Local Infiltrations and Topical Anesthesia

Surface Anesthesia

Surface anesthesia of the larynx by local anesthetic sprays has long been contraindicated in children, but the efficacy and safety of the technique is now established^[10] for administration of low doses of 5% lidocaine (i.e., 8 mg in infants weighing less than 10 kg and 16 mg in infants weighing more than 10 kg). Topical anesthesia can be achieved by spraying lidocaine on operative wounds such as the tonsillar bed after tonsillectomy or by applying anesthetic ointments on the incision site before or after circumcision, which can provide adequate post-operative pain relief.^{[294] [295] [296]}

Interest in topical anesthesia has been renewed in pediatrics by the availability of ointments containing mixture of local anesthetics such as EMLA cream, TAC cream, or lidocaine-adrenaline-tetracaine gel. When applied on the skin and maintained in place with a sterile dressing for a minimum of 1 hour, these formulations can provide complete analgesia of the skin and subcutaneous structures. The duration of application may vary among the different cream formulations. They all make venous cannulation and most techniques requiring needle puncture (e.g., lumbar taps, repair of oral or scalp lacerations) possible without pain.

Intradermal Wheals

Intradermal wheals are routinely performed to anesthetize the skin covering deeper structures to be approached. The technique consists of inserting a 25-gauge, short needle almost tangential to the skin, with the bevel facing downward and without penetrating the subcutaneous layers. A small amount (<0.5 mL) of local anesthetic (0.5% to 1% lidocaine or prilocaine, with or without epinephrine) is then injected. The skin covering the wheal looks like an orange peel, and anesthesia of the area is obtained almost immediately.

Local Infiltrations and Field Blocks

Infiltration of local anesthetic (i.e., lidocaine or prilocaine, with or without epinephrine) in a fan-shape manner in subcutaneous tissues and muscles surrounding the operative site (or the edges of a wound) provides adequate analgesia for soft tissue operations and wound repair. Great attention must be paid to avoid bacterial contamination and overdosage, especially in cases of

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Intracapsular Injections

Intra-articular injections of local anesthetic provide consistent analgesia for joint capsules. The technique can be used for diagnostic or therapeutic procedures (e.g., injection of painful joints), but it is not widely used because the efficacy varies.

Transtracheal Injections

Instillation of local anesthetic into the trachea by cricoid puncture is commonly used in adults for awake tracheal intubation and prevention of laryngospasm, but it is not usually employed in children because of the dangers of systemic toxicity and of producing lesions of the cricoid cartilage and vocal cords.

Intraperitoneal Injections

The increasing use of laparoscopic surgery in children has generated new types of abdominal pain. Intraperitoneal injections of local anesthetics have led to contradictory results regarding postoperative pain relief in adult patients. ^{[298] [299]} The safety and efficacy of the technique have not been evaluated in children,^[300] and caution is recommended when considering intraperitoneal injections.