NOVEL TIPS FOR AIRWAY MANAGEMENT
Author: Joe Rogers, MD (Senior EM Resident, Rutgers-NJMS) // Editor: Alex Koyfman, MD & Justin Bright, MD
The following is a compilation of helpful tips for managing the airway in the emergency department.
**EAR TO STERNAL NOTCH POSITIONING**
Why do it?
-Position yourself (and your patient) for success!
-Universal position for both ventilation and intubation
– Facilitates maximal jaw distraction and mouth opening
– Independent of age and size, though especially helpful in obese patients
– Contraindicated in context of known or suspected cervical spine pathology
– Horizontally align the sternal notch with the external auditory meatus
– The facial plane should be parallel to the ceiling; hyperextending the neck may worsen your view
– In adults, the head usually needs to be raised; in infants, the torso may need to be raised
Why do it?
– Administration of high-flow nasal oxygen during pre-oxygenation and after RSI improves arterial oxygenation during apnea
– High-flow nasal oxygen saturates the nasopharynx with oxygen, patients inhale a higher percentage of oxygen, and the oxygen reservoir in the lungs increases prior to apnea
– Oxygen saturation can be maintained without respirations if a continuous path of oxygen is supplied from the pharynx to the glottis because alveolar oxygen absorption continues during paralysis (“apneic oxygenation”)
– “NO DESAT”: Nasal Oxygen During Efforts Securing A Tube
– During pre-oxygenation apply high-flow nasal oxygen at 15 lpm as well as a face mask at 15 lpm
– 3 minutes is an acceptable duration of pre-oxygenation
– Leave on high-flow nasal cannula during intubation attempts
Why do it?
-External laryngeal manipulation by the laryngoscopist is the easiest, fastest, and most effective modification to improve view
This is not B.U.R.P or cricoid pressure (both of which are done by an assistant, neither of which are helpful)
– Manipulation is most effective at the thyroid cartilage, where vocal cords attach anteriorly
– Once the view is optimized, an assistant can maintain pressure at the right location, freeing the right hand to place the tube
Why do it?
– Improves visualization by enlarging space beneath tongue and epiglottis
– Less force required for full laryngeal exposure
– After bimanual laryngoscopy, head elevation is the second easily performed manipulation to improve laryngeal view
– Like ear to sternal notch positioning, head elevation is contraindicated in context of known or suspected cervical spine pathology
– Performed while holding the laryngoscope with the left hand
– Lift the patient’s head at the occiput with the right hand, keeping the face parallel to the ceiling
– When ideal view is achieved, release the right hand
– If possible, briefly suspend the head with the laryngoscope and attempt intubation
– If the head is too heavy, have an assistant support the patient’s head and shoulders
**STRAIGHT-TO-CUFF STYLET SHAPE**
Why do it?
– Narrower long-axis dimension allows greater visibility
– Better maneuverability within the hypopharynx
– Ideal shape of styletted tracheal tube is straight to the proximal cuff, then ≤ 35 degree angle bend at the proximal cuff (> 35 degrees increases likelihood of mechanical impaction)
– Use far right corner of mouth to insert and pivot tube
– Tube stays below the line of sight until tracheal insertion
– Keep tip visible as it approaches target
– If tube catches on tracheal rings after insertion, rotate clockwise and advance tube
Why do it?
– The epiglottis is the first reliable anterior landmark at the top of the laryngeal inlet
– Prepare suction to maximize anatomical clarity
– Slide blade gently and slowly down tongue
– Once the epiglottis is in view, move the tongue to the left and lift epiglottis edge off the posterior pharynx
– If the epiglottis is not seen, blade may be too deep: slowly pull back until epiglottis drops into view
– Advance blade fully into the vallecula
– Create anterior pressure at the hyoepiglottic ligament, causing the ligament to pull the epiglottis forward to expose the glottis
– Optimize glottic view with bimanual laryngoscopy and/or head elevation
**PREDICTORS OF DIFFICULT AIRWAY IN ED**
– Thyroid-to-hyoid less than two fingers
– Hyoid-to-mental less than three fingers
– Airway obstruction
– Poor neck mobility, cervical collars, spinal immobilization
– Trauma, facial distortion, secretions, mandibular injury
– Large tongue, large teeth
– Grade 4 Cormack and Lehane score
– Correlates to hyoid-mental distance, thyroid-hyoid distance
– Mallampati classification not practical in ED setting
– Beware the short fat neck
– Mallampati not helpful
– Look externally
– Evaluate 3-3-2
– Neck mobility
**PEDIATRIC AIRWAY ANATOMY**
The unique features of the pediatric airway persist until about age 8 or 9 years, then become more adult-like:
– The head and occiput in children are proportionally larger than in adults
– In supine position may cause neck flexion and airway obstruction
