Complications and Emergencies
Sedation in dentistry has an excellent safety record. If intravenous (IV), inhalation, intranasal or oral sedation is administered correctly to carefully selected patients, by trained dental clinicians, with appropriate facilities and support, then the incidence of untoward problems should be very low. However, complications can and do occur and it is essential that all members of the dental team practising sedation be trained and regularly updated in the management of sedation‐related complications and medical emergencies. Where sedation is being carried out, it is essential that the appropriate emergency equipment and drugs are available, ready for immediate use should the need arise.
To ensure the safe practice of conscious sedation, dental clinicians and their assisting staff must be suitably qualified and experienced. Postgraduate training in sedation is mandatory. As a minimum requirement, training should cover the theoretical and practical aspects of conscious sedation and provide hands‐on supervised clinical experience.
By definition, a true emergency is one which occurs without warning and which could not reasonably have been foreseen. Medical emergencies can affect anyone, at any time, irrespective of whether they are at home, at work, walking down the street or in a dental surgery.
Many sedation‐related complications are predictable and thus emergencies should be avoidable by good planning and skilful technique. The need for careful and thorough pre‐sedation patient assessment cannot be over‐emphasised. The fitness of each patient to undergo treatment under sedation, and thus the risk that sedation presents to the patient, must be individually assessed. If any aspect of the medical history suggests a potential problem, then expert advice should be sought, either from the patient’s medical practitioner or by referral to a hospital specialist. Dental treatment requiring sedation is never so urgent as to put the patient’s life at risk from inadequate assessment and planning.
Adherence to the principles of good sedation practice should minimise the incidence of problems. However, despite careful preparation and technique, complications and emergencies can still arise. This chapter will discuss the emergency equipment and drugs required when practising sedation, the aetiology, clinical features and management of specific sedation‐related problems and medical emergencies and the prevention and treatment of local complications.
In July 2013, the Resuscitation Council (UK) published guidelines specific to dental practice dealing with the management of medical emergencies and resuscitation. The guiding principles of this document state:
Medical emergencies can happen at any time in dental practice. If you employ, manage or lead a team, you should make sure that:
- There are arrangements for at least two people to be available to deal with medical emergencies when treatment is planned to take place.
- All members of staff, not just the registered team members, know their role if a patient collapses or there is another kind of medical emergency.
- All members of staff who might be involved in dealing with a medical emergency are trained and prepared to deal with such an emergency at any time and practise together regularly in a simulated emergency so they know exactly what to do.
This chapter will consider the management of general medical emergencies and specific sedation‐related emergencies with reference to the adult patient. With regard to the management of children, readers should access the Resuscitation Council (UK) website and their own National Drug Formulary for paediatric drug doses.
It is recommended by the Resuscitation Council (UK) that the equipment used for any medical emergency or cardiopulmonary arrest should be standardised throughout general dental practices. All clinical areas should have immediate access to resuscitation drugs, equipment for airway management and an automated external defibrillator (AED). Staff must be familiar with the location of all resuscitation equipment within their working area. The necessary equipment is listed in Table 8.1.
Table 8.1 Emergency equipment essential for the provision of conscious sedation.
Independent Oxygen Supply
The most important piece of emergency equipment (or drugs) is an independent oxygen supply. A full oxygen cylinder, size CD (460 litres), size D (340 litres) or size E (680 litres), which is independent of any routine oxygen supply, should be available for an emergency. The cylinder must have a reducing valve, key, flow meter, tubing and suitable connectors. It must be readily attachable to a face mask, nasal cannula and ambu‐bag or pocket‐mask. It is essential that the level of oxygen in the cylinder is checked before the start of a sedation session and the cylinder should be turned on ready for immediate use if necessary. E size cylinders should be stored on a portable trolley so that they can be used anywhere in the practice.
A selection of Guedel oral airways must be available (Figure 8.1). These are used to maintain a patent airway in an unconscious patient. The commonest cause of airway obstruction in the unconscious patient is caused by the tongue falling back onto the anterior wall of the pharynx. This problem can usually be relieved by placing the patient in the lateral recovery position or by pulling the mandible forwards using the chin lift or jaw thrust.
A simple means of assisting airway maintenance is to insert a Guedel oral airway. This sits over the back of the tongue, preventing it falling posteriorly into the pharynx. Air can then pass freely in and out via the hollow airway lumen. The oral airway requires careful insertion to ensure that the tongue is not pushed backwards upon insertion. For this reason it is inserted upside down as far as the back of the hard palate, then it is turned over into the correct orientation. The Guedel airway can only be used in an unconscious patient. It will be forcefully ejected once the patient regains consciousness and the pharyngeal reflexes return.
Nasopharyngeal airways are very useful in a semi‐conscious patient. They are designed to be inserted into the nasal passageway to secure an open airway. The correct size airway is chosen by measuring the device on the patient: the device should reach from the patient’s nostril to the earlobe or the angle of the jaw. The outside of the tube is lubricated with a water‐based lubricant so that it enters the nose more easily. The device is inserted until the flared end rests against the nostril (Figure 8.2).
