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Dealing with Difficult Airways

Role of supraglottic airway devices in the American Society of Anesthesiologists' Difficult Airway Algorithm

The practice guidelines for management of the difficult airway ("difficult airway algorithm") developed by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway have proven to be particularly useful as a guide to clinical airway management. Originally published in 1993 [4], they were revised in 2003 [5] in order to incorporate new developments. In particular, as supraglottic airway techniques have evolved, they have been explicitly incorporated into the algorithm. This is illustrated in Figure 1 below, where the bottom right of the illustration shows how the supraglottic airways can be employed should ventilation using a face mask be unsatisfactory in a patient who was unable to be intubated. That is, the current guidelines recommend the use of the LMA, Combitube or other suitable supraglottic airway as rescue devices in the “cannot intubate - cannot ventilate” situation, advice that switches from an earlier emphasis on  laryngoscopy and intubation to an emphasis focusing on ventilation and oxygenation.

 It should be emphasized that supraglottic airways other than the LMA or Combitube may be considered in settings where they are inappropriate, not liked, not available or have been unsuccessful. For instance, Matioc and Olson [6] reported two cases in which the laryngeal tube (LT) was used in unexpected difficult airway situations. The first case involved undiagnosed lingual tonsillar hyperplasia and the LT provided the means to ventilate and administer anesthesia in what had moments earlier been a "cannot intubate-inadequate mask ventilation" scenario. In the second case the LT was used in a morbidly obese patient (BMI = 93) to allow extrication from a "cannot intubate- cannot ventilate" setting.

Figure 1. Graphical summary of practice guidelines for management of the difficult airway ("difficult airway algorithm") developed by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway [5].

 

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