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Problematic anaesthetic

02 August 2017

Mrs B was a 57 year old lady with a past history of breast cancer treated with mastectomy and adjuvant therapy. She re-presented to her specialist breast surgeon Dr F three years after the original surgery with a worrying 2cm lump in the vicinity of her mastectomy scar. Dr F recommended an urgent excision biopsy of the lump under general anaesthetic.

On the day of surgery, Mrs B was reviewed by consultant anaesthetist Dr S. She told Dr S that she had been fine with her previous anaesthetic and that she had no new health problems. Dr S reassured Mrs B that it should be a routine procedure and that he anticipated no problems. He warned her about the possibility of dental damage and sore throat and promised that he would not use her left arm for IV access or blood pressure readings, because of the previous lymph node dissection on that side.

In the anaesthetic room, Dr S reviewed the anaesthetic chart for Mrs B’s mastectomy procedure. He saw that Mrs B had received a general anaesthetic along with a paravertebral block for post-operative analgesia, and this technique appeared to have worked well. He did not, however, discuss this with Mrs B.

Dr S inserted a cannula in Mrs B’s right arm and induced anaesthesia with fentanyl and propofol. He inserted a laryngeal mask airway and anaesthesia was maintained with sevoflurane in an air/oxygen mixture. Mrs B was then turned on to her side and Dr S proceeded to insert left sided paravertebral blocks at C7 and T6. Although Dr S used a stimulating needle and a current of 3mA, he had difficulty eliciting a motor response at either level. At T6, Dr S finally saw intercostal muscle twitching after a number of needle passes. Twitches were still just visible when the current was reduced to 0.5mA and Dr S therefore slowly injected 10mL of Bupivicaine 0.375% with clonidine. At the upper level, Dr S could not elicit a motor response despite several needle passes. He eventually decided to use a landmark technique and injected the same volume of local anaesthetic mixture at approximately 1cm below the transverse process.

Dr S then administered atracurium 30mg and Mrs B was ventilated for the duration of the operation. The operation was largely uneventful apart from modest hypotension which Dr S treated with boluses of ephedrine and metaraminol.

At the end of surgery, Dr S reversed the neuromuscular blockade and attempted to wake Mrs S. However, Mrs B’s respiratory effort was poor and she was not able to move her limbs. Dr S diagnosed an epidural block caused by spread of the local anaesthetic. He reassured Mrs B and then re-sedated her for approximately 40 minutes. Following that she was woken again and her airway was removed. Weakness of all four limbs was still noted.

Over the next five hours Mrs B regained normal sensation and power in her lower limbs and left arm. However, her right arm remained weak, with an absence of voluntary hand movements. She also had gait ataxia on attempting to mobilise. An MRI was performed the following day which demonstrated signal change and subdural haemorrhage in the spinal cord at a level consistent with her persistent symptoms.

Mrs B remained in hospital for physiotherapy and rehabilitation. Her walking and right hand function gradually improved and she was discharged three weeks after her operation.  Six months later, Dr S received an attorney’s letter stating that Mrs B was still having problems with her hand and was seeking compensation.

Expert Opinion

Medical Protection instructed Dr M, a specialist anaesthetist, to comment on the standard of care. Dr M was critical of Dr S for four major reasons:

  1. Dr S had failed to inform Mrs B that he intended to perform a paravertebral block and failed to discuss the risks and benefits of such a technique. He was somewhat critical of the decision to perform the block with Mrs B anaesthetised. He opined that had Mrs B been conscious or lightly sedated, she would have alerted Dr S when the needle was in proximity to nerve tissue. However, Dr M did concede that there was a body of responsible anaesthetists who would support the notion of performing a paravertebral block with the patient anaesthetised.
  2. He was critical of Dr S’s decision to keep persisting with the block when he was struggling to locate the correct needle position. He felt that Dr S should have abandoned the block or called for help. He also concluded that the technique used by Dr S was very poor given the complications that followed.
  3. Dr M was critical of the levels chosen by Dr S to perform the block. He felt that C7 was too high, given that the dermatomal level of the surgery was approximately T4. He also felt that the surgery was very minor and did not warrant the paravertebral block. Dr M was of the opinion that infiltration of local anaesthetic by the surgeon, combined with simple analgesics, would have sufficed.

On the basis of the expert evidence Medical Protection concluded that there was no reasonable prospect of defending the claim. The case was eventually settled for a substantial sum.

Learning points
  1. Local anaesthetic blocks should only be performed when there is a clear indication.
  2. The risks and benefits of the block should be discussed with the patient and clearly documented. The process of consent for any operation should be a detailed conversation between clinician and patient with documented evidence. The incidence and potential impact of any common and potentially serious complications should always be discussed and documented.
  3. Local anaesthetic blocks should only be performed by practitioners with appropriate training and expertise.
  4. If difficulties are encountered, either the procedure should be abandoned or assistance summoned.