| Course | PA 520 Comprehensive Clinical Module Pulmonology |
|---|---|
| Week | 4 |
| Paper type | ABG analysis worksheet |
| Length | About 730 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 4
ABG Analysis Worksheet: A Room-Air Radial Sample at 10:20 With a pH of 7.46, a PaCO2 of 33 and a PaO2 of 68, an Acute Respiratory Alkalosis and an A-a Gradient of 35 at 735 mm Hg
Student Name
Chamberlain University
PA 520: Comprehensive Clinical Module Pulmonology
Instructor Name
Month Day, Year
ABG Analysis Worksheet: A Room-Air Radial Sample at 10:20 With a pH of 7.46, a PaCO2 of 33 and a PaO2 of 68, an Acute Respiratory Alkalosis and an A-a Gradient of 35 at 735 mm Hg
The Box That Is Not Results
Sample: arterial, left radial artery, after a modified Allen test showed brisk return of color. Time drawn: 10:20 a.m., at the hospital pulmonary laboratory before lung volume testing. Position: seated for 15 minutes beforehand. Inspired oxygen: room air, fraction 0.21; no supplemental oxygen at home or in transit. Temperature: 36.9 C. Barometric pressure in the laboratory that morning: 735 mm Hg. Hemoglobin from the same draw: 14.6 g/dL. Analysis within 10 minutes, sample on no ice. The co-oximeter reports measured saturation directly rather than estimating it from light through the skin, which is why it serves as the check on a finger reading (Jubran, 2015).
Values in Template Order
Table 1
Arterial Blood Gas Results in the Order Printed by the Template
| Measure | Value | Unit |
|---|---|---|
| pH | 7.46 | none |
| PaCO2 | 33 | mm Hg |
| HCO3 (calculated) | 23 | mEq/L |
| Base excess | minus 0.5 | mEq/L |
| PaO2 | 68 | mm Hg |
| SaO2 (co-oximetry) | 94 | percent |
| Carboxyhemoglobin | 1.8 | percent |
Note. Note. Co-oximetry measured; SpO2 on the finger at the same time read 95 percent.
Worked Lines
pH 7.46 is above 7.45: alkalemia.
PaCO2 33 is below 35, the direction that raises pH: the primary process is respiratory alkalosis.
HCO3 23 is near the normal value of 24: little metabolic change so far.
Expected HCO3 for an acute respiratory alkalosis falls about 2 mEq/L for each 10 mm Hg drop in PaCO2: 24 minus 1.4 is about 22.6. For a chronic one it falls about 4 to 5 mEq/L per 10 mm Hg: about 20.5 to 21. The measured 23 fits the acute rule, so compensation is minimal (Berend et al., 2014).
Base excess minus 0.5: within normal, consistent with no meaningful metabolic process.
Compensation as Direction and Degree
Direction: the kidneys lower bicarbonate to offset a respiratory alkalosis, and the small fall from 24 to 23 is in that direction. Degree: the fall matches what is expected within hours, not days. The worksheet records the disorder as acute or recent respiratory alkalosis without a second primary disorder. A measured bicarbonate much lower than 22 would have raised the question of an added metabolic acidosis.
Oxygenation Against What Was Inhaled
The alveolar oxygen tension is calculated from what L.B. was breathing. With an inspired fraction of 0.21, a barometric pressure of 735 mm Hg and water vapor pressure of 47 mm Hg, the inspired oxygen tension is 0.21 times 688, about 144.5 mm Hg. Subtracting PaCO2 divided by 0.8, which is 41.3, gives an alveolar oxygen tension of about 103 mm Hg. The alveolar to arterial gradient is 103 minus 68, or 35 mm Hg. A commonly used estimate of the upper normal gradient for age is the age divided by four, plus four, which for L.B. is about 20.5 mm Hg. The gradient is widened. PaO2 68 on room air is mildly low. The carboxyhemoglobin of 1.8 percent is within the normal range for a nonsmoker, which matters because L.B. works with a diesel skid steer and propane heaters in an enclosed barn.
One Moment, Not a Trend
This sample describes L.B. seated, at rest, at 10:20 on one morning. It does not show whether the gradient widens with effort, which the walk test is meant to address, and it does not show a trend, since no earlier gas exists. The mild hyperventilation may reflect the anxiety of an arterial puncture as much as the lung disease.
Closing Interpretation
Acute respiratory alkalosis with minimal compensation, mild hypoxemia on room air and an alveolar to arterial gradient wider than expected for age. Together these point to impaired gas exchange in the lung, consistent with the suspected disease of the lung tissue, and fit a widened gradient rather than low ventilation as the cause of the low oxygen. The interpretation is limited to this single resting sample.
