Questions and Answers
What is perfusion?
the flow of blood through arteries and capillaries delivering nutrients and oxygen to cells
What does perfusion require?
the heart to generate sufficient cardiac output to transport blood through blood vessels for distribution in the tissues throughout the body
What is a key factor to optimal perfusion?
cardiovascular health
What is myocardial ischemia?
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What is death of myocardial tissue with an inability to regenerate?
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What can lead to changes in perfusion?
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What is cardiac output?
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What is central perfusion?
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When does central perfusion begin?
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What is normal cardiac output (CO)?
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What two factors contribute to CO?
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What is preload?
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What is preload influenced by?
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What is tissue perfusion?
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How is tissue perfusion supplied?
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What is created by the force of ventricular contractions?
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Is the pressure higher in veins or arteries?
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What are infant cardio considerations?
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What are older adult cardio considerations?
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What factors decrease cardiac output?
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What do central perfusion problems result from?
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If SVR is sustained what will it lead to?
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What will result from significant reduction in central perfusion?
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What does impaired tissue perfusion result from?
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What will result if the blood flow to the myocardium is constricted?
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What does malfunction of heart valves impair?
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What is shock?
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When does shock occur?
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What causes impaired tissue perfusion?
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What are examples of dilation?
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What can occlude arteries and veins?
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What does impaired tissue perfusion interfere with?
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Study Notes
Overview of Perfusion
- Perfusion refers to the circulation of blood through arteries and capillaries, delivering oxygen and nutrients to cells.
- Effective perfusion necessitates adequate cardiac output generated by the heart to pump blood through the vascular system.
Factors Affecting Perfusion
- Cardiovascular health is critical for optimal perfusion.
- Myocardial ischemia occurs when blood supply to the heart is restricted, leading to insufficient oxygen for heart tissue.
- Myocardial infarction (MI) results in the death of heart muscle tissue with no regeneration ability.
- Conditions such as shock, hypertension, heart failure, and stroke can significantly alter perfusion.
Cardiac Output and Central Perfusion
- Cardiac output (CO) is the volume of blood the heart pumps per minute, normal values range from 4 to 6 L/min in adults.
- CO is determined by stroke volume (amount of blood ejected with each heartbeat) and heart rate.
- Central perfusion initiates when an electrical impulse stimulates the heart, leading to ventricular contractions and proper blood flow through arteries and back to the heart.
Preload and Tissue Perfusion
- Preload is the volume of blood in the ventricles at the end of diastole, influenced by myocardial fiber stretch and systemic blood return.
- Tissue perfusion is the blood volume flowing through target tissues, supplied by arteries to capillary networks.
Hemodynamics and Pressure
- Capillary hydrostatic pressure is created by ventricular contractions, driving blood through capillaries to deliver essential nutrients.
- Arterial pressure is consistently higher than venous pressure, facilitating effective blood flow.
Age-Related Considerations
- Infants display lower systolic pressure due to underdeveloped cardiac function; arteries and veins adapt in length as they grow.
- Older adults experience arterial stiffening, leading to increased blood pressure and workload on the heart; decreased cardiac output may result in postural hypotension and falls.
Impairments to Cardiac Output and Perfusion
- Reduced cardiac output can stem from alterations in myocardial conduction.
- Central perfusion issues may arise from increased systemic vascular resistance (SVR) and blood viscosity.
- Sustained high SVR can lead to inadequate central perfusion, escalating to shock, characterized by a failure in delivering necessary blood to peripheral tissues.
Mechanisms of Impaired Tissue Perfusion
- Impaired tissue perfusion occurs due to poor central perfusion or localized issues such as vessel blockages.
- Constricted blood flow to the myocardium can trigger myocardial infarction.
- Malfunctioning heart valves disrupt proper blood flow within the heart.
Blood Vessel Pathologies
- Impaired tissue perfusion can result from arterial and venous occlusions, caused by conditions such as atherosclerosis or thrombi.
- Dilation issues in arteries and veins can manifest as aneurysms or varicose veins, affecting blood flow.
Shock and Its Etiology
- Shock is defined as the failure of central perfusion to supply blood adequately to peripheral tissues.
- The condition can be triggered when the heart cannot pump effectively, when significant fluid loss occurs, or during systemic vasodilation.
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Description
Test your knowledge on the crucial topic of perfusion in nursing. This quiz covers key definitions, the importance of cardiac output, and factors influencing optimal perfusion. Ideal for nursing students and professionals alike.