DNP 649 Module 3 Fetal and Neonatal Physiology Case Study: PPHN Example

Reviewed by Ingrid Vasterling, MSN, RN Arizona State University Updated October 2026

This DNP 649 Module 3 sample is the fetal and neonatal case study in Advanced Physiology, part of the core sequence in ASU's DNP program. ASU DNP 649 closes the term with this case, which asks students to interpret data and explain mechanisms after the unit on fetal and neonatal physiology. Faculty post the actual case in Canvas, so this answer works a similar composite: a term newborn born through meconium-stained fluid who becomes hypoxemic, with a pre-ductal saturation of 95% and a post-ductal saturation of 82%. The answer explains fetal circulation and its shunts, the normal transition at birth, what fails in persistent pulmonary hypertension of the newborn and how treatments act on that physiology.

CourseDNP 649 Advanced Physiology
ModuleModule 3
Paper typePhysiology case study
LengthAbout 616 words, 5 pages
FormatAPA 7 student paper
SchoolArizona State University
ProgramDoctor of Nursing Practice
UpdatedOctober 2026

Free sample paper for DNP 649 Module 3

1

A Transition That Did Not Happen: A Fetal and Neonatal Physiology Case Study of Persistent Pulmonary Hypertension

Student Name

Edson College of Nursing and Health Innovation, Arizona State University

DNP 649: Advanced Physiology

Instructor Name

Month Day, Year

What this page is doingThe title frames the condition as a failure of the normal circulatory transition at birth, which is how the case explains it.
2

A Transition That Did Not Happen: A Fetal and Neonatal Physiology Case Study of Persistent Pulmonary Hypertension

Case

A boy is born at 40 weeks by emergency cesarean after meconium-stained amniotic fluid. At one hour he is breathing fast with retractions. Pre-ductal oxygen saturation (right hand) is 95% and post-ductal saturation (foot) is 82% on 60% oxygen. A chest radiograph shows patchy infiltrates. An echocardiogram shows a structurally normal heart, right-to-left flow across the ductus arteriosus and the foramen ovale and estimated pulmonary pressures near systemic levels.

1. Fetal Circulation

Before birth, the placenta is the organ of gas exchange and the fluid-filled lungs receive little blood. Pulmonary vascular resistance is high and systemic resistance is low because of the low-resistance placenta. Three shunts route oxygenated blood away from the lungs: the ductus venosus carries umbilical venous blood past the liver, the foramen ovale lets blood cross from the right to the left atrium, and the ductus arteriosus carries most right ventricular output from the pulmonary artery into the aorta (Hall & Hall, 2026).

2. The Normal Transition at Birth

Aeration of the lungs is the key event. As the newborn breathes, lung liquid clears, alveoli fill with air and rising oxygen and the physical expansion of the lungs dilate the pulmonary vessels, so pulmonary vascular resistance falls and pulmonary blood flow rises sharply. Clamping the cord removes the placenta, raising systemic resistance. With more blood returning from the lungs, left atrial pressure exceeds right atrial pressure and the flap of the foramen ovale closes. Higher oxygen and falling prostaglandins constrict the ductus arteriosus. Research in this area shows that when the lungs are aerated before the cord is clamped, pulmonary blood flow can rise to replace placental venous return, which helps keep cardiac output stable during the transition (Hooper et al., 2015).

What this page is doingLaying out the normal sequence before the abnormal one lets the reader see exactly which step failed, which is the reasoning a physiology case asks for.
3

3. What Went Wrong: Persistent Pulmonary Hypertension

In this infant, pulmonary vascular resistance stayed high. Meconium aspiration inactivated surfactant, blocked airways and caused inflammation, so parts of the lung were poorly aerated. Low alveolar oxygen causes hypoxic pulmonary vasoconstriction, and inflammation and acidosis constrict the pulmonary vessels further. Meconium aspiration ranks among the leading causes of persistent pulmonary hypertension of the newborn, which may also arise from abnormal vascular development or underdeveloped lungs (Singh & Lakshminrusimha, 2021).

With pulmonary pressures near systemic pressure, blood takes the path of least resistance through the fetal shunts, now flowing right to left: across the foramen ovale into the left atrium and across the ductus arteriosus into the descending aorta. Deoxygenated blood bypasses the lungs.

4. Interpreting the Data

The 13-point saturation gap. The right hand receives blood from the aorta before the ductus arteriosus, while the foot receives blood after it. Right-to-left flow through the ductus mixes deoxygenated blood into the descending aorta, so post-ductal saturation is lower. A pre- to post-ductal difference of this size points to ductal-level shunting.

High oxygen need despite some improvement. Oxygen cannot fully correct hypoxemia caused by blood bypassing the lungs.

Echocardiogram. A normal heart structure excludes cyanotic congenital heart disease, and right-to-left flow with high pulmonary pressures confirms the diagnosis.

Patchy infiltrates. These fit meconium aspiration with uneven aeration.

