NU653 Unit 9 Reflective Narrative, Digoxin Toxicity Example

Three Facts on Three Screens: A Reflective Narrative on Nearly Missing Digoxin Toxicity After a Course of Clarithromycin

[Student Name]

Purdue University Global

NU653: AGACNP Acute Care Diagnosis and Management Clinical II

Unit 9 Reflective Narrative

[Instructor Name]

[Date]

The patient and encounter are composite; values, doses and days are bracketed.

What?

Mrs. [N.], [84], lives with heart failure and atrial fibrillation, and she came in with [three] days of nausea, poor appetite and fatigue. The triage note read "nausea, probable viral gastroenteritis," and the emergency department had started intravenous fluids. Her heart rate was [48], her blood pressure [104/60] and her creatinine [1.8] mg/dL, up from about [1.0] two months earlier.

I drafted an admission plan: fluids for the kidney injury, ondansetron for nausea, and a note that her heart rate was slow, probably from her metoprolol. I had the order screen open. Before signing, I went through her home medication list line by line, as I do for every admission. The fourth line was digoxin [0.125 mg] daily. I stopped. Then I remembered a line from the outside records tab: urgent care had prescribed clarithromycin [four] days ago for a sinus infection.

Nausea, a slow heart rate, kidney injury, digoxin and a new macrolide together pointed to digoxin toxicity. I held the plan, asked for a digoxin level and an ECG, and called my preceptor. Her digoxin level was [3.4] ng/mL. The ECG showed atrial fibrillation with a slow ventricular response and scooped ST segments. Digoxin was held, clarithromycin stopped, and cardiology advised on whether digoxin-specific antibody fragments were needed; with her potassium normal and no dangerous arrhythmia, they were not given, and she recovered over [three] days.

So What?

The first question I asked myself was why I nearly signed the other plan. I think there are two explanations, and they are different.

The first is that the label arrived already written. "Probable viral gastroenteritis" was in the triage note, and everything I read afterward was read through it. The nausea fit, the kidney injury fit as dehydration, and the slow pulse had a ready explanation in her beta-blocker. Accepting an early label and fitting later findings to it is a well-described cognitive error, and it is most likely when the first explanation is plausible (Croskerry, 2003).

The second is that each fact lived on a different screen. The slow pulse was on the vital signs flowsheet, the creatinine on the results tab, the digoxin on the home medication list and the clarithromycin in the outside records. No single screen showed all four. The diagnosis was not hidden; it was divided, and it took the act of putting the pieces side by side to see it.

What made the difference was a habit. When I worked as a nurse on a cardiac unit, a pharmacist taught us to read every home drug against the patient's new complaint and ask whether the drug could explain it. I had kept that habit without thinking of it as a diagnostic tool. Research supports it: in a population study of older adults, those admitted with digoxin toxicity were about twelve times more likely to have received clarithromycin in the preceding week (Juurlink et al., 2003), and a later study confirmed that macrolides, particularly clarithromycin, raise the risk of digoxin toxicity (Gomes et al., 2009). Clarithromycin inhibits P-glycoprotein, which clears digoxin, and her kidney injury reduced clearance further.

I also have to be honest about how close it was. If the fourth line of her medication list had been lower on the screen, or if I had been interrupted before reaching it, I would have signed the plan. Fluids would have helped her kidneys and slowly lowered the digoxin level, and ondansetron would have eased her nausea, so she might even have improved for a day. That is part of what makes this kind of miss dangerous: a wrong plan can look as if it is working.

Now What?

Rolfe's third question asks what follows (Rolfe et al., 2001). Three things follow for me.

First, I will keep the home medication review as a separate, deliberate step in every admission, done before I write the assessment rather than after, so that it can change the diagnosis instead of only the orders.

Second, I will look for recent outside prescriptions in every patient on a narrow-therapeutic-index drug such as digoxin, warfarin or lithium, since a short course of an antibiotic from urgent care often never reaches the hospital medication list.

Third, I will treat a triage label as a hypothesis. It is useful, and it is often right, but I will write my own one-line assessment before I read it.

I also told the urgent care clinic what had happened, through the patient's primary care provider, because the next patient on digoxin who receives clarithromycin there may not be admitted to someone with the same habit.

References

Croskerry, P. (2003). The importance of cognitive errors in diagnosis and strategies to minimize them. Academic Medicine, 78(8), 775-780. https://doi.org/10.1097/00001888-200308000-00003

Gomes, T., Mamdani, M. M., & Juurlink, D. N. (2009). Macrolide-induced digoxin toxicity: A population-based study. Clinical Pharmacology & Therapeutics, 86(4), 383-386. https://doi.org/10.1038/clpt.2009.127

Juurlink, D. N., Mamdani, M., Kopp, A., Laupacis, A., & Redelmeier, D. A. (2003). Drug-drug interactions among elderly patients hospitalized for drug toxicity. JAMA, 289(13), 1652-1658. https://doi.org/10.1001/jama.289.13.1652

Rolfe, G., Freshwater, D., & Jasper, M. (2001). Critical reflection for nursing and the helping professions: A user's guide. Palgrave.