Sedation and General Anaesthesia in Special Care Dentistry
To describe the different techniques available to manage special care patients who are unable to cope with conventional delivery of dental care and whose treatment needs are beyond those that can be provided by non-invasive techniques.
After reading this chapter the practitioner will be aware of the range of available sedation techniques, and the disadvantages/advantages of general anaesthesia (GA), for special care patients.
Historically, GA has been used to treat people requiring Special Care Dentistry who had complicated medical histories, or a physical or mental disability making it difficult for them to cooperate with dental care. In addition to their disability, they may also have been anxious. Access to GA has become more difficult subsequent to its restriction to a hospital setting. Aside from access difficulties, GA is not an ideal method of providing dental care as:
treatment planning can be difficult
limited time and facilities are available to complete all dental treatment in one session
a patient who can not be examined preoperatively could be subjected to the inconvenience and risk of GA only to find that no treatment is required
it is difficult to justify GA to carry out scaling on a regular basis for patients with learning disabilities who are unable to carry out efficient oral hygiene procedures.
Conscious sedation offers an alternative method of behaviour management to GA. Sedative drugs may be administered by a variety of routes each of which have advantages and disadvantages. This chapter describes the use of sedation techniques in providing dental care for adult patients who require special care, and the appropriate use of GA.
IV sedation regulations require that dental staff involved in its use have been properly trained and that it is only used in appropriate settings. In the UK the most commonly used IV sedative drug is midazolam. This is a water soluble benzodiazepine with a short half-life that provides:
rapid onset sedation
rapid recovery allowing discharge within one or two hours.
It has the disadvantage of requiring venous access, which can be difficult to achieve in uncooperative or anxious patients. Also, midazolam can lead to respiratory depression, particularly in older people or if injected rapidly. For this reason, pulse oximetry is mandatory throughout treatment for all sedation patients. IV sedation can be used for people with learning difficulties if they are able to cooperate with the placement of a cannula. The main challenge, in someone who has little or no verbal communication, is determining the level of sedation and the dental team must rely on observations such as the patient appearing relaxed and accepting dental treatment.
IV sedation can be safer for anxious people with cardiac conditions than local anaesthesia alone, as anxiety is reduced and oxygen saturation can be maintained with supplemental oxygen (two litres per minute via a nasal cannula) throughout treatment. There are also dental advantages in carrying out treatment under sedation in stages rather than in a single GA appointment.
IS produces sedation using a mixture of nitrous oxide and oxygen delivered in varying concentrations by a dedicated machine through a nasal mask. Modern machines deliver a minimum of 30% oxygen at all times. Most adults require between 30 and 50% of nitrous oxide for sedation. The technique is operator sensitive as the sedative effect of the nitrous oxide is supplemented by semihypnotic suggestion. IS is an extremely safe technique that can be used to treat adults and children with mild to moderate anxiety, mild to moderate learning disabilities, and medical conditions (such as cardiac defects and angina) that benefit from additional oxygenation. The technique requires patient cooperation and it may not be possible for patients with more severe learning disabilities to understand the suggestions which are important for the success of the technique. It also requires the individual to breathe through their nose only. This is difficult for people with nasal congestion, as is common in Down’s syndrome. An advantage of IS is that nitrous oxide has a short half-life and, as a consequence, the technique causes no post-operative drowsiness.
Oral sedation offers significant advantages over IV and IS techniques as it avoids the need for intravenous access and requires little patient cooperation. It has the disadvantage of variab/>