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Transoesophageal echocardiography (TOE) is regarded as a safe procedure and is widely practised by doctors with variable training. However, TOE often involves the use of intravenous sedation. Cardiorespiratory depression is well recognised during gastroscopy, accounting for up to two thirds of deaths.1 2 Information on the safety of sedation for TOE is more limited. There has been one large study involving 15 European centres and 10 419 TOE examinations.3 TOE was associated with acceptable low risk with a serious complication rate of 0.18% and mortality of < 0.01%. However, only one centre used routine intravenous sedation.
A Working Party report “Guidelines for sedation by non-anaesthetists” was published in 1993 by the Royal College of Surgeons of England to promote the safe practice of sedation across all specialties.4 In a survey of 45 UK hospitals, we report on the variation in sedation and monitoring techniques during TOE and assess compliance with the Working Party report.
Questionnaires were returned from 45 centres performing TOE randomly selected from The Hospital Directory (30 tertiary centres, 15 district general hospitals). Primary operators included 31 consultant cardiologists, 11 registrars, and three sonographers. Experience ranged from 20 to 2000 scans, median 300. Table 1 summarises the results of the questionnaire.
The Working Party recommended a pre-procedural risk assessment including blood pressure measurement. Sedation technique should include titration with a short acting benzodiazepine (midazolam) to the minimum dose facilitating treatment but allowing verbal communication to be maintained with an additional trained staff member, such that the patient responds to command. Where sedation is exceeded and contact with the patient is lost, one may be judged medicolegally to be administering an anaesthetic and will be responsible for all the attendant risks of anaesthesia. All patients undergoing sedation should have continuous intravenous access, should receive supplemental oxygen, and be monitored with ECG and oximetry. The procedure should be performed on a trolley with facilities for head down tilt, and with immediate access to resuscitation equipment and flumazenil. The recovery area should have adequate facilities and staff. Patients must satisfy minimum discharge criteria.
In our survey, sedation with intravenous midazolam was used in the vast majority of patients, with a mean dose of 5 mg, range 2–10 mg. Consistent with the guidelines, TOE was performed with at least one other trained member of staff, and immediate access to resuscitation equipment and flumazenil. However, sedation was administered as a bolus by 30% of operators and 58% reported patients becoming verbally unresponsive; this group used on average a higher total dose of midazolam (mean (SD) 6 (2.3) mg v 3.9 (1.7) mg, p < 0.01). Furthermore, only 20% of operators used routine supplemental oxygen, 29% failed to employ routine pulse oximetry, and 47% rarely or never measured blood pressure. The routine use of a local anaesthetic throat spray was almost universal. A link has been reported between the use of pharyngeal sprays and the development of aspiration pneumonia after gastroscopy1; this risk needs to be clarified. At present there is no unanimity in antibiotic prophylaxis. Antibiotics, even in high risk patients, are currently not recommended routinely by the British Society of Echocardiography.5 Finally, the wide variation in TOE practice was reflected in the finding that most operators have received no formal training in the administration of sedation and are unaware of published guidelines.
In an era of clinical governance, it should be a priority to formulate comprehensive guidelines on TOE practice which concur with established national recommendations. Training in monitoring and resuscitation for both medical and technical staff as well as availability of monitoring equipment will be required to integrate these into clinical practice. Furthermore, a framework for accurately recording data and monitoring the service is needed to determine whether this approach improves standards of care and cost effectiveness. These issues should be addressed if we are to promote a safe, high quality TOE service in the UK.
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