Background and references

The objectives of DIFFICAIR were:

  • To quantify the proportion of unanticipated difficult intubation and difficult mask ventilation in Denmark
  • To design a cluster randomised trial, using state of the art methodology in order to test the clinical impact of using a modified ‘Simplified Airway Risk Index’ (SARI) for preoperative airway assessment compared with a clinical judgement based on usual practice for airway assessment.
  • To test if implementation of the SARI would reduce the proportion of unanticipated difficult intubation compared with usual care for airway assessment.
  • To compare the effect of a systematic assessment protocol vs. existing practice (i.e. no fixed protocol) for predicting difficult face-mask ventilation.
  • To develop a weighted risk score for predicting difficult face-mask ventilation

Detailed information has to be found in the following publications

Prediction of difficult mask ventilation using a systematic assessment of risk factors vs. existing practice – a cluster randomised clinical trial in 94,006 patients. Nørskov AK, Wetterslev J, Rosenstock CV, Afshari A, Astrup G, Jakobsen JC, Thomsen JL, Lundstrøm LH; Collaborators. Anaesthesia. 2017 Mar;72(3):296-308. doi: 10.1111/anae.13701. Epub 2016 Nov 24. PMID: 27882541

Preoperative airway assessment – experience gained from a multicentre cluster randomised trial and the Danish Anaesthesia Database. Nørskov AK. Dan Med J. 2016 May;63(5). pii: B5241. Review. PMID: 27127020

Effects of using the simplified airway risk index vs usual airway assessment on unanticipated difficult tracheal intubation – a cluster randomized trial with 64,273 participants. Nørskov AK, Wetterslev J, Rosenstock CV, Afshari A, Astrup G, Jakobsen JC, Thomsen JL, Bøttger M, Ellekvist M, Schousboe BM, Horn A, Jørgensen BG, Lorentzen K, Madsen MH, Knudsen JS, Thisted BK, Estrup S, Mieritz HB, Klesse T, Martinussen HJ, Vedel AG, Maaløe R, Bøsling KB, Kirkegaard PR, Ibáñez CR, Aleksandraviciute G, Hansen LS, Mantoni T, Lundstrøm LH. Br J Anaesth. 2016 May;116(5):680-9. doi: 10.1093/bja/aew057. PMID: 27106972

Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice: a cohort study of 188 064 patients registered in the Danish Anaesthesia Database. Nørskov AK, Rosenstock CV, Wetterslev J, Astrup G, Afshari A, Lundstrøm LH. Anaesthesia. 2015 Mar;70(3):272-81. doi: 10.1111/anae.12955. Epub 2014 Dec 16. PMID: 25511370

Detailed statistical analysis plan for the difficult airway management (DIFFICAIR) trial. Nørskov AK, Lundstrøm LH, Rosenstock CV, Wetterslev J. Trials. 2014 May 15;15:173. doi: 10.1186/1745-6215-15-173. PMID: 24885548

Incidence of unanticipated difficult airway using an objective airway score versus a standard clinical airway assessment: the DIFFICAIR trial – trial protocol for a cluster randomized clinical trial. Nørskov AK, Rosenstock CV, Wetterslev J, Lundstrøm LH. Trials. 2013 Oct 23;14:347. doi: 10.1186/1745-6215-14-347. PMID: 24152537

A simplified score for predicting difficult face-mask ventilation: the DIFFMASK score – a cohort study in 46 804 patients. Lundstrøm LH, Rosenstock CV, Wetterslev J, Nørskov AK. Submittet for publ in Anaesthesia

Preoperative airway assessment: predictive value of a multivariate risk index. el-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Anesth Analg. 1996 Jun;82(6):1197-204. PMID: 8638791