# A nurse is caring for a 58-year-old male patient in the intensive care unit admitted following acute myocardial infarction with cardiogenic shock, who has a pulmonary artery catheter in place. The patient's hemodynamic parameters show: pulmonary artery pressure (PAP) 45/25 mmHg, pulmonary capillary wedge pressure (PCWP) 22 mmHg, cardiac output (CO) 3.2 L/min, and systemic vascular resistance (SVR) 1800 dynes/sec/cm⁵. What is the nurse's priority intervention? > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=542599 > language: ko > subject: Critical Care ## 문제 A nurse is caring for a 58-year-old male patient in the intensive care unit admitted following acute myocardial infarction with cardiogenic shock, who has a pulmonary artery catheter in place. The patient's hemodynamic parameters show: pulmonary artery pressure (PAP) 45/25 mmHg, pulmonary capillary wedge pressure (PCWP) 22 mmHg, cardiac output (CO) 3.2 L/min, and systemic vascular resistance (SVR) 1800 dynes/sec/cm⁵. What is the nurse's priority intervention? The patient is a 58-year-old male admitted to the ICU following acute myocardial infarction with cardiogenic shock. ## 보기 1. Increase intravenous fluid administration to improve preload 2. Administer vasopressor medications to increase blood pressure 3. Prepare for immediate cardioversion due to arrhythmias 4. Administer inotropic agents to improve cardiac contractility **✔ 정답** **정답: 4** ## 해설 Elevated PCWP and low CO indicate cardiogenic shock requiring inotropic agents to improve contractility. Other options may worsen the condition by increasing preload or not addressing the primary pump failure. ## 심화 해설 Hemodynamic Analysis The patient's parameters reveal a classic profile of cardiogenic shock following acute myocardial infarction. The pulmonary capillary wedge pressure (PCWP) is markedly elevated at 22 mmHg (normal: 6–12 mmHg), indicating significant left ventricular filling pressure and pulmonary congestion. The cardiac output (CO) is critically low at 3.2 L/min (normal: 4–8 L/min), reflecting severe pump failure. The systemic vascular resistance (SVR) is elevated at 1800 dynes/sec/cm⁵ (normal: 800–1200 dynes/sec/cm⁵), which is a compensatory vasoconstriction in response to the low cardiac output state. This combination of high filling pressure, low output, and high afterload confirms that the primary problem is the heart's inability to pump effectively, not a lack of fluid volume. Prioritization Rationale The priority intervention is to administer inotropic agents to improve cardiac contractility. In cardiogenic shock following myocardial infarction, the fundamental defect is impaired myocardial contractility . The goal of therapy is to break the vicious cycle of low output, hypoperfusion, and worsening cardiac function. Inotropes such as dobutamine or milrinone directly enhance contractility, which will increase cardiac output, improve tissue perfusion, and secondarily allow the compensatory SVR to decrease as the sympathetic drive is reduced. This directly addresses the underlying pathophysiology of pump failure. Analysis of Incorrect Options Increasing intravenous fluid administration (Option 1) is contraindicated. The PCWP of 22 mmHg already indicates volume overload and pulmonary venous congestion. Administering more fluid would further increase the filling pressure without improving contractility, worsening pulmonary edema and respiratory failure. Vasopressor medications (Option 2), such as norepinephrine, would increase SVR and blood pressure but at the cost of increasing the workload of the already-failing left ventricle. While vasopressors may be necessary for refractory hypotension, they are not the first-line priority when the primary issue is contractile dysfunction and afterload is already elevated. Preparing for immediate cardioversion (Option 3) is not indicated as there is no evidence of a tachyarrhythmia in the presented data; the hemodynamic profile is consistent with sinus tachycardia as a compensatory mechanism, not a primary arrhythmic event. Clinical Integration and Monitoring Advanced hemodynamic monitoring, as provided by the pulmonary artery catheter, is a cornerstone of goal-directed therapy in cardiac surgery and critical care to differentiate shock states and guide management . In this case, it precisely identifies a cardiogenic rather than hypovolemic or distributive etiology. After initiating inotropic support, the nurse would monitor for an increase in CO, a decrease in SVR, and a gradual reduction in PCWP as forward flow improves. For patients with refractory shock despite pharmacological support, mechanical circulatory support devices like veno-arterial ECMO or an intra-aortic balloon pump (IABP) may be considered to unload the left ventricle and support systemic perfusion, though their impact on myocardial recovery remains an area of active investigation . The presence of a low cardiac output state in this context is a critical marker of disease severity, and its correction is the immediate clinical priority . ## 임상 시나리오 Cardiogenic Shock Hemodynamic ManagementInterpreting PA Catheter Values in Pump Failure The classic profile includes elevated PCWP (>18 mmHg), low CO/CI, and elevated SVR. This patient's PCWP 22 mmHg confirms pulmonary congestion, not hypovolemia. The priority is to enhance contractility with inotropes (e.g., dobutamine). This increases CO and breaks the compensatory vasoconstriction cycle, reducing SVR. CautionAvoid fluid boluses when PCWP is high; they worsen pulmonary edema. Vasopressors increase already high SVR, raising myocardial oxygen demand. ## 핵심 개념 - **Cardiogenic Shock** — A life-threatening condition where the heart's pumping function fails, preventing adequate oxygen delivery to tissues. Myocardial infarction is a major cause. - **Pulmonary Capillary Wedge Pressure** — Pressure measured through a pulmonary artery catheter, which indirectly reflects left atrial pressure. It is used to assess left ventricular preload and function. - **Inotropic Agent** — Drugs that increase the contractile force of the heart muscle. Used to improve cardiac output in cardiogenic shock (e.g., dobutamine, milrinone). - **Systemic Vascular Resistance** — Resistance of the systemic blood vessels. Along with cardiac output, it determines mean arterial pressure. When cardiac output decreases, SVR increases as a compensatory mechanism. - **Pulmonary Artery Catheter** — A catheter inserted into the pulmonary artery to directly measure pressures in the heart and lungs, as well as cardiac output. 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