Detailed statistical analysis plan for the difficult airway management (DIFFICAIR) trial

Anders Kehlet Nørskov, Lars Hyldborg Lundstrøm, Charlotte Vallentin Rosenstock, Jørn Wetterslev, Anders Kehlet Nørskov, Lars Hyldborg Lundstrøm, Charlotte Vallentin Rosenstock, Jørn Wetterslev

Abstract

Background: Preoperative airway assessment in Denmark is based on a non-specific clinical assessment left to the discretion of the responsible anesthesiologist. The DIFFICAIR trial compares the effect of using a systematic and consistent airway assessment versus a non-specific clinical assessment on the frequency of unanticipated difficult airway management.To prevent outcome bias and selective reporting, we hereby present a detailed statistical analysis plan as an amendment (update) to the previously published protocol for the DIFFICAIR trial.

Method/design: The DIFFICAIR trial is a stratified, parallel group, cluster (cluster = department) randomized multicenter trial involving 28 departments of anesthesia in Denmark randomized to airway assessment either by the Simplified Airway Risk Index (SARI) or by a usual non-specific assessment. Data from patients' preoperative airway assessment are registered in the Danish Anesthesia Database. An objective score for intubation grading the severity, that is the severity of the intubations, as well as the frequency of unanticipated difficult intubation, is measured for each group.Primary outcome measures are the fraction of unanticipated difficult and easy intubations.The database is programmed so that the registration of the SARI is mandatory for the intervention group but invisible to controls.Data recruitment was commenced in October 2012 and ended in ultimo December 2013.

Conclusion: We intend to increase the transparency of the data analyses regarding the DIFFICAIR trial by an a priori publication of a statistical analysis plan.

Trial registration: ClinicalTrials.gov: NCT01718561.

References

    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. doi: 10.1093/bja/aem344.
    1. Hove LD, Steinmetz J, Christoffersen JK, Møller A, Nielsen J, Schmidt H, Moller A. Analysis of deaths related to anesthesia in the period 19962004 from closed claims registered by the Danish Patient Insurance Association. Anesthesiology. 2007;106:675–680. doi: 10.1097/01.anes.0000264749.86145.e5.
    1. 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. doi: 10.1097/00000542-200507000-00009.
    1. Rosenstock C, Møller 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. doi: 10.1034/j.1399-6576.2001.450109.x.
    1. McClure JH, Cooper GM, Clutton-Brock TH. Saving mothers’ lives: reviewing maternal deaths to make motherhood safer: 2006-8: a review. Br J Anaesth. 2011;107:127–132. doi: 10.1093/bja/aer192.
    1. Cook T, Woodall N, Frerk C. Major complications of airway management in the UK:results of the Fourth National Audit Project of the royal college of anaesthesiologists and the difficult airway society. Part 1: Anaesthesia. Br J Anaesth. 2011;106:617–631. doi: 10.1093/bja/aer058.
    1. 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. doi: 10.1093/bja/aer292.
    1. 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. doi: 10.1213/01.ane.0000217211.12232.55.
    1. 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.
    1. 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. doi: 10.1093/bja/aep124.
    1. 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. doi: 10.1111/j.1365-2044.2009.06057.x.
    1. Shiga T, Wajima Z, Inoue T, Sakamoto S, Sakamoto A. Predicting difficult intubation in apparently normal patients. Anesthesiology. 2005;103:429–437. doi: 10.1097/00000542-200508000-00027.
    1. 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.
    1. 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. doi: 10.1097/00000542-200611000-00007.
    1. 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. doi: 10.1097/ALN.0b013e31819b5b87.
    1. Kheterpal S, Healy D, Aziz M. Incidence, predictors, and outcome of difficult mask ventilation combined with difficult laryngoscopy: a report from the Multicenter Perioperative Outcomes Group. Anesthesiology. 2013;6:1–10.
    1. Nørskov AK, Rosenstock CV, Wetterslev J, Lundstrøm LH. 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. 2013;14:347. doi: 10.1186/1745-6215-14-347.
    1. Chan A, Tetzlaff JM, Altman DG, Laupacis A, Gøtzsche PC, Krleža-Jerić K, Hróbjartsson A, Mann H, Dickersin K, Berlin JA, Doré CJ, Parulekar WR, Summerskill WSM, Groves T, Schulz KF, Sox HC, Rockhold FW, Rennie D, Moher D. SPIRIT 2013 statement: defining standard protocol items for clinical trials. Ann Intern Med. 2013;158:200–207. doi: 10.7326/0003-4819-158-3-201302050-00583.
    1. Dwan K, Gamble C, Williamson PR, Altman DG. Reporting of clinical trials: a review of research funders’ guidelines. Trials. 2008;9:66. doi: 10.1186/1745-6215-9-66.
    1. Campbell MK, Piaggio G, Elbourne DR, Altman DG. Consort 2010 statement: extension to cluster randomised trials. BMJ. 2012;345:e5661. doi: 10.1136/bmj.e5661.
    1. Hayes RJ, Bennett S. Simple sample size calculation for cluster-randomized trials. Int J Epidemiol. 1999;28:319–326. doi: 10.1093/ije/28.2.319.
    1. Kahan B, Morris T. Reporting and analysis of trials using stratified randomisation in leading medical journals: review and reanalysis. BMJ. 2012;345:e5840. doi: 10.1136/bmj.e5840.
    1. Crespi CM, Wong WK, Wu S. A new dependence parameter approach to improve the design of cluster randomized trials with binary outcomes. Clin Trials. 2011;8:687–698. doi: 10.1177/1740774511423851.
    1. Fergusson D, Aaron SD, Guyatt G, Hébert P. Post-randomisation exclusions: the intention to treat principle and excluding patients from analysis. BMJ. 2002;325:652–654. doi: 10.1136/bmj.325.7365.652.
    1. Klar N, Donner A. Current and future challenges in the design and analysis of cluster randomization trials. Stat Med. 2001;20:3729–3740. doi: 10.1002/sim.1115.
    1. Hayes RJ, Moulton LH. Cluster Randomised Trials. Pharmaceutical Statistics, vol 11, Issue 1.
    1. Kahan BC, Morris TP. Assessing potential sources of clustering in individually randomised trials. BMC Med Res Methodol. 2013;13:58. doi: 10.1186/1471-2288-13-58.
    1. Zhang J, Yu KF. What’s the relative risk? A method of correcting the odds ratio in cohort studies of common outcomes. JAMA. 1998;280:1690–1691. doi: 10.1001/jama.280.19.1690.
    1. Schafer JL. Multiple imputation: a primer. Stat Methods Med Res. 1999;8:3–15. doi: 10.1191/096228099671525676.
    1. Gøtzsche PC. Blinding during data analysis and writing of manuscripts. Control Clin Trials. 1996;17:285–290. doi: 10.1016/0197-2456(95)00263-4.
    1. Peters T. Comparison of methods for analysing cluster randomized trials: an example involving a factorial design. Int J Epidemiol. 2003;32:840–846. doi: 10.1093/ije/dyg228.
    1. Ma J, Raina P, Beyene J, Thabane L. Comparison of population-averaged and cluster-specific models for the analysis of cluster randomized trials with missing binary outcomes: a simulation study. BMC Med Res Methodol. 2013;13:9. doi: 10.1186/1471-2288-13-9.

Source: PubMed

Спонсоры и соавторы

Заболевания

Медикаментозные вмешательства

Подписаться