# Situation: A nurse works in the neonatal intensive care unit (NICU) of a tertiary hospital. She cares for newborns admitted in the first days of life. An infant born at 30 weeks of gestation is now 9 days old and has a central venous line. The incubator is on servo control, and the skin probe is secure. Over the past 12 hours the nurse notes: Axillary temperature: 36.8 °C → 36.1 °C Apnea with bradycardia: 1 episode → 6 episodes Blood glucose: 72 mg/dL (4.0 mmol/L) → 165 mg/dL (9.2 mmol/L) Capillary refill: 2 seconds → 4 seconds Which interpretation is MOST accurate?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=629444  
> language: ko  
> subject: Nursing Practice II — Maternal and Child Health Nursing

## 문제

Situation: A nurse works in the neonatal intensive care unit (NICU) of a tertiary hospital. She cares for newborns admitted in the first days of life.

An infant born at 30 weeks of gestation is now 9 days old and has a central venous line. The incubator is on servo control, and the skin probe is secure. Over the past 12 hours the nurse notes:
Axillary temperature: 36.8 °C → 36.1 °C
Apnea with bradycardia: 1 episode → 6 episodes
Blood glucose: 72 mg/dL (4.0 mmol/L) → 165 mg/dL (9.2 mmol/L)
Capillary refill: 2 seconds → 4 seconds
Which interpretation is MOST accurate?

## 보기

1. Late-onset sepsis is likely and must be reported at once **✔ 정답**
2. Early-onset sepsis from birth canal organisms is likely
3. Apnea of prematurity is worsening and needs more caffeine
4. Cold stress from the environment explains the changes

**정답: 1**

## 해설

New or worsening apnea, temperature instability (hypothermia is more common than fever in preterm infants), glucose instability, and poor perfusion together point to sepsis. After 72 hours of life, in an infant with a central line, this is late-onset sepsis, usually acquired in the hospital. Apnea of prematurity is a diagnosis of exclusion, so sepsis must be ruled out first.

## 심화 해설

Clinical interpretation

The most accurate interpretation is that this infant is showing signs of late-onset sepsis (LOS). The combination of new or worsening apnea, temperature instability, glucose instability, and poor perfusion in a 30-week preterm infant at 9 days of age with a central venous line points strongly to hospital-acquired infection.

Late-onset sepsis is defined as sepsis occurring after 72 hours of life, and this infant is now 9 days old, placing the presentation firmly in the LOS window. The central venous line is a major risk factor because it provides a direct portal for skin flora and hospital organisms to enter the bloodstream.

Why the clinical changes fit sepsis

Each trend in the data reflects the systemic inflammatory response and hemodynamic compromise of neonatal sepsis. In preterm infants, hypothermia is more common than fever as a sign of infection because their immature thermoregulatory and immune systems often fail to mount a febrile response. The drop in axillary temperature from 36.8 °C to 36.1 °C is therefore a meaningful warning sign, not simple environmental cooling.

The increase in apnea with bradycardia from 1 episode to 6 episodes over 12 hours is also characteristic. Sepsis can trigger apnea through cytokine-mediated central nervous system depression, altered respiratory drive, and metabolic stress. Key point! Apnea of prematurity is a diagnosis of exclusion; when apnea worsens acutely in a previously stable preterm infant, infection must be ruled out before attributing the change to prematurity alone.

The blood glucose rise from 72 mg/dL (4.0 mmol/L) to 165 mg/dL (9.2 mmol/L) reflects stress hyperglycemia. During sepsis, counter-regulatory hormones such as cortisol, catecholamines, and glucagon increase, while peripheral insulin sensitivity decreases, leading to elevated glucose levels even without exogenous glucose infusion changes.

The prolongation of capillary refill from 2 seconds to 4 seconds indicates worsening peripheral perfusion. In sepsis, vasodilation, capillary leak, and myocardial dysfunction reduce effective circulating volume and tissue oxygen delivery.

