| Course | PA 520 Comprehensive Clinical Module Pulmonology |
|---|---|
| Week | 5 |
| Paper type | Pulse oximetry limits brief |
| Length | About 680 words, 5 pages |
| Format | APA 7 student paper |
| School | Chamberlain University |
| Program | Master of Physician Assistant Studies (MPAS) |
| Updated | October 2026 |
Free sample paper for PA 520 Week 5
Pulse Oximetry Limits Brief for the Clinic Nurse Before L.B.'s Walk Test: What the Number Reports, Cold Barn Fingers, Carbon Monoxide, Skin Pigment and the Fields Every Reading Needs
Student Name
Chamberlain University
PA 520: Comprehensive Clinical Module Pulmonology
Instructor Name
Month Day, Year
Pulse Oximetry Limits Brief for the Clinic Nurse Before L.B.'s Walk Test: What the Number Reports, Cold Barn Fingers, Carbon Monoxide, Skin Pigment and the Fields Every Reading Needs
What the Figure Reports
SpO2 is an estimate of the share of hemoglobin carrying oxygen, calculated from how two wavelengths of light are absorbed as blood pulses through a fingertip or earlobe. It is not a blood sample and does not measure the amount of oxygen in the blood or how much reaches the tissues (Jubran, 2015).
Signal Problems
These limits come from the quality of the pulse the device detects.
Cold or poorly perfused fingers: L.B. arrives after morning chores in an unheated barn, often with cold hands. Warm the hands for 10 minutes or use an earlobe probe if the waveform is flat.
Motion: walking and arm swing create artifact. Use a probe designed for motion if available, and trust only readings with a regular waveform and a displayed pulse that matches a manual count.
Nail coverings and dirt: barn work leaves grime under and on the nails; clean the finger, and remove any dark polish or artificial nail.
Light interference: bright overhead light can reach the sensor; keep the probe covered.
Species the Light Cannot Tell Apart
A standard two-wavelength oximeter cannot tell oxyhemoglobin from carboxyhemoglobin, so carbon monoxide makes the reading falsely high; it also misreads methemoglobin, which pulls readings toward about 85 percent. Exhaust from the farm's skid steer and the gas heaters that warm the calf pens both put carbon monoxide into closed air, so this exposure is real for L.B. The arterial gas last week showed carboxyhemoglobin of 1.8 percent, which is normal, but if L.B. ever has headache or confusion after barn work, a co-oximetry sample is needed, because the finger probe will not show the problem.
Accuracy Is Not Scope
Even when the signal is good and no unusual hemoglobin is present, oximeters have a stated accuracy of about 2 to 3 percent in the 70 to 100 percent range, and accuracy worsens below 80 percent (Jubran, 2015). In addition, oximeters have been shown to overestimate arterial saturation in Black patients compared with White patients, so that hidden low oxygen is missed more often in patients with darker skin (Sjoding et al., 2020). L.B. is White, but the clinic serves many patients for whom this matters, and the walk test protocol should set a lower threshold for checking an arterial gas when readings are near a decision point.
What the Device Does Not Measure
It does not measure carbon dioxide, so a patient can have a normal SpO2 while breathing too little, especially on supplemental oxygen. It does not show anemia: a person with a low hemoglobin can read 98 percent and still carry little oxygen. It does not show whether oxygen reaches the muscles. For L.B., the walk test question is narrow, how far saturation falls with effort, and the oximeter can answer that if the signal is good.
For the Walk Test Today
Use the clinic's motion-tolerant probe on the right middle finger, warmed first. Record a resting value after five minutes seated. During the walk, the nurse walks behind and reads the display at the end of each minute, noting the lowest value and the minute it occurred. A sustained value below 88 percent for more than a minute means the test is paused and the supervising clinician is called, according to clinic protocol.
The Documentation Line
Every reading in L.B.'s record should carry: the value; rest or effort, and which minute of effort; room air or oxygen with the flow and device; probe site; whether the waveform was steady; and the time. For example: "SpO2 86 percent, minute 4 of 6-minute walk, room air, right middle finger, steady waveform, 09:14."
