As a rule patients should be premedicated with atropine to reduce oral secretions and to reduce the occurrence of vasovagal syncope.(In children this may be administered at the dose of 0.02mg/kg IV following induction and iv line placement) In a co operative child the IV cannula may be secured after topical application of EMLA cream also. Intravenous induction with Propofol and lidocaine may be condsidered for children above 3 yrs. A nasal mask or LMA may be used to protect the airway with additional pre op oral packing, particularly when nasal mask is used for delivering inhalational anaesthesia. Maintenance of anaesthesia is continued with oxygen, nitrous oxide with isoflurane allowing spontaneous ventilation. Alternatively inhalation induction with sevoflurane or halothane is preferred for children less than 3 yrs.The eyes should be protected. For maintenance, propofol or sevoflurane may be continued. Additional analgesia may be obtained by local nerve blocks by surgeon. If possible the child my be placed in the lateral position keeping the head low with proper stabilisation of head and neck.Use of nitrous oxide may be reduced or stopped with concurrent administration of short acting analgesics like fentanyl, to prevent hypoxia,provide analgesia and to make available 100% oxygen. Post op analgesia can be achieved with paracetamol or diclofenac suppositories or with intramuscular opioids.
Another technique called inhalational sedation is used for adults who are unwilling for local anaesthesia. Here conscious sedation is given using iv anaesthetic agents followed by analgesia supplemented with local anaesthetics once the sedative effect is established.Patients are given slow incremental doses of midazolam with oxygen and less than 50% nitrous oxide.A soft but weighted mask is put over the nostrils. It is essential that patient is conscious throughout the procedure and can control his airway. The patient should be able to communicate with the surgeon during the procedure. Mouth props are discouraged as they mask the patients inability to keep the mouth open, - an ominous sign of oversedation. Standard monitoring include NIBP, ECG, Temperature probe and Pulse Oximetry. Patient should be given 100 % oxygen following the procedure to avoid diffusion hypoxia and flumazenil should be available to reverse the residual effect of benzodiazepines effect, if required.
When to think of intubation?
- Difficult access as in impacted tooth, macroglossia, short neck
- Excessive uncontrolled bleeding
- maxillofacial or major dental surgery
- Mentally handicapped
- Obstruction of nasal passages, large adenoids where nasal mask is not effective
Problems in dental chair
- Reduced venous return, so more severe reaction to a vasovagal attack due to pain
- Increased chance of air embolism in sitting position
- Unprotected airway ie shared airway between surgeon and anaesthetist
- Aspiration of blood or mucus can cause laryngospasm,
- Adrenaline in local anaesthetic can cause arrhythmias in presence of halothane
- Higher incidence of arrhythmias due to stimulation of 5 th cranial nerve
- Nasal bleeding if nasal airway is used to deliver the anaesthetic
- Fainting due to cerebral hypoxia or cardiac arrest may be unrecognised
- Difficulty in initiating CPCR once cardiac arrest occurs
- Foreign body obstruction of the airway by needles or dentures,necessitating removal by bronchoscopy
- Uncontrolled and profuse bleeding into the airway in patients not screened for coagulopathies especially in out patients
- Higher incidence of infective endocarditis
- Anaphylaxis, to local anaesthetics or other drugs
- Malignant hyperpyrexia if halothane is used
- Difficulty in administering post op analgesia
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