FRCPath Haem Part 1 MCQs-Transfusion 462
- amirhayat2527
- 1 day ago
- 1 min read
A 62-year-old man is admitted to the intensive care unit with severe community-acquired pneumonia complicated by septic shock. He required vasopressor support and invasive mechanical ventilation for 9 days. His shock has resolved, inflammatory markers are improving, and renal function is normal. Sedation has been discontinued and the intensive care team plans spontaneous breathing trials to facilitate extubation.
His observations are:
Temperature 36.8°C
Heart rate 88 bpm
Laboratory results:
Hb 69 g/L
WBC 10.8 ×10⁹/L
Platelets 265 ×10⁹/L
There is no active bleeding, no evidence of myocardial ischaemia, and no chronic transfusion-dependent anaemia.
The ICU consultant asks whether transfusing one unit of red cells is likely to improve the chance of successful liberation from mechanical ventilation.
Which ONE of the following statements is most consistent with current evidence?
A. Transfuse because maintaining Hb >100 g/L significantly shortens the duration of mechanical ventilation.
B. Transfuse because all patients undergoing weaning from ventilation should receive red cells when Hb is below 90 g/L.
C. Transfuse because a restrictive transfusion threshold of 70 g/L remains appropriate during weaning from mechanical ventilation in stable critically ill patients.
D. Avoid transfusion because anaemia has no effect whatsoever on respiratory muscle performance during weaning.
E. Delay weaning until Hb exceeds 90 g/L because extubation failure is primarily determined by oxygen-carrying capacity.
Correct Answer
✅ C. Transfuse because a restrictive transfusion threshold of 70 g/L remains appropriate during weaning from mechanical ventilation in stable critically ill patients.
Explanation
Weaning from mechanical ventilation increases respiratory muscle work and oxygen demand. It was previously hypothesised that increasing haemoglobin concentration might reduce respiratory muscle fatigue and improve extubation success.
However, multiple randomised trials and systematic reviews have not demonstrated a benefit from liberal transfusion strategies in stable ICU patients, including those undergoing ventilator weaning.
Current recommendations therefore continue to support:
Restrictive transfusion threshold of approximately 70 g/L
Transfuse if Hb is <70 g/L in haemodynamically stable, non-bleeding critically ill adults.
Higher thresholds are reserved for selected patients such as acute coronary syndrome, ongoing major haemorrhage, or…