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A bloody epidural

01 September 2010

Mrs M, a 70-year-old woman, was admitted to the local hospital’s cardiac surgery unit. Six years ago, a triple coronary artery bypass graft (CABG) had given her a new lease of life, but since then the grafts had gradually become blocked, and she could no longer exercise. As a result, she had put on weight and was now obese. She had always been hypertensive.

Angiography showed diffuse disease in the grafts, which was not amenable to stenting, and she was offered revision surgery.

Dr E, a consultant anaesthetist, went to assess Mrs M prior to the surgery. Dr E told her that as part of his anaesthetic technique, he often inserted a thoracic epidural to provide good postoperative analgesia and support weaning from the ventilator. Mrs M was uncertain about the epidural, but Dr E reassured her it was a very effective analgesic technique. However, he made no specific mention of any risks of the epidural.

The following day, the epidural was placed uneventfully, and general anaesthesia was induced in the routine manner. As is routine for cardiac surgery, a large dose of heparin (300 units/kg, a total of 24,000 units) was given intravenously after induction to facilitate cardiopulmonary bypass (CPB). The operation took place without incident and three new vein grafts were inserted. Mrs M came off bypass readily, and the heparin was reversed as normal with protamine. She was transferred to the intensive care unit. An epidural infusion was commenced as planned, and she had a stable night.

The next morning, as the sedation was reduced, the nurse noted that Mrs M was moving her arms, but not her legs. The nurse documented that Mrs M could not feel or move her legs. However, as Mrs M seemed comfortable, she put it down to the normal effects of the epidural and did not call for medical review.

Mrs M was extubated without difficulty mid-morning. At lunchtime, she complained to the nurse that she was still unable to move her legs. The nurse called Dr E for advice. Dr E was in theatre and unable to attend. He asked that the epidural infusion be stopped and the catheter removed. He also sent for his registrar, Dr T, who arrived an hour later.

Dr T examined Mrs M and found a dense motor and sensory block with a level at T6 bilaterally. Dr T reported her findings to Dr E, who arranged an emergency CT scan of Mrs M’s spine. The scan showed a large haematoma in the epidural space in the mid thoracic spine, compressing the cord. later that evening, the neurosurgical team performed an emergency laminectomy and evacuation of the haematoma.

Although she recovered from both operations, Mrs M remained paraplegic. She insisted that she had never been warned that this complication might arise, and brought a claim against Dr E.

The experts were critical of several points. The ICU records were poorly kept, and observations were incompletely recorded. They were also critical of the nursing staff failing to appreciate the significance of a patient unable to move her legs. Neither Dr E nor the cardiac surgeon performed a postoperative review. The experts also concluded that there were unnecessary delays in recognising the problem, arranging the appropriate scan and carrying out the evacuation.

Finally, they questioned the wisdom of Dr E’s instruction to remove the epidural catheter prior to the scan. The case was settled for a high sum.

Learning points

  • Obtaining informed consent requires making the patient aware of potential complications. It may not be practical to list every possible complication of a procedure. However, common complications, relative to the patient, should be discussed routinely, as should rare but potentially catastrophic complications. 
  • Good documentation is essential for a good legal defence. In this case, although both the surgeon and Dr E said they had visited Mrs M after the operation, there was no record of her having been seen by a doctor for a period of more than 12 hours. 
  • It is the doctor’s responsibility to give clear instructions to the nursing staff when delegating a task. Nurses need to know what adverse signs to look for, and when to ask for help if things go wrong.

References

  • Bracco, D, Hemmerling, T, Epidural Analgesia in Cardiac Surgery: An Updated Risk Assessment, The Heart Surgery Forum, 10(4):334-337 (2007).
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