Catherine Bull M.S.N, P.N.P-CClinical Coordinator, Pediatric and Adult Congenital Cardiac Surgical ServicesDepartment of Cardiothoracic SurgeryNYU Medical Center

Qp Pulmonary blood flow~ 1 cup

Qp:Qs ratio is the amount of blood going to the lungs compared to the amount of blood going to the body.

Qp : Qs (LUNGS : BODY)

Qp : Qs 1 : 1

Qs Systemic blood flow~ 1 cup

Blood flow to the body or the lungs is not 100% ductal dependent

Transposition of the Great Arteries

Truncus ArteriosusTotal Anomalous Venous return

TGA : Aorta arises

from the anatomic RV

PA arises from the anatomical LV

NORMAL

• Parallel circulations• Mixing can occur at

PFO, PDA or VSD• Most mixing occurs at

the PFO• Without a mixing:

– cyanosis, hypercarbia, tachypnea, tachycardia and acidosis may occur

nn

To increase SaO2 you must increase mixing: PGE to

open duct BAS Volume Oxygen

PDAPDA PFOPFO

NORMAL

Arterial Switch The aorta and the PA

are transected and the coronary arteries are removed.

The aorta and the coronary arteries and attached to the neoaortic root

PA is attached to the neopulmonary root

Decreased LV function Coronary ischemia Nitroglycerine/Heparin

▪ Usually a surgical problem In older patients with IVS whose LV only

exposed to pulmonary pressures pre-operatively

Decreased cardiac outputArrhythmias

Failure of pulmonary veins to connect to the to the LA

Blood from both the systemic and pulmonary venous systems return to the RA the RA, RV & pulmonary

arteries enlarge to compensate for the increased volume

An ASD is essential for CO and always present

NORMAL

Supracardiac: pulmonary veins attach to SVC.

NORMAL

Cardiac: pulmonary veins attach directly to the heart via RA or coronary sinus

NORMAL

Infracardiac: pulmonary veins attach below the diaphragm. Prone to obstruction.

NORMAL

• Unobstructed:Unobstructed:– May be asymptomatic at first– CHF, FTT & frequent upper

respiratory infections will occur

SupracardiacSupracardiac

InfracardiacInfracardiac

• Obstructed:Obstructed:― Profound cyanosis within

the first few hours of life ― Typical “ground glass”

CXR― No PGE― Surgical Emergency

CXR: Typical “ground

glass” appearance of lung fields

Small heart

Attach pulmonary vein confluence to posterior LA and close the ASDLigate the vertical vein

•Create a large ASD and baffle veins from the RA to LA

Unroof coronary sinus and baffle pulmonary venous return to the LA

•Attach pulmonary vein confluence to posterior LA•Ligate the vertical vein•Close the ASD

Low cardiac output: Noncompliant LV. Treated w/ inotropes. Avoid aggressive volume overload-unresolved

LA hypertension & PHTN. PHTN:

r/o pulmonary venous obstruction. Ventilation, O2, NO & sedation to decrease PVR.

Respiratory failure: Due to obstructed veins preop and resultant

pulmonary vascular congestion. Treated with mechanical ventilation, paralysis,

sedation, PEEP & possibly ECMO. Re obstruction

occurs in 10% of patients-usually obstructed infracardiac type

CHF, mild cyanosis & FFT within the first month of life.

Can develop pulmonary hypertension by 3 months.

NORMAL

The pulmonary arteries are excised from the truncus

RV to PA conduit placed

VSD is closed in a manner in which the truncal valve recieves blood from the left ventricle

PHTN: preop overcirculation results in PA

pressures=>Paralyze, sedate, O2 and NO. Low CO:

RV dysfunction=> volume (need a high CVP), inotropes & vasodilators.

Cyanosis: RL PFO =>will resolve with RV function.

Pulmonary blood flow is ductal dependant

Tetralogy of Fallot

Pulmonary Atresia

w/ Intact Ventricular

Septum

Tricuspid Atresia

Regular Pulmonary Atresia Real Pulmonary Atresia Pulmonary Atresia w/ MAPCA’s

TOF is characterized by 4 cardiac anomalies: Ventricular septal defect Pulmonary stenosis or

pulmonary atresia/right ventricular outflow tract obstruction (RVOTO)

Overriding aorta Right ventricular

hypertrophy

Hemodynamics depends on the amount of PS and the size of the VSD Severe PS: Cyanotic

▪ RL shunt▪ Qp<Qs

Mild PS: Pink Tet▪ LR shunt▪ Qp>Qs▪ CHF

NORMAL

Patch closure of VSD Relieve RVOTO

Resect muscle below the valve

Enlarge the pulmonary artery above the valve

OR transannular patch

with removal of valve

• RV dysfunction– Inotropes – May have pleural effusions (esp. right) and ascites

• Junctional Eptopic Tachycardia– PREVENTIONPREVENTION– keep HR low with cooling, no chronotropic drugs,

sedation– Amiodarone

• CyanosisCyanosis– due to right to left shunt across PFO if present

• Pulmonary insufficiency– all patients with transannular patch

• Residual VSD– not well tolerated

• Residual RVOTO– well tolerated

Pulmonary valve & main pulmonary artery are atretic

Pulmonary blood flow is supplied by PDA (most

common) multiple

aortopulmonary collateral arteries (MAPCAs)

TOF/PATOF/PA

TOF/PA w/ MAPAC’sTOF/PA w/ MAPAC’s

Blalock-Taussig Shunt followed by full repair later in infancy

Pulmonary valve atresia with no VSD

Hypoplastic RV (Variable) Size of the RV is determined

by the size of the TV High RV pressure RV sinusoids (Variable)

May form due to high RV pressure.

