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26 Cards in this Set
- Front
- Back
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Changes in the CVS during Pregnancy in relation to blood volume |
1. Maternal volume increases by 45% for single, 75-100% in twins or triplets 2. Increase due to both plasma and erythrocyte volume 3. Increased volume need to meet demands of enlarged uterus, protect against impaired venous return and blood loss during parturition (Child Birth) |
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Changes in CVS during pregnancy in relationship to Cardiac Output |
1. Main increase from SV but also from Heart Rate 2. 35-40% increase in first trimester, 45% by third trimester 3. Increase in renal, uterine, heart, skin, and breast blood flow. |
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Changes in the CVS during pregnancy in relation to blood pressure |
1. Systemic Arterial pressure falls during first trimester, reaches lowest in mid pregnancy then returns to normal 2. Decrease in blood pressure as a result of a fall in systemic vascular resistance |
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What causes the decrease in blood pressure |
1. Gestational hormonal activity 2. Increased heat production by the developing fetus 3. formation of a low resistance circulation in the uterus. |
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Hemodynamic Changes during labor |
1. Alteration result of uterine contractions, pain and anxiety 2. CO rises because increased SV and HR 3. Increase in Systolic and Diastolic BP |
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Hemodynamic changes postpartum |
1. Tempory increase in Venous return results in a raised Stroke Volume and Cardiac Output 2. Mean Bloop Pressure and Stroke volume return to normal within 24 hours |
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What functions does the placenta replace |
1. Lungs - Gas Exchange 2. G.I.T - Nutrition 3. Liver - Nutrition and Waste removal 4. Kidneys - Fluid electrolyte balance, waste removal |
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What are the four shunts in fetal circulation |
1. Placenta 2. Ductus Venosus 3. Foramen Ovale 4. Ductus Arteriosus |
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Circulatory Related Causes of Hypoxemia after birth |
1. Pulmonary vascular resistance and pressure remains high 2. Ductus Arteriosus remains Patent 3. Patent Ductus Arteriosus maintains a right to left shunt |
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What are the three responses of the fetal Cardiovascular system responses |
1. Tansient mild hypoxemia 2. Worsening of hypoxemia 3. Prolonged hypoxemia |
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What is the Response to Transient mild hypoxemia by the fetal CVS
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Chemoreceptors in the carotid arteries and aortic arch trigger the brain to stimulate the sympathetic system. This stimulation increases catecholamines causing an increase in fetal heart rate and variability |
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What is the response to worsening hypoxemia by the fetal CVS |
Peripheral arterial vasoconstriction causing systemic hypertension. Baroreceptors then respond by signaling the brain stem to give vegal stimulation lowering the Fetal Heart Rate and Acceleratoins |
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What is the response to prolonged hypoxemia by the fetal CVS |
Loss of baseline variability, followed by bradycardia and late decelerations. Fetus may be acidotic and fetal breathing movement and body tone may be lost. |
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Normal Baseline Fetal Heart Rate |
130 to 140 beats per minute with preserved beat to beat and long-term variability Accelerations peak at 15 beats per minute and last about 15 seconds |
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What is early deceleration |
Decrease in heart rate. Usually coincides with the start and stop of a labor contraction |
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What is late deceleration |
Decrease in fetal heart rate that begins after the contraction has ended. Repeated contractions have a more shallow and subtle deceleration |
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What is Late deceleration with loss of variability |
like late deceleration but no variability in baby's heart rate Ominous pattern and requires immediate delivery |
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What can cause a late deceleration |
Uterine contractions reducing placental-fetal blood flow |
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What can cause variable deceleratoin |
Compression of the umbilical cord reducing blood flow |
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What can cause early deceleration |
1. Fetal head compression causing increased intracranial pressure 2. Reflexive slowing of the Fetal Heart Rate |
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Results of moderate to large Patent Ductus Arteriosus |
1. Pulmonary Edema 2. Hemorrhage 3. Bronchopulmonary Dysplasia |
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Clinical Features of PDA |
1. Symptoms develope 2 - 3 days after birth 2. Murmur heard initially only in systole 3. Later murmur hear in systole and diastole (continuous murmur - machinery) 4. Prominent Left Ventricle Impulse 5. Bounding pulses w/ high pressure |
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What is persistent Left to Right Shunting |
Left to right shunting of blood that occurs in neonates until the septum primum and septum secundum fuse (age 2) Not considered an Atrial Septal Defect because no septal tissue is missing |
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What is a paradoxical embolism |
An embolism that would normally get lodged in the lungs travels through the patent foramen ovale and causes a stroke |
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What is Persistent Pulmonary Hypertension (PPHN) |
When pulmonary vascular resistance remain abnormally high after birth Leads to continued Right - Left Shunting causing Hypoxemia |
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Clinical Features of Persistent Pulmonary Hypertension |
1. Primary finding is Cyanosis associated with tachypnea and respiratory distress 2. Cardiac examination reveals loud, single second heart sound or harsh systolic murmur secondary to tricuspid regurgitation 3. May present with systemic hypotension and symptoms of shock, poor cardiac function and perfusion |
