NCC Review Cardiac - Mother Baby University PDF No… · NCC Review Cardiac Tracey Buckley MSN,RNC, ... 2 100% hood for 5-10 minutes ... • ↓ cyanosis with crying = respiratory

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NCC Review Cardiac

Tracey Buckley MSN,RNC, NNP-BC Cape Fear Valley Health System

Topics

•  Transition to Extrauterine Life •  Cyanosis •  Congenital Heart Disease (CHD) •  Clinical Manifestations of CHD •  Therapeutic agents in cardiac

disease

Intrauterine Blood Flow

•  Key Points •  Umbilical Cord = 1 vein and 2 arteries •  Umbilical Vein (UV) - O2 blood from

placenta to fetus •  Umbilical Arteries (UA) - O2 blood from

fetus to placenta •  Right ventricle - main pumping chamber •  Systemic vascular resistance (SVR) - LOW •  Pulmonary vascular resistance (PVR) - HIGH

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Fetal Shunts

•  Ductus venosus – allows for blood to bypass the liver and enter the IVC

•  Foramen Ovale – allows blood to bypass the pulmonary system

•  Ductus arteriosus – allows blood to bypass the pulmonary system

RA

RV

LA

LV

BODY LUNGS

PLACENTA

IVC/SVC PV’s

PA’s

DA

DA

Picture by T. Buckley NNP_BC

Fetal Circulation

Blood Gas Parameters of Umbilical Vessels

Vessel pH pCO2 pO2 % O2 UA 7.35 48 15 30%

UV 7.38 43 27 68%

Normal blood gas parameters in term Newborn (ABG)

pH pCO2 pO2 HCO3 >7.30 40-50 50-70 20-24

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How does the fetus survive ???

•  Fetus tolerates lower pO2 because •  Fetal hemoglobin (Hgb F) has a higher affinity

for oxygen •  Increased Hgb in fetus = increased oxygen

carrying capacity •  Increased ability to utilize glucose by

anaerobic metabolism

RA

RV

LA

LV

BODY LUNGS

PLACENTA

IVC/SVC PV’s

PA’s

DA

DA

Picture by T. Buckley NNP_BC

Hemodynamic Changes at Birth

AfterDelivery

Normal Circulation after birth

Courtesy of Microsoft Office. http://office.microsoft.com/en-us/images/

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Hemodynamic Changes at Birth

•  After delivery • Gas exchange occurs in lungs (not

placenta) • Lungs expand with air PVR

pulmonary blood flow LA pressure (now > RA pressure) FO closes

• SVR increases • Ductus venosus closes (no more blood

flow) • PDA closes

Cardiac Output

•  Cardiac Output = Heart Rate x Stroke Volume •  Factors affecting cardiac output

• Preload • Afterload • Contractility • Heart Rate

•  Stroke Volume: Amount of blood ejected from the LV with each heartbeat

Incidence of CHD

•  8 in 1000 live births •  2 in 1000 presenting <1 year of age

•  2-5% recurrence if a previous child has CHD •  6-7% if mother has CHD •  1.5-3% if father has CHD

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Incidence of specific defects

•  VSD 16% •  Pulmonary stenosis with intact ventricular septum

7.5-12% •  TOF 8-10% •  ASD 10% •  TGA 5-10% •  PDA 4-10% (full-term infants) •  Coarctation of Aorta 5-8% •  HLHS 1.5%

Incidence of specific defects

•  VSD – most common CHD •  TOF – most common CHD beyond infancy •  TGA – most common CHD in 1st week of life •  HLHS – 2nd most common CHD in 1st week of

life and MOST common cause of mortality in 1st week of life

It is only after the maternal circulation is eliminated and the cardiovascular system of the infant becomes independent that the input of the anatomical and hemodynamic abnormalities become apparent

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Clinical Manifestations of CHD

•  Cyanosis***** •  Respiratory Distress****** •  Congestive Heart Failure and diminished cardiac output •  Abnormal rhythm •  murmurs

