Cardiac Emergencies in Infants › meetings › 2017fall › guide › program › fil… · Understand the scope of congenital heart disease ... – Strongly consider cyanotic heart

Cardiac Emergencies in Infants

Michael Luceri, DO

October 7, 2017

I have no financial obligations or

conflicts of interest to disclose.

Objectives

Understand the scope of congenital heart disease

Recognize the presentation of a critically ill neonate

Categorize the disease to facilitate its treatment

Background

Congenital heart defect (CHD)

– “A gross structural abnormality of the heart or intrathoracic great vessels that is actually or potentially of functional significance” Mitchell, et al (Circulation, 1971)

– 8-10/1000 live births, ~1%

– About half require an intervention

Recent increased detection

Birth Prevalence of Congenital Heart Disease Worldwide: A Systematic Review and Meta-Analysis

J Am Coll Cardiol. 2011;58(21):2241-2247. doi:10.1016/j.jacc.2011.08.025

Time course of reported total congenital heart disease (CHD) birth prevalence from 1930 until 2010. The blue line shows the time trend, and the squares represent

the calculated birth prevalence values for each time period.

Total CHD Birth Prevalence Over Time

Congenital Heart Defects

Recent increased detection

– Improvements in echocardiography

Doppler

Fetal echocardiography

Transesophageal echocardiography

3D echocardiography

– Advanced non-invasive imaging

CT

MRI

No increase in disease severity!!!



Time course of birth prevalence of the 8 most common CHD subtypes from 1945 until 2010. AoS = aortic stenosis; ASD = atrial septal defect; Coarc = coarctation;

PDA = patent ductus arteriosus; PS = pulmonary stenosis; TGA = transposition of the great arteries; TOF = tetralogy of Fallot; VSD = ventricular septal defect.

Birth Prevalence of CHD Subtypes Over Time



Reported birth prevalence of the 8 most common CHD subtypes per continent. Distribution of subtypes within total CHD is mentioned as percentages above bars.

*Reported PS and TOF birth prevalence in Asia was significantly higher than in Europe (p < 0.001) and North America (p < 0.001). †Reported Coarc birth prevalence in Asia

was significantly lower than in Europe (p < 0.001). ‡Reported TGA and AoS birth prevalence in Asia was significantly lower than in Europe (p < 0.001), North America (p <

0.001) and Oceania (p < 0.001). §No data on TOF and AoS birth prevalence in Africa were available. Abbreviations as in Figure 4.

Birth Prevalence of CHD

Subtypes

Circulation

Fetal circulation

– Fetal lungs collapsed, alveoli filled with fluid

– High pulmonary vascular resistance (PVR), thus minimal pulmonary blood flow (Qp)

Ohm’s Law: V = I • R (Voltage = Flow • Resistance)

In hemodynamics: Pressure (gradient) = Flow • Resistance

– Flow = Pressure/Resistance

– Oxygenation from placenta via umbilical vein

– PFO & PDA shunt RL

Normal

Heart

Normal

Heart

w/PDA

Circulation

Neonatal circulation

– Hormones of labor cease production of lung liquid

i.e. Epinephrine, vasopressin, cortisol, etc.

– First breath and lung expansion

Remaining liquid absorbed

PVR decreases Qp increases

Functional closure of PFO & PDA

– Now pulmonary & systemic circulation in series!

Circulation

Certain lesions can interrupt serial blood flow:

– i.e. TOF, aortic stenosis, coarctation

– Transposition of the great arteries (TGA)

Newborn then depends on the presence of a shunt

– Balloon atrial septostomy

Balloon Atrial Septostomy

First interventional procedure: Rashkind Septostomy (1966)

No animal studies

Prone to material embolization

Circulation

Certain lesions can interrupt serial blood flow:

– i.e. TOF, aortic stenosis, coarctation

– Transposition of the great arteries (TGA)

Newborn then depends on the presence of a shunt

– Balloon atrial septostomy

– Prostagladins!!!

Very forgiving, almost foolproof!

When in doubt, try it out!

Usually 0.01 mcg/kg/min works, can go up to 0.1 mcg/kg/min

Watch for fever (14%), apnea (12%), and flushing (10%)

Presentation

Varies dependent upon cardiac lesion, though can include:

– Cyanosis

Peripheral/Acrocyanosis: common and benign

Central: always pathologic

– Incomplete oxygenation in the lung

– Abnormal hemoglobin

– Intracardiac shunting

Hyperoxia Test: – Measure pre-ductal (RUE) PAO2 in room air

– Measure again after 5-10 minutes of 100% FiO2

– Strongly consider cyanotic heart disease if PAO2 is <150 mmHg

– Caveat #1: PPHN may also have PAO2 <150 mmHg!

– Caveat #2: Hyperoxia can close a PDA that might be needed!

