# A 3-month-old infant with ventricular septal defect (VSD) is admitted to the pediatric unit with signs of congestive heart failure. The infant is receiving digoxin 0.01 mg/kg/day divided into two doses. Which nursing assessment finding requires the most immediate intervention?

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> subject: Child Health

## 문제

A 3-month-old infant with ventricular septal defect (VSD) is admitted to the pediatric unit with signs of congestive heart failure. The infant is receiving digoxin 0.01 mg/kg/day divided into two doses. Which nursing assessment finding requires the most immediate intervention?

## 보기

1. Heart rate of 140 beats per minute
2. Apical pulse of 80 beats per minute **✔ 정답**
3. Respiratory rate of 50 breaths per minute
4. Weight gain of 30 grams in 24 hours

**정답: 2**

## 해설

An apical pulse below 100 bpm in an infant indicates digoxin toxicity requiring immediate intervention. Other findings (HR 140, RR 50, weight gain 30g) are expected in CHF or require monitoring but are less urgent.

## 심화 해설

Clinical Context

A 3-month-old infant with a ventricular septal defect (VSD) is in congestive heart failure (CHF) and receiving digoxin. In this scenario, the nurse must recognize which assessment finding signals a potentially life-threatening complication of digoxin therapy requiring the most immediate intervention.

Correct Answer Analysis

The correct answer is 2. Apical pulse of 80 beats per minute.

Digoxin is a cardiac glycoside with a narrow therapeutic index, classified as a high-alert medication (HAM). The systematic review by Hernández-Gago et al. emphasizes that high-alert medications carry a heightened risk of causing significant patient harm when used in error, and their dosing requires extreme precision, especially in vulnerable populations like infants with altered physiology [1]. One of the earliest and most critical signs of digoxin toxicity in pediatric patients is bradycardia. The standard nursing procedure, and a critical safety checkpoint identified in HAM administration protocols, is to assess the apical pulse for a full minute before administering digoxin. For an infant, the generally accepted heart rate parameter for withholding digoxin and notifying the provider is an apical pulse less than 90-100 beats per minute. An apical pulse of 80 beats per minute is significantly below this threshold and indicates excessive vagal stimulation from digoxin, which can rapidly progress to more severe arrhythmias like second- or third-degree heart block. The physiological changes of CHF, such as reduced renal perfusion, can further decrease digoxin clearance, increasing the risk of toxicity even with a standard weight-based dose. This finding requires the nurse to immediately hold the medication and contact the prescriber, making it the highest priority intervention.

Distractor Analysis

1. Heart rate of 140 beats per minute

A heart rate of 140 beats per minute is within the normal range for a 3-month-old infant (typically 100-160 bpm while awake). While tachycardia can be a sign of worsening CHF, it is an expected compensatory mechanism in this scenario and does not represent an immediate contraindication to the prescribed therapy. The priority is the drug-related safety issue.

3. Respiratory rate of 50 breaths per minute

A respiratory rate of 50 breaths per minute is at the upper limit of normal for an infant (normal range 30-60 bpm). Tachypnea is a common finding in CHF due to pulmonary congestion. While it requires ongoing monitoring, it is an expected clinical manifestation of the admitting diagnosis, not an immediate, drug-related crisis.

4. Weight gain of 30 grams in 24 hours

A weight gain of 30 grams in 24 hours is a subtle finding. While it could indicate fluid retention associated with worsening CHF, it is not an acutely life-threatening sign. The nurse would document this and report it as part of the overall assessment, but it does not demand the same immediate, moment-to-moment intervention as a critically low heart rate prior to administering a high-alert negative chronotrope like digoxin.

Safety and Pharmacokinetic Considerations

The heightened risk with digoxin in this infant aligns with the core concerns raised in the systematic review on high-alert medications in pediatric patients. The review highlights that physiological changes, such as those from CHF (e.g., decreased renal perfusion and hepatic congestion), can significantly alter drug pharmacokinetics, specifically clearance, leading to drug accumulation even with correctly calculated weight-based doses [1]. For an infant with CHF, a reduced cardiac output can lower the glomerular filtration rate, directly impairing the renal excretion of digoxin. This creates a precarious situation where the therapeutic and toxic doses are dangerously close. The nursing assessment of the apical pulse is the most direct, real-time clinical indicator of this pharmacokinetic-to-pharmacodynamic relationship, serving as the final safety barrier before a potentially harmful dose is administered.References (research sources)

- [1]Dosing Strategies for High-Alert Medications in Obese Pediatric Patients: A Systematic Review.Meta-analysis/systematic reviewHernández-Gago Y, Minagorre PJA, Sánchez-Hernández JG, Marrodán BR, Hernández Sabater L, Negrín ACR, Rodríguez-Suárez CA, Research Group on High-Alert Medication Dosing in Obese Pediatric Patients, Spanish Society of Hospital Pharmacy (SEFH) and The Spanish Society of Hospital Pediatric Internal Medicine (SEPIH). (2026) · DOI: 10.3390/ph19050766

## 임상 시나리오

Clinical Practice Guide: Pediatric Digoxin Administration Safety

**Core Principle:** Digoxin is a high-alert medication with a narrow therapeutic index. The most critical nursing action before each dose is a thorough assessment to prevent life-threatening toxicity, with bradycardia being the primary early warning sign in infants.

Assessment Protocol

- **Apical Pulse Check:** Auscultate the apical pulse for a full 60 seconds prior to administration.

- **Hold Parameter:** Withhold the dose and notify the provider immediately if the infant's apical pulse is less than 90-100 beats per minute.

- **Signs of Toxicity:** Monitor for early signs beyond bradycardia, including vomiting, poor feeding, and lethargy. Advanced toxicity can manifest as arrhythmias (e.g., second- or third-degree heart block).

Safety and Administration

- **Double-Check:** Adhere to institutional high-alert medication policies, which typically require an independent double-check of the dose, calculation, and patient identity by another registered nurse.

- **Accurate Dosing:** Use the prescribed microgram (mcg) or milligram (mg) dose precisely. Pediatric doses are often in micrograms; clarify any order that uses "ml" only without the corresponding mg/mcg dose.

- **Missed Dose Protocol:** If a dose is held for bradycardia, document the finding and the notification. Do not double the next dose if the heart rate recovers.

Parent and Caregiver Education

- **Pulse Monitoring:** Teach caregivers to check the infant's pulse before each home dose and to hold the medication and call the provider if it falls below the specified threshold.

- **Toxicity Recognition:** Instruct them to seek immediate medical attention for signs like persistent vomiting, extreme sleepiness, or a very slow heart rate.

## 핵심 개념

- **Digoxin Toxicity** — An adverse effect of the cardiac glycoside digoxin, often presenting initially with bradycardia due to excessive vagal stimulation, especially in pediatric patients.
- **High-Alert Medication** — A drug that bears a heightened risk of causing significant patient harm when used in error, requiring stringent safety protocols during administration.
- **Apical Pulse Hold Parameter** — A critical safety checkpoint for digoxin administration; for infants, the medication is typically withheld if the apical pulse is less than 90-100 beats per minute.
- **Ventricular Septal Defect** — A congenital heart defect characterized by an opening in the septum between the ventricles, allowing left-to-right shunting of blood and potentially leading to congestive heart failure.

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