Transcript 09 Embriogenesis of cardiovascular system

Physiologic anatomical
peculiarities of the heart and
blood vessels in children.
Percussion of theDoc.
heart.
Nykytyuk S.O.
Timeline for development of the heart
Paired endocardial
tubes form in
cardiogenic region of
splanchnic
mesoderm
Fuse to form a single
heart tube
Ectoderm - blue
Mesoderm - red
Endoderm - yellow
Four layers contribute to the wall of the heart tube
Lumen of
heart
Constrictions & expansions foreshadow adult heart
Development of the septae of the heart
• The single heart tube is divided into four
definitive chambers by internal partitioning
during weeks 4-7
1. Interatrial
2. Atrioventricular
3. Interventricular
4. Ventricular outflow tract
• Many congenital heart defects arise during
septation
Fetus
Neonate
Fetal and neonatal circulatory systems:
shunts and changes at birth
1. Fetal foramen ovale shunts blood from right to
left atrium
•Adult remnant is fossa ovalis
2. Fetal ductus arteriosus shunts 90% of blood from
pulmonary trunk to aorta
•Adult remnant is ligamentum arteriosum
3. Fetal ductus venosus shunts 50% of blood from
umbilical vein to inferior vena cava by passing liver
•Adult remnant is ligamentum venosum
Differences in circulatory systems
Prenatal:
•
•
•
•
Little pulmonary blood flow
Gas exchange via placenta
Nutrient delivery to fetus through placenta
Right to left shunting of blood in heart
Postnatal:
• Functional pulmonary respiration and gas
exchange
• Loss of placental circulation
• Occlusion of right to left shunt in heart and
fetal anastomoses
Congenital heart defects
• Most common type of congenital malformations
• Incidence of nearly 1% of live births
• Causes elusive, multifactoral: single gene &
chromosome defects, environmental factors,
viruses, toxins, alcohol, drugs
• Specific etiology unknown in many cases but most
arise during critical period of heart dev. 20-50
days after fertilization
• Well tolerated before birth because of fetal shunts
• Most produce symptoms postnatally
FIGURE 26–1 Fetal circulation. Blood leaves the placenta and enters the fetus through the umbilical vein. The ductus venosus, the
foramen ovale, and the ductus arteriosus allow the blood to bypass the fetal liver and lungs. After circulating through the fetus, the blood
returns to the placenta through the umbilical arteries. From Ladewig, P. W., London, M. L., Moberly, S., & Olds, S. B. (2002).
Contemporary Maternal-Child Nursing Care (8th ed,. p. 51 ). Upper Saddle River, NJ: Prentice Hall.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
FIGURE 26–2 A, Fetal (prenatal) circulation. B, Pulmonary (postnatal) circulation. LA, left atrium; LV, left ventricle; RA, right atrium;
RV, right ventricle.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
Normal pressure gradients and oxygen saturation levels in the heart chambers and great
vessels. The ventricle on the right side of the heart has a lower pressure during systole than the left
ventricle because less pressure is needed to pump blood to the lungs than to the rest of the body.
FIGURE 26–3
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
THE PECULIARITIES
OF INTRAUTERINE CIRCULATION.
Superior
vena
cava
Pulmonai
artery
Plumonary
vein
Descending
aorta
Inferior vena cava
Postnatal circulation.
Spumoni
artery
Pulmonary
vein
Ligamentum
teres
Conductive system of heart
2 – SA node;
3 – Bachman tract;
4 – tracts of Bachman,
Venkebach,
Torel
6 – AV node
7 – Hiss bungle
8 – right leg of Hiss bungle
9 – anterior brunch of left leg of
Hiss bungle
10 – posterior brunch of left leg of
Hiss bungle
11 - Kent bungle
12 – Jams bungle
Cardiac cycle
Systole
• 1. period of tension
•
asynchrony contraction
•
isometric contraction
•
(all valves are closed)
• 2. period of ejection
•
protosphigmic interval
(opening of semilunear valves)
•
fast ejection
•
slow ejection
Cardiac cycle
Diastole
• 1. Period of relaxation
•
protodiastolic interval (closing of
semilunear valves)
•
phase of isometric relaxation
(opening of AV-valves is end of this phase)
• 2. Period of filling
•
phase of rapid filling
•
phase of slow filling
•
phase of filling by help of atrium
systole
Hypoxemia in the infant
• below 95% pulse oximetry.
• cyanosis results from hypoxemia
• perioral cyanosis indicates central
hypoxemia
• acrocyanosis does not.
ASSESSMENT OF HEART
DISORDERS IN CHILDREN


History
Physical
assessment
general
appearance
 pulse, blood
pressure, &
respirations

Hypoxemia in the infant




below 95% pulse oximetry.
cyanosis results from hypoxemia
perioral cyanosis indicates central hypoxemia
acrocyanosis does not.
clinical symptoms

