Basic Airway Management

Review of Important Facts and Concepts: Airway Anatomy Airway Assessment Review basic drugs and equipment setup for managing airway

The Pharynx

The Glottis

While this only basic, you will become an expert in airway management and expected to communicate and document in proper anatomical terms:

Definitions Difficult Airway –“A conventionally trained anesthetist experiences difficulty with mask ventilation, endotracheal intubation, or both”. Difficult Mask Ventilation –"It is not possible for the unassisted anesthesiologist to maintain SaO2 >90% using 100% O2 and positive pressure mask ventilation in a patient whose SaO2 was >90% before anesthetic intervention”.

Definitions Difficult laryngoscopy –"It is not possible to visualize any portion of the vocal cords with conventional laryngoscopy”. Difficult endotracheal intubation –"Proper insertion of the endotracheal tube with conventional laryngoscopy requires more than three attempts or more than 10 minutes."

Airway Management 1 in 10,000 patients have an unpredicted difficult airway –Caplan RA et al: Anesthesiology 1993; 78: % of patients will have a difficult intubation –Walls RM et al: Ann Emerg Med 1999; 34: S14 Risk of difficult intubation in general population is 1 in 2400 SHOULD BE DONEProspective evaluation of the airway SHOULD BE DONE systematically in every patient before they become apneic

Principles in Evaluating the Upper Airway: “ Concept 1)—look for things that correlate with difficult mask ventilation” “Concept 2)—this can be done in seconds 1.Size of Tongue versus Pharynx –Mallampati classification 2.Facial features that can directly compromise mask seal –Beard, edentulous 3.Neck features associated with difficult mass ventilation –Thyromental distance, large neck, laryngeal tongue

Understanding Upper Airway Obstruction— ”cork in the bottle”

1. Size of Tongue vs Pharynx “Mallampati Classification” Concept: Patient’s with a Class 3-4 airway have a relatively large tongue relative to the volume of their pharynx which can lead to difficulty performing positive pressure ventilation.

2. Facial features: Concept: Be wary of facial features in sedation candidates that could make trying to obtain a mask seal very difficult (they all leak).

3. ↓ Anterior Mandibular Space & Large Neck Concept: “neck features that in the presence of sedation, relaxed airway, recumbent position: a) place a patient at higher risk for obstruction and b) that if needed, could make positive pressure ventilation difficult”.

Predictors of Difficult Mask Ventilation: Summary—watch out! High Mallampatti score Beard Large neck BMI > 26 kg/m 2 History of Snoring (??OSA) Edentulous

Assessing for Intubation

Preoperative Evaluation of the Upper Airway for signs of difficulty with intubation: 1.Size of Tongue versus Pharynx –Mallampati classification 2.Atlanto-Occipital Joint Extension –Cervical spine mobility 3.Anterior Mandibular Space –Thyromental distance 4.Dental Examination

Size of Tongue vs Pharynx

Atlanto-Occipital Joint Extension or “Buck teeth”

Anterior Mandibular Space (Thyromental distance)

Dental Examination Ascertain the presence of –Loose teeth –Dental Prostheses –Co-existing dental abnormalities

PREOP EXAMACCEPTABLE ENDPOINTSSIGNIFICANCE OF ENDPOINTS 1. Length of upper incisorsQualitative/short incisorsLong incisors-blade enters mouth in cephalad direction 2. Involuntary: Maxillary teeth anterior to mandibular teeth No overriding of maxillary teeth ant. to the mandib. teeth Overriding maxillary teeth-Blade enters mouth in a more cephalid direction. 3. Voluntary: Protrusion of mandibular teeth anterior to the maxillary teeth Anterior protrusion of the mandibular teeth relative to the maxillary teeth Test of TMJ function ; means good mouth opening and jaw will move anteriorly with laryngoscopy. 4. Intercisor distance> 3 cm2-cm phlange on blade can be easily inserted between teeth. 5. Oropharyngeal class (Mallampatti exam)< Class IITongue is small in relation to size of oropharyngael cavity. 6. Narrowness of palateShould not appear very narrow and/or highly arched A narrow palate decreases the oropharyngeal volume and room for both blade and ETT. 7. Mandibular space length (Thyromental Distance) = 5 cm or = 3 ordinary - sized fingerbreadths Larynx is relatively to other upper airway structures. 8. Mandibular space (MS) complianceQualitative palpation of normal resilience / softness Laryngoscopy retracts tongue into the MS. Compliance of the MS determines if tongue fits into MS. 9. Length of neckQualitative. A quantitative index is not available. A short neck decreases the ability to align the upper airway axes. 10. Thickness of neckQualitative. A quantitative index is not available. A thick neck decreases the ability to align the upper airway axes. 11. Palpation of cricoid membraneCricoid membrane can be readily identified. If the cricoid membrane can not be palpated readily, then the ability to perform TTJV or establish a surgical airway are not available as options in an emergency. 12. Cervical range of motionNeck flexed on chest 35 degrees + head extended on neck 35 degrees = sniff position The sniff position aligns the oral, pharyngeal and laryngeal axes to create a favorable line of sight.

Basic Setup for intubation: Equipment & tubes Drugs Airway Emergency equipment (readily accessible)

Equipment 1.Laryngoscope handle 2.3 MAC blade 3.3 Miller blade 4.4 MAC blade 5.6.0, 7.0, 8.0 Endotracheal Tube with stylets 6.10cc syringe 7.Tongue blade 8.Oral/Nasal airways 9.Suction available

Drugs for airway management 1.Atropine - 1 x 10cc syringe 2.Ephedrine - 1 x 10cc syringe 3.Epinephrine - 1 x 10cc syringe 4.Fentanyl - 1 x 5cc syringe 5.Lidocaine - 1 x 10cc syringe 6.Nitroglycerin - 1 x 10cc syringe 7.Propofol- 1 x 20cc syringe (2 nd dose immediately available!) 8.Phenylephrine - 1 x 10cc syringe 9.Rocuronium - 1 x 5cc syringe 10.Succinylcholine - 1 x 10cc syringe (2 nd dose immediately available!)

Airway Emergency equipment (readily accessible) Bougie (great for anterior view) BMV (backup for machine failure) A supraglottic airway device (LMA & or FTLMA, range of sizes) A subglottic technique—TTJV (hand jet vent & 14G jelco) Know how to quickly get help if needed (charge person, attending pager & cell#)

Adequate Pre-oxygenation Purpose of pre-oxygenationPurpose of pre-oxygenation –Provide the patient with maximum available oxygen store (for “denitrogenation”) –A fully denitrogenated subject with normal lungs can tolerate apnea for up to 8 minutes before they desaturate below 90% –Give yourself good time to intubate

Why Pre-oxygenate? Discuss two methods for pre-oxygenation (3 breaths vs 5 min.) What can you do if the patient is claustrophobic?

Notes: While this is a “basic” course in airway management, you will receive training in an additional two courses covering a) difficult airway management and b) FOB