5. How Treatment Acts on the Physiology

Oxygen is a pulmonary vasodilator, but excess oxygen produces free radicals that can worsen vascular reactivity, so saturation targets avoid both hypoxemia and hyperoxia. Recruiting the lung with ventilation and surfactant improves aeration and reverses hypoxic vasoconstriction. Inhaled nitric oxide relaxes pulmonary vascular smooth muscle by raising cyclic GMP, and because it is inhaled it reaches only ventilated areas, improving matching of ventilation and perfusion. Supporting systemic blood pressure reduces right-to-left shunting by keeping systemic resistance above pulmonary resistance (Singh & Lakshminrusimha, 2021).

What this page is doingExplaining each treatment by the mechanism it targets, rather than listing therapies, shows the reader the integration of physiology and practice that advanced practice requires.
4

References

Hall, J. E., & Hall, M. E. (2026). Guyton and Hall textbook of medical physiology (15th ed.). Elsevier.

Hooper, S. B., te Pas, A. B., Lang, J., van Vonderen, J. J., Roehr, C. C., Kluckow, M., Gill, A. W., Wallace, E. M., & Polglase, G. R. (2015). Cardiovascular transition at birth: A physiological sequence. Pediatric Research, 77(5), 608-614. https://doi.org/10.1038/pr.2015.21

Singh, Y., & Lakshminrusimha, S. (2021). Pathophysiology and management of persistent pulmonary hypertension of the newborn. Clinics in Perinatology, 48(3), 595-618. https://doi.org/10.1016/j.clp.2021.05.009

Reading the DNP 649 Module 3 assignment instructions

The fetal and neonatal case study comes at the end of the posted syllabus, after the unit on fetal and neonatal physiology, Guyton and Hall chapter 84, and is due in early December before the final exam. As with the earlier two cases, the job is to analyze a patient, interpret the numbers and explain the mechanism, following the Canvas instructions and rubric. Expect a newborn or fetal problem that requires you to explain the normal transition from fetal to neonatal life and identify where it went wrong. Diagrams of the fetal shunts and pressure changes can help you organize the explanation before you write. Keep the case's numbers in view throughout the answer.

How this DNP 649 Module 3 example is built

The answer restates the composite case, then explains fetal circulation and the three shunts. A section on the normal transition at birth describes lung aeration, falling pulmonary resistance, cord clamping and closure of the shunts, citing research on the sequence. A third section explains how meconium aspiration kept pulmonary resistance high and reversed flow through the shunts. A data section interprets the saturation gap, oxygen response, echocardiogram and radiograph. A final section explains how each treatment acts on the physiology. Three sources support it: the course text, a physiology review and a review of the condition's pathophysiology and management. The data section links each finding to the mechanism that produces it. Treatment is explained by mechanism.

Reading the DNP 649 Module 3 grading rubric

Good answers give an accurate account of fetal circulation and the transition at birth, a clear explanation of the abnormal physiology, correct interpretation of the data, such as the pre- and post-ductal saturation gap, and treatment explained by mechanism, with credible sources. The strongest answers show the normal sequence first and then name the failed step. Linking each data point to a mechanism demonstrates analysis. Explaining why both hypoxia and hyperoxia are harmful shows depth. Organized headings and correct terminology make the explanation easy to follow. A clear reason why the shunts reverse direction is also worth including. Terms such as hypoxic pulmonary vasoconstriction should be used precisely.

DNP 649 Module 3 help from the desk

One frequent weakness is describing the condition without first explaining normal fetal circulation. Start with the shunts and pressures. Another is reading the saturation gap without explaining which vessels supply the right hand and the foot. For your own neonatal case, send the desk the faculty's text and your chapter 84 notes. Draw the circulation before and after birth. Explain each treatment by the mechanism it targets. State which vessels supply the right hand and the foot before interpreting the saturation gap. Use a two-column diagram of pressures before and after birth. Keep each mechanism tied to one data point. Explain why oxygen helps but cannot fully fix shunting.

Write yours, or have the desk draft it

This paper is an original model document written by our desk, not a submitted student paper and not an official Arizona State University document. Read it for the moves, then write your own to the instructions in your classroom. If you want one built to your exact prompt and rubric, the first custom sample is free and arrives in 24 to 48 hours.

Request this one custom, free All DNP 649 module samples

More DNP 649 and Doctor of Nursing Practice sample papers

DNP 649 Module 3 questions, answered

Where can I find a free DNP 649 Module 3 sample paper?

The complete DNP 649 fetal and neonatal case study sample on persistent pulmonary hypertension of the newborn, explained through the transition at birth, is on this page.

What are the three fetal shunts?

The ductus venosus, the foramen ovale and the ductus arteriosus.

Why is post-ductal saturation lower in PPHN?

Deoxygenated blood flows right to left through the ductus arteriosus into the descending aorta, which supplies the legs.

What triggers the fall in pulmonary resistance at birth?

Aeration of the lungs and rising oxygen dilate pulmonary vessels, increasing pulmonary blood flow.

How does inhaled nitric oxide help PPHN?

It relaxes pulmonary vascular smooth muscle in ventilated areas, lowering pulmonary resistance and improving oxygenation.