A proposal for a new approach in the prevention of laryngospasm in children.

Sir,

Laryngospasm is a potentially fatal complication of general anesthesia is more common in children (17.4/1000) than in adults (8.7/1000). The most frequent risky factors are: Infections of the upper airways, the young age of the child, the stimulation of the upper airway in insufficient depth of anesthesia (secretions, blood, pharyngeal aspiration, and extubation) and the inexperience of the anesthetist.[1]

Laryngospasm can be defined as a glottic closure reflex secondary to a contraction of the laryngeal muscles. It may be complete or partial.

Complete is recognized at the extubation by inefficient chest movements, breathing silence, and no movement at the ball of the anesthetic circuit and unable to ventilate the child.

Whereas partial laryngospasm is recognized by thoracic movements inefficient, stridor and respiratory effort mismatch between the child and the movements seen at the ball of the anesthesia circuit.[3]

We propose a new approach in the prevention of laryngeal spasm, especially in children using a modified tracheal tube. Unlike conventional endotracheal tube, the new tube is provided with a second pilot tube other than the tube allowing to inflate the cuff which its path is located along the concave face of the endotracheal tube with a distal extremity which ends at the proximal region of the cuff insertion of the tracheal tube [Figure 1]. The distal orifice of this tube is used to inject the local anesthetic at the glottis.

Figure 1

The modified tracheal tube with tubulure to inject local anesthetic

After surgery (without reducing the level of anesthesia) and after suction of the oropharynx, the child is placed in a semi-sitting position, to bring the axis of the trachea in the most upright position that allows homogeneous distribution of local anesthetic.

We inject through the additional pilot tube the 2% lidocaine at a dose of 4 mg/kg. This first phase allows to anesthetize the glottic structures located above the cuff of the tracheal tube.

We keep the child in this position for 15 min to allow a homogeneous and durable contact of local anesthetic with epiglottic and glottic structures, which are immersed in the local anesthetic [Figure 2].

Figure 2

Diffusion of the local anesthetic in the glottis

After 15 min elapsed (second phase), the cuff of the tracheal tube may be deflated slightly to permit the diffusion of local anesthetic between the cuff membrane and the tracheal mucosa.

Finally, the child is put in a supine position, and we proceed to wake. We proposed this method to facilitate extubation of the child awake and prevent laryngospasm.

Theoretically, this method increases the postoperative glottic dysfunction with an increased risk of aspiration. But do not forget that tracheal intubation causes alone glottic dysfunction within 4 h after extubation.

Laryngospasm remains a critical situation faced by the anesthetist in his daily practice. The proposal of this new approach in the prevention of laryngeal spasm remains in the realm of theory whose effectiveness remains to be confirmed by further study.