Monday, 14 March 2016

Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. BJA December 2015.

This is the revised version of the DAS guidelines for management of the unanticipated difficult airway, originally published in 2004.

The majority of the changes have come about from the findings of NAP4. Analysis of the adverse airway events in the UK from 2008-2009 showed that human factors were directly responsible for poor outcomes in 40% of the cases reported, and a contributing factor for all cases. The authors acknowledge that this was occurring despite the DAS guidelines being published and widely available.

One of the factors that they attribute this to is the confusing nature of the original DAS algorithm. They acknowledge that the original guidelines had too many choices or options at each level and this could lead to paralysis of indecision. In view of this the new guidelines are much simpler.

A brief over view of the new algorithm for the unanticipated difficult airway:
During assessment of the patient’s airway consider ease of BMV, LMA insertion, intubation and front of neck access for all patients. Have a plan that will give you the best likelihood of first attempt success for all possible interventions.

Plan A:
  • BMV and direct laryngoscopy using optimum equipment and positioning, pre-oxygenation etc as dictated by your assessment of the patient.
  • No more than 3 attempts at direct laryngoscopy (one more allowed if more senior anesthetist available)
  • No repeat attempts at laryngoscopy without changing something in your approach learned by the experience gained in previous intubation attempts.
  • If fail to intubate move to Plan B

Plan B:
  • Plan B is always a supraglotic device
  • Supraglotic device should be chosen and available prior to induction
  • 2nd generation are preferred
  • If failed then no more than 3 attempts at insertion, consider changing size or type
  • If succeed STOP and THINK: Wake patient? Intubate via LMA? Proceed with procedure under LMA? Tracheostomy or cric?
  • If fail proceed to Plan C

Plan C:
  • One final attempt at rescuing situation by BMV
  • Be aware that this is highly unlikely to be successful after multiple airway interventions
  • Use knowledge of BMV gained during plans A and B to optimize attempt at BMV during Plan C
  • Prepare for Plan D
  • If fail proceed to plan D

Plan D:
  • Surgical airway
  • Position patient appropriately for surgical airway
  • Advocate either scalpel bougie or needle cric, operators choice
  • More emphasis on scalpel bougie due to support from literature including NAP4
  • STOP and Think – proceed with case or postpone surgery?

Other changes

Cricoid:
Still advocated in 10N/30N form but now advocates removal if difficulty intubating rather than waiting till failed ventilation via LMA to remove as per old guidelines

Choice of muscle relaxant for RSI:Rocuronium or sux supported for RSI
BMV should not be deemed to be impossible unless the patient is fully paralysed

Apneoic oxygenationApnoeic oxygenation using normal NP or HFNP is recommended for the expected difficult intubation

CICO
Regular practice is the best way to prepare for this, ANZCA’s efforts to ensure regular CICO training was acknowledged in the paper

There is a large emphasis on human factors in this publication. Particularly they note the importance in calling for help, ensuring someone maintains situational awareness and the importance of announcing when a particular intervention has failed so that the team is aware that we are proceeding to the next step.

Overall these guidelines are a massive improvement over the 2004 version. They also more accurately reflect current practice and provide a better framework with in which to operate.

I have included an editorial by Professor Keith Greenland that discuss the role of human factors in more detail. Several other editorials and articlesrelated to airway management are also published in this months BJA.

DD

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