Difficult AirwayComponents of Airway Exam Shape of palate Narrow or high-arched Relation of upper &...
Transcript of Difficult AirwayComponents of Airway Exam Shape of palate Narrow or high-arched Relation of upper &...
Difficult AirwayDepartment of Anesthesiology
University of Colorado Health Sciences Center(prepared by Brenda A. Bucklin, M.D.)
Objectives
• Definition & incidence of the difficult airway• Evaluation of the airway• Co-morbidities and the difficult airway• Management of the known difficult airway• Management of the unrecognized difficult
airway
Definition & Incidence ofDifficult Airway
A difficult airway is defined as the clinical situationin which a conventionally trained anesthesiologistexperiences difficulty with mask ventilation, difficultywith tracheal intubation, or both.
Incidence:
• Non-obstetric population: up to 1:2500• Obstetric population: 1:250
http://www.asahq.org/publicationsAndServices/Difficult%20Airway.pdf
Components of Airway Exam
Narrow or high-archedShape of palate
Prominent “overbite”Relation of upper & lower jaw
LimitedNeck range of motion“Thick”Thickness of neckShortLength of neckLess than 3cmThyromental distance
Mallampati class > IIVisibility of uvula
Relatively longUpper incisor lengthNon-reassuring FindingComponent
Mallampati Classification &Glottic View
Mallampati Classification
Glottic View
Factors Related to DifficultAirway
• Obesity• Pregnancy• Tumor• Infection• Inflammatory
disorders
• Acromegaly• Cervical spine
problems• Gastric reflux• Congenital
syndromes• Trauma
The ASA Algorithm for Recognizedand Unrecognized Difficult Airways
Recognized Difficult Airway
• Regional anesthesia, if possible• Can we be sure the regional will work?
• Awake intubation
The Recognized DifficultAirway
Role of the laryngeal mask airway (LMA) in the American Society of Anesthesiologists (ASA) Difficult Airway Algorithm. (Adapted from Benumof JL: Laryngeal maskairway and the ASA difficult airway algorithm. Anesthesiology 84:686, 1996.)
Recognized
Preparation for AwakeIntubation
• Intravenous drying agent: glycopyrrolate• Topical upper airway anesthesia
– Pledgets soaked with local anesthetic– Atomized local anesthetic
• + Superior laryngeal nerve block• + Transtracheal nerve block
Suggested Difficult AirwayCart Contents
• Rigid laryngoscope blade of different sizesand designs
• Assorted endotracheal tubes• Endotracheal tube guides• Supragottic airway devices (e.g. LMA)• Fiberoptic intubation equipment• Retrograde intubation equipment• Equipment for emergency surgical airway• Exhaled carbon dioxide detector
http://www.asahq.org/publicationsAndServices/Difficult%20Airway.pdf
Awake Intubation:superior laryngeal nerve block
Superior laryngeal nerve block is performedby passing a needle through the thyrohyoidmembrane and depositing local anestheticbilaterally.
In the absence of tumor or infection, the superiorlaryngeal nerve block can be used to anesthetizethe airway above the glottis as well as theepiglottis and arytenoepiglottic folds. Because itremoves some protective reflexes, it should beused with caution in patients with full stomach.
Superior Laryngeal Nerve Block
Transtracheal Nerve Block
Transtracheal nerve block is performed bypassing a needle through the cricothyroidmembrane and depositing local anesthetic.
The transtracheal injection blocks sensoryinnervation supplied by the vagus nerve via therecurrent laryngeal nerve. Lidocaine is used forthis block and is rapidly absorbed into thesystemic circulation via the trachea. A maximumsafe dose of topical lidocaine in the trachea(atomizer + transtracheal) is 4mg/kg.
Transtracheal Nerve Block
Awake Fiberoptic Intubation
An alternative in theuncooperative patient: LMA
(laryngeal mask airway)
Other technique: retrogradeintubation
Retrograde Wire
Fiberoptic-assisted Retrograde Wire
The Unrecognized DifficultAirway
Figure 42-24 Role of the laryngeal mask airway (LMA) in the American Society of Anesthesiologists (ASA) Difficult Airway Algorithm. (Adaptedfrom Benumof JL: Laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology 84:686, 1996.)
Downloaded from: Miller's Anesthesia (on 27 March 2007 08:48 PM)© 2007 Elsevier
Unrecognized
The LMA can be lifesaving inthe can’t ventilate/intubate
situation.
Alternative Airways
Bullard Laryngoscope
Fiberoptic Intubation through LMA
LMA
Emergency Cricothyrotomy
Anatomic Landmarks
Rescue technique: cricothyrotomy andtracheostomy
Canadian Journal of Anesthesia 52:765-769 (2005)
Conclusion: The ASA DifficultAirway Algorthm