Canadian Journal of Anaesthesia

, Volume 41, Issue 5, pp 372–383 | Cite as

The airway: problems and predictions in 18,500 patients

  • D. Keith Rose
  • Marsha M. Cohen
Reports of Investigation

Abstract

The purpose of this study was to describe methods, risk factors, and outcomes of airway management in all patients (obstetrics excluded) attended by anaesthetists over 27 months. Preoperatively, anaesthetists recorded patient factors and assessed four airway characteristics. Methods of tracheal intubation and ease of direct laryngoscopy following general anaesthesia (easy, awkward, difficult) were noted. Factors predictive of poor outcome and the value of the preoperative airway examination were determined. For 18,205 patients following a direct laryngoscopy, (GA), tracheal intubation was difficult (> 2 laryngoscopies) in 1.8% and awkward (≤2 laryngoscopies) in 2.5%. This approach was a failure in 0.3%, and surgery was postponed in 0.05%. However, an alternative approach to direct laryngoscopy, (GA) was the first choice in 353 patients. Risk factors for difficult tracheal intubation included male sex, age 40–59 yr and obesity (P≤0.01). For direct laryngoscopy, (GA), airway characteristics predictive of difficult tracheal intubation were decreased mouth opening (relative risk 10.3), shortened thyromental distance (9.7), poor visualization of the hypopharynx (4.5), and limited neck extension (3.2), any two (7.6) and more than two (9.4) (P< 0.01). For 1,856 patients (10.0%) where at least one airway characteristic was abnormal, a direct laryngoscopy, (GA) resulted in 8.3% awkward and 6.0% difficult tracheal intubations. For patients with no abnormal airway characteristics, tracheal intubation was easy in 96.3%. Where tracheal intubation was difficult, 34.3% of patients had one or more abnormal airway characteristics preoperatively. Patients with difficult tracheal intubation had an increased rate of desaturation (< 90%), hypertension (> 200 mmHg) and dental damage on induction of anaesthesia. It is concluded that difficult tracheal intubations occurred infrequently but were associated with increased morbidity. Patient factors and four physical airway characteristics were useful predictors but limited in identifying all problems.

Key words

airway: assessment intubation: tracheal 

Résumé

Cette étude porte sur la description des méthodes, des facteurs de risque et sur les résultats de la gestion des voies aériennes chez tous les patients (l’obstétrique exclue) suivis par des anesthésistes sur une période de 27 mois. A la période préopératoire, les anesthésistes enregistrent les facteurs propres aux patients et évaluent quatre caractéristiques de leur voies aériennes. On note les méthodes d’intubation endotrachéale et le degré de facilité (facile, malaisée, difficile) de la laryngoscopie directe après l’anesthésie générale (AG). Les facteurs prédictifs de résultats défavorables et la valeur prédictive de l’examen préopératoire des voies aériennes sont déterminés. Chez 18,205 patients, l’intubation sous laryngoscopie directe (AG) a été difficile (> 2 laryngoscopies) dans 1,8% et malaisée (≤2 laryngoscopies) dans 2,5%. Cette approche a échoué dans 0,3% et la chirurgie reportée dans 0,05%. Cependant une alternative à la laryngoscopie directe (AG) a constitué le premier choix chez 353 patients. Les facteurs de risque de l’intubation difficile comprennent le sexe masculin, l’âge de 40 à 59 ans, et l’obésité (P ≤ 0,01). Pour la laryngoscopie directe (AG), les caractéristiques des voies aériennes prédictives d’une intubation difficile sont la réduction de l’ouverture buccale (risque relatif 10,30), la diminution de la distance thyromentonnière (9,7), l’nsuffisance de la visualisation de l’hypopharynx (4,5) et la limitation de l’extension du cou (3,2), deux (7,6) ou plus de deux de celles-ci (9,4) (P < 0,01). Chez 1,856 patients (10,0%), on trouve au moins une caractéristique anormale: chez ceux-ci la laryngoscopie directe (AG) s’avère malaisée dans 8,3% et difficile chez 6,0% des cas. Pour les patients sans anomalies, l’intubation est facile dans 96,3% des cas. Quand l’intubation est difficile, 34,3% des patients ont au moins une caractéristique anormale en préopératoire. Les patients intubés difficilement présentent une désaturation (< 90%) plus fréquente, de l’hypotension (> 200 mmHg) et des dommages dentaires à l’induction de l’anesthésie. En conclusion, les intubations trachéales difficiles surviennent peu fréquemment mais sont associées à une augmentation de la morbidité. Les facteurs propres aux patients et quatre caractéristiques des voies aériennes sont des facteurs prédictifs utiles mais sont insuffisants pour identifier tous les problèmes.

