The laryngeal mask airway in children

Abstract

SummaryClinical and jibreoptic assessment of the positioning of the laryngeal mask airway was performed in 100 children. Clinical observation indicated a patent airway in 98% and severe airway obstruction in 2% of cases. Perfect positioning, as judged by jibreoptic laryngoscopy, was found in 49% and the epiglottis was within the mask in 49%. Fibreoptic evidence of partial airway obstruction in 17% was not detected clinically. Key wordsAnaesthesia; paediatric. Equipment; laryngeal mask airway, fibreoptic laryngoscope.The laryngeal mask airway (LMA) was designed following studies on the cadaveric adult larynx,' Three out of the four sizes of laryngeal mask currently available are appropriate for use in infants and children; size 1 in infants up to 6.5 kg, size 2 for infants and children from 6.5 to 25 kg and size 3 for larger children or small adults. Sizes 1 and 2 are scaled-down versions of adult masks. However, the relative anatomy of the larynx of infants and young children is known to differ from that of the adult; a higher and more anteriorly placed glottis with a relatively large floppy epiglottis may make correct placement of the LMA more difficult. We assessed the position of three sizes of LMA in anaesthetised children using a fibreoptic laryngoscope. MethodObservations were made on 100 consecutive healthy children (inpatients and outpatients) presenting for elective general surgery. Patients who were not fasted or those requiring tracheal intubation or intermittent positive pressure ventilation as part of the anaesthetic technique were not studied. Masks were inserted by the authors; two had previous experience with the technique in children and one had experience in adults. Clinical assessment of airway patency and fibreoptic laryngoscopy were performed by two observers.Premedication and the method of induction of anaesthesia (inhalational with halothane in nitrous oxide and oxygen or intravenous with propofol 3 mg/kg) were at the discretion of the anaesthetist. Masks were all inserted when the children were anaesthetised and breathing 4% halothane in nitrous oxide and oxygen (2: I). A Bain anaesthetic system was used in children over 15 kg and an Ayre's T-piece in smaller children.The LMA was inserted in a standard fashion according to the maker's recommendations (Intavent Laryngeal Mask Airway, DJ. Colgate Ltd., UK) and the cuff inflated with air. Correct positioning of the LMA was clinically determined as follows; resistance to continued advancement of the LMA with forward bulging of the larynx during insertion and outward movement of the LMA with cuff inflation. Airway patency was confirmed by observing synchronous respiratory movements of the chest and anaesthetic reservoir bag, by a lack of indrawing of intercostal and supraclavicular spaces and by confirming, on auscultation, air entry in both axillae when gently inflating the lungs.The actual position of the LMA was then ascertained by fibreoptic laryngoscopy (Olympus ENF P2) while an assistant prevented the mask from moving. Laryngoscopic find...

Laryngeal mask insertion in children: a rational approach

“…Rowbottom et al. (11) obtained a clinically patent airway in 98% of the paediatric patients with severe airway obstruction in 2% cases. The wide variation in obtaining satisfactory airway conditions after insertion of LMA with various techniques indicates the need for an ideal insertion technique in the paediatric population having inherent airway complexities.…”

Fiber‐optic assessment of LMA position in children: a randomized crossover comparison of two techniques

“…After insertion, the cuff was inflated, and cuff pressure was kept at 60 cm H 2 O. Successful LMA insertion was judged clinically by confirming airway patency as described by Rowbottom et al (15), i.e., visualizing the adequate bag movements and adequate chest inflation after assisting patient's ventilation. Additionally, capnography was used to assess the adequacy of ventilation.…”

Laryngeal mask airway insertion in children: comparison between rotational, lateral and standard technique

“…After insertion, the cuff was inflated as per manufacturer's recommendation. Successful LMA insertion was judged clinically by confirming airway patency as described by Rowbottom et al (14). Additionally, capnography was used to assess the adequacy of ventilation.…”