Focused Issue of This Month SiOh Kim, MD. Department of Anesthesiology and Pain Medicine, Kyungpook National University College of Medicine Email : sokim@knu.ac.kr J Korean Med Assoc 2007; 50(12): 1048-1056 Abstract Airway management is still perceived as the greatest patient safety issue and the key task that anesthesiologists perform. Management includes mask ventilation, use of a laryngoscope, and the endotracheal intubation and extubation of the patient. Difficulty can be encountered at any of these stages, and can be a major cause of anesthesiarelated morbidity and mortality. Competence in airway management requires knowledge of the anatomy and physiology of the airway, ability to access the patient's airway for the anatomic features that correlate with difficulties in airway management, skill with the many devices used in airway management, including a variety of recentlyintroduced airway tools, and the appropriate application of the sophisticated algorithm for difficult airway management. Development and clinical distribution of supraglottic airway devices and their enhancement, as well as the broad acceptance of awake fiberoptic intubation, has led to profound changes in the strategy for managing a difficult airway. Including the American Society of Anesthesiologists, many countries have developed their own airway management algorithm these days. Nevertheless, massive national and international deficits still exist in implementing these guidelines into practice as well as the implicated structural requirements with respect to education, reflection, team building and equipment concerning each individual institution. In regard to this situation, it is the recommendation of the author that our country develop and institute such a standardized system of airway management. Keywords : Airway management; Difficult airway; Intubation; Fiberoptic bronchoscope; Supraglottic airway devices 1048
Table 1. Disease states associated with difficult airway management Congenital PierrreRobin syndrome TreacherCollins syndrome Goldenhar's syndrome Mucopolysaccharidoses Achondroplasia Micrognathia Down's syndrome Acquired Morbid obesity Acromegaly Infections involving the airway (Ludwig's angina) Rheumatoid arthritis Obstructive sleep apnea Ankylosing spondylitis Tumours involving the airway Trauma (airway, cervical spine) Table 2. Components of the preoperative airway physical examination Airway examination component Nonreassuring findings 11. Length of upper incisors Relatively long 12. Relation of maxillary and mandibular Prominent 'overbite' (maxillary incisors incisors during normal jaw closure anterior to mandibular incisors) 13. Relation of maxillary and mandibular Patient mandibular incisors anterior to incisors during voluntary protrusion (in mandible front of) maxillary incisors 14. Interincisor distance Less than 3 cm 15. Visibility of uvula Not visible when tongue is protruded with patient in sitting position (e.g. Mallampati class II) 16. Shape of palate Highly arched or very narrow 17. Compliance of mandibular space Stiff, indurated, occupied by mass, or non resilient 18. Thyromental distance Less than three ordinary finger breadths 19. Length of neck Short 10. Thickness of neck Thick 11. Range of motion of head and neck Patient cannot touch tip of chin to chest or cannot extend neck 1049
Kim SO Figure 1. Mallampati classification. 1050
15mm connector Integral biteblock Airway tube Introducer strap Airway tube orifice Internal drain tube Drain tube orifice Handle Inflation line Laryngeal mark Epiglottic elevator Figure 2. Laryngeal Mask Airways. A) Classic LMA TM with different sizes. B) LMA Fastrack TM. C) LMA ProSeal TM (from www.lmana.com). Rigid anatomically curved airway 15mm standard connector accepts 8mm cuffed tube Drain tube Inflation tube Pilot balloon Valve Cuff A B C 1051
Kim SO A C Figure 3. Insertion of the laryngeal mask airway (LMA). A) The tip of the cuff is pressed upward against the hard palate by the index finger while the middle finger opens the mouth. B) The LMA is pressed backward in a smooth movement. Notice that the nondominant hand is used to extend the head. C) The LMA is advanced until definite resistance is felt. D) Before the index finger is removed, the nondominant hand presses down on the LMA to prevent dislodgment during removal of the index finger. The cuff is subsequently inflated, and outward movement of the tube is often observed during this inflation. (from www.lmana.com) B D 1052
Figure 4. Four grades of laryngoscopic view. Grade I is visualization of the entire laryngeal aperture, grade II is visualization of just the posterior portion of the laryngeal aperture, grade III is visualization of only the epiglottis, and grade IV is visualization of just the soft palate. A B Figure 5. Combitube (A) and Light wand (B). 1053
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Kim SO Peer Reviewer Commentary 1056