# Situation: A 58-year-old man is brought to the emergency room (ER) at 10:00 with crushing substernal chest pain that began at 09:20 while he was resting at home. He has hypertension and smokes one pack of cigarettes a day. He has no known drug allergies and no history of bleeding, peptic ulcer, or stroke. The ER nurse reviews reperfusion time targets with a newly hired nurse. For a client with ST-elevation myocardial infarction (STEMI) who cannot receive primary percutaneous coronary intervention in time, fibrinolytic therapy should be started within how many minutes of hospital arrival?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=629688  
> language: ko  
> subject: Nursing Practice III — Care of Clients with Problems in Surgery, Oxygenation, Fluid and Electrolytes, Infectious, Inflammatory and Immunologic Response, Cellular Aberrations

## 문제

Situation: A 58-year-old man is brought to the emergency room (ER) at 10:00 with crushing substernal chest pain that began at 09:20 while he was resting at home. He has hypertension and smokes one pack of cigarettes a day. He has no known drug allergies and no history of bleeding, peptic ulcer, or stroke.

The ER nurse reviews reperfusion time targets with a newly hired nurse. For a client with ST-elevation myocardial infarction (STEMI) who cannot receive primary percutaneous coronary intervention in time, fibrinolytic therapy should be started within how many minutes of hospital arrival?

## 보기

1. 10 minutes
2. 90 minutes
3. 60 minutes
4. 30 minutes **✔ 정답**

**정답: 4**

## 해설

When primary percutaneous coronary intervention cannot be done within its 90-minute target, fibrinolytic therapy is started within 30 minutes of arrival. The 12-lead electrocardiogram is done within 10 minutes of arrival. Nurses in facilities without primary percutaneous coronary intervention need this target because fibrinolysis is often the reperfusion strategy there.

## 심화 해설

Reperfusion time targets in STEMI

The question asks for the door-to-needle time for fibrinolytic therapy when primary PCI cannot be performed within its own time window. The correct target is 30 minutes from hospital arrival. This is a core quality metric in acute coronary syndrome care and appears repeatedly on licensure examinations because it tests whether you can distinguish the separate time goals for ECG, fibrinolysis, and PCI.

The underlying rationale is that myocardial necrosis progresses as a wavefront of ischemic cell death from the endocardium toward the epicardium after coronary occlusion. The faster blood flow is restored, the more myocardium can be salvaged, the smaller the infarct size, and the lower the mortality. Fibrinolytic agents lyse the culprit thrombus pharmacologically, so their benefit is highly time-dependent. A 30-minute door-to-needle target reflects the maximum acceptable delay when fibrinolysis is the chosen reperfusion strategy.

The other options represent different steps in the STEMI pathway. A 10-minute target applies to obtaining and interpreting the 12-lead ECG after arrival, not to drug administration. A 90-minute target is the door-to-balloon time for primary PCI. A 60-minute figure is not a standard reperfusion benchmark in this context.

| Time target | Intervention | Clinical meaning |
| --- | --- | --- |
| 10 minutes | 12-lead ECG acquisition and interpretation | Rapid identification of STEMI; triggers the reperfusion pathway |
| 30 minutes | Fibrinolytic therapy (door-to-needle) | Reperfusion when primary PCI is unavailable or delayed |
| 90 minutes | Primary PCI (door-to-balloon) | Preferred reperfusion if a PCI-capable center is immediately accessible |

Key point! The 30-minute door-to-needle benchmark applies specifically to facilities where primary PCI cannot be achieved within 90 minutes. In such settings, fibrinolysis is often the only realistic reperfusion option, so nurses must recognize that the clock starts at hospital arrival and that every minute of delay reduces myocardial salvage.

Watch out! Do not confuse door-to-needle with door-to-balloon. The former is for fibrinolysis and has a shorter target because the drug can be prepared and administered more quickly than mobilizing a catheterization team. The latter is for PCI and allows 90 minutes because of the logistical complexity of the procedure.

The emphasis on rapid fibrinolysis is supported by evidence that timely lysis of the culprit clot restores perfusion, reduces infarct size, and saves lives. In practice, achieving the 30-minute target requires a coordinated response: immediate ECG, prompt recognition of STEMI, rapid screening for contraindications to fibrinolysis, and preparation of the thrombolytic agent without waiting for cardiac enzyme results. The decision to give fibrinolysis is based on the ECG and clinical presentation, not on troponin levels, because biomarker elevation lags behind the ischemic injury.

## 임상 시나리오

STEMI Reperfusion Time TargetsDoor-to-Needle vs Door-to-Balloon
When primary PCI cannot be performed within its 90-minute target, fibrinolytic therapy should be started within 30 minutes of hospital arrival.

The 12-lead ECG must be obtained and interpreted within 10 minutes of arrival to rapidly identify STEMI and trigger the reperfusion pathway.

CautionDo not confuse the three time targets: 10 minutes for ECG, 30 minutes for fibrinolysis, and 90 minutes for primary PCI. In facilities without PCI capability, fibrinolysis is often the only reperfusion option, making the door-to-needle target critical.

## 핵심 개념

- **door-to-needle time** — Time from hospital arrival to initiation of fibrinolytic therapy; target is within 30 minutes for STEMI when PCI is not timely available.
- **door-to-balloon time** — Time from hospital arrival to balloon inflation during primary PCI; target is within 90 minutes.
- **fibrinolytic therapy** — Pharmacologic reperfusion using agents that dissolve the culprit coronary thrombus in STEMI.
- **STEMI** — ST-elevation myocardial infarction; transmural infarction caused by acute total coronary occlusion.
- **12-lead ECG** — Electrocardiogram obtained and interpreted within 10 minutes of arrival to rapidly identify STEMI.

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