Mr C, a 47-year-old self-employed electrician, was admitted for a routine arthroscopic menisectomy of the knee. He was in good health and did not take any regular medication. His past medical history was unremarkable. He was keen to resume his active lifestyle, and return to work as soon as possible since he was the sole breadwinner. Preoperative assessment confirmed that he was healthy and fit for the procedure.
He was listed to undergo surgery as a day case. The anaesthetist failed to carry out any checks of the anaesthetic equipment, either in the anaesthetic room or in the operating theatre.
The induction of anaesthesia was straightforward. The airway was easily secured with spontaneous ventilation through a laryngeal mask airway. Anaesthesia was maintained with a mixture of isoflurane in nitrous oxide and oxygen. An opioid and nonsteroidal anti-inflammatory were administered to provide suitable analgesia.
About 20 minutes into surgery, the anaesthetist noticed that the oxygen saturation had fallen from 98% to 46%. Simultaneously, the heart rate fell from 64 to 30.The patient’s colour had turned dusky and his pulse was slow and weak. A rapid assessment of the airway confirmed that it was still patent.
The anaesthetist was unable to find an immediate cause, and increased the oxygen concentration to 100% with no improvement in the saturation.
He administered 0.6mg of atropine as well. The heart rate increased to 100 beats per minute.
The saturation, however, remained low. The anaesthetist then conducted a check of the entire anaesthetic breathing circuit and anaesthetic machine.
He found a leak in the circle breathing system. This was replaced and the oxygen saturation gradually returned to 96%. The rest of the procedure was uneventful. Return of consciousness was delayed, and it soon became apparent that the patient had suffered a hypoxic brain injury.
Subsequent neurological assessment confirmed that the patient had suffered a significant hypoxic brain injury with no prospect of a return to his former activities. He was unable to return to his livelihood and required fulltime care.
A consultant anaesthetist provided an expert opinion about the standard of care provided by the anaesthetist. He concluded that there had been a glaring failure to check the anaesthetic machine and equipment prior to administering the anaesthetic.
The expert felt that the fault in the breathing circuit would have been apparent from the outset had the machine been checked. Subsequent events might then have been avoided. He was also critical of the immediate management of the bradycardia in the presence of the severe hypoxaemia. He felt that more attention should have been given to searching for a cause of the bradycardia; in this case it was hypoxaemia.
His conclusions were that the standard of care fell short of what might have been reasonably expected. The case was indefensible, and was settled for a substantial amount.
- It is mandatory to carry out a proper check of the anaesthetic machine, equipment and monitoring equipment prior to their use. A major contributory factor to hypoxic brain injury during anaesthesia has been the use of equipment and breathing circuits that had not been checked by the anaesthetist.
- A record of the check should be kept.
- A local policy should be in place to ensure that anaesthetists are well acquainted with the anaesthetic equipment they are using and the checking procedure.
- There are several well-known causes of bradycardia under anaesthesia. These include drugs and certain surgical stimuli. In the absence of any other obvious immediate cause for a sudden bradycardia during anaesthesia, hypoxaemia should always be foremost in the differential diagnosis. Bradycardia is a late manifestation of hypoxaemia in adults. Urgent efforts should be directed to finding and correcting the immediate cause of the hypoxaemia.
The Association of Anaesthetists of Great Britain and Ireland (AAGBI) has published a guidelines booklet entitled Checking Anaesthetic Equipment (2004).
The AAGBI has also produced Checklist for Anaesthetic Equipment 2004. This is available in A4 laminated format for attachment to all anaesthetic machines.
Both at www.aagbi.org.
The Royal College of Anaesthetists requires trainees to demonstrate competency in checking the equipment as part of their assessment. www.rcoa.ac.uk