skip to main content

Breathlessness Under Spinal Anaesthesia — FRCA Final MCQ

Instant feedback + full explanation. One question, done properly.

EasyObstetric AnaesthesiaBreathlessness Under Spinal AnaesthesiaFRCA Final

A 40-year-old woman (ASA II, 65 kg) at 38 weeks gestation has an elective caesarean section under spinal anaesthesia. The block reaches T4 bilaterally and is adequate for surgery. She becomes breathless and anxious. SpO2 is 98%, ETCO2 via nasal prongs is 4.2 kPa, and BP is 110/60 with phenylephrine. What is the most likely cause of her breathlessness?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Anxiety with intact diaphragmatic function

Breathlessness with a block to T4 is extremely common and is primarily caused by loss of proprioceptive feedback from the chest wall and abdominal muscles (intercostal and abdominal muscle paralysis). The diaphragm (C3-C5) remains functional and respiratory parameters (SpO2, ETCO2) are normal. This confirms adequate ventilation. The sensation is frightening for patients who cannot feel their chest moving normally. Reassurance that breathing is adequate (demonstrating normal SpO2 and speech) is the key management. If the block is truly excessively high (above C5), respiratory failure would occur.

Reference: OAA – 2024 – Quick Reference Handbook: High spinal; RCOA – 2023 – Obstetric anaesthesia