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

Trials

Lars Hyldborg Lundstrøm¹  Jørn Wetterslev²  Charlotte Valentin Rosenstock¹  Anders Kehlet Nørskov² 

[1] Department of Anaesthesiology, Copenhagen University Hospital, Nordsjælland Hospital, 3400, Hillerød, Denmark;Copenhagen Trial Unit, Centre for Clinical Intervention Research, Copenhagen University Hospital, Rigshospitalet 2100, Copenhagen, Denmark

关键词: Specificity;    Sensitivity;    Randomized controlled trials;    Difficult intubation;    Cluster analysis;    Airway management;   

Others  :  1092932
DOI  :  10.1186/1745-6215-14-347

 received in 2013-05-21, accepted in 2013-10-04,  发布年份 2013

【 摘 要 】

Background

Pre-operative airway assessment in Denmark is based on a non-specific clinical assessment. Systematic, evidence-based and consistent airway assessment may reduce the incidence of unanticipated difficult airway management. By assessing multiple predictors for difficult airway management, the predictive value of the assessment increases. The Simplified Airway Risk Index (SARI) is a multivariate risk score for predicting difficult intubation.

This study aims to compare the use of the SARI with a non-specified clinical airway assessment on predicting difficult intubation. Further, to compare the examination and registration of predictors for difficult mask ventilation with a non-specified clinical airway assessment on prediction of difficult mask ventilation.

Method/Design

We cluster-randomized 28 Danish departments of anaesthesia to airway assessment either by the SARI or by usual non-specific assessment. Data from patients’ pre-operative airway assessment are registered in the Danish Anaesthesia Database. Objective scores for intubation and mask ventilation grade the severity of airway managements. The accuracy of predicting difficult intubation and mask ventilation is measured for each group. The primary outcome measure is the fraction of unanticipated difficult and easy intubation.

The fraction of unanticipated difficult intubation in Denmark is 1.87%. With a stratified randomization, type 1 error risk of 5% and a power of 80%, 30 departments are required to detect or reject a 30% relative risk reduction equalling a number needed to treat of 180. Sample size estimation is adjusted for the study design and based on standards for randomization on cluster-level. With an average cluster size of 2,500 patients, 70,000 patients will be enrolled over a 1-year trial period. The database is programmed so that registration of the SARI and predictors for difficult mask ventilation are mandatory for the intervention group but invisible to controls.

Discussion

It is innovative to use a national clinical database as the basis for a randomized clinical trial. The method can serve as a precedent for implementation of evidence-based recommendations and database registration.

The trial will forward understanding of how to predict and reduce unanticipated difficult airways and how to produce evidence-based recommendations for airway assessment and clinical database development.

Trial registration

(NCT01718561)