Generalised moderate
peripheral cyanosis in
a shocked new
born with vasomotor
instability and poor
lung expansion.
clinical symptoms
A‘ blue baby' There is
severe peripheral and
central cyanosis.
Post-mortem revealed
Fallot's tetralogy. Note
the malformed low-set
ear.
clinical symptoms
Severe peripheral and
central cyanosis
Convulsion
was produced by
increased hypoxia after
prolonged crying. Postmortem revealed atresia
of the pulmonary artery
and a single ventricle.
clinical symptoms
“pitting” edema
Abnormal Pulse patterns
Pulse patterns
Water hammer
Description
Very forceful and bounding pulse
(Corrigan's pulse)and capillary
pulsation may be apparent even in
the fingernails suggest cardial
insufficiency, as in patient ductus
arteriosus
Pulsus alternant
Dicrotic
Adouble radial pulse for every
apical beat, symptomatic of aortic
stenosis
Average pulse rates at rest (beats per minute)
Newborn
6 months
1 year
2 years
3 years
140-160
130-135
120-125
110
105
4 years
5 years
6-7 years
10 years
12 years
100
98-100
90-85
78-85
70-75
The normal rate is not
more then 10 % of
average
Blood pressure, mmHg
Upper extremity
Newborn
systolic: 70-76
diastolic: 35
For children younger
12 months
systolic: 76 + 2 x n (n is
age in months)
diastolic: 1/2-1/3 of
systolic
Lower extremity
Newborn
systolic: 70-76
diastolic:35
For children younger 9
months
systolic: 76 + 2 x n (n is
age in months)
diastolic: 1/2-1/3 of
systolic
Blood pressure, mmHg
Upper extremity
1 year
systolic:90-100
diastolic: 60
For children older 1 year
systolic: min. 90 + 2 x n (n is
age in years)
max. 100 + 2 x n (n is
age in years)
diastolic: 1/2-1/3 of systolic
Lower extremity
In children older 9-10
months
the blood pressure is 5-20 mm
Hg more than upper
extremity
Hypotension

Blood Pressure

Lowest acceptable systolic blood pressure
Birth – 1 month: 60 mmhg
 1 month – 1 year: 70 mmhg
 1 year – 10 year: 70 + (2 X age in years)
 >10 years : 90 mmhg


Normal systolic
80 + (2 x age in years)
 or fiftieth percentile

Border's of heart relative
dullness
Border
Right
Upper
Left
until 2 years
•right parasternal line
•the II rib
•2 cm outward from left
midclavicular line
Transvers
•6-9 cm
Border
Right
Upper
Border
Right
Border
Right
Upper
Left
older 12 years
•the right sternal line
•the III intercostals space
•0.5 cm medially from left
midclavicular line
Transversal
size
•9-14 cm
al size
7-12 years
•Between the right parasternal line and the right sternal
line
Upper
Left
Transversa
l size
•the III rib
•0.5 cm outward from left
midclavicular line
•9-14 cm
Left
Transversal
size
2-7 years
•right parasternal line
•the II intercostals
space
•1 cm outward from left
midclavicular line
•8-12 cm
Border's of heart absolute
dullness
Border
Right
Upper
Left
until 2 years
•left sternal line
•the II intercostal space
•1.0-0.5 cm outward from
left midclavicular line
Transvers •2-3 cm
al size
Border
Right
Upper
Left
Transversa
l size
7-12 years
•left sternal line
•the III intercostal space
•Between the left
midclavicular line and left
parasternal line
•5-5.5 cm
Border
Right
Upper
Left
2-7 years
•left sternal line
•the III rib
•left midclavicular line
Transversal
size
•4 cm
Border
Right
Upper
Left
Transversal
size
older 12 years
•left sternal line
•the IV rib
•left parasternal line
•5-5.5 cm
Clinical symptoms


Tachycardia
Bradycardia
Pulsus alternans

Pulsus bigeminus





Increased rate
Decreased rate
Strong beat followed by
weak beat
Coupled rhythm in
which beat is felt in pairs
FIGURE 26–13 Clubbing of the fingers is one manifestation of a cyanotic defect in an older child. What neurologic signs may be
associated with such a defect?
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
Blue-or-tet-spells
FIGURE 26–12
Place the infant who has a hypercyanotic spell in the knee–chest
position. This position increases systemic vascular resistance in the lower extremities.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
FIGURE 26–10
A child with a cyanotic heart defect squats (assumes a knee–chest
position) to relieve cyanotic spells.
Jane W. Ball and Ruth C. Bindler
Child Health Nursing: Partnering with Children & Families
© 2006 by Pearson Education, Inc.
Upper Saddle River, New Jersey 07458
All rights reserved.
Thank you for attention