18. Anesthesia for Dental Procedures in Children

Lisa Khoo¹

(1)

Department of Anaesthesia and Pain Management, Perth Children’s Hospital, Nedlands, WA, Australia

Lisa Khoo

Email: Lisa.Khoo@health.wa.gov.au

Keywords

Endotracheal intubation, nasalExtraction of teeth, anesthesiaEndocarditis prophylaxis for dental proceduresAnesthesia for dental abscessRestorative dental treatment in children, anesthesia

Dental procedures are the third commonest reason for general anesthesia in children. These procedures vary in duration from a few minutes for removal of a tooth, to a few hours for dental restoration procedures. Anesthesia for pediatric dental procedures can be challenging because it involves sharing the airway with the dentist, care of a pediatric patient and management of an uncooperative child who was unable to have their treatment while awake in the dental chair.

Dentists gain the cooperation of children during dental procedures in the dental chair with a combination of behavioral techniques, local anesthesia, and inhalational sedation with nitrous oxide through a nose (Wesson) mask. A proportion of children do not tolerate treatment despite these techniques, and deeper sedation or general anesthesia is required. If a sedated child is not alert enough to hold open their mouth, then they are more sedated than ‘conscious sedation’. Office-based sedation of children that is deeper than conscious sedation is fraught with hazard and is not recommended. In the United Kingdom, there were deaths in children being sedated in the dental chair, and now sedation of children younger than 16 years with anything other than nitrous oxide can only be performed in a hospital. In Australia and New Zealand, there are ANZCA Guidelines regarding sedation. These guidelines mandate broadly the same staffing, monitoring and facilities as would be present for general anesthesia in a hospital. Apart from reasons of safety, dentists may opt to treat a child requiring extensive treatment under general anesthesia in a hospital to avoid several separate treatments in the dental chair and possible psychological trauma to the child.

18.1 Nasal Endotracheal Intubation

Nasal intubation is performed in children for two groups of reasons. The first is for ventilation in intensive care or for transport—a nasal ETT is more secure than an oral ETT. For example, when postoperative ventilation is planned for a child, a nasal tube is inserted. The second is for some procedures requiring access to mouth (not tonsillectomy however). Nasal intubation is often used during dental procedures to allow unrestricted access to the child’s mouth and teeth. ETTs used for oral intubation can be used for nasal intubation. The depth of insertion is best judged by observing the depth of the ETT during laryngoscopy and noting the marking at the nose. Alternatively, a formula or table can be used, by adding 20% to the distance from the oral formula. So, for children over the age of 1 year, the depth at the nose for nasal intubation is:

$Depth\kern0.5em (cm)\kern0.5em in\kern0.5em children\kern0.5em older\kern0.5em than\kern0.5em 1\ year= age/2+15$

For dental procedures, a preformed, nasal (north-facing) RAE impinges least on the dentist’s work (Fig. 18.2). These tubes are inserted until the pre-formed curve is against the child’s nose. There is limited availability of pediatric, cuffed nasal RAE tubes. Some tubes are too long and likely to cause endobronchial intubation if inserted with the curve against the nose, and uncuffed nasal RAE tubes are often used instead. An alternative is to use a wire reinforced ETT and curve the ETT upwards away from the mouth. The tubes have a slightly larger outside diameter than a standard tube with the same size internal diameter. They are also expensive and may place pressure on the nostril as the tube curves upwards.

Preparation for nasal intubation includes spraying the nasal mucosa with vasoconstrictor after induction, softening the ETT with warm water and lubricating the outside of the ETT. The same sized tube is used for nasal and oral intubation in children—the diameter of the cricoid determines the size of the ETT in children, whereas the nose limits the size of the ETT in adults. Nasal intubation is often more difficult than oral intubation, with three areas that can cause problems during passage of the ETT (Fig. 18.1).

../images/467929_2_En_18_Chapter/467929_2_En_18_Fig1_HTML.png — Fig. 18.1

The three sites of difficulty during a nasal intubation—passing the ETT through the bony part of the nose, making the ETT turn downwards into the oropharynx towards the larynx, and aligning the axis of the ETT with the trachea

Note

The same sized ETT is used for oral and nasal intubation in children.

The first area is the bony turbinates in the nose. The patency of the nostrils can be assessed before induction, but the child needs to be cooperative to do this. Resistance at the turbinates can be overcome by firm but careful, constant pressure. Rotation of the tube to change the orientation of the bevel may also help. Passing the endotracheal tube along the nasal floor, under the inferior turbinate, avoids the complications of passing it above the inferior turbinates. The middle turbinate, which sits above the inferior turbinate, is porous, fragile and vascular, and trauma from an endotracheal tube may result in fracture, CSF leak and olfactory nerve dysfunction. Inserting a suction catheter as a guide for the endotracheal tube increases the chances of passing below the inferior turbinates.

The second area that may cause problems is the nasopharynx, as the ETT often hits the posterior wall of the nasopharynx or adenoidal tissue in its passage towards the larynx. Softening the tube by placing it in warm water helps it to curve downwards with gentle pressure. Orientating the tube so the bevel is facing the posterior wall may also help. It is important not to just push harder—forcing the tube may traumatize the posterior pharyngeal wall, and there even are case reports of nasal ETT’s entering the brain in neonates. If the tube will not curve downwards towards the larynx, the most successful strategy is to insert a suction catheter through the ETT and use it as a guide (Fig. 18.2). The catheter is passed through the nose and into the oropharynx, then the ETT can then be “railroaded” over the catheter. The catheter may also prevent mucus and tissue from plugging the lumen of the ETT. Some use this technique routinely for nasal intubation because of these advantages.