References

  1. 1.
    Caplan RA, Posner KL, Ward RJ, Cheney FW Adverse respiratory events in anesthesia: a closed claim analysis. Anesthesiology 1990; 72: 828–33.PubMedCrossRefGoogle Scholar
  2. 2.
    Cheney FW, Posner KL, Caplan RA. Adverse respiratory events infrequently leading to malpractice suits. A closed claims analysis. Anesthesiology 1991; 75: 932–9.PubMedCrossRefGoogle Scholar
  3. 3.
    Benumof JL. Management of the difficult adult airway. With special emphasis on awake tracheal intubation. Anesthesiology 1991; 75: 1087–110.PubMedCrossRefGoogle Scholar
  4. 4.
    Cobley M, Vaughan RS. Recognition and management of difficult airway problems. Br J Anaesth 1992; 68: 90–7.PubMedCrossRefGoogle Scholar
  5. 5.
    Nolan JP, Wilson ME. An evaluation of the gum elastic bougie. Intubation times and incidence of sorer throat. Anaesthesia 1992; 47: 878–81.PubMedCrossRefGoogle Scholar
  6. 6.
    Fisher JA, Ananthanarayan C, Edelist G. Role of the laryngeal mask in airway management (Editorial). Can J Anaesth 1992; 39: 1–3.PubMedGoogle Scholar
  7. 7.
    McCoy EP, Mirakhur RK. The levering laryngoscope. Anaesthesia 1993; 48: 516–9.PubMedCrossRefGoogle Scholar
  8. 8.
    Dich-Nielsen JO, Nagel P. Flexible fibreoptic bronchoscopy via the laryngeal mask. Acta Anaesthesiol Scand 1993; 37: 17–9.PubMedGoogle Scholar
  9. 9.
    Knill RL. Difficult laryngoscopy made easy with a “BURP.” Can J Anaesth 1993; 40: 279–82.PubMedGoogle Scholar
  10. 10.
    Ellis DG, Jakymec A, Kaplan RM, et al. Guided orotracheal intubation in the operating room using a lighted stylet: a comparison with direct laryngoscopic technique. Anesthesiology 1986; 64: 823–6.PubMedCrossRefGoogle Scholar
  11. 11.
    Fox DJ, Castro TJ Jr, Rastrelli AJ. Comparison of intubation techniques in the awake patient: the Flexi-lum® surgical light (lightwand) versus blind nasal approach. Anesthesiology 1987; 66: 69–71.PubMedCrossRefGoogle Scholar
  12. 12.
    Marks RRD, Hancock R, Charters P. An analysis of laryngoscope blade shape and design: new criteria for laryngoscope evaluation. Can J Anaesth 1993; 40: 262–70.PubMedGoogle Scholar
  13. 13.
    Davies J, Weeks S, Crone LA, Pavlin E. Difficult intubation in the parturient. Can J Anaesth 1989; 36: 668–74.PubMedGoogle Scholar
  14. 14.
    King TA, Adams AP Failed tracheal intubation. Br J Anaesth 1990; 65: 400–14.PubMedCrossRefGoogle Scholar
  15. 15.
    American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway. Anesthesiology 1993; 78: 597–602.Google Scholar
  16. 16.
    Bellhouse C, Dore C. Criteria of estimating likelihood of difficulty of endotracheal intubation with the Macintosh Laryngoscope. Anaesth Intensive Care 1988; 16: 329–37.PubMedGoogle Scholar
  17. 17.
    Mallampati SR, Gatt SP, Gugino LD, et al. A clinical sign to predict difficult tracheal intubation: a prospective study. Can J Anaesth 1985; 32: 429–34.Google Scholar
  18. 18.
    Davies JM, Eagle CJ. M.O.U.T.H.S. (Letter). Can J Anaesth 1991; 38: 687–8.PubMedGoogle Scholar
  19. 19.
