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Difficulty: Very hardPhysiological Adaptation

A nurse is assessing a client admitted 12 hours ago with an acute anterior wall myocardial infarction. The client is receiving a continuous intravenous heparin infusion. The client suddenly reports feeling extremely apprehensive and restless.

Current clinical data:
- Blood pressure: 90/74 mmHg (decreased from 118/76 mmHg two hours ago)
- Heart rate: 116 beats/min
- Respiratory rate: 26 breaths/min
- Jugular venous distention is noted when the head of the bed is elevated to 45 degrees
- Lung fields are clear to auscultation bilaterally
- Urine output was 15 mL over the past hour

Based on these findings, which physiological complication should the nurse suspect the client is developing?

  1. Cardiac tamponadeAnswer
  2. B
    Cardiogenic shock
  3. C
    Hypovolemic shock
  4. D
    Right ventricular myocardial infarction

Answer

The client is developing cardiac tamponade.
The correct answer is cardiac tamponade. The client is exhibiting a severely narrowed pulse pressure (90/74 = 16 mmHg), which is a hallmark sign of restricted ventricular filling. The presence of jugular venous distention indicates increased right-sided pressures, but the clear lung fields rule out left-sided failure (which would be expected in cardiogenic shock resulting from an anterior MI). Hypovolemic shock would present with flat, not distended, neck veins. While a right ventricular MI presents with similar signs, it is associated with inferior, not anterior, infarctions. The continuous heparin infusion places this client at high risk for a hemorrhagic pericardial effusion, precipitating cardiac tamponade.

Step-by-Step Solution

1
Analyze the vital sign trends and calculate the pulse pressure.
The blood pressure dropped, but specifically, the pulse pressure narrowed severely from 42 mmHg (118 - 76) to 16 mmHg (90 - 74). The client is also tachycardic and tachypneic.
A severely narrowed pulse pressure is a hallmark sign of restricted ventricular filling and decreased stroke volume, combined with compensatory systemic vasoconstriction.
2
Evaluate the physical assessment findings in the context of the medical history.
The client has an anterior wall MI (left-sided injury) but is presenting with jugular venous distention (right-sided backup) and clear lung sounds (absence of left-sided backup).
Left-sided heart failure (common in anterior MI) would cause crackles/pulmonary edema. The presence of JVD with clear lungs indicates an obstructive or right-sided issue, rather than left-sided pump failure.
3
Synthesize the data to identify the specific shock state.
The combination of narrowed pulse pressure, JVD, clear lungs, and hypotension in a client receiving an anticoagulant (heparin) points to fluid compressing the heart.
The heparin infusion places the client at high risk for hemorrhagic pericarditis or free wall rupture leading to cardiac tamponade. The clinical picture perfectly aligns with Beck's triad (hypotension, JVD, muffled heart sounds—though muffled sounds aren't explicitly listed, the other signs strongly indicate tamponade).

Key Concept

Differentiating obstructive shock (cardiac tamponade) from cardiogenic and hypovolemic shock using complex hemodynamic and physical assessment data.
Estimated Time:2m 30s
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Topics

Physiological Adaptation

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