Supraglottic airways in children: past lessons, future directions

Abstract

The first prototype of the laryngeal mask airway (LMA) was used clinically in the summer of 1981 at Ashford, Kent, UK, by Dr. Archie Brain. Dr. Brain followed in the worthy footsteps of Clover, O’Dwyer, Shipway, Leech, and others in developing a supraglottic airway to facilitate the delivery of anesthetic gases via a reliable supraglottic airway. The LMA was released in the UK in 1988 and in the USA in 1992. Since the original range of pediatric LMAs was soon found to be inadequate to address all children’s sizes, half-sizes (1.5 and 2.5) were developed. As with adult practice, the LMA and other supraglottic airways have radically changed pediatric anesthesia practice and have become a key component of airway management in children, both in the operating room and in remote anesthesia locations. These devices have increasingly been advocated for emergency airway control in the field, in the emergency department, and in the delivery suite. So what have we learned about pediatric supraglottic airways over the past two decades and where does the future lie with respect to these devices? Much of the published research in this area relates to the LMA Classic. From the clinical anesthesiologist’s perspective, the following questions relating to the LMA Classic are important: When should it be used (patient and procedure related factors), how should it be used, and when should an alternative device be used? Indications for the use of the LMA Classic are extensive, and it is often the airway of choice in routine general anesthesia for minor procedures in children. In a prospective study of 1,400 children who had LMA-based anesthesia conducted by supervised trainees, the device was found to be highly effective for a broad range of surgical procedures, and there was no instance where the LMA had to be replaced with an endotracheal tube (ETT). Initial misgivings about the use of the LMA for head and neck procedures were shown to be largely unfounded. For example, the LMA was shown to be safe and effective when used for ophthalmological surgery and adenotonsillectomy in children; however, these situations require a surgeon with some insight that the trachea is not intubated. Pediatric anesthesia is increasingly being delivered in areas outside the operating room where the LMA has been proven to be particularly valuable. For instance, the LMA has been used for radiotherapy, magnetic resonance imaging, fibreoptic bronchoscopy, and upper gastrointestinal endoscopy. Its relative stability combined with the ease of respiratory monitoring and the relative lack of airway complications are distinct advantages in these remote locations. One clinical scenario of particular interest is the difficult pediatric airway. Here the LMA has proven to be invaluable both as a rescue airway device in the child with a difficult airway and as a conduit for fibreoptic bronchoscopy and endotracheal intubation. Consequently, the LMA has a role in both anticipated and unanticipated difficult airways, and it now features in pediatric difficult intubation algorithms. Even if tracheal intubation is difficult in a child, it must be remembered that the airway is often easy to manage with an LMA. Are there particular co-morbidities in children where the LMA is especially valuable? A common situation is children with upper respiratory infections (URIs) presenting for elective surgery. Children with mild URIs, minimal systemic symptoms, and normal lung fields on physical R. G. Cox, MBBS (&) D. R. Lardner, MBChB Division of Pediatric Anesthesia, Alberta Children’s Hospital, University of Calgary, 2888 Shaganappi Trail N.W., Calgary, AB T3B 6A8, Canada e-mail: robin.cox@albertahealthservices.ca