| Course | NU104 Pathophysiology for Nursing |
|---|---|
| Unit | Unit 5 |
| Paper type | Systems review |
| Length | About 920 words, 6 pages double-spaced |
| Format | APA 7 student paper |
| School | Purdue University Global |
| Program | BSN (prelicensure) |
| Updated | October 2026 |
Free sample paper for NU104 Unit 5
A Pump Weakened by a Cure: A Systems Review of Cardiac Output and Its Compensation in a Composite 52-Year-Old Breast Cancer Survivor With Anthracycline Cardiomyopathy, From Helpful Responses to Harmful Ones
[Student Name]
Purdue University Global
NU104: Pathophysiology for Nursing
Unit 5 Systems Review
[Instructor Name]
[Date]
The patient is a composite; values are typical for the condition and bracketed where illustrative.
Normal Cardiac Output
Cardiac output is the volume of blood the heart pumps each minute: beats per minute multiplied by the volume of each beat. A resting adult pumps about five liters a minute. Stroke volume, the amount ejected with each beat, depends on three things. Preload is the stretch of the ventricle at the end of filling; within limits, a ventricle that is stretched more contracts more forcefully, the Frank-Starling relationship. Afterload is the load the ventricle pushes against during ejection, mostly determined by arterial pressure. Contractility is the strength of contraction independent of stretch. The ejection fraction, the portion of ventricular blood sent out per contraction, normally sits above roughly half (Rogers, 2023).
The Injury: Anthracycline Cardiomyopathy
[Elena], a composite 52-year-old, was treated with doxorubicin, an anthracycline chemotherapy drug, for breast cancer four years ago. Anthracyclines damage heart muscle cells, in part by generating oxygen radicals and disrupting enzymes needed for DNA and energy production in the cells. The damage is dose-related and can appear months or years after treatment. In a large series of patients followed with regular echocardiograms after anthracycline treatment, most cases of reduced heart function appeared within the first year, often before symptoms, and early heart failure treatment led to recovery of function in many of them (Cardinale et al., 2015). Elena did not have follow-up imaging after her first year, and her heart muscle has slowly lost contractile cells.
On her echocardiogram the left ventricle is now enlarged and ejects only [30] percent of its volume per beat. Her problem is a loss of contractility: each beat ejects less of the blood in the ventricle, so stroke volume falls and, at first, so does cardiac output.
Compensation Stage One: Helpful Responses
The body detects the fall in output and responds through three main systems, each of which helps in the short term.
The sympathetic nervous system responds first. Pressure sensors in the aorta and carotid arteries sense the lower pressure, and sympathetic activity increases. Heart rate rises, the remaining muscle contracts harder, and arterioles constrict to maintain blood pressure. Elena's resting heart rate is [98].
The renin-angiotensin-aldosterone system follows. Reduced blood flow to the kidneys triggers renin release, leading to angiotensin II, a strong vasoconstrictor, and aldosterone, which makes the kidneys retain sodium and water. Antidiuretic hormone adds to water retention. The extra volume increases preload, and, following the Frank-Starling relationship, the extra stretch wins back part of the lost stroke volume.
The ventricle itself remodels. Over months, it enlarges, which allows it to hold more blood and eject a near-normal stroke volume even with a lower ejection fraction.
Each of these responses is designed for a sudden loss of blood, where it saves life, which is why it misfires when the cause is a weak pump that will not recover on its own.
Compensation Stage Two: Harmful Responses
Over time, the same responses begin to harm. Constant sympathetic stimulation raises the heart's oxygen demand, can trigger abnormal rhythms and is toxic to heart muscle cells. Vasoconstriction raises afterload, so the weak ventricle must pump against greater resistance, lowering stroke volume further. Retained salt and water raise preload beyond the point where more stretch helps; the overstretched ventricle contracts less effectively. Angiotensin II and aldosterone also promote fibrosis in the heart. Remodeling continues until the ventricle is large, thin-walled and spherical, and pumps even less efficiently. This cycle, in which compensation worsens the original problem, is the reason heart failure tends to progress (Rogers, 2023). Reviews of neurohormonal activation describe it as sustained rather than temporary in reduced ejection fraction, with the sympathetic and renin-angiotensin-aldosterone systems reinforcing each other (Hartupee & Mann, 2017).
The Signs Each Stage Produces
Elena's signs map onto these stages. Her resting tachycardia reflects sympathetic activation. Her cool hands reflect vasoconstriction. Breathlessness when she lies down, and waking at night gasping for air, reflect fluid backing up from the weak left ventricle into the pulmonary veins and lungs; lying flat returns more blood to the chest and worsens it. Crackles at both lung bases come from fluid in the alveoli. Swollen ankles and a weight gain of [3] kg over two weeks reflect retained salt and water, which collect in dependent tissues. Fatigue and reduced exercise tolerance reflect a cardiac output that cannot rise to meet demand. Her blood test for B-type natriuretic peptide, a hormone released by stretched ventricles, is high.
Why the Treatment Targets Compensation
Most medicines prescribed when the ejection fraction is low block the harmful compensations: beta-blockers reduce sympathetic stimulation, and drugs that block the renin-angiotensin-aldosterone system reduce vasoconstriction, fluid retention and fibrosis. Diuretics remove excess fluid. In anthracycline cardiomyopathy, these same drugs can improve heart function, especially when started early (Cardinale et al., 2015). Understanding compensation explains why a patient may feel worse briefly when a beta-blocker is started, and why it is still continued.
