SHN2004 - Circulation
Circulation
Circulation in children
The primary function of the cardiovascular system is to transport oxygen, nutrients, and
substrates around the body, thus ensuring that the appropriate amounts of these
products are present to meet metabolic demands within the cells.
The prime determinant of efficacy of the transport system is cardiac output.
Cardiac output is the amount of blood that is ejected from the heart every minute and is
the product of the equation.
HEART RATE X STROKE VOLUME
Stroke volume is the amount of blood that is ejected from the heart with each beat and
is affected by three factors.
- Preload: affected by the volume status of the child.
- Afterload: impacted by the systemic vascular resistance
- Contractility: the power created by the heart muscle to pump blood around the
body.
In infants and children cardiac output is influenced by heart rate rather than stroke
volume.
Infant heart muscle is less compliant, which means it has a limited ability to distend or
expand to increase stroke volume, therefore children rely on increased heart rate to
increase cardiac output.
Therefore, cardiac output is increased during periods of stress, exercise, pyrexia, or
respiratory distress.
Definitions
Bradycardia – is a slow heart rate.
Perfusion – is the process of oxygenated blood being delivered to the tissues.
Shock – means the condition of low blood perfusion to the tissues, resulting in celluar
injury and inadequate tissue function.
Sepsis – is defined as life threatening organ dysfunction caused by deregulated host
response to infection.
Supraventricular tachycardia – is the most common arrhythmia (abnormal heart rhythm)
diagnosed in children. When a child has SVT, the heart suddenly starts to beat very fast,
at rates of 180 to 280 beats a minute and up to 300 beats a minute in infants.
Intravascular – means within the blood vessels or blood vascular system
Interstitial – refers to something within the interstices (between structures) so the
interstitial space is the gaps between cells within the tissues.
Arrhythmia – is a condition in which the heart beats with an irregular or abnormal
rhythm.
Circulatory failure and shock
The most common causes of circulatory causes of circulatory failure in children are:
- Hypovolaemia – decreased circulatory volume caused by severe fluid loss
(dehydration) or haemorrhage.
Circulation
Circulation in children
The primary function of the cardiovascular system is to transport oxygen, nutrients, and
substrates around the body, thus ensuring that the appropriate amounts of these
products are present to meet metabolic demands within the cells.
The prime determinant of efficacy of the transport system is cardiac output.
Cardiac output is the amount of blood that is ejected from the heart every minute and is
the product of the equation.
HEART RATE X STROKE VOLUME
Stroke volume is the amount of blood that is ejected from the heart with each beat and
is affected by three factors.
- Preload: affected by the volume status of the child.
- Afterload: impacted by the systemic vascular resistance
- Contractility: the power created by the heart muscle to pump blood around the
body.
In infants and children cardiac output is influenced by heart rate rather than stroke
volume.
Infant heart muscle is less compliant, which means it has a limited ability to distend or
expand to increase stroke volume, therefore children rely on increased heart rate to
increase cardiac output.
Therefore, cardiac output is increased during periods of stress, exercise, pyrexia, or
respiratory distress.
Definitions
Bradycardia – is a slow heart rate.
Perfusion – is the process of oxygenated blood being delivered to the tissues.
Shock – means the condition of low blood perfusion to the tissues, resulting in celluar
injury and inadequate tissue function.
Sepsis – is defined as life threatening organ dysfunction caused by deregulated host
response to infection.
Supraventricular tachycardia – is the most common arrhythmia (abnormal heart rhythm)
diagnosed in children. When a child has SVT, the heart suddenly starts to beat very fast,
at rates of 180 to 280 beats a minute and up to 300 beats a minute in infants.
Intravascular – means within the blood vessels or blood vascular system
Interstitial – refers to something within the interstices (between structures) so the
interstitial space is the gaps between cells within the tissues.
Arrhythmia – is a condition in which the heart beats with an irregular or abnormal
rhythm.
Circulatory failure and shock
The most common causes of circulatory causes of circulatory failure in children are:
- Hypovolaemia – decreased circulatory volume caused by severe fluid loss
(dehydration) or haemorrhage.
