby alive

Needs mixing, usually via ASD and PDA
Prostin keeps the ductus arteriosus open
Without intervention, this is not compatible with survival

Staged palliative surgery

Stage 1: neonatal period
Stage 2: around 4–6 months / when weight allows
Later: Fontan-type circulation in childhood

Important wording

These are palliative, not curative surgeries
They do not make the heart structurally normal
They create a circulation that can support life

Clinical pearl

Cardiac is "plumbing + electrics." HLHS is the ultimate plumbing problem – the left-side pump is barely there, so staged surgery re-routes the entire circulation around a single functioning ventricle.

Rhythm, Feeding & Nursing Care

Beyond the structural defects – what does day-to-day cardiac nursing actually involve?

SVT (supraventricular tachycardia)

Fast rhythm above the ventricles, often >200 bpm
P waves may be absent/hard to see
Starts and stops suddenly – unlike a gradual rise from fever/pain
Vagal manoeuvres: swaddle + cold stimulus (babies), syringe blow (older)

Vagal stimulation in babies

Mask ventilation pressure near the nose/face
Passing an NG tube
Very cold feeds/stimulation
Straining – all can trigger sudden bradycardia

Feeding & fluid balance

Cardiac babies need calories to grow, but feeding is hard work
Too much fluid raises preload, can worsen heart failure
High-calorie feeds in smaller volumes; diuretics if overloaded
Fluid boluses often smaller/more cautious (e.g. 5 ml/kg)

Oxygen therapy nuance

Not automatically "bad" – give it in an emergency
Some cyanotic children have individual target sats (~75–85%)
Oxygen is a pulmonary vasodilator – too much can raise pulmonary flow
Check the child’s own cardiac plan once immediate safety is addressed

Red flags

New arrhythmia with symptomsSudden bradycardia during handling/NG insertionSigns of fluid overload in a cardiac baby

Clinical pearl

The ECG tells you the rhythm; the child’s pulse, CRT, colour, and consciousness tell you whether that rhythm is actually producing effective circulation. Always link the monitor to the bedside.

Heart Development Timeline

Timing	What happens
Around day 22	The primitive heart tube starts to form.
Around day 28	Heart looping begins – the tube twists and starts forming atria, ventricles, and the septum.
Around week 5–7	The aortic and pulmonary trunks divide into the two great vessels; valves develop.
By about week 7	The fetal heart has a recognisable structure, though fetal circulation still differs from postnatal circulation.

Risk Factors for CHD

Risk factor group	Examples from the lecture
Genetic/family	Consanguineous parents, monozygotic twins, chromosomal abnormalities (22q11 deletion, trisomy 18, trisomy 21)
Genetic syndromes	Marfan syndrome, Noonan syndrome, Duchenne muscular dystrophy
Maternal/environmental	Maternal diabetes, maternal alcohol use, maternal drug use including anticonvulsants and methamphetamines

Presentation: Why Each Sign Happens

Sign	Why it may happen	Nursing meaning
Low saturations/cyanosis	Not enough oxygenated blood is reaching systemic circulation.	Assess A–B–C, give oxygen as prescribed/appropriate, escalate.
Tachypnoea / increased work of breathing	Trying to improve oxygen delivery, or pulmonary overcirculation/fluid.	Respiratory signs can be cardiac, not just respiratory in origin.
Poor feeding	Feeding is hard work; cardiac babies tire quickly with poor reserve.	Monitor intake, weight, fatigue, sweating, breathlessness, feed duration.
Poor weight gain	High energy use plus poor intake can cause failure to thrive.	Feeding support and dietetic/cardiac review may be needed.
Cool peripheries / delayed CRT	Peripheral perfusion is reduced.	Suggests compromised circulation or compensation.
Poor or unequal pulses	Cardiac output or vessel flow reduced; obstruction can cause inequality.	Compare central/peripheral and upper/lower limb pulses.

SVT Reference

Feature	What to remember
Meaning	An abnormally fast rhythm arising above the ventricles.
Rate	Often very fast, commonly over 200 bpm in babies/children.
ECG clue	P waves may be absent or very hard to see – QRS complexes come too rapidly.
Pattern	Starts and stops suddenly, unlike a gradual rise from fever, pain, crying, or sepsis.
Why it matters	Ventricles may not have enough time to fill, reducing stroke volume, cardiac output, and BP.

Clinical pearl

Vagal stimulation is a useful concept beyond SVT management too: mask ventilation pressure near the nose/face, passing an NG tube, very cold feeds, and straining can all trigger sudden bradycardia in babies. If a baby's heart rate suddenly drops during handling, think vagal response as one possible cause.