References
Jubran, A. (2015). Pulse oximetry. Critical Care, 19, Article 272. https://doi.org/10.1186/s13054-015-0984-8
Sjoding, M. W., Dickson, R. P., Iwashyna, T. J., Gay, S. E., & Valley, T. S. (2020). Racial bias in pulse oximetry measurement. New England Journal of Medicine, 383(25), 2477-2478. https://doi.org/10.1056/NEJMc2029240
Reading the PA 520 Week 5 instructions
The fifth week asks for a brief on the limits of pulse oximetry, written for someone who will use a reading soon. Open with one sentence saying what the figure measures and how. Group the limits by cause rather than listing them at random: problems with the signal, such as poor perfusion, motion and nail coverings; other hemoglobin species the device cannot distinguish; and the device's stated accuracy range, including known bias across skin tones. Add a short section on what the device does not measure at all, such as carbon dioxide or oxygen content. Give practical instructions for the reading the reader is about to take. End with a documentation line listing the fields every recorded value should carry. Write in headed sections and cite current evidence.
How this PA 520 Week 5 example is built
The brief begins with a one-sentence definition citing Jubran. Signal problems are grouped with instructions: warming L.B.'s cold hands after barn chores, using a motion-tolerant probe, cleaning grime from the nail and shielding the sensor. A section on hemoglobin species explains falsely high readings with carbon monoxide and the drift toward 85 percent with methemoglobin, tied to exhaust from farm machinery and gas heaters and to the normal carboxyhemoglobin found on the gas. An accuracy section gives the 2 to 3 percent range and cites Sjoding and colleagues on overestimation in Black patients. A short section lists what is not measured. A walk test protocol sets a minute-by-minute reading and a pause threshold, and the brief closes with a sample documentation line naming value, minute, oxygen, site, waveform and time.
Reading the PA 520 Week 5 grading rubric
The marks on this brief favor organization and usefulness. A list of oximeter facts with no grouping by cause loses the most, since the reader cannot tell which problem applies when. Next comes accuracy about hemoglobin species: stating that carbon monoxide lowers the reading, when it raises it, is a heavy deduction. Faculty give credit for separating stated accuracy from what the device cannot measure at all, and for addressing documented bias across skin tones with a source. Practical instructions tied to the reader's next task earn marks because the brief is meant for use. The documentation line is graded on completeness: value, rest or effort, oxygen and flow, site, signal quality and time. Headed sections and current citations complete the format.
PA 520 Week 5 help: mistakes that cost points
The common gap in oximetry briefs is a list of warnings that never tells the reader what to do. Send your case and who the brief is for, and the custom sample will define the reading in one sentence, then group the limits by cause with an action beside each one. If your patient has exposures that matter, such as smoke, exhaust or certain medicines, the sample addresses them under hemoglobin species. Accuracy and bias are covered with current sources. A section on what the device never measures keeps the reader from over-trusting a normal number. The brief ends with a documentation line suited to your setting. Check device instructions and your clinic's protocol before adapting any threshold the model uses.
Get a PA-520 Week 5 example written to your instructions
Send the brief assignment, any word limit and the audience your section named, and an example written to that audience returns inside 24-48h, free on the first request. Where a particular device or a published accuracy figure is specified in your classroom, the example is built around that one rather than a generic substitute.
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PA 520 Week 5 questions, answered
Does the brief have to cite a device manual?
A published standard or a peer-reviewed accuracy study carries more weight than a manufacturer sheet, and citing both is stronger still where the classroom supplies a particular device. What the marker is checking is whether the accuracy range in the brief came from somewhere identifiable rather than from memory or from a lecture slide.
How much physics does a brief like this need?
Enough for the mechanism behind each limit group to be intelligible, and no more. Two absorbing species and two wavelengths explains most of the brief, including why a third species breaks the assumption outright. Extended optics tends to push out the documentation line, and that line is where several of the rubric points usually sit.
Should the brief recommend what to do about an unreliable reading?
It should say what the reading is worth and which measurement would settle the question, not what care to give. Naming the sample that answers the question directly stays inside the assignment, while instructions about treatment move the piece into territory this module does not grade and some rubrics take points for.
Where can I find a free PA 520 Week 5 sample paper?
This page holds the full PA 520 Week 5 pulse oximetry brief, limits grouped by cause with a walk test protocol and a documentation line.
Why does the PA 520 Week 5 brief mention carbon monoxide?
Farm exhaust and gas heaters expose the patient to carbon monoxide, which a standard finger probe reads as oxygenated hemoglobin, making the figure falsely high.