    Wilson ME, Spiegelhalter D, Robertson JA, Lesser P. Predicting the difficult intubation. Br J Anaesth 1988; 61: 211–6.PubMedCrossRefGoogle Scholar
  20. 20.
    Oates JDL MacLeod AD, Oates PD, Pearsall FJ, Howie JC, Murray GD. Comparison of two methods for predicting difficult intubation. Br J Anaesth 1991; 66: 305–9.PubMedCrossRefGoogle Scholar
  21. 21.
    Deller A, Schreiber MN, Gramer J, Ahnefeld FW Difficult intubation: incidence and predictability. A prospective study of 8,284 adult patients. Anesthesiology 1990; 73: A1054.CrossRefGoogle Scholar
  22. 22.
    Horton WA, Fahy L, Charters P. Defining a standard intubating position using “angle finder.” Br J Anaesth 1989; 62: 6–12.PubMedCrossRefGoogle Scholar
  23. 23.
    Rose DK, Cohen MM. Patient problems during anaesthesia — are they related to the surgical approach? Can J Anaesth 1992; 39: (Supplement): A111.Google Scholar
  24. 24.
    Rose DK, Cohen MM, Wigglesworth DF, Yee DA. Development of a computerized database for the study of anaesthesia care. Can J Anaesth 1992; 39: 716–23.PubMedGoogle Scholar
  25. 25.
    Tiret L, Desmonts JM, Hatton F, Vourch G. Complications associated with anaesthesia — a prospective surgey in France. Can J Anaesth 1986; 33: 336–44.Google Scholar
  26. 26.
    Fear DW Failed intubation in the partiturent (Editorial). Can J Anaesth 1989; 36: 614–6.PubMedGoogle Scholar
  27. 27.
    Morgan M. Anaesthetic contribution to maternal mortality. Br J Anaesth 1987; 59: 842–55.PubMedCrossRefGoogle Scholar
  28. 28.
    Lockhart PB, Feldbau EV, Gabel RA, Connolly SF, Silversin JB. Dental complications during and after tracheal intubation. J Am Dent Assoc 1986; 112: 480–3.PubMedGoogle Scholar
  29. 29.
    Tartell PB, Hoover LA, Friduss ME, Zuckerbraun L. Pharyngoesophageal intubation injuries: three case reports. Am J Otolaryngol 1990; 11: 256–60.PubMedCrossRefGoogle Scholar
  30. 30.
    Volpi D, Lin PT, Kuriloff DB, Kimmelman CP. Risk factors for intubation injury of the larynx. Ann Otol Rhinol Laryngol 1987; 96: 684–6.PubMedGoogle Scholar
  31. 31.
    Lesser T, Williams G. Laryngographic investigation of postoperative hoarseness. Clin Otolaryngol 1988; 13: 37–42.PubMedCrossRefGoogle Scholar
  32. 32.
    Jones MW, Catling S, Evans E, Green DH, Green JR. Hoarseness after tracheal intubation. Anaesthesia 1992; 47: 213–6.PubMedCrossRefGoogle Scholar
  33. 33.
    Sampson GLT, Young JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42: 487–90.CrossRefGoogle Scholar
  34. 34.
    Norton ML, Brown ACD. Evaluating the patient with a difficult airway for anesthesia. Otolaryngol Clin North Am 1990; 23: 771–85.PubMedGoogle Scholar
  35. 35.
    Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105–11.PubMedCrossRefGoogle Scholar
  36. 36.
    Sutherland AD, Sale JP. Fibreoptic awake intubation — a method of topical anaesthesia and orotracheal intubation. Can Anaesth Soc J 1986; 33: 502–4.PubMedGoogle Scholar
  37. 37.
    Ovassapian A, Krejcie TC, Yelich SJ, Dykes MH. Awake fibreoptic intubation in the patient at high risk of aspiration. Br J Anaesth 1989; 62: 13–6.PubMedCrossRefGoogle Scholar
  38. 38.
