NURS 8544 Week 2 Learning Problem Analysis Example

The pH Is Not the Answer: A Learning Problem Analysis of Arterial Blood Gas Interpretation in a Second-Semester Medical-Surgical Course

Student Name

College of Nursing, Walden University

NURS 8544: Strategies for Teaching Innovations in Nursing Education

Instructor Name

Month Day, Year

The pH Is Not the Answer: A Learning Problem Analysis of Arterial Blood Gas Interpretation in a Second-Semester Medical-Surgical Course

The Problem as Faculty Describe It

Faculty in the second-semester medical-surgical course of a composite associate degree nursing program describe arterial blood gas interpretation as the topic learners find hardest. Each term the unit exam's blood gas items have the lowest scores, and clinical instructors report that learners can recite normal ranges but freeze when handed a result. Calling the topic hard does not help anyone teach it. This analysis asks a narrower question: what, specifically, are learners getting wrong, and why? It does not propose a teaching method. A strategy chosen before the problem is understood is likely to address the wrong cause, and Ambrose et al. (2010) argue that prior knowledge, including inaccurate prior knowledge, shapes what learners take from instruction more than any feature of the instruction itself.

The Pattern in the Results

The unit exam contains eight blood gas items, which fall into two kinds. Four ask learners to determine whether a result shows compensation, given the values. Four ask learners to identify the primary disorder, meaning whether the underlying problem is respiratory or metabolic and whether it is acidosis or alkalosis. Item results from four cohorts of 28 to 34 learners, taught by three different instructors, show a consistent split. On compensation items, 74% to 81% of learners answered correctly. On primary disorder items, only 41% to 52% did.

The split is odd. Determining compensation is usually thought to be the harder step, since it requires a learner to have already identified the primary disorder. A learner who can do the harder step but not the easier one is not simply finding the topic difficult. Something more specific is happening. The split also held across all three instructors, which makes it unlikely to come from one person's teaching.

Three Explanations Tested Against the Pattern

Insufficient practice. The simplest explanation is that learners need more practice. If that were true, cohorts with more practice should show better results on both kinds of item. Practice volume varied considerably: one instructor assigned two worksheets and another assigned six, plus an online module. Overall scores rose slightly with more practice, but the split between the two kinds of item did not narrow at all. More practice made learners somewhat better at what they already did well. It did not touch the gap, so practice volume does not explain the pattern.

A prerequisite gap in chemistry. A second explanation is that learners lack the chemistry needed to understand acids, bases and buffers. If so, the same learners should struggle with other chemistry-based content. They do not. On the same exam, items requiring dosage calculation with concentrations and conversion between units are answered correctly by more than 80% of learners. Their prerequisite chemistry grades are also unremarkable. A chemistry gap would affect both kinds of blood gas item and other content as well; this problem is confined to one kind of item.

A specific misconception. The third explanation is that learners hold a particular wrong idea about how to read a blood gas. The pattern of wrong answers supports this. On primary disorder items, the most commonly chosen wrong answer was the option matching the direction of the pH alone, regardless of the other values. When the pH was low, learners chose respiratory acidosis or metabolic acidosis almost at random, as though the pH settled the question and the rest did not matter. Learners appear to read the pH value as the answer, rather than as one of three readings that must be considered together with carbon dioxide and bicarbonate.

What the Misconception Looks Like in an Item

Consider an item giving a pH of 7.32, a carbon dioxide level of 30 and a bicarbonate level of 16. The correct reading is metabolic acidosis with partial respiratory compensation: the low bicarbonate explains the low pH, and the low carbon dioxide reflects the lungs blowing off acid. A learner operating under the misconception sees the low pH, concludes acidosis and then has to guess which kind. The low carbon dioxide may even lead them toward respiratory acidosis, because they have learned that carbon dioxide is linked to respiratory problems, without checking which direction it moved. On compensation items, by contrast, the question tells learners the primary disorder, so the misconception never has a chance to operate. That is why learners do better on the step usually considered harder.

Five learners from the most recent cohort agreed to talk through two items aloud after the exam. Four of the five began by announcing the pH and naming acidosis or alkalosis, then said they were unsure what to do next. None described looking for which value moved in the same direction as the pH. Five interviews cannot establish the misconception's prevalence, but they match what the item results suggest.

Why This Matters for What Comes Next

Misconceptions are known to resist correction when instruction simply presents the right method again, because learners fit the new information into the existing wrong idea (Ambrose et al., 2010). That would explain why more worksheets helped little: learners practiced the procedure on compensation items, where the misconception does no harm, and continued guessing on primary disorder items. Physiology educators have documented similar patterns, in which learners hold durable wrong models of respiratory and acid-base relationships that survive conventional teaching (Michael, 2007; Michael et al., 1999).

The analysis therefore defines the problem precisely enough for a later strategy to target it. Learners do not lack practice or chemistry. They treat one value as the answer when the task requires comparing three. Any strategy chosen for this course should be judged by whether it makes learners compare pH with carbon dioxide and bicarbonate before naming a disorder, and whether primary disorder scores rise while compensation scores hold.

Limits

Four cohorts give a consistent pattern but small numbers, and exam items may differ in difficulty for reasons other than their kind. The interviews involved volunteers, who may differ from other learners. And the analysis cannot rule out a fourth explanation not considered here, such as how the textbook sequences the topic. A short diagnostic item set given at the start of the next term, before teaching, would show whether learners arrive with the misconception or develop it during the course, which would sharpen the diagnosis further.

References

Ambrose, S. A., Bridges, M. W., DiPietro, M., Lovett, M. C., & Norman, M. K. (2010). How learning works: Seven research-based principles for smart teaching. Jossey-Bass.

Michael, J. (2007). What makes physiology hard for students to learn? Results of a faculty survey. Advances in Physiology Education, 31(1), 34-40. https://doi.org/10.1152/advan.00057.2006

Michael, J. A., Richardson, D., Rovick, A., Modell, H., Bruce, D., Horwitz, B., Hudson, M., Silverthorn, D., Whitescarver, S., & Williams, S. (1999). Undergraduate students' misconceptions about respiratory physiology. Advances in Physiology Education, 277(6), S127-S135. https://doi.org/10.1152/advances.1999.277.6.S127