Paper I
Question
Spinal anaesthesia - complications and treatment
Answer
- Hypotension (the commonest complication) — sympathetic (vasomotor) fibre blockade occurs at a higher spinal level than sensory block, causing venodilation, reduced venous return, and a fall in cardiac output. Treatment: IV fluid preloading; vasopressors (ephedrine/phenylephrine) if it occurs.
- Bradycardia — blockade of cardiac accelerator sympathetic fibres (T1-T4) if the block rises high enough, leaving vagal tone unopposed. Treatment: atropine.
- Total (high) spinal — block ascending high enough to affect the phrenic nerve (C3-C5) and brainstem function, causing respiratory paralysis and loss of consciousness — a medical emergency. Treatment: airway support and ventilation.
- Post-dural puncture headache — persistent CSF leak through the dural puncture site causing intracranial hypotension; classically postural (worse sitting/standing, relieved lying flat). Treatment: conservative (fluids, caffeine, analgesia) or, if severe/persistent, an epidural blood patch (autologous blood injected at the puncture site to seal the leak).
- Nausea/vomiting — usually secondary to the hypotension above rather than a direct drug effect; treated by correcting the underlying hypotension.