FCA1-0323

FCA1-0323

A 68-year old man, is admitted in hospital. He is scheduled to undergo a femoro-popliteal bypass graft, for which he has been administered a spinal-epidural anaesthetic. Intrathecal heavy bupivacaine (0.5%) was injected at L3-4 with good effect. On insertion of the epidural catheter, he remained asymptomatic. During surgery, 5000 I.U. of IV heparin was given. The surgery is successful and required no epidural top-ups. Six hours later, he complains of a severe back pain with weakness in his lower limbs. What is the most important first step?