Читать книгу Principles of Dentoalveolar Extractions - Seth Delpachitra - Страница 20

There are a number of different methods of anaesthesia available for dentoalveolar extractions. These include:

 Local anaesthesia only.

 Local anaesthesia with relative analgesia.

 Local anaesthesia with minor oral sedation.

 Local anaesthesia with intravenous (IV) sedation.

 Local anaesthesia with general anaesthesia.

Local anaesthesia alone can be administered for in‐chair treatment, and is generally considered the safest option. It is appropriate for most simple dentoalveolar procedures and extractions. The main limitation of local anaesthesia is that it may be unsuitable for complex procedures, when a duration of more than 40 minutes is anticipated, or when the patient is anxious or otherwise uncooperative.

Relative analgesia involves the use of inhaled agents, such as nitrous oxide, to produce conscious sedation. It can be used as an adjunct with local anaesthesia, to improve patient comfort without significant airway risk. Nitrous oxide is usually administered through a nasal hood at concentrations of 50–70%. The advantage of this method is that it can be titrated and rapidly adjusted. However, there is a variable dose–response relationship between individuals, and patients may experience a number of unpleasant side effects if too high a dose is administered. Use of relative analgesia requires additional training, and it is recommended that at least two trained personnel are present in the clinic room when employing this technique.

Oral sedation, when employed effectively, can provide a greater level of sedation than nitrous oxide. Common drug classes used for oral sedation include benzodiazepine and barbiturate medications (Table 1.1). These drugs have a significant depressant effect on the central nervous system, and hence carry the serious risk of respiratory depression and loss of airway reflexes. Therefore, the use of oral sedation should only be considered when the surgeon and clinic personnel are sufficiently trained in anaesthesia, resuscitation, and airway management.

Table 1.1 Comparisons between commonly used oral benzodiazepine sedatives.

Drug name	Dose	Onset
Temazepam	10–20 mg	30–120 minutes
Diazepam	10–15 mg	30–90 minutes
Oxazepam	15–30 mg	2–3 hours

IV sedation typically involves more powerful sedative agents, such as midazolam, propofol, or fentanyl. It can only be administered in a setting which is fully prepared for airway management, such as a hospital theatre. As with all methods of anaesthesia where the airway is not secure, there is a risk that the patient will aspirate on any foreign object present in their mouth. This can be particularly dangerous when their reflexes are not protecting the airway. The administration of IV sedation may only be undertaken by a suitably qualified medical specialist or dental specialist with advanced training.

General anaesthesia will render the patient completely unconscious, and involves securing the airway using a laryngeal mask or endotracheal tube. It should be provided by a specialist anaesthetist or a suitably qualified medical professional. Dentoalveolar extractions carried out under general anaesthesia involve a shared airway, and communication with the anaesthetist throughout the procedure is essential.