# A nurse is caring for a patient in cardiogenic shock who has an intra-aortic balloon pump. The patient is experiencing severe left ventricular dysfunction with compromised cardiac output despite mechanical circulatory support. The nurse notes the following hemodynamic parameters: Cardiac output (CO): 4.5 L/min, Cardiac index (CI): 2.2 L/min/m², Pulmonary artery wedge pressure (PAWP): 10 mmHg, Systemic vascular resistance (SVR): 1,200 dynes/sec/cm⁵. Which nursing intervention is most appropriate?

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> subject: Adult Health

## 문제

A nurse is caring for a patient in cardiogenic shock who has an intra-aortic balloon pump. The patient is experiencing severe left ventricular dysfunction with compromised cardiac output despite mechanical circulatory support. The nurse notes the following hemodynamic parameters: Cardiac output (CO): 4.5 L/min, Cardiac index (CI): 2.2 L/min/m², Pulmonary artery wedge pressure (PAWP): 10 mmHg, Systemic vascular resistance (SVR): 1,200 dynes/sec/cm⁵. Which nursing intervention is most appropriate?

## 보기

1. Increase the IABP frequency to 1:1 ratio
2. Administer additional IV fluids to improve preload
3. Position the patient in Trendelenburg position
4. Collaborate with the physician to initiate inotropic therapy **✔ 정답**

**정답: 4**

## 해설

Hemodynamic parameters show cardiogenic shock with low CO/CI and high SVR, indicating poor contractility. Inotropic therapy (e.g., dobutamine) is needed to improve contractility, while fluids are contraindicated due to high filling pressures.

## 심화 해설

Hemodynamic Profile Analysis

The patient’s hemodynamic parameters reveal a critical clinical picture. The cardiac index (CI) is 2.2 L/min/m², which falls below the normal range of 2.5–4.0 L/min/m², confirming a persistent low-output state. The pulmonary artery wedge pressure (PAWP) is 10 mmHg, sitting at the upper limit of the normal range (8–12 mmHg) and indicating that the patient is not volume-depleted. The systemic vascular resistance (SVR) is elevated at 1,200 dynes/sec/cm⁵ (normal: 800–1200 dynes/sec/cm⁵), reflecting profound compensatory vasoconstriction in response to the failing left ventricle. This combination of low CI, adequate preload, and high afterload is the hallmark of advanced cardiogenic shock where the primary problem is impaired myocardial contractility, not inadequate filling [1].

Rationale for Inotropic Therapy

The most appropriate intervention is to collaborate with the physician to initiate inotropic therapy. The core physiological derangement here is severe left ventricular dysfunction that persists despite the afterload reduction and diastolic augmentation provided by the intra-aortic balloon pump (IABP). Invasive hemodynamic monitoring serves precisely this purpose: to phenotype the shock state and guide therapeutic escalation based on the patient’s objective response to the initial care bundle [1]. The data clearly phenotype this as a cardiogenic shock state driven by pump failure, where the clinical trajectory necessitates escalation to pharmacological support with positive inotropes like dobutamine or milrinone to directly enhance contractility and improve forward flow [1].

Analysis of Incorrect Options

**Option 1: Increasing the IABP frequency to a 1:1 ratio** is not the priority. While maximizing IABP support can augment diastolic pressure and reduce afterload, the device is already providing mechanical circulatory support. The persistent low CI and high SVR indicate that the patient’s native cardiac contractility is insufficient, and the hemodynamic trajectory shows a need for pharmacological escalation beyond what the IABP alone can achieve [1].

**Option 2: Administering additional IV fluids** is contraindicated. The PAWP of 10 mmHg demonstrates adequate left ventricular filling pressure. In the setting of severe ventricular dysfunction, additional volume would not effectively increase stroke volume and would instead precipitate pulmonary congestion, further compromising an already failing heart. The principle of venous return dictates that in a failing heart with normal filling pressures, the problem is not a lack of volume but the heart’s inability to pump the volume it already has .

**Option 3: Positioning the patient in Trendelenburg position** is an outdated and potentially harmful intervention. This position transiently increases preload by shifting blood from the lower extremities to the central circulation. In a patient with a failing left ventricle and adequate PAWP, this sudden increase in venous return can overwhelm the heart, worsening pulmonary congestion and increasing myocardial oxygen demand without providing a sustained improvement in cardiac output .References (research sources)

- [1]Invasive Hemodynamic Monitoring in Acute Heart Failure and Cardiogenic Shock.Research articleBaldetti L, Cosenza M, Galdieri C, Gallone G, Ricchetti G, Gaspardone C, Peveri B, Gramegna M, Cianfanelli L, Calvo F, Pazzanese V, Pieri M, Sacchi S, Ajello S, Scandroglio AM. (2025) · DOI: 10.31083/rcm27034

## 임상 시나리오

Hemodynamic-Guided Escalation in Cardiogenic ShockInterpreting the Numbers to Move Beyond Mechanical Support
A Cardiac Index (CI) below 2.5 L/min/m² confirms a persistent low-output state despite IABP support. When combined with a normal PAWP (10 mmHg) and elevated SVR (1200 dynes/sec/cm⁵), the primary problem is pump failure, not volume depletion or vasodilation.

The core intervention is to collaborate for inotropic therapy. Agents like dobutamine or milrinone directly increase myocardial contractility, addressing the root cause when the IABP has maximized afterload reduction and diastolic augmentation.

CautionDo not administer additional IV fluids when PAWP is at the upper limit of normal. This risks pulmonary edema and further strains the failing ventricle. Avoid Trendelenburg positioning, as it increases venous return and afterload in a patient already in a high-SVR state.

## 핵심 개념

- **Cardiac Index (CI)** — Cardiac output adjusted for body surface area; normal range is 2.5–4.0 L/min/m². A value of 2.2 L/min/m² indicates a low-output state.
- **Pulmonary Artery Wedge Pressure (PAWP)** — An indirect measure of left ventricular preload; normal range is 8–12 mmHg. A value of 10 mmHg indicates adequate filling volume.
- **Systemic Vascular Resistance (SVR)** — A measure of afterload or resistance the left ventricle must overcome to eject blood; normal range is 800–1200 dynes/sec/cm⁵. A value of 1200 indicates high afterload.
- **Intra-Aortic Balloon Pump (IABP)** — A mechanical circulatory support device that augments diastolic coronary perfusion and reduces systolic afterload to support the failing heart.
- **Inotropic Therapy** — Pharmacological agents (e.g., dobutamine, milrinone) that increase myocardial contractility, used when pump failure is the primary cause of shock.

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