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Editors,—Drs Lawson and Bray1 have presented arguments for and against deep sedation of children by non-anaesthetists. We would like to contribute to the debate by expanding on issues which have influenced and encouraged the development of a nurse led sedation service for magnetic resonance imaging (MRI) at our hospital.2
There continues to be a huge demand for MRI and as a result we have had to meet the challenge of providing a sedation and anaesthesia service with limited resources. With safety in mind, in 1996 we sought funding for sufficient staffing to provide an anaesthesia only service for one MR scanner, for four days a week. Funding was refused because of high costs, and because the option of improved sedation by non-anaesthetists had not been fully explored. Fortunately, we have been successful in developing our nurse led sedation service and have needed only a modest increase in anaesthesia sessions from two in 1996 to three currently. We now have two MRI scanners providing a total of eight days a week of clinical service, and we are able to look back and reflect that if we had held the philosophy that only anaesthesia was safe enough this would have severely limited any expansion and flexibility in the totality of the anaesthetic service we provide to the hospital. We believe we have developed a sedation service by non-anaesthetists that is safe and effective.
Everyone seems to agree that conscious sedation, where the patient can be roused by verbal command, is safe for non-anaesthetists but is impractical for imaging in small children because they must be “asleep” to be still enough. We have always accepted the danger of deeply sedated children becoming effectively anaesthetised during imaging. Indeed, one of us (DH) was a member of the working party that developed the guidelines for sedation in adults quoted by Lawson and Bray.3 We have therefore applied the following definition of sedation for MRI: a technique in which the use of a drug or drugs produces a state of depression of the nervous system such that the patient is not easily roused but which has a safety margin wide enough to render the loss of airway and breathing reflexes unlikely.
We accept that in an ideal world, anaesthetists are the best people to manage deep sedation. However, this statement is too broad and overlooks the fact that sedation is specific to a particular procedure. Gastroscopy for example, requires sedation to a degree which suppresses the gag reflex and consequently airway reflexes are often reduced. Such a “depth” of sedation is unnecessary for non-painful imaging and therefore mortality data about sedation for endoscopy are not helpful in answering the question “is deep sedation by non-anaesthetists of children for MRI safe?”
We believe that our nurse led sedation service is safe because we have developed a protocol that makes any airway or breathing problem extremely unlikely and, if it should occur, our nurses have sufficient resuscitation skills to cope until help arrives. Reducing the risks to acceptable levels depends on the strict adherence to exclusion criteria, the characteristics of the drug regimen, and finally, but most crucially, the judgement, skills, and experience of the nurses. Our nurses are carefully assessed after an initial training period, and those who are accepted as sedationists receive regular retraining and reassessment. They work to strict protocols devised by a multidisciplinary team consisting of radiologists, anaesthetists, paediatricians, senior nurses, and radiographers. If such a strictly controlled system is not developed, or suitable people cannot be found to implement it, we have no doubt that an anaesthesia service is safer. The references quoted by Dr Bray show that accidents can happen if good practice is not followed.
Our latest figures are encouraging. We have sedated almost 3500 children according to our published sedation guidelines and so far no child has required the use of any airway or breathing device. Oxygen saturation has not dropped below 87%. Can anaesthesia, including postoperative recovery by nurses, match these statistics?
It is fair to suggest that a sedation service might be made even safer with anaesthetists present throughout the procedure. Nevertheless in our hospital, we do not believe that such an expense could be justified. Furthermore, if anaesthetists are available they are more cost effective when administering anaesthesia than supervising sedation.