– To achieve ear to sternal notch positioning, a blanket may be placed under the shoulders and torso
– Child’s tongue is relatively larger
– Lower muscle tone increases risk of passive airway obstruction; MCC airway obstruction in children
– Can be managed by better positioning or use of an adjunct device such as oropharyngeal airway or nasopharyngeal airway
– Larynx is more anterior and cephalad in children, C4 vs. C6 in adults
– Vocal cords slant anteriorly
– Bimanual laryngoscopy more likely necessary to visualize the cords; alternatively, the fifth finger of the left hand can be used to improve glottic visualization
– Also may be helpful to lower oneself to below the level of the patient and look up at an angle when intubating
– The pediatric epiglottis is floppy, long, and narrow
– A straight blade (Miller) can more easily pick up the epiglottis to facilitate intubation in infants and children ≤ 8 years
– Risk of mainstem bronchus intubation much higher in small child
– Tracheal length in adults is 12-15 cm, as opposed to 4 cm in newborn
– Useful formulas for tube insertion depth in centimeters:
– ≤ 2 y/o: Depth at the lip = tube size times 3
– > 2 y/o: Depth at the lip = 12 + half the age in years
– In children the narrowest part of the airway is the subglottic region, at the cricoid cartilage
– This has been the rationale for use of uncuffed ET tubes in children < 8 years
– Uncuffed tubes are historically preferred due to better safety profile (less mucosal injury), larger tube diameter and hence better airflow, and lack of necessity due to good seal at the cricoid ring
– Tube size (uncuffed) = (Age / 4) + 4
– Arguments for use of cuffed tubes include complete protection from aspiration, decreases risk of inadvertent tube displacement, research confirmed safety of long-term use of cuffed ET tubes in children in large studies
– Tube size (cuffed) = (Age / 4) + 3
Why do it?
– Easier to pass into the trachea than an endotracheal tube
– Complications are rare
– Verifies placement before passing tube
– Various methods may be used for holding and manipulating the bougie (traditional pencil grip, Kiwi Grip, Shake Grip)
– Laryngoscope is used as usual
– Try to visualize the bougie passing over the interarytenoid notch
– If best view is epiglottis only, keep the Coudé tip pointing anteriorly and feel for the click of the tracheal rings
– Another indication you are in the right spot is the “hold up sign” (when the tip reaches the small bronchi) at 24-40 cm; if the bougie continues beyond 40 cm you are likely in the esophagus
– Hold bougie in place while maintaining laryngoscopy
– Have an assistant pass the tube over the proximal end of the bougie and advance the tube
– If resistance occurs at the laryngeal inlet, withdraw tube slightly, turn 90 degrees and re-attempt placement
**NONINVASIVE POSITIVE-PRESSURE VENTILATION FOR PRE-OXYGENATION**
Why do it?
– Consider NIPPV for patients unable to achieve an oxygen saturation > 95% on high-flow oxygen before tracheal intubation
– Shunt pathology (alveoli perfused but not ventilated, e.g. pneumonia, pulmonary edema) is likely in such cases, thus increasing FiO2 not helpful
– Augmenting mean airway pressure can partially overcome shunt pathology, improving pre-oxygenation prior to tracheal intubation
– May be of limited utility in patients needing emergent intubation, with mental status change, vomiting, etc.
– CPAP, or BVM with PEEP
– Add nasal oxygen at 15 lpm for paralysis and intubation
**DELAYED SEQUENCE INTUBATION (DSI)**
Why do it?
– Hypoxia and hypercapnia can cause delirium, complicating efforts to pre-oxygenate patients prior to intubation as patients are unable to tolerate NRB or NIV masks
– Think of DSI as procedural sedation, with the procedure being pre-oxygenation prior to paralysis and intubation
– Limited published evidence supporting DSI
– Ideal agent is ketamine as it preserves airway reflexes and respiratory drive and provides dissociative state allowing for use of NRB or NIV
– Pre-oxygenate with NRB and nasal cannula, or NIV
– Once adequate pre-oxygenation is achieved, give paralytic and proceed with intubation
– Weingart, S., Levitan R. (2012). Preoxygenation and Prevention of Desaturation During Emergency Airway Management. Ann Emerg Med. 2012;59:165-175.
– Levitan, R., Kinkle W., Levin W., Everett W. (2006). Laryngeal View During Laryngoscopy: A Randomized Trial Comparing Cricoid Pressure, Backward-Upward-Rightward Pressure, and Bimanual Laryngoscopy. Ann Emerg Med. 2006;47:548-555.
– Levitan, R., Everett W., Ochroch E. (2004). Limitations of Difficult Airway Prediction in Patients Intubated in the Emergency Department. Ann Emerg Med. 2004;44:307-313.
– Soyuncu, S., Eken, C., Cete, Y., Bektas, F., Akcimen, M. (2009). Determination of difficult intubation in the ED. American Journal of Emergency Medicine (2009) 27, 905–910.
– Weingart, S. (2011). Preoxygenation, reoxygenation, and delayed sequence intubation in the emergency department. The Journal of Emergency Medicