A 41-year-old project manager, Mrs F, underwent breast uplift surgery, performed on a private basis.
Induction of anaesthesia was performed by Dr T using propofol and fentanyl, and a laryngeal mask airway was inserted. A muscle relaxant was also administered. Anaesthesia was maintained with a propofol infusion, and a remifentanil infusion was also used.
Shortly after Mrs F had been transferred from the anaesthetic room to theatre, her heart rate significantly increased, as did her blood pressure. This change was recorded on the anaesthetic monitoring printout, but not recorded in the handwritten anaesthetic chart.
Dr T interpreted the increase in heart rate and blood pressure as indicative of the level of anaesthesia as being light. He increased the rate of infusion of both propofol and remifentanil and gave midazolam. Dr T did not record on the anaesthetic chart why these measures had been taken.
The surgery proceeded uneventfully, but on recovering from anaesthesia, Mrs F stated to ward staff that she had “woken up” during the operation, had heard the surgeon talking and had felt tugging and pushing. She tried to scream and move away but could not.
Mrs F brought a claim against Dr T for intraoperative accidental awareness resulting in psychiatric injury.
Dr T contacted Medical Protection, who instructed a consultant anaesthetist to provide an expert report.
The expert was supportive of the decision by Dr T to give midazolam and to increase the rate of infusion of propofol and remifentanil when Mrs F’s heart rate and blood pressure increased, and anaesthesia was suspected to be light.
However, the expert identified four clinical concerns regarding Dr T’s care:
1. that a target-controlled infusion pump (which would have used mathematical modelling to calculate and adjust the dose) was not used;
2. there had been a failure to perform any calculation or refer to an infusion regime about the rate of propofol infusion that would be required to keep Mrs F adequately anaesthetised;
3. there was no surgical or anaesthetic requirement for muscle relaxation to be used in this particular case, and the use of a muscle relaxant contributed to the occurrence of awareness, as did the failure to monitor the depth of anaesthesia (although such monitoring would not be mandatory); and
4. there was a failure to clearly document the changes on the anaesthetic chart.
Medical Protection met with Dr T and held a detailed discussion about the medical records, the expert opinion, Dr T’s own views on the case, and options on strategy. Dr T consented for Medical Protection to resolve the claim on best terms, and Medical Protection achieved a swift settlement of the claim for a low sum to reflect Mrs F’s psychiatric injury.
Learning points
If a target-controlled infusion pump is not used to administer total intravenous anaesthesia, then careful consideration and calculation of the rate to be infused must be performed. A number of infusion regimes have been described for use when manually adjusting infusion rates of propofol.
∙ The risk of anaesthetic awareness is increased when a patient is paralysed, and thought should be given on whether use of a muscle relaxant is necessary for the particular procedure being performed.
∙ Consider using a depth of anaesthesia monitor when administering total intravenous anaesthesia, especially when a muscle relaxant is also administered.
∙ Contemporaneous record keeping should be accurate and reflect the events that have occurred.
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