    Cahen CR. An aid in cases of difficult tracheal intubation (Letter). Anesthesiology 1991; 74: 197.PubMedCrossRefGoogle Scholar
  39. 39.
    Benumof JL. Use of the laryngeal mask airway to facilitate fiberscope-aided tracheal intubation (Letter). Anesth Analg 1992; 74: 313–4.PubMedCrossRefGoogle Scholar
  40. 40.
    Abou-Madi MN, Trop D Pulling versus guiding: a modification of retrograde guided intubation. Can J Anaesth 1989; 36: 336–9.PubMedGoogle Scholar
  41. 41.
    Sivarajan M, Fink BR. The position and the state of the larynx during general anesthesia and muscle paralysis. Anesthesiology 1990; 72: 439–42.PubMedCrossRefGoogle Scholar
  42. 42.
    Ovassapian A, Dykes MH, Golmon ME. A training programme for fibreoptic nasotracheal intubation. Use of model and live patients. Anaesthesia 1983; 38: 795–8.PubMedCrossRefGoogle Scholar
  43. 43.
    Dykes MHM, Ovassapian A. Dissemination of fibreoptic airway endoscopy skills by means of a workshop utilizing models. Br J Anaesth 1989; 63: 595–7.PubMedCrossRefGoogle Scholar
  44. 44.
    Rocke DA, Murray WB, Rout CC, Gouws E. Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia. Anesthesiology 1992; 77: 67–73.PubMedCrossRefGoogle Scholar
  45. 45.
    Williams KN, Carli F, Cormack RS. Unexpected, difficult laryngoscopy: a prospective survey in routine general surgery. Br J Anaesth 1991; 66: 38–44.PubMedCrossRefGoogle Scholar
  46. 46.
    Reissell E, Orko R, Maunuksela EL, Lindgren L. Predictability of difficult laryngoscopy in patients with long-term diabetes mellitus. Anaesthesia 1990; 45: 1024–7.PubMedCrossRefGoogle Scholar
  47. 47.
    Aiello G, Metcalf I. Anaesthetic implications of temporomandibular joint disease. Can J Anaesth 1992; 39: 610–6.PubMedCrossRefGoogle Scholar
  48. 48.
    Nichol HC, Zuck D. Difficult laryngoscopy — the “anterior” larynx and the atlanto-occipital gap. Br J Anaesth 1983; 55: 141–4.PubMedCrossRefGoogle Scholar
  49. 49.
    Chow FL, Duncan PG, Code WE, Yip RW. Can bedside neck extension predict difficult intubation? Can J Anaesth 1993; 40: A4.Google Scholar
  50. 50.
    King TA, Adams AP. Predicting difficult intubation. What factors influence the thyromental distance? (Letter). Anaesthesia 1992; 47: 623.PubMedCrossRefGoogle Scholar
  51. 51.
    Frerk CM. Predicting difficult intubation. Anaesthesia 1991; 46: 1005–8.PubMedCrossRefGoogle Scholar
  52. 52.
    Tham EJ, Gildersleve CD, Sanders LD, Mapleson WW, Vaughan RS. Effects of posture, phonation and observer on Mallampati classification. Br J Anaesth 1992; 68: 32–8.PubMedCrossRefGoogle Scholar

Copyright information

© Canadian Anaesthesiologists 1994

Authors and Affiliations

  • D. Keith Rose
    • 1
  • Marsha M. Cohen
    • 2
    • 3
    • 4
  1. 1.Department of AnaesthesiaSt. Michael’s HospitalTorontoCanada
  2. 2.Clinical Epidemiology UnitSunnybrook Health Science Centre and The Institute for Clinical Evaluative SciencesToronto
  3. 3.Department of Health AdministrationUniversity of TorontoToronto
  4. 4.Department of Anaesthesia, Sunnybrook Health Science CentreUniversity of TorontoToronto

Personalised recommendations