Steal coronary blood flow from CA

NORMAL

RV SinusoidsRV Sinusoids

Need to do 2 things: establish pulmonary blood flow and get the RV to grow Pulmonary valve balloon angioplasty

▪ Works best when the leaflets of valve are only fused

BTS Transannular patch

2 Ventricle Repair (Adequate RV without sinusoids) Balloon angioplasty +/- BTS

1 ½ Ventricle Repair (Borderline RV +/-sinusoids) +/- Balloon angioplasty BTS +/- Transannular patch

Single Ventricle Repair (Inadequate RV +/- sinusoids) BTS

Borderline RV +/-sinusoids: BTS & transannular patch

to allow pulmonary insufficiency and subsequent RV growth.▪ Adequate RV growth:

complete repair▪ Inadequate RV growth:

Bidirectional Glenn procedure (1 ½ ventricle repair)

The tricuspid valve is absent w/ no communication between the RA and RV

Results in RV and PA hypoplasia and a single left ventricle

NORMAL

No VSD, PA, hypoplastic RV Pulmonary blood flow is ductal dependant

Small VSD, hypoplastic PV, hypoplastic RV (most common) Pulmonary blood flow is ductal dependant

Large VSD, small to adequate PV & RV Qp:Qs is variable

Cyanosis, hypoxemia and metabolic acidosis usually occur within the first few days of life if pulmonary blood flow is not adequate and the PDA closes. Qp<Qs

Management strategies should be aimed at balancing pulmonary and systemic blood flow to maintain Qp=Qs.

Blalock Taussig Shunt Pallative shunt

between the right innominate artery and the RPA that provides pulmonary blood flow.

Variable Qp:Qs

Blood flow to the body is ductal dependant

Coarctation of the Aorta Interrupted Aortic Arch Hypoplastic Left Heart Syndrome

Systemic blood flow is ductal dependant

Blood to the upper body comes from the LV & aorta: pre-ductal sats are higher

Blood to the lower part of the body comes from the PA and PDA: post-ductal sats are lower

Decreased peripheral perfusion & metabolic acidosis if duct closes

NORMAL

Type A= awayType BType C= close

End-to-end anastomosis w/ PDA ligation

Pulmonary hypertension

Issues related to DiGeorge Syndrome

Recurrent laryngeal nerve palsy

Pherenic nerve damage

Recurrent stenosis at site of repair

Underdevelopment of the left side of the heart due to:1. Mitral stenosis/atresia2. Aortic stenosis/atresia 3. Hypoplastic left

ventricle4. Hypoplastic aortic arch

100% of systemic blood flow is ductal dependent

NORMAL

The amount of blood flow to the pulmonary and systemic circulations depends on the relationship between SVR & PVR

As PVR falls blood will naturally go to the lungs & away from the body

NORMAL

• 1st few days of life: well appearing baby (Qp=Qs) Sat 80% Pink and warm

• As the ductus closes blood flows into the lungs resulting in CHF and decreased cardiac output. (Qp>Qs 3:1) Sat >90%– Ashen, tachypeanic, cool, difficulty feeding

• There is progressive deterioration resulting in pulmonary edema and cardiogenic shock. (Qp>>Qs 5:1)– Metabolic acidosis, cold & gray

Prevent the natural progression Lower the systemic vascular resistance Give extra circulating blood volume

The sick neonate requires aggressive intervention Goal is to re-establish systemic perfusion

(Qp:Qs=1) and provide blood flow to the systemic organs▪ Lower the systemic vascular resistance▪ Give extra circulating blood volume

BT ShuntBT Shunt Sano ShuntSano Shunt

1. Creation of Neoaorta

2. Oversew MPA

3. Atrial septectomy

4. BTS/Sano

Patient Management

Systemic blood flow is grossly indicated by Lactate and BE/BD on ABG. BD < -2 or Lactate > 2 indicates

metabolic acidosis and too little systemic blood flow.

BE > 0 or Lactate < 2 indicates adequate systemic blood flow.

Pulmonary blood flow is indicated by PaO2 on ABG. PaO2 > 50 indicates too much PBF PaO2 < 30 indicates too little PBF

O2 Sats = pulmonary blood flow (gross measurement)

O2 Sat 80%= Qp:Qs of 1:1 Sats > 90%: too much pulmonary blood

flow Sats < 75%: too little pulmonary blood

flow

O2 Sats in patients with single ventricle physiology tell you how much blood is going to the lungs-not necessarily how well the lungs are working.

