Core interpretation
This patient has cardiogenic shock following a large anterior MI. At 16:00, the MAP of 68 mmHg meets the ordered target of 65 mmHg or higher. However, the clinical picture does not support the conclusion that shock is resolving. Urine output of 30 mL/h remains below his individualized goal of 40 mL/h (calculated as 0.5 mL/kg/h × 80 kg). Lactate has decreased only slightly, from 5.2 mmol/L to 4.9 mmol/L, and is still markedly elevated. Persistent crackles, cool knees, and mottling indicate that tissue perfusion and pulmonary congestion have not meaningfully improved.
A MAP at target does not by itself confirm adequate end-organ perfusion. In cardiogenic shock, blood pressure can be supported pharmacologically while cardiac output and microcirculatory flow remain severely impaired. The nurse must integrate perfusion markers—urine output, lactate trend, skin findings—rather than rely on a single hemodynamic number.
Watch out! Option 1 is unsafe because stopping noradrenaline based only on a MAP of 68 mmHg ignores the ongoing hypoperfusion. Option 2 is incorrect because crackles and a large anterior MI point to a cardiogenic rather than hypovolemic cause; a fluid bolus may worsen pulmonary edema. Option 4 is incomplete because although some parameters improved slightly, the overall picture still shows inadequate perfusion requiring escalation.
Lactate elevation in cardiogenic shock primarily reflects the magnitude and duration of systemic hypoperfusion caused by reduced cardiac output, often compounded by regional ischemia, particularly in the splanchnic territory. A lactate that remains above 4 mmol/L after initial resuscitation is a strong signal of persistent shock and poor tissue oxygen delivery. The small decline from 5.2 to 4.9 mmol/L over four hours is not convincing evidence of reversal.
Key point! Urine output is a direct and continuous marker of renal perfusion. In this patient, 30 mL/h is still below the goal of 40 mL/h, meaning the kidneys are not receiving enough blood flow despite the improved MAP. Persistent oliguria plus cool, mottled knees indicates that vasoconstriction and microcirculatory dysfunction are ongoing.
The correct action is to report now. The physician or rapid response team needs to know that pressure is at goal but perfusion remains poor, because this pattern often requires escalation—such as adding an inotrope, adjusting vasopressor strategy, or considering mechanical circulatory support.
| Parameter | 12:00 | 16:00 | Interpretation |
|---|---|---|---|
| MAP | 58 mmHg | 68 mmHg | At target, but not sufficient alone |
| Urine output | 15 mL/h | 30 mL/h | Still below goal of 40 mL/h |
| Lactate | 5.2 mmol/L | 4.9 mmol/L | Minimal decline; remains very high |
| Skin | Cool, clammy | Cool knees, mottled | Persistent hypoperfusion |
| Lungs | Crackles | Crackles | Pulmonary congestion persists |
In cardiogenic shock, lactate interpretation should not be oversimplified as a single threshold. The trend matters, but so does the absolute value and the clinical context. A lactate that falls only slightly while oliguria and mottling continue indicates that the shock state is not yet reversed, even if the blood pressure reading looks acceptable.
A MAP at goal does not confirm adequate tissue perfusion. In cardiogenic shock, vasopressors can raise pressure while cardiac output and microcirculatory flow remain severely impaired. Always assess urine output, lactate trend, and skin findings together.
For this 80 kg patient, the urine output goal is 40 mL/h (0.5 mL/kg/h). A urine output of 30 mL/h is still below target. A lactate that has barely fallen from 5.2 to 4.9 mmol/L remains more than twice the upper limit of normal.
Do not stop vasopressors based on a single MAP reading. Persistent crackles, cool knees, and mottling indicate ongoing hypoperfusion and pulmonary congestion. Report immediately so therapy can be escalated, such as with mechanical circulatory support. Avoid fluid boluses in cardiogenic shock with pulmonary edema.
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