Failed extradural anaesthesia for caesarean section. Complication of subsequent spinal block.

Two cases of unexpected high spinal anaesthesia following failed extradural anaesthesia for Caesarean section are described. In both cases rapid and unexpected advance of blockade, after the subarachnoid injection of moderate doses of local anaesthetic, required tracheal intubation. In one of the cases 15 ml of 0.9% saline, but no local anaesthetic, had been injected into the extradural space, suggesting that the mechanism involved is the cephalad displacement of the cerebrospinal fluid by extradural fluid, and not leakage of extradural anaesthetic solution into the subarachnoid space.