Presentation

Varies dependent upon cardiac lesion, though can include:

– Murmur

– Tachycardia

– Respiratory distress

Tachypnea, retractions

– Poor feeding and/or inadequate weight gain

Irritability or sweating with feeds

– Shock

Gallop, HSM, poor capillary refill, pallor, weak pulses

Classification

Transposition of the great arteries

Obstructed systemic perfusion

Obstructed pulmonary blood flow

Single ventricle lesions

Heart failure

Transposition of the Great Arteries (TGA)

5-7% of all CHD

Male/female ratio ~3:1

Blood must mix via ASD, VSD, or PDA


Presentation

– 1 day old term male infant with poor feeding & severe cyanosis

– PE: tachypneic, symmetric pulses, single S2, no murmur, no HSM

– “Reverse differential cyanosis”

– ECG: RVH (normal)

– CXR: normal cardiac size, increased pulmonary vascularity

– Hyperoxia Test: PAO2 = 42 mmHg on 100% FiO2

Treatment

– Cath: Emergent balloon atrial septostomy

– Surgical repair: Atrial vs Arterial Switch


Mustard (“Atrial Switch”)


Jatene Procedure (“Arterial Switch”)

Classification





Heart failure


Examples include:

– Coarctation of the aorta


Examples include:

– Critical aortic stenosis


Examples include:

– Interrupted aortic arch

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwiOqNGd-tXTAhWCPCYKHf3nASUQjRwIBw&url=http%3A%2F%2Faccesssurgery.mhmedical.com%2Fcontent.aspx%3Fbookid%3D963%26sectionid%3D55179458&psig=AFQjCNGrZfZDfSY_w_g64wOQ0deYRQJxdg&ust=1493977543766844


Systemic flow is critically compromised when PDA closes

If untreated, will lead to shock and eventually death

Ductal-dependent

– PDA will allow for right to left shunting

Obstructed systemic perfusion Presentation

– 3 day old term infant acutely develops feeding and breathing difficulties

– PE: tachypneic, tachycardic, murmur, gallop, HSM, poor capillary refill and pulses

– Dusky appearance

– ECG: RVH

– CXR: cardiomegaly, increased pulmonary vascularity


Treatment

– Rx: PGE1 infusion; inotropic support; NO Afterload Reduction!

– Eventual catheter-based and/or surgical intervention

Classification





Heart failure


Examples include:

– Tetralogy of Fallot


Examples include:

– Critical pulmonic stenosis


Acute and marked cyanosis

May have adequate perfusion initially (especially if atrial level communication)

Severe cyanosis can induce shock due to limited systemic O2 delivery that alters myocardial function

Ductal-dependent

– PDA will allow for left to right shunting

Obstructed pulmonary blood flow Presentation

– 1 day old term infant initially feeds well and appears healthy, then acutely becomes cyanotic

– PE: tachypneic, increased work of breathing, tachycardic, murmur

– Severely cyanotic

– ECG: RVH

– CXR: decreased pulmonary vascularity


Treatment

– Rx: PGE1 infusion; sedation, preload, B-blockers, phenylephrine, Avoid inotropes!


Classification





Heart failure


Examples include:

– Tricuspid atresia


Examples include:

– Hypoplastic left heart syndrome


Initial presentation as glorified ductal-dependent lesions

– Tricuspid Atresia*: Ductal-dependent pulmonary circulation

– HLHS: Ductal-dependent systemic circulation

Small/underdeveloped ventricle cannot serve as a functional pumping chamber

Must undergo staged repair culminating in a Fontan circulation

* Assuming normally related great vessels

Single ventricle lesions Presentation

– Rapid onset with ductal closure

– Often no murmur!

– Ductal-dependent systemic circulation

Reduced cardiac output

Metabolic acidosis

Profound shock

Respiratory failure

– Ductal-dependent pulmonary circulation

Profound cyanosis

– ECG & CXR: Variable

– Hyperoxia Test: PAO2 < 150 mmHg on 100% FiO2

Single ventricle lesions Treatment

– Rx: PGE1 infusion!

Manipulate SVR with systemic vasodilators

– i.e. Milrinone and Nipride

Manipulate PVR with ventilatory strategies

– Hypoxic gas admixture (FiO2 18%)

– Controlled respiratory acidosis

Optimize hematocrit


Stage 1: Norwood Procedure with Blalock-

Taussig (BT) Shunt or Sano (RV-PA) Conduit

Stage 2: Glenn Procedure

SVC connected to pulmonary arteries

Stage 3: Fontan Procedure

IVC connected to pulmonary arteries

Classification





Heart failure

– Volume overload

Heart failure: volume overload

Examples include:

– Ventricular septal defect


Examples include:

– Atrioventricular septal defect


Examples include:

– Patent ductus arteriosus


Left to right shunting results in “pulmonary overcirculation”

– Wasted of ineffective blood flow

Degree of shunting depends on PVR/SVR ratio

Heart failure: volume overload Presentation

– 3 month old infant with chronic feeding difficulties, failure to thrive, history of respiratory difficulties/pneumonia

– PE: tachypneic, retractions, single loud S2, murmur, HSM, symmetric pulses

– ECG: Biventricular hypertrophy

– CXR: cardiomegaly, hyperinflation, congestion, increased pulmonary vascularity


Heart failure: volume overload Treatment

– Diuretics

– Inotropic support

– Optimize O2 carrying capacity

– Manipulate PVR/SVR ratio

Systemic vasodilators (i.e. ACE-inhibitors)

Optimize hemoglobin to balance circulation

Ventilatory strategies to increase PVR


Ventilatory strategies to manipulate Qp/Qs ratio

Treatment PVR SVR Qp/Qs Ratio

Reduce FiO2 Increase Decrease Decrease

Increase CO2 Increase Decrease Decrease

Reduce pH Increase Decrease Decrease

PEEP Increase Decrease Decrease

Summary

Congenital heart disease is relatively common

Cardiac emergencies are rare

Recognize symptoms early and keep a high index of suspicion

Attempt to categorize the suspected lesion according to presentation and testing results

When in doubt, start PGE1 infusion!

Questions?

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Documents

Cardiac Emergencies in Infants › meetings › 2017fall › guide › program › fil… · Understand the scope of congenital heart disease ... – Strongly consider cyanotic heart