Quarterly Airway Management Research Update

A recent quarterly update on airway management research from Airway World discussed the difficult pediatric airway and patients with mandibular fixation, among other topics.

During the hour-long September 3 webinar, Ron M. Walls, MD, Ali S. Raja, MD, MBA, MPH and Cheryl Lynn Horton, MD, began by looking at the differences between pediatric and adult airways. In particular, pediatric patients typically have a relatively large head; small nares; short neck; a large tongue relative to mouth size; the larynx is more cephalad in infants at C2 until it approaches that of the adult at C4; the epiglottis is long an angled, projecting above the glottis opening; and vocal cords are slanted anteriorly and rostrally.

Walls noted the child is the model of the difficult airway. In adult patients, difficult intubations often occur because of some combination of a small mouth and large tongue; that’s exacerbated in children because those conditions are present along with the presentation of a higher glottis.

Horton offered the following helpful tips for managing the pediatric airway:

• Bag mask ventilation
• Make sure the head is in a slightly extended position
• Use an oral and/or nasopharyngeal airway to help displace the larger tongue and make BVM more effective
• Use a “squeeze, release, release” technique to give the child adequate time to ventilate
• Preintubation
• Position the patient correctly, with a towel underneath the shoulders to align the axes
• Preoxygenation is really important because children will desaturate rapidly
• Prepare and select properly sized equipment for children: (Age + 16)/4 gives you the proper ET tube size; 3 x ET tube size gives you the proper depth

• Intubation
• Look up (anteriorly) in the patient
• Use a stylet

A case study presented discussed how to handle a small child in respiratory distress who also happens to have Down syndrome. Horton said one thing that works well in Down syndrome children is nasal CPAP, which should be considered as an option, among other common options such as BVM, high-flow nasal cannula and others. Raja added that many children with Down syndrome are already used to wearing positive pressure ventilation at night because they have obstructive sleep apnea, especially as they get a little older, so nasal CPAP could be an easy option to turn to during transport.

Horton noted that while congenital difficult airways are rare, they’re talked about often because they’re so scary. There are a number of congenital syndromes with varying features that make for a difficult airway, but common abnormalities include a small chin, large tongue, a small or limited mouth opening and a short or immobile neck. All of these can combine to make intubation very difficult in children with congenital syndromes. So, extra-or supraglottic devices may make more sense.

The presenters discussed the use of fiberoptic intubation, particularly comparing a free-hand, normal method of fiberoptic intubation vs. air-Q assisted fiberoptic intubation. What was found in a study published in the May issue of Anaesthesia was fiberoptic-guided tracheal intubation times were similar with and without the use of the air-Q, but supraglottic airway devices may be a consideration for their other practical advantages. Essentially, fewer maneuvers were needed to obtain adequate laryngeal view with the air-Q, but the choice of technique is up to the operator’s preference.

Next, the discussion turned to patients with mandibular fixation. In these cases, the room to work in is often extremely tight and rapid sequence intubation is unlikely, as might be BVM. Fiberoptic intubation might work, but what about blind nasotracheal intubation in the event that a fiberoptic scope isn’t available? It was noted that nasotracheal intubation is best accomplished via the lower pathway rather than the upper pathway.

A study published in the April issue of Anaesthesia looked at the use of a nasogastric tube to facilitate nasotracheal intubation. What was found was overall was NG-tube guided NT intubation resulted in:

• Similar success rate (everyone was intubated);
• Less frequent epistaxis;
• And less severe, when it occurred
• Improved navigability of the tube; and
• Fewer number of manipulations.

Another study, just published in Anaesthesia, compared the i-gel to laryngeal mask airways (LMAs). The results of the study show:

• There is no difference in rates of successful insertion;
• The i-gel was quicker to insert than 1st but not 2nd generation LMAs;
• Leak pressures were better in the i-gel but best in the 2nd generation LMAs;
• The i-gel was less likely to result in a sore throat and slightly more likely to provide a better fiberoptic view.

Finally, a study from the August issue of Anaesthesia was discussed, which determined it is not advisable to use cricoid pressure with the i-gel or LMAs. Adequate ventilation via the i-gel was more successful when cricoid pressure was not applied (100% vs. 85%), and fiberoptic examination showed that the rate of optimal i-gel positioning was also improved without cricoid pressure, as was time to achieve adequate ventilation. Ultimately, cricoid pressure during LMA insertion appears to have no proven benefit and can actually make LMA placement more difficult.

The next Airway World quarterly airway management research update will be held December 5, from 2:30–3:30 p.m. EST.