Nursing Relevance
Daily weights, intake and output, and attention to new breathlessness lying flat are the nurse's early warnings of worsening fluid overload. For survivors of anthracycline treatment, the case also shows why long-term heart monitoring matters after the cancer itself is gone.
References
Cardinale, D., Colombo, A., Bacchiani, G., Tedeschi, I., Meroni, C. A., Veglia, F., Civelli, M., Lamantia, G., Colombo, N., Curigliano, G., Fiorentini, C., & Cipolla, C. M. (2015). Early detection of anthracycline cardiotoxicity and improvement with heart failure therapy. Circulation, 131(22), 1981-1988. https://doi.org/10.1161/CIRCULATIONAHA.114.013777
Hartupee, J., & Mann, D. L. (2017). Neurohormonal activation in heart failure with reduced ejection fraction. Nature Reviews Cardiology, 14(1), 30-38. https://doi.org/10.1038/nrcardio.2016.163
Rogers, J. L. (Ed.). (2023). McCance & Huether's pathophysiology: The biologic basis for disease in adults and children (9th ed.). Elsevier.
What the NU104 Unit 5 assignment asks for
Unit 5 typically asks for a broad review of cardiac function rather than a single mechanism. Prompts often want normal physiology first, then what goes wrong in a failing heart, then the body's compensatory responses and how they eventually cause harm, ending with the signs produced at each stage. A paper of four to five pages is common, sometimes built around a case. Instructors expect precise handling of preload, afterload, contractility and ejection fraction, and for compensation explained as the same systems switching from helpful to harmful. Linking each sign to a stage of the process, and treatment to the compensation it blocks, shows understanding beyond recall. A diagram of the compensation cycle can help, though most prompts want it explained in prose as well.
How the NU 104 Unit 5 example is put together
The review begins with normal cardiac output and the three determinants of stroke volume. The injury section explains anthracycline damage to heart muscle and cites a large follow-up study of patients after chemotherapy. Stage one describes sympathetic activation, the renin-angiotensin-aldosterone system and remodeling as helpful responses, with the highlighted line on why responses designed for blood loss misfire. Stage two shows the same three systems becoming harmful, supported by a review of neurohormonal activation. A section maps each of her signs to its cause. The final sections explain why most heart failure drugs block compensation and what nurses monitor daily, including weight and breathlessness when lying flat. Each section ends with a sentence leading into the next, so the review reads as one argument.
Reading the NU104 Unit 5 grading rubric
Systems reviews in NU 104 tend to be graded on accuracy of normal physiology, explanation of the disease process, analysis of compensation, and application to signs and care. Normal physiology earns credit when cardiac output and its determinants are defined correctly. Disease process points go to a clear account of what damaged the heart and which determinant failed. Compensation analysis is weighted heavily and rewards showing each system's early benefit and later harm. Application is judged on matching signs to stages and treatment to mechanism. Scholarly sources in APA 7, logical headings and plain, careful prose earn what is left in most rubrics, with deductions for unexplained terms. A short case woven through the review often earns credit for application.
NU104 Unit 5 help: mistakes that cost points
Reviews often describe compensation as a list of harmful effects without first showing why the responses help, which misses the core idea of the unit. Another frequent gap is mixing up preload and afterload, or using ejection fraction and cardiac output as if they were the same. Some papers explain left-sided failure but attribute ankle swelling to it without explanation. Others never connect treatment to mechanism. Define each determinant before using it, show each compensatory system in both its helpful and harmful phase, match every sign to its stage, and explain treatment as blocking compensation. A case keeps the review concrete and easier to grade. Read your draft once just for terms and check each one is defined before it is used.
Get an NU104 Unit 5 example written to your instructions
For a Unit 5 systems review, the first sample is free: upload the prompt, the rubric and any heading structure your instructor gives, and it is returned in 24-48h shaped to those requirements. Mention whether your section includes shock alongside chronic failure, since that changes the scope. Patient details are composites. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
More NU104 papers and BSN samples
- NU104 Unit 1: Discussion Board Post
- NU104 Unit 2: Concept Map
- NU104 Unit 3: Case Study Analysis
- NU104 Unit 4: Mechanism Write-Up
- NU104 Unit 6: Seminar Reflection
- NU104 Unit 7: Lab Value Interpretation
- NU104 Unit 8: Case Study Analysis
- NU104 Unit 9: Concept Map
- NU104 Unit 10: Final Synthesis Paper
NU104 Unit 5 questions, answered
Where can I find a free NU104 Unit 5 sample paper?
You can read the full NU104 Unit 5 systems review here, covering normal cardiac output, anthracycline injury, compensation in two stages, the signs each stage produces, treatment and nursing relevance, with three references. Send us your case and we will build a review around it.
What are preload, afterload and contractility?
Preload is the stretch of the ventricle at the end of filling, afterload is the resistance it pumps against, and contractility is the strength of contraction apart from stretch. Together they set stroke volume.
Why does compensation make heart failure worse over time?
Sympathetic activation raises oxygen demand, vasoconstriction raises afterload, retained fluid overstretches the ventricle, and hormones promote fibrosis. Each response worsens the weak pump it was meant to support, so the condition tends to progress.
How does doxorubicin damage the heart?
Anthracyclines injure heart muscle cells, partly by generating oxygen radicals and disrupting cell enzymes. Damage depends on dose and can appear months or years after treatment, which is why long-term monitoring is advised.
Why does breathlessness worsen lying flat?
Lying down returns more blood to the chest. With a weak left ventricle, that extra volume backs up into the lungs, adding fluid to the alveoli and making breathing harder.