Intermittent Positive Pressure Device
A ventilating device for administering oxygen under intermittent positive pressure is an essential piece of equipment. This is used to support ventilation in a patient who becomes significantly hypoxic, apnoeic or has a respiratory arrest. The classic example is the ‘ambu‐bag’ which consists of a self‐inflating bag, with an oxygen attachment, one‐way valve and face mask (Figure 8.3).
When attached to an oxygen supply this bag will deliver approximately 40% oxygen in air. A higher percentage of oxygen, up to 80%, can be administered by attaching an oxygen reservoir bag to the main self‐inflating bag. The ambu‐bag requires two people to operate it efficiently, one to hold the mask on the face to maintain a good seal and to support the airway, the other to squeeze the bag and ventilate the patient. It is possible to use the ambu‐bag single‐handedly but it can be difficult to perform these tasks simultaneously. Another example of an intermittent positive pressure device is the simple pocket‐mask with an oxygen attachment (Figure 8.4).
This is easier to use by a single person than the ambu‐bag because the manual effort is aimed at holding the mask in position and maintaining the airway. Ventilation is achieved by the practitioner actually breathing into the mask. The percentage of oxygen delivered is less than that achieved with an ambu‐bag, but the device is easier to operate and may be more efficient than an improperly used ambu‐bag.
Portable suction equipment (preferably totally independent of the main suction supply) should always be available. Although the laryngeal reflexes in a sedated patient are intact they do have a reduced gag reflex and less ability to remove vomit or foreign bodies from the mouth. The suction apparatus should be portable so that it can be used in the recovery area or any other part of the dental practice. It should also be independent of the power supply so it will still function if there is a power failure. Manual suction devices are available which do not require a power source.
A list of recommended emergency drugs is shown in Table 8.2. It is essential that the dental surgeon understands the indication for each drug and how it is administered. There is little point in stocking a drug if it cannot be used appropriately.
Table 8.2 Emergency drugs, doses and application.
A range of disposable syringes (5 ml and 2 ml) and needles (23 g) should be available to administer parenteral drugs, intramuscularly or intravenously, in an emergency. A selection of teflonated cannulae (20 g) should also be kept in the emergency stock so that additional venous access can be gained should the original sedation cannula become blocked or dislodged (see Figure 8.5).
The most important ‘drug’ for any dental practice to stock is oxygen. This is the first and, in many cases, the only substance that is required in an emergency situation. It is of particular importance in sedation because almost all sedation agents produce some degree of respiratory depression. The normal concentration of oxygen in the air is 21%. By administering 100% oxygen from a cylinder, via a nasal cannula or face mask, the inspired percentage of oxygen can be significantly increased. This will help to compensate for the slight desaturation that can occur as a result of mild respiratory depression. The administration of 100% oxygen is also an essential first step in the management of nearly all medical emergencies.
Adrenaline at a concentration of 1 mg/1 ml (1 in 1,000 dilution) is required for the treatment of anaphylaxis. Adrenaline is administered either intramuscularly or subcutaneously. It must never be delivered via the IV route in general dental practice.
Glucose or Dextrose
Glucose or dextrose tablets or gel should be available for use in the early stages of a hypoglycaemic attack in a diabetic patient. A conscious patient should be given tablets to suck or the gel can be smoothed onto the oral mucosa. Alternatively, a glucose‐based drink can be given. However, if the patient’s condition is deteriorating there should be no hesitation about giving IV glucose or 1 mg of glucagon intramuscularly (see below).
Glucagon (1 mg) is required if the hypoglycaemic patient loses consciousness. It is administered subcutaneously, intramuscularly or intravenously. Sterile glucose or dextrose (50 ml of a 50% solution) which is delivered intravenously should also be available. This acts more rapidly than glucagon but its high viscosity can make it difficult to administer through the narrow bore cannulae used to administer sedation drugs. A 25% dilution is also available and is easier to administer.
Glyceryl trinitrate tablets (0.3 mg) or glyceryl trinitrate spray (0.4 mg/dose) are required for the management of angina. Both tablets and spray are administered sublingually to maximise the rate of absorption.
Soluble aspirin tablets (300 mg) should be stocked for use in the event of a myocardial infarction. Aspirin reduces platelet adhesiveness and is used to reduce the morbidity of myocardial infarction. There is good evidence that early administration improves outcomes and reduces mortality after myocardial infarction.
A salbutamol inhaler (0.1 mg/dose) or a salbutamol nebuliser with nebules (2.5 mg) should be available for the management of an acute asthma attack.
Buccal midazolam (10 mg/1 ml or 10 mg/2 ml) is recommended for the treatment of status epilepticus. However, for any patient who has already received midazolam sedation, care must be taken not to overdose the patient.