Airway Management Augusto Torres, MD Department of Anesthesiology MetroHealth Medical Center

Outline Review of airway anatomy Airway evaluation Mask ventilation Endotracheal intubation The difficult airway

Airway Anatomy Ab-ductor Tensor Ad-ductors Posterior cricoarytenoid Cricothyroid Ad-ductors All the rest

Airway Anatomy Innervation Vagus n. Superior laryngeal n. External branch – motor to cricothyroid m. Internal branch – sensory larynx above TVC’s Recurrent laryngeal n. Right – subclavian Left – Aortic arch (board question) Motor to all other muscles, Sensory to TVC’s and trachea

Airway Anatomy Innervation of oropharynx Glossopharyngeal n. innervates tongue base and oropharynx

Airway Anatomy Membranes Cartilages Thyrohyoid Cricothryoid Hyoid Thyroid Cricoid

Airway Evaluation Take very seriously history of prior difficulty Head and neck movement (extension) Alignment of oral, pharyngeal, laryngeal axes Cervical spine arthritis or trauma, burn, radiation, tumor, infection, scleroderma, short and thick neck

Airway Evaluation Jaw Movement Receding mandible Both inter-incisor gap and anterior subluxation <3.5cm inter-incisor gap concerning Inability to sublux lower incisors beyond upper incisors Receding mandible Protruding Maxillary Incisors (buck teeth)

Airway Evaluation Obesity Distribution, i. e. short, thick neck more concerning Neck circumference

Airway Evaluation Thyromental distance: bony point on mentum (mandible) to thyroid notch If short (<3FB’s or 6cm), pharyngeal and laryngeal axis off

Airway Evaluation Oropharyngeal visualization Mallampati Score Sitting position, protrude tongue, don’t say “AHH”

Airway Evaluation Difficulty ventilating Age >55 Beard History of snoring Lack of teeth BMI >26

Preoxygenation Replaces the nitrogen volume of the lungs (69% of FRC) with oxygen Functional residual capacity (residual volume and expiratory reserve volume) Preoxygenation with 100% oxygen via tight-fitting mask for 5 minutes  up to 10 min of oxygen reserve following apnea Four vital capacity breaths over 30 seconds (time to desaturation quicker)

Patient Positioning Sniffing position Lower neck flexion Upper neck extension Important in obesity

Mask Ventilation Induction of anesthesia produces upper airway relaxation and possible collapse Downward displacement of mask with thumb and index finger www.aic.cuhk.edu.hk

Mask Ventilation Upward traction of remaining fingers upward Fingers on bony mandible Fifth digit at angle displacing mandible anteriorly www.aic.cuhk.edu.hk

Mask Ventilation Oral airway Two-handed technique www.aic.cuhk.edu.hk www.haworth21.karoo.net

LMA Placement Carries prominent position in ASA algorithm May be held like a pencil Balloon partially inflated Directed posteriorly and upwards towards the palate Jaw thrust and sniffing position may help placement www.brandianestesia.it/Images/LMA-ins.jpg

LMA Placement Verify placement by ventilating Check for good chest rise, ETCO2, and adequate tidal volumes Check for leak – if significant leak at around 10cm H2O problematic May try size larger or smaller May try to inflate/deflate cuff to obtain better seal If difficulty passing may try inserting upside down and then flipping around

Endotracheal Intubation Open the mouth with right hand Scissor technique Gently insert laryngoscope into right side of mouth pushing tongue to the left Careful with insertion not to hit teeth Advance laryngoscope further into oropharynx with applied traction 45 degrees

Endotracheal Intubation Look for epiglottis If initially not found insert laryngoscope further If this maneuver does not work slowly pull laryngoscope back Once epiglottis visualized, push laryngoscope into vallecula and apply traction at 45 degree angle to “push” epiglottis up and out of the way www.int-med.uiowa.edu/Research/TLIRP/Bronchos

Endotracheal Intubation Look for vocal cords or arytenoid cartilages and try to optimize view (i.e. lift head, apply more traction at 45 degree angle if necessary) Do not move once view is optimized! Assistant will hand you ETT Insert ETT into far right aspect of mouth Traction of laryngoscope slightly to left may assist Traction of laryngoscope at 45 degrees will also help keep mouth open

Endotracheal Intubation Insert ETT above and between arytenoids and through vocal cords Try to visualize the ETT passing between the vocal cords If this is not possible, then you must visualize the ETT passing above and between the arytenoids

Endotracheal Intubation Common problems: “I can’t see anything!” Make sure tongue is swept to the left You are probably too shallow or too deep. Even with difficult intubations the epiglottis can be visualized Insert laryngoscope in further looking for epiglottis Pull laryngoscope back if this fails

Endotracheal Intubation Common problems “I can’t see the cords!” Epiglottis is visualized, vocal cords are not Removing the epiglottis partly from view is necessary to visualize the vocal cords below Push the end of the laryngoscope blade further into the vallecula and “toe up” Lifting the patient’s head with your other hand may improve the sniffing position and bring the vocal cords into view

Endotracheal Intubation Common problems “I can see the cords. But I can’t get the tube there!” You may not be giving yourself adequate room in the oral cavity Push up and to the left with the laryngoscope to make sure the mouth is still fully opened and the tongue adequately swept away Slide the ETT in the mouth all the way to the right side, perhaps even sideways

Difficult Intubation ASA Difficult Airway Algorithm www.metrohealthanesthesia.com

Fiberoptic Intubation Oral or nasal routes Topicalization is key Aerosolized lidocaine 4% Airway blocks Thin bronchoscope inserted into trachea

Other airway options GlideScope Needle cricothyroidotomy

Conclusion Airway management is an extremely important aspect of the practice of anesthesiology and critical care A firm basis in airway anatomy is needed Skills such as mask ventilation, endotracheal intubation, LMA placement are necessary In the case of a difficult airway, a logical algorithm and airway equipment assist the physician in safely managing the situation