Differentiating early-onset vs. late-onset sepsis

| Feature | Early-onset sepsis (EOS) | Late-onset sepsis (LOS) |
| --- | --- | --- |
| Timing | Within 72 hours of birth | After 72 hours of life |
| Typical source | Maternal birth canal flora (vertical transmission) | Hospital environment, central lines, equipment (horizontal/nosocomial) |
| Common organisms | Group B Streptococcus, Escherichia coli | Coagulase-negative staphylococci, Staphylococcus aureus, Gram-negative rods |
| This case | Not applicable (infant is 9 days old) | Highly applicable (central line present, NICU stay) |

Watch out! Do not confuse the timing. This infant is 9 days old, which is well beyond the 72-hour cutoff for early-onset sepsis. The presence of a central venous line further supports a hospital-acquired, late-onset pathway.

Why the other options are less accurate

Early-onset sepsis from birth canal organisms is incorrect because the infant is already 9 days old. EOS is defined by onset within the first 72 hours of life and is typically associated with vertical transmission from maternal genital tract flora during labor and delivery.

Apnea of prematurity worsening and needing more caffeine is a tempting but incomplete answer. While apnea of prematurity is common in infants born at 30 weeks, the acute worsening of apnea accompanied by temperature instability, hyperglycemia, and poor perfusion is not explained by prematurity alone. Apnea of prematurity is a diagnosis of exclusion, and sepsis must be ruled out first when apnea acutely worsens. Increasing caffeine without evaluating for infection could delay life-saving antibiotic therapy.

Cold stress from the environment is unlikely because the incubator is on servo control with a secure skin probe. Servo control adjusts heater output to maintain the set skin temperature, so a drop in core temperature despite a functioning servo system suggests the infant is losing the ability to maintain temperature due to physiologic instability, not environmental failure. Cold stress alone would not explain the simultaneous worsening of apnea, hyperglycemia, and capillary refill.

Nursing priority

Late-onset sepsis is likely and must be reported at once. Early recognition of clinical signs, rapid evaluation, and prompt initiation of treatment are critical to prevent life-threatening deterioration in preterm infants. The nurse should notify the provider immediately, prepare for blood cultures and other sepsis workup, and anticipate initiation of broad-spectrum antibiotics after cultures are obtained. Close monitoring of respiratory status, perfusion, glucose, and temperature must continue, with readiness to support ventilation and circulation if the infant deteriorates.

## 임상 시나리오

Late-Onset Sepsis in the Preterm InfantRecognizing the clinical pattern and acting promptly
Late-onset sepsis occurs after 72 hours of life and is usually hospital-acquired. A central venous line is a major risk factor because it provides a direct portal for skin flora and hospital organisms to enter the bloodstream.

In preterm infants, hypothermia is more common than fever as a sign of infection. A drop in axillary temperature from 36.8 °C to 36.1 °C is a meaningful warning sign, not simple environmental cooling.

New or worsening apnea with bradycardia, glucose instability, and poor perfusion together reflect the systemic inflammatory response and hemodynamic compromise of neonatal sepsis. Apnea of prematurity is a diagnosis of exclusion, so sepsis must be ruled out first when apnea worsens acutely.

CautionDo not attribute worsening apnea to prematurity or environmental cooling without first excluding infection. Report the full clinical picture immediately and prepare for sepsis evaluation and empiric treatment.

## 핵심 개념

- **Late-onset sepsis** — Sepsis occurring after 72 hours of life, usually hospital-acquired, often associated with central venous catheters
- **Apnea of prematurity** — Diagnosis of exclusion in preterm infants; acute worsening requires ruling out infection first
- **Temperature instability** — Hypothermia is more common than fever in preterm infants with sepsis due to immature thermoregulation
- **Central venous line** — Major risk factor for late-onset sepsis as it provides a portal for skin flora and hospital organisms
- **Capillary refill** — Prolonged refill time indicates poor peripheral perfusion, a sign of hemodynamic compromise in sepsis

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