Central Cyanosis

•  Definition: the absolute amount of reduced hemoglobin

•  Observed when Hgb is reduced by 3-5g/dl •  Anemia decreases clinical appearance •  Polycythemia increases clinical appearance

Six components of oxygen delivery

•  CNS •  Musculoskeletal •  Airways •  Gas exchange interference in the lungs •  Hemoglobin •  CV System

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Central Cyanosis versus Peripheral Cyanosis

Peripheral cyanosis •  Due to poor blood flow to the skin

(acrocyanosis) Central cyanosis

•  Generally due to R to L shunting •  Desaturated venous blood mixes with saturated blood • Decreased blood to the lungs

Left to Right Shunts

• SVR and PVR • Blood takes the path of least resistance • Blood shunts from the oxygenated side to the deoxygenated side (returns to lungs) • Via ASD, VSD, PDA

RA

RV

LA

LV

BODY LUNGS

IVC/SVC PV’s

PA’s

Left to Right Shunts

PVR SVR

ASD/PFO

VSD

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Right to Left Shunts

•  Blood shunts from the deoxygenated side to the oxygenated side (skips the lungs)

•  Examples • Pulmonary atresia: from RV thru PDA to

aorta • Tricuspid atresia: from RA thru ASD to LA • Hypoplastic right heart: from RA thru ASD

to LA •  Usually PATHOLOGIC!!!

RA

RV

LA

LV

BODY LUNGS

IVC/SVC PV’s

PA’s

Right to Left Shunts

PVR SVR

Arterial Sampling Sites

•  Pre-ductal •  R radial

•  Post-ductal •  L radial •  Umbilical •  Lower extremities

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Cardiac versus Pulmonary Cyanosis Hyperoxia Test

1  ABG from right arm in room air 2  100% hood for 5-10 minutes 3  Repeat ABG 4  PaO2 >150mmHg = Respiratory 5  PaO2 unchanged = CHD

Clinical Pearls •  GET A CENTRAL HEMATOCRIT

•  r/o polycythemia as a cause of cyanosis •  ↓ cyanosis with crying = respiratory disease •  ↑ cyansis with crying = CHD •  Be sure you hear a split S2 on cardiac exam •  Respirations

•  Hyperpnea = hypoxia •  Tachypnea = pulmonary edema

Classification of Cardiac Defects •  Lesions which increase pulmonary blood flow

•  Lesions which decrease pulmonary blood flow

•  Lesions which decrease systemic blood flow

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Cyanotic versus Acyanotic Cardiac Defects

•  Cyanotic •  Results in decreased oxygen in blood •  Right to left shunt

•  Acyanotic •  Defect that does not lower blood oxygenation •  Left to right shunts

Physical Exam

•  Heart sounds •  Murmurs •  Pulse Pressure •  Blood Pressure

Heart Sounds

RA

RV

LA

LV

BODY LUNGS

IVC/SVC PV’s

PA’s

S1 Tricuspid/Mitral Valves

Closes

S2 Pulmonic/Aortic

Valves close

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Murmurs

Clipart courtesy of Microsoft Office. Labels by T. Buckley NNP-BC

ULSB

URSB

ICS 1st

4th

2nd

3rd

5th

LLSB Nipple Line APEX

Pulse Pressure

•  Difference between the SBP and DBP •  Widened pulse pressure

•  Most common: PDA, truncus arteriosus •  Narrow Pulse Pressure

•  Most Common: Pericardial tamponade, AS

Blood Pressure

•  Varies with gestational age •  Mean ~ gestational age

•  Cuff selection is very important •  Small cuffs give falsely high values

•  Hypertensive Infant •  Term – SBP >95 •  Preterm – SBP>80

•  Most common cardiac cause of hypertension - Coarctation

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Shock

•  Acute failure of circulatory function •  Characterized by inadequate tissue and organ

perfusion •  Early compensated shock

•  Blood flow preserved to heart, lung, brain, and kidneys

•  Late Decompensated shock •  Tissue ischemia and metabolic acidosis

•  S/S: UOP, HR, BP

CHF •  Inability if the heart to meet the metabolic requirements

of the body •  Etiology of CHF:

•  Volume overload •  Pressure overload •  Cardiomyopathy •  Dysrhythmias

Radiographic Findings of CHD

•  Boot shaped heart TOF •  Egg on a string d-TGA •  Snowman TAPVR

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Congenital Heart Disease

•  Cyanotic Heart Disease •  Left to Right Shunts •  Left and right sided obstructive lesions •  Valvular Disease •  Other abnormalities

Cyanotic Heart Lesions

•  TGA •  TOF •  PA (with intact ventricular septum) •  Truncus Arteriosus •  Tricuspid Atresia •  Ebstein’s Anomaly •  Single Ventricle •  TAPVR •  Double Outlet Right Ventricle

Left to Right Shunts

•  VSD •  ASD •  PDA •  Complete AV canal •  Partial APVR

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Left and Right Sided Obstructive Lesions

•  Coarctation of the Aorta (CoA)

Valvular Diseases

•  Aortic Valve Regurgitation (AR) •  Mitral Valve Regurgitation (MR) •  Tricuspid Valve Regurgitation (TR)

Other Diseases

•  Hypoplastic Left heart syndrome (HLHS) •  Cardiomyopathy •  Eisenmenger’s Complex •  Cor Pulmonale •  Pericardial Effusion

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Prostaglandins •  Maintains patency of the ductus arteriosus in

utero •  Administered to maintain blood flow through the

DA •  TA, PA, severe PS, AS, coarctation or

interrupted aortic arch •  Dosage: 0.05 – 0.10 mcg/kg/min IV •  Adverse effects

•  APNEA •  Vasodilation, hypotension,Thrombocytopenia

Cardiac Tamponade •  Blood, serous fluid, or air, under tension, fills the

pericardial sack, •  Causes life-threatening compromise of

venous return and decreased stroke volume •  Classic signs (Beck’s Triad):

•  Hypotension • Pulsus paradoxus (acute drop in SBP)

•  Jugular venous distention •  Muffled heart sounds

•  Often associated with Central Lines in neonates

Basic Principles of EKG

P wave: Atrial depolarization

QRS complex : ventricular depolarization

T wave: ventricular repolarization

U wave: late phase of repolarization

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ECG Waves

Courtesy of: Anthony Atkielski, public domain.

Cardiac Conduction

Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist.http://creativecommons.org/licenses/by/2.5/

ECG Interpretation

•  1. Measurements •  2. Rhythm analysis •  3. Conduction analysis •  4. Waveform description •  5. ECG interpretation •  6. Comparison with previous ECG (if

available)

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Practice Questions

References •  Fetal Circulation flash videos.

http://www.indiana.edu/~anat550. Permission granted by Valerie O’Loughlin, Associate Professor, Indiana State University.

•  Verklan, M. & Walden. M. (2010). Core curriculum for neonatal intensive care nursing. Saunders/Elsevier.

•  Brodsky, D. & Martin, C. (2003). Neonatology review. Hanley & Belfus.

•  Merenstein, G & Gardner, S. (2002). Mosby. •  Ribcage clipart & Heart Clipart. Courtesy of Microsoft

Office (public). http://office.microsoft.com/en-us/images.

References •  Image: Heart anterior view coronal section. Patrick

J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist. Permission: Creative Commons Attribution 2.5 License 2007. (http://creativecommons.org/licenses/by/2.5/ ). http://en.wikipedia.org/wiki/File:RLS_12blauLeg.

•  Schematic diagram of normal sinus rhythm for a human heart as seen on ECG. (2007). Agateller (Anthony Atkielski). Permission: Public Domain. http://en.wikipedia.org/wiki/File:SinusRhythmLabels.svg