The Collapsed Infant (Child) with Suspected Heart Disease

(A Pragmatist’s Guide)

Nick PigottStaff Specialist in Paediatric Intensive Care

Children’s Hospital at Westmead

PAC 2012, November 16th and 17th

Resus room perspective…• The collapsed newborn…

– The case for considering heart disease– Diagnostic approach– Clinical management– (HLHS)

• Other customers:– Cardiomyopathy/myocarditis– (arrhythmias)– ‘known’ cardiac patients

Congenital Heart Disease (CHD) accounts for 20% of all congenital malformations

Modes of detection of CHD

• Fetal USS• Post natal examination• Six week check• Parental concern/acute presentation

• 1590 with CHD• (~300,000 live births)• 523 presented before neonatal exam• Routine neonatal examination failed to detect more than half babies

with heart disease• Routine exam at 6/52 missed 1/3

‘Normal’ circulation

effectively 2 pumps in series

Systemic blood flow (Qs) = Pulmonary blood flow (Qp)

LEFTVENTRICLE

BODY’STISSUES

RIGHTVENTRICLE

LUNGS

Qp

Qs

3 main ways babies present with congenital heart disease…1. SHOCK (obstructed flow to body)

2. “BLUE” (obstructed or restricted flow to lungs)

3. HEART FAILURE (excess volume load, eg. large AV canal defect)

[at least the ones intensivists worry about…]

Fetal circulation and the duct

In some newborns with CHD…

• Emulating a ‘balanced’ circulation may be dependent on maintaining flow across a persistent arterial duct

• Ductal patency can be sustained using an infusion of Prostaglandin E

[5 – 100ng/kg/min]

‘Varieties’ of duct-dependent circulation

• Duct-dependent mixing

• Duct-dependent pulmonary circulation

• Duct-dependent systemic circulation

‘Mixing’ lesionsTransposition of the Great Arteries

(with or without VSD)

• Systemic oxygenation dependent on mixing at atrial, ductal levels (+VSD)

Presentation: Cyanosis

Management:• PGE infusion• May require ventilation for transfer• Definitive balloon atrial septostomy (BAS)• Occasionally babies will have intractable

hypoxaemia and metabolic acidosis despite ductal patency – urgent transfer for BAS

Duct-dependent pulmonary circulation(obstructed pulmonary circulation)

• Pulmonary atresia with intact ventricular septum• Critical pulmonary stenosis• Tricuspid atresia

Presentation: Cyanosis (murmur)

Management: • PGE infusion• Often results in significant improvement• Aim for percutaneous sats of 70 – 85%• Adequate urine output, absence of metabolic acidosis• May require ventilation for airway control/systemic collapse

Duct-dependent pulmonary circulation

Management (continued):• If confident underlying cause is cardiac aim for ‘normo’- ventilation and

keep FiO2 between 0.21 and 0.4

HOWEVER!• May be indistinguishable from Persistent Pulmonary Hypertension

of the Newborn (PPHN)!• …in which case, will need mechanical ventilation optimised to reduce PVR• Aim for: PaO2 > 80mm Hg (~100% FiO2)

pH 7.40 – 7.45

iNO, MgS04,, bicarbonatemuscle relaxation, sedation

Duct-dependent systemic circulation(critically obstructed systemic circulation)

• Coarctation of the aorta• Interruption of the aortic arch• Hypoplastic left heart syndrome (HLHS)

Presentation:Collapse, metabolic acidosis, oliguria, absent femoral pulses

NB. Systemic, myocardial (coronary) and pulmonary circulations are all in parallel

Duct-dependent systemic circulation(critically obstructed systemic circulation)

Management:• PGE infusion to re-open duct

AIM is to ‘Balance’ pulmonary, systemic (and coronary) circulations by manipulating PVR and SVR

• If collapsed intubation and ventilation• Fluid resuscitation• Inotropes/inodilators (dopamine, adrenaline,

milrinone)

Mini summary…

• CHD commonest congenital anomaly

• Should be considered as underlying cause in

presentation of collapsed newborn

• Effective clinical mx does not require knowledge of

specific underlying lesion

Clinical approach

• Physical examination– Cyanosis– Murmur– Pulses

– Signs of heart failure (resp rate, hepatomegaly)

Clinical approach…

CXR• Heart size• Pul vascularity (too much/too little)

ECG

Initial management of the newborn in shock with suspected CHD

• Airway Management

• IV Access

• PGE1

• Antibiotics

• Volume, Calcium, Glucose

• Supplemental O2 if needed

• Crossmatch

Call for Help!

Case

• Born at 42 weeks gestation. Normal delivery and Apgar score.

• Poor feeding and breathlessness noted at 2 days.• Readmitted to hospital. • Hepatomegaly, weak peripheral pulses and acidosis.• Retrieval requested.

Team arrival…

• Gasping, grey and grunting• Impalpable peripheral pulses• Single heart sound• CXR: Cardiomegaly• Blood gases: Base deficit of -22, pH = 7.01• Blood glucose: 1mmol/L• Echo: HLHS, tiny arterial duct

Resuscitation on site

• Intubated and ventilated• Paralysed and sedated• Central venous and arterial catheters• Prostaglandin infusion increased• Ventilated

• FiO2 = 0.21 (O2 sat = 80%)• pCO2 = 6

• Transferred

I

II

III

aVR

aVL

aVF

ECG

Parallel circulations

• Reduced systemic perfusion = Excessive pulmonary blood flow (PBF) until proven otherwise

• Poor Ventricular function = Poor myocardial blood flow = Excessive PBF

• Usually, high-dose Inotropes not required

HLHS

RA

LA

RV

LV

HLHS

HLHS

Other ‘cardiac’ customers…

• Cardiomyopathy/myocarditis• (Arrhythmias)• The “known” cardiac patient

Dilated cardiomyopathy (DCM)

• 36.5/100 000• Most commonly within first 2y• Heart usually huge, big liver• Ejection Fraction~10-20%!

Other ‘cardiac’ customers…

• Cardiomyopathy/myocarditis• (Arrhythmias)• The “known” cardiac patient

Other ‘cardiac’ customers…

• Cardiomyopathy/myocarditis• (Arrhythmias)• The “known” cardiac patient

Summary

• Newborns present collapsed as a consequence of congenital heart disease surprisingly often

• Consideration of the likely underlying physiology (rather than the exact lesion) may usefully guide clinical management

• Some features are more useful than others…

The Money…• Murmur• Cyanosis• Diminished peripheral pulses

• Physical signs of heart failure

• Prostaglandin infusion

• CXR• (ECG)

• ?Oxygen might not be the best thing…

Thank you!