Presentation on theme: "Airtraq versus standard laryngoscopy by experienced pre-hospital laryngoscopists in a model of difficult intubation: a randomised cross-over trial M Woollard,*"— Presentation transcript:
Airtraq versus standard laryngoscopy by experienced pre-hospital laryngoscopists in a model of difficult intubation: a randomised cross-over trial M Woollard,* † D Lighton,* W Mannion, † I Johns, † P O’Meara,* C Cotton,** M Smyth †† *School of Biomedical Sciences, Charles Sturt University, Bathurst, Australia * † Pre-hospital, Emergency, & Cardiovascular Care Applied Research Group, Coventry University (UK) † ACAP New South Wales Branch **ACAP South Australia Branch †† West Midlands Ambulance Service NHS Trust, Birmingham, UK
Conflict of interest The authors confirm that the manufacturers of the Airtraq had no involvement in the conceptualisation, design, conduct, analysis, or write-up of this trial However, samples of the Airtraq were donated by the manufacturers at no cost in support of the trial Funding was provided by Charles Sturt University and the Australian College of Ambulance Paramedics
Research question When used by [experienced pre-hospital laryngoscopists managing a model of a difficult airway] does [the Airtraq] [improve intubation success rates] compared with [standard laryngoscopy]?
Justification Some reports of high ETT success rates (98.4%, n= 2,700) (Bulger et al, 2002) However, paramedic intubation skills are criticised –prospective, multi-centre study reported overall ETI success rate of 91.8% (95% CI=90.2% to 93.3%, n = 1,272) success rates progressed from 69.9% to 84.9% to 89.9% for the first, second and third attempts respectively (Wang et al, 2006) –prospective observational study (n= 208) misplaced ETT unrecognized in 5.8% of patients (95% CI = 2.6% to 8.9%) (Jones et al, 2004)
Justification Prospective in-hospital observational study n= 52 –Cumulative success rate of 71.5% after 2 attempts –Success rate by Cormack and Lehane (1984) view Grade I = 87.5% Grade II = 56% Grade III = 0% Grade IV = 0% –Recommended ETT should be withdrawn as a paramedic skill (Deakin et al, 2005)
Methods Ethics approval from Charles Sturt University Convenience sample of pre-hospital practitioners attending the Australian College of Ambulance Professionals conference in Adelaide, Nov 2006 –Previously intubation trained –Authorised to practice intubation Written informed consent obtained
Methods Study-related training –Hand-out with text and diagrams –Maximum of five minutes training with Airtraq Explanation by researcher Demonstration by researcher One practice attempt by subject
Methods Model of difficult intubation: –Manikin immobilised with collar + spine board Subjects not permitted to loosen / remove collar or straps –Tongue inflated –Cormack & Lehane grade III (epiglottis +/- arytenoids visible) or grade IV (tip of epiglottis / no airway structures visible) view Depends on operator skill
Methods Prospective randomisation of sequence in which students attempted intubation with an 8.0mm cuffed tube using either –Airtraq or –Macintosh laryngoscope with size 4 blade and malleable stylet One intubation attempt undertaken with each device –Attempt limited to 30 seconds –Researcher confirmed ETT placement ‘Difficulty of use’ scored by subjects for each device using a 100mm visual analogue scale
Results For Macintosh and Airtraq respectively: –Success rates 14/56 (25%) vs. 47/56 (84%) (59% difference, 95% CI 42 to 72%, P<0.0001); –Oesophageal intubation rates 9/56 (16%) vs. 0/56 (0%) (-16% difference, 95% CI -9 to -28%, P=0.0014); –Subject-rated difficulty of use scores 86 (IQ range 71 to 93, range 12 to 100) vs 20 (IQ range 5 to 28, range 1 to 75), p<0.001
Other observations Significant dental damage inflicted during all Macintosh intubation attempts / successes! Subjects always reported an excellent (grade I) view when using the Airtraq, regardless of whether intubation successful
Limitations Recruiting volunteers at a clinically-focused conference risks reducing the generalisability of findings (selection bias): –Population is likely to consist of practitioners with a greater commitment to their on-going education –May, therefore, be more skilled in tracheal intubation than non-attendees Trials involving models cannot be used as a basis for quantitatively predicting benefit in patients
Conclusions In experienced pre-hospital laryngoscopists managing a manikin model of a grade III / IV airway view, with minimal additional training, the Airtraq significantly: –Increases first-time intubation success rates –Reduces the number of oesophageal intubations –Reduces the difficulty of intubation attempts It also has the potential to: –Consistently provide grade I views –Reduce oral / dental trauma during intubation attempts
Contact details: Malcolm.firstname.lastname@example.org Prof. Malcolm Woollard, Coventry University, Room 304 Richard Crossman Building, Priory Street, Coventry, CV1 5FB, UK Tel: +44 24 7679 5837
References Bulger EM, Copass MK, Maier RV, Larsen J, Knowles J, Jurkovich GJ. An analysis of advanced prehospital airway management. J Emerg Med 2002;23(2):183-9 Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia, 1984;39:1105-11. Deakin CD, Peters R, Tomlinson P, Cassidy M. Securing the prehospital airway: a comparison of laryngeal mask insertion and endotracheal intubation by UK paramedics. Emerg Med J 2005;22(1):64-7 Jones JH, Murphy MP, Dickson RL, Somerville GG, Brizendine EJ. Emergency physician-verified out-of-hospital intubation: miss rates by paramedics. Acad Emerg Med, 2004;11(6):707-9. Wang HE, Yealy DM. How many attempts are required to accomplish out-of-hospital endotracheal intubation? Acad Emerge Med, 2006;13(4):372-7.