References
Berend, K., de Vries, A. P. J., & Gans, R. O. B. (2014). Physiological approach to assessment of acid-base disturbances. New England Journal of Medicine, 371(15), 1434-1445. https://doi.org/10.1056/NEJMra1003327
Jubran, A. (2015). Pulse oximetry. Critical Care, 19, Article 272. https://doi.org/10.1186/s13054-015-0984-8
Reading the PA 520 Week 4 instructions
For week four you complete an arterial blood gas worksheet. Fill the box above the results with the sampling facts: arterial or venous, site, time, patient position, inspired oxygen as room air or a stated flow and device, temperature and barometric pressure where the template asks. List the values in the order the template prints them, each with its unit. Then work the analysis in short lines, one decision per line, naming the figure each line uses: pH status, primary process, expected compensation with the rule applied, and whether a second disorder is present. Assess oxygenation against what was inhaled, calculating the alveolar to arterial gradient. Note that a single sample shows one moment. Finish with a three- or four-sentence interpretation tying the gas to the clinical question. Cite the rules you apply.
How the PA 520 Week 4 example is put together
The sampling box records a left radial puncture after a modified Allen test at 10:20, seated rest, room air, a temperature of 36.9 C and 735 mm Hg in the laboratory. Table 1 lists pH, PaCO2, bicarbonate, base excess, PaO2, co-oximetry saturation and carboxyhemoglobin. Worked lines identify alkalemia, a respiratory primary process and expected bicarbonate of about 22.6 for acute and about 20.5 for chronic compensation, citing Berend and colleagues, so the measured 23 fits an acute process. A section states direction and degree of compensation. The oxygenation section calculates an alveolar tension of about 103 and a gradient of 35 against an age estimate near 20.5. Carboxyhemoglobin is checked because of barn exhaust. A one-moment section and a closing interpretation finish the sheet.
Where the points sit in the PA 520 Week 4 rubric
Grading on this worksheet follows the sequence of decisions. A disorder named without the worked lines beneath it loses the largest share, because the reasoning cannot be followed. Faculty then look closely at compensation: applying the wrong rule or skipping the acute versus chronic question costs significant marks. The sampling box matters more than students expect, since an oxygen tension cannot be judged without the inspired fraction and pressure. Credit goes to an alveolar to arterial gradient calculated with the patient's actual conditions and compared with an age-adjusted expectation. Deductions apply to trend language drawn from a single sample. The closing interpretation is marked on linking the gas to the clinical question. Units on every value and a cited source for the rules complete the expected form.
PA 520 Week 4 help: mistakes that cost points
A frequent problem with gas worksheets is a correct label with no arithmetic to support it. Provide the gas values and sampling details, and the worksheet drafted for you would fill the sampling box, list the results in your template's order and work every step on its own line. Compensation is calculated with the rule your course teaches, and the result is compared with the measured value. The alveolar gas equation is worked with your patient's inspired oxygen and local pressure where given. If your case is on supplemental oxygen, the sample uses the stated flow and device. A short closing paragraph ties the result to your clinical question. Recalculate every value yourself from your own case before you copy any of the method.
Get a PA-520 Week 4 example written to your instructions
Send the worksheet file itself, the case your section published and any reference ranges printed on the form, and a completed example comes back inside 24-48h at no cost the first time. The sheet is filled to your template, field by field, rather than rewritten as prose that your rubric was never built to mark.
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PA 520 Week 4 questions, answered
The template has no field for inspired oxygen. Should it still appear?
Yes, written into the first line of the interpretation where the form gives it nowhere else. Every oxygenation statement on the sheet depends on it, and a marker reading the working has no way to check that reasoning without it. Adding a field is safer than assuming room air on a case that never said so.
Are venous values ever acceptable on this worksheet?
Only where the assignment supplies them deliberately, and the answer is then about what they can and cannot support. Venous figures carry some acid-base statements and none of the oxygenation ones, and the finished sheet says which is which. Working them through as though they were arterial is the version that loses the record.
Does the arithmetic have to be shown?
Show enough that each conclusion can be traced back to the figures it came from, which usually means one line per decision naming the values used rather than a full derivation. Markers are checking whether the working belongs to this case, and figures that never reappear in the working are the clearest sign that it does not.
Where can I find a free PA 520 Week 4 sample paper?
The full PA 520 Week 4 ABG worksheet is on this page, with a sampling box, worked compensation lines and an A-a gradient calculated at 735 mm Hg.
How does the PA 520 Week 4 sample decide the alkalosis is acute?
The measured bicarbonate of 23 matches the roughly 22.6 expected for acute compensation, while chronic compensation would have lowered it to about 20.5 to 21.