【 授权许可】

   
2013 Nørskov et al.; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Cooper GM, McClure JH: Anaesthesia chapter from saving mothers’ lives; reviewing maternal deaths to make pregnancy safer. Br J Anaesth 2008, 100:17-22.
• [2]Hove LD, Steinmetz J, Christoffersen JK, Møller A, Nielsen J, Schmidt H: Closed claims analysis of deaths related to anesthesia in the period 1996–2004 registered by the Danish patient insurance association. Anesthesiology 2007, 106:2780-2781.
• [3]Peterson GN, Domino KB, Caplan RA, Posner KL, Lee LA, Cheney FW: Management of the difficult airway - a closed claims analysis. Anesthesiology 2005, 103:33-39.
• [4]Rosenstock C, Moller J, Hauberg A: Complaints related to respiratory events in anaesthesia and intensive care medicine from 1994 to 1998 in Denmark. Acta Anaesthesiol Scand 2001, 45:53-58.
• [5]Lundstrøm LH, Vester-Andersen M, Møller AM, Charuluxananan S, L’hermite J, Wetterslev J: Poor prognostic value of the modified Mallampati score: a meta-analysis involving 177,088 patients. Br J Anaesth 2011, 107:659-667.
• [6]Lee A, Fan LTY, Gin T, Karmakar MK, Ngan Kee WD: A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway. Anesth Analg 2006, 102:1867-1878.
• [7]Lundstrøm LH, Møller AM, Rosenstock C, Astrup G, Wetterslev J: High body mass index is a weak predictor for difficult and failed tracheal intubation: a cohort study of 91,332 consecutive patients scheduled for direct laryngoscopy registered in the Danish anesthesia database. Anesthesiology 2009, 107:266-274.
• [8]Lundstrøm LH, Møller AM, Rosenstock C, Astrup G, Gätke MR, Wetterslev J: Avoidance of neuromuscular blocking agents may increase the risk of difficult tracheal intubation: a cohort study of 103,812 consecutive adult patients recorded in the Danish anaesthesia database. Br J Anaesth 2009, 103:283-290.
• [9]Lundstrøm LH, Møller AM, Rosenstock C, Astrup G, Gätke MR, Wetterslev J: A documented previous difficult tracheal intubation as a prognostic test for a subsequent difficult tracheal intubation in adults. Anaesthesia 2009, 64:1081-1088.
• [10]Shiga T, Wajima Z, Inoue T, Sakamoto S, Sakamoto A: Predicting difficult intubation in apparently normal patients. Anesthesiology 2005, 103:429-437.
• [11]Kheterpal S, Han R, Tremper KK, Shanks AM, Tait AR, O’Reilly M, Ludwig TA, Martin L: Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology 2006, 105:885-891.
• [12]Kheterpal S, Martin L, Shanks AM, Tremper KK: Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics. Anesthesiology 2009, 110:891-897.
• [13]Apfelbaum JL, Hagberg CA, Caplan RA, Blitt CD, Connis RT, Nickinovich DG, Benumof JL, Berry FA, Bode RH, Cheney FW, Guidry OF, Ovassapian A: Practice guidelines for management of the difficult airway: an updated report by the American society of anesthesiologists task force on management of the difficult airway. Anesthesiology 2013, 118:251-270.
• [14]Caplan R, Benumof J, Berry F: Practice guidelines for management of the difficult airway: an updated report by the American society of anesthesiologists task force on management of the difficult airway. Anesthesiology 2003, 98:1269-1277.
• [15]Henderson JJ, Popat MT, Latto IP, Pearce AC: Difficult airway society guidelines for management of the unanticipated difficult intubation. Anaesthesia 2004, 59:675-694.
• [16]Woodall NM, Cook TM: National census of airway management techniques used for anaesthesia in the UK: first phase of the fourth national audit project at the royal college of anaesthetists. Br J Anaesth 2011, 106:266-271.
• [17]El-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD: Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg 1996, 82:1197-1204.
• [18]Campbell MK, Elbourne DR, Altman DG: CONSORT statement: extension to cluster randomised trials. BMJ Br Med J 2004, 328:702-708.
• [19]Hahn S, Puffer S, Torgerson DJ, Watson J: Methodological bias in cluster randomised trials. BMC Med Res Methodol 2005, 5:10. BioMed Central Full Text
• [20]Samsoon GLT, Young JRB: Difficult tracheal intubation: a retrospective study. Anaesthesia 1987, 42:487-490.
• [21]Cormack RS, Lehane J: Difficult tracheal intubation in obstetrics. Anaesthesia 1984, 39:1105-1111.
• [22]Hayes RJ, Bennett S: Simple sample size calculation for cluster-randomized trials. Int J Epidemiol 1999, 28:319-326.
• [23]Kahan BC, Morris TPT: Reporting and analysis of trials using stratified randomisation in leading medical journals: review and reanalysis. BMJ Br Med J 2012, 345:e5840.
• [24]Lundstrøm LH: Detection of risk factors for difficult tracheal intubation. Dan Med J 2012, 59:B4431.
• [25]Rosenstock C, Ostergaard D, Kristensen MS, Lippert A, Ruhnau B, Rasmussen LS: Residents lack knowledge and practical skills in handling the difficult airway. Acta Anaesthesiol Scand 2004, 48:1014-1018.
• [26]Rubin DB: Multiple Imputation for Nonresponse in Surveys. Wiley online library; 2008. [http://onlinelibrary.wiley.com/book/10.1002/9780470316696 webcite]
• [27]Schafer JL: Multiple imputation: a primer. Stat Methods Med Res 1999, 8:3-15.
• [28]Schafer JL, Graham JW: Missing data: our view of the state of the art. Psychol Methods 2002, 7:147-177.
• [29]Chan AW, Tetzlaff JM, Gøtzsche PC, Altman DG, Mann H, Berlin JA, Dickersin K, Hróbjartsson A, Schulz KF, Parulekar WR, Krleza-Jeric K, Laupacis A, Moher D: SPIRIT 2013 explanation and elaboration: guidance for protocols of clinical trials. BMJ 2013, 346:e7586.
• [30]Von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP: The strengthening the reporting of observational studies in epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol 2008, 61:344-349.
• [31]Grimshaw JM, Thomas RE, MacLennan G, Fraser C, Ramsay CR, Vale L, Whitty P, Eccles MP, Matowe L, Shirran L, Wensing M, Dijkstra R, Donaldson C: Effectiveness and efficiency of guideline dissemination and implementation strategies. Health Technol Assess (Rockv) 2004, 8(iii–iv):1-72.
• [32]Grimshaw JM, Eccles MP: Is evidence-based implementation of evidence-based care possible? Med J Aust 2004, 180(6 Suppl):S50-S51.