(ABG sat) (VBG sat)

Ao Sat SVO2 Qp/Qs= 80% - 60% =20=1

100% - 80% 20 1PV sat PA sat(Assumed) (ABG sat)

Not enough cardiac output Sats>90% Poor peripheral perfusion Cool extremities Tachypnea Diaphoresis Poor weight gain “Norwood gray”

Too little pulmonary blood flow Sats < 75% Bounding pulses Cyanotic with good perfusion “Blue is better than gray!”

What affects Qp:Qs? Systemic vascular

resistance (SVR) Pulmonary vascular

resistance (PVR)

Always Remember BLOOD FLOWS THE PATH OF LEAST RESISTANCE

• Too little cardiac output Lactate > 2.5, Sats>90%, PaO2 > 50

decrease the SVR or increase PVR

• Too little pulmonary blood flow Sats<75%, PaO2 < 30

decrease the PVR or fill the tank*be very careful of increasing SVR in patients with

single ventricle physiology— DON’T DO IT!

The easiest way to increase CO is to vasodilate the patient

Other ways to manipulate PVR & SVR Temperature FiO2 Ventilator changes Sedation

Factors that PVR Factors that PVRHypoxia PaO2 (NITROGEN) Hyperoxia PaO2 (OXYGEN)Hypoventilation PaCO2 Hyperventilation PaCO2 Hypothermia Normothermia

Agitation Analgesics

Factors that SVR **Factor that SVR**Hypothermia NormothermiaAgitation Analgesics/sedationCatecholamines (high dose dopa, epi) Vasodilators (Milrinone)

 

NO

In all post-op patients w/ single ventricle physiology you MUST do two things ….

1. Ask yourself “is the patient warm, well perfused and non-acidotic?” If so then STOP and revaluate whatever you where going to do next.

2. Relearn how to read an ABG– 7.31/35/58/-4; lactate :5 like this?– lactate :5; -4/58/35/7.31 or like

this?

• Sat 75-90%, PaO2 35-50, BE > 0, Lactate < 2.5

• Investigate, correct and reinvestigate any metabolic acidosis

• Afterload reduction: • Milrinone 0.25-0.75 mcg/kg/min

• Volume: • Based on perfusion and acid base

status• Anticipate volume requirement

• Hgb= 13-15…..always above 11

• Normal sinus rhythm• Normothermia to slightly

cool but not hot

Avoid unnecessary noxious stimuli No baths or weights on night shift Cluster cares No excessive crying or IV sticks

Normothermia Avoid dehydration Weight gain- calories, calories, calories….

3KG baby needs 60 cc q 3h of 24 cal/oz formula to achieve 130 cal/kg/day- we do not always get here prior to DC

NG/PO feedings to achieve 10g/day wt gain

AcidosisArrhythmiasAnemiaSats > 93%Sats < 70%Dehydration

A ventricle that is working double time

Variable cardiac output Increased caloric

requirement/difficulty feedingTachypneaA need for close supervision/follow-

upA risk for sudden death

• Stressful hospitalization– Fetal dx: long time to think and web surf

– Antenatal dx: no time to prepare

– Long hospitalization: 14-36 days

• Transition home– Most fragile between the 1st and 2nd stage

• Must have scale and pulse ox prior to DC

– 20% risk of death prior to the second stage– Close follow-up by NP’s in clinic in addition to

Nutritionist• Anticipation of future surgeries

High Risk Patient population: Single Ventricle requiring staged

repairs Hybrid procedures and palliations MBT shunts PA, VSD, MAPCAs Other complex lesions including

heterotaxy syndrome

Approximately 7 to 15% of these infants will die unexpectedly at home before Stage 2.

Possible Causes Coronary artery obstruction or spasm Aortic arch obstruction Low cardiac output Arrhythmia Shunt thrombosis Sepsis or infection

Predictors Intact atrial septum Older age at the time of surgery Post op arrhythmias Airway complications Decreased ventricular fx pre and post op Anatomic subtypes

▪ Aortic atresia▪ Small ascending aorta diameter

Infants with Complex Single Ventricle have significant growth failure after Stage I palliation.

Only 3.6% at or above 50th percentile in weight at the time of Stage II palliation (Atz et al, 2004)

Feeding difficulties and inadequate nutrition can strongly influence outcomes!

All Single Ventricle patients go home with a scale and pulse ox

Family keeps daily log of feeding, weight and O2 saturations

Monitored by NPs either by phone or in high risk clinic

Family has “red flags” to call for: Weight loss: 30

grams of weight in one day

Lack of weight gain: 20 grams of over 3 days

O2 sats drop below 70%

Weekly visits after discharge x 4 weeks Every other week visits until Pre-Glenn

Cath (~3-4 months of age). Special attention to Sats, weight,

vomiting, diarrhea, feeding difficulties, URI

Monitor Pulse oximetry Weight BP Echocardiogram as necessary

Monthly Monitor EKG, Chest X-ray

Reduce interstage mortality to 0% Improved nutritional status and

weight gain will positively influence timing of Stage II palliation and outcome of surgical treatment.