Q:1
An 8-year-old with septic shock is intubated and receiving norepinephrine. ScvO₂ is 82%, lactate is 5 mmol/L, and capillary refill is delayed. Echocardiography shows preserved systolic function. What is the most likely explanation for the elevated ScvO₂?
A. Excess oxygen delivery relative to demand
B. Impaired tissue oxygen extraction
C. Severe anemia
D. High cardiac output with normal extraction
E. Measurement artifact
Answer:
B
Explanation:
In septic shock, microcirculatory dysfunction and mitochondrial impairment reduce oxygen extraction, leading to paradoxically elevated ScvO₂ despite tissue hypoperfusion.
Q 2:
A 10-year-old ventilated child with septic shock has tidal volume 8 mL/kg, sinus rhythm, and no spontaneous breaths. Pulse Pressure Variation is 18%. What does this suggest?
A. Patient is unlikely fluid responsive
B. High pulmonary vascular resistance
C. Fluid responsiveness is likely
D. Elevated intracranial pressure
E. Severe left ventricular dysfunction
Answer:
C
Explanation:
In fully mechanically ventilated patients with adequate tidal volumes and regular rhythm, PPV >13–15% predicts preload responsiveness.
Q 3:
A 5-year-old post-cardiac surgery patient has an arterial line waveform that appears flattened with reduced systolic peak and elevated diastolic pressure. What is the most likely cause?
A. Hypovolemia
B. Overdamping of the arterial system
C. Underdamping
D. Severe aortic stenosis
E. Hyperdynamic circulation
Answer:
B
Explanation:
Overdamped systems underestimate systolic and overestimate diastolic pressure, narrowing pulse pressure and flattening waveform morphology.
Q 4:
A child with meningococcal septic shock has initial lactate 8 mmol/L. After 6 hours of resuscitation, lactate decreases to 4 mmol/L. What does this most strongly indicate?
A. Complete resolution of shock
B. Adequate oxygen delivery restoration
C. Improved global perfusion trend
D. Normal hepatic function
E. Absence of microcirculatory dysfunction
Answer:
C
Explanation:
Lactate clearance is associated with improved outcomes and reflects improving perfusion, though it does not guarantee normalization of microcirculation.
Q 5:
A ventilated child with septic shock has CVP of 14 mmHg but remains hypotensive with poor perfusion. Which interpretation is most appropriate?
A. High CVP excludes hypovolemia
B. CVP reliably predicts fluid responsiveness
C. Static CVP poorly predicts preload responsiveness
D. CVP >12 mandates diuresis
E. CVP confirms cardiogenic shock
Answer:
C
Explanation:
Static CVP is a poor predictor of fluid responsiveness. Elevated values may reflect intrathoracic pressure or reduced compliance rather than adequate preload.
Q 6:
6.
A post–cardiac surgery infant shows cerebral NIRS values decreasing from 70% to 50% despite stable systemic blood pressure.
What does this most likely represent?
A. Increased cerebral oxygen delivery
B. Reduced cerebral perfusion or extraction mismatch
C. Measurement calibration error
D. Hypercapnia
E. Improved cardiac output
Answer:
B
Explanation:
Declining NIRS values indicate reduced regional oxygen saturation, often from decreased cerebral perfusion or increased metabolic demand.
Q 7:
Which limitation applies to pulse contour cardiac output systems in pediatrics?
A. Require pulmonary artery catheter
B. Unaffected by vascular tone changes
C. Accuracy reduced in vasoplegic states
D. Not usable in ventilated patients
E. Cannot provide stroke volume variation
Answer:
C
Explanation:
Pulse contour analysis depends on arterial waveform characteristics and may lose accuracy when vascular tone changes significantly, as in septic shock.
Q 8:
Compared with SvO₂ (pulmonary artery), ScvO₂ typically:
A. Is identical in all shock states
B. Is lower in sepsis
C. Overestimates global venous saturation
D. Cannot be used clinically
E. Reflects coronary sinus oxygenation
Answer:
C
Explanation:
ScvO₂ often overestimates true mixed venous saturation because it excludes coronary sinus blood, which has low oxygen content.
Q 9:
A 7-year-old child with septic shock is spontaneously breathing. Pulse Pressure Variation is 16%, but tidal volumes are inconsistent. What is the best conclusion?
A. Patient is fluid responsive
B. PPV remains reliable
C. PPV interpretation is unreliable in this context
D. Immediate fluid bolus indicated
E. Severe RV failure present
Answer:
C
Explanation:
Dynamic indices such as PPV require controlled mechanical ventilation and regular tidal volumes. Spontaneous breathing invalidates interpretation.
Q 10:
A 9-year-old with trauma has HR 150 bpm and systolic BP 80 mmHg. What does an elevated shock index indicate?
A. Adequate perfusion
B. Absence of bleeding
C. Normal cardiovascular compensation
D. Increased risk of hemodynamic instability
E. Reliable cardiac output measurement.
Answer:
D
Explanation:
Shock index (HR/SBP) reflects circulatory compromise. Elevated values correlate with increased risk of shock and adverse outcomes in pediatric trauma.