Summary: The Five Sentences

Delivery system

The cardiovascular system moves oxygen, nutrients, and waste around the body

CO depends on 4 things

Heart rate, preload, afterload, and contractility – any can reduce perfusion

Shunts can be lifesaving

The ductus arteriosus can bridge duct-dependent CHD until repair

Cyanotic vs acyanotic

Depends on whether oxygenation/mixing or shunting/obstruction dominates

Quick self-test

Sources & References

British Congenital Cardiac Association — Standards and resources for congenital heart disease NHS England — Congenital heart disease standards and specifications Resuscitation Council UK (2021) — 2021 Resuscitation Guidelines BNF for Children — Current dosing guidance – always verify against the live BNFc before clinical use

Also practice with

Core Quiz — test your recall →OSCE Stations — apply it clinically →

Discussion (0)

Open account page

←Children's Nursing Hub

Nursing Process in Action · Children's Nursing

Year 2

Congenital Heart Disease: A Year 2 Deep Dive

Duct-dependent circulation, cyanotic vs acyanotic categories, coarctation, transposition, Tetralogy of Fallot spells, and HLHS — the CHD detail that builds on first-year cardiovascular basics.

← New to heart anatomy and fetal circulation? Start with the Year 1 Cardiovascular System guide first.

Children's nursing · Year 2 · The Nurse Lab

Save for later

Student note

Mindset

Cardiac is "plumbing + electrics." Plumbing = flow, valves, vessels, pressure. Electrics = rhythm and conduction.

Duct-dependent rule

If the duct closes and nothing bridges the gap, flow can fail suddenly – classic day 2–3 collapse pattern.

Cyanotic vs acyanotic

Cyanotic = oxygenation problem is visible. Acyanotic = shunting/obstruction, may not look blue at first.

Tet spell response

Knees-to-chest, calm the child, high-flow oxygen, escalate urgently.

Duct-Dependent Circulation

Why can a baby with CHD collapse suddenly in the first days of life?

What duct-dependent means

The baby needs the ductus arteriosus to stay open
It is bridging a structural problem elsewhere
If it closes, pulmonary or systemic flow can fall suddenly
Prostin (prostaglandin) keeps the duct open medically

Pre-ductal saturations

Taken from the right hand
Reflects blood reaching the brain and upper body
Sits before the ductal mixing point

Post-ductal saturations

Taken from a foot
Reflects blood reaching the lower body
Sits after ductal-level mixing

Why the difference matters

A significant pre/post gap can suggest ductal shunting
May suggest pulmonary hypertension or duct-dependent flow
Always interpret alongside the full clinical picture
Escalate a significant difference

Red flags

Sudden collapse in the first days of lifeLarge pre/post-ductal saturation gap

Clinical pearl

Cyanotic vs Acyanotic: Four Groups

How does the lecture actually sort congenital heart disease?

Cyanotic – decreased pulmonary flow

Tetralogy of Fallot, tricuspid atresia
Not enough blood reaches the lungs to oxygenate

Cyanotic – mixed blood flow

TGA, TAPVD, HLHS, truncus arteriosus
Oxygenated and deoxygenated blood mix or circulate abnormally

Acyanotic – left-to-right shunt

VSD, ASD, AVSD, PDA
Blood moves high-pressure left → right, raising pulmonary flow

Acyanotic – obstruction

Pulmonary/aortic stenosis or atresia, coarctation
Flow out of the ventricles or through a major vessel is restricted

Clinical pearl

Coarctation & Transposition

One is an obstruction problem, one is a plumbing problem – how do you tell them apart?

Coarctation – the question to ask

"Can blood get past the narrowing to the lower body?"
Do four-limb blood pressures if concerned
Weak/absent femoral pulses, cool lower limbs
Poor gut perfusion raises NEC risk

Coarctation – management

Often needs Prostin if duct-dependent, then surgical repair
Post-op: BP monitoring, pain control (high BP stresses the repair)
Watch limb perfusion and gut perfusion/NEC risk

TGA – why mixing is lifesaving

Aorta and pulmonary artery are switched
Creates two parallel circuits that never meet
Without mixing, oxygenated blood cannot reach the body

TGA – how mixing happens

Via PDA, ASD, or VSD
Balloon atrial septostomy if needed
Two separate circuits + no mixing = rapid deterioration

Red flags

Weak or absent femoral pulsesUpper/lower limb BP differenceRapid deterioration in suspected TGA

Clinical pearl

Coarctation is a "can blood get past?" problem. TGA is a "does blood ever meet?" problem. Keeping that distinction clear stops the two conditions blurring together in revision.

Tetralogy of Fallot & TOF Spells

What are the four features, and what actually happens in a tet spell?

The classic four

Pulmonary stenosis – less blood reaches the lungs
VSD – hole allowing right/left ventricle mixing
Overriding aorta – sits over the VSD, receives mixed blood
Right ventricular hypertrophy – RV thickens against obstruction

What triggers a tet spell

Pulmonary blood flow suddenly falls
Often when the child is upset, crying, or agitated
Child becomes very blue, distressed, and unwell

Emergency response

High-flow oxygen – a pulmonary vasodilator
Knees-to-chest positioning
Keep the child calm; escalate urgently
Morphine may be prescribed in some cases

Why knees-to-chest works

Increases systemic vascular resistance
Makes it harder for blood to flow out to the body
Pushes more blood towards the lungs instead

Red flags

Sudden severe cyanosis with agitationChild becoming increasingly distressed and blue

Clinical pearl

A tet spell is one of the few paediatric cardiac emergencies with an immediate physical first-aid response you can start before any drug: knees-to-chest, calm the child, high-flow oxygen, escalate.

Hypoplastic Left Heart Syndrome

How does a baby survive when the left side of the heart barely functions?

What HLHS is

Severely underdeveloped left ventricle
Mitral and/or aortic valve problems
Very small/underdeveloped aorta
The right ventricle has to support the whole circulation

Keeping the baby alive

Needs mixing, usually via ASD and PDA
Prostin keeps the ductus arteriosus open
Without intervention, this is not compatible with survival

Staged palliative surgery

Stage 1: neonatal period
Stage 2: around 4–6 months / when weight allows
Later: Fontan-type circulation in childhood

Important wording

These are palliative, not curative surgeries
They do not make the heart structurally normal
They create a circulation that can support life

Clinical pearl

Rhythm, Feeding & Nursing Care

Beyond the structural defects – what does day-to-day cardiac nursing actually involve?

SVT (supraventricular tachycardia)

Fast rhythm above the ventricles, often >200 bpm
P waves may be absent/hard to see
Starts and stops suddenly – unlike a gradual rise from fever/pain
Vagal manoeuvres: swaddle + cold stimulus (babies), syringe blow (older)

Vagal stimulation in babies

Mask ventilation pressure near the nose/face
Passing an NG tube
Very cold feeds/stimulation
Straining – all can trigger sudden bradycardia

Feeding & fluid balance

Cardiac babies need calories to grow, but feeding is hard work
Too much fluid raises preload, can worsen heart failure
High-calorie feeds in smaller volumes; diuretics if overloaded
Fluid boluses often smaller/more cautious (e.g. 5 ml/kg)

Oxygen therapy nuance

Not automatically "bad" – give it in an emergency
Some cyanotic children have individual target sats (~75–85%)
Oxygen is a pulmonary vasodilator – too much can raise pulmonary flow
Check the child’s own cardiac plan once immediate safety is addressed

Red flags

New arrhythmia with symptomsSudden bradycardia during handling/NG insertionSigns of fluid overload in a cardiac baby

Clinical pearl

The ECG tells you the rhythm; the child’s pulse, CRT, colour, and consciousness tell you whether that rhythm is actually producing effective circulation. Always link the monitor to the bedside.

Heart Development Timeline

Timing	What happens
Around day 22	The primitive heart tube starts to form.
Around day 28	Heart looping begins – the tube twists and starts forming atria, ventricles, and the septum.
Around week 5–7	The aortic and pulmonary trunks divide into the two great vessels; valves develop.
By about week 7	The fetal heart has a recognisable structure, though fetal circulation still differs from postnatal circulation.

Risk Factors for CHD

Risk factor group	Examples from the lecture
Genetic/family	Consanguineous parents, monozygotic twins, chromosomal abnormalities (22q11 deletion, trisomy 18, trisomy 21)
Genetic syndromes	Marfan syndrome, Noonan syndrome, Duchenne muscular dystrophy
Maternal/environmental	Maternal diabetes, maternal alcohol use, maternal drug use including anticonvulsants and methamphetamines

Presentation: Why Each Sign Happens

Sign	Why it may happen	Nursing meaning
Low saturations/cyanosis	Not enough oxygenated blood is reaching systemic circulation.	Assess A–B–C, give oxygen as prescribed/appropriate, escalate.
Tachypnoea / increased work of breathing	Trying to improve oxygen delivery, or pulmonary overcirculation/fluid.	Respiratory signs can be cardiac, not just respiratory in origin.
Poor feeding	Feeding is hard work; cardiac babies tire quickly with poor reserve.	Monitor intake, weight, fatigue, sweating, breathlessness, feed duration.
Poor weight gain	High energy use plus poor intake can cause failure to thrive.	Feeding support and dietetic/cardiac review may be needed.
Cool peripheries / delayed CRT	Peripheral perfusion is reduced.	Suggests compromised circulation or compensation.
Poor or unequal pulses	Cardiac output or vessel flow reduced; obstruction can cause inequality.	Compare central/peripheral and upper/lower limb pulses.

SVT Reference

Feature	What to remember
Meaning	An abnormally fast rhythm arising above the ventricles.
Rate	Often very fast, commonly over 200 bpm in babies/children.
ECG clue	P waves may be absent or very hard to see – QRS complexes come too rapidly.
Pattern	Starts and stops suddenly, unlike a gradual rise from fever, pain, crying, or sepsis.
Why it matters	Ventricles may not have enough time to fill, reducing stroke volume, cardiac output, and BP.

Clinical pearl

Summary: The Five Sentences

Delivery system

The cardiovascular system moves oxygen, nutrients, and waste around the body

CO depends on 4 things

Heart rate, preload, afterload, and contractility – any can reduce perfusion

Shunts can be lifesaving

The ductus arteriosus can bridge duct-dependent CHD until repair

Cyanotic vs acyanotic

Depends on whether oxygenation/mixing or shunting/obstruction dominates

Quick self-test

Sources & References

Also practice with

Core Quiz — test your recall →OSCE Stations — apply it clinically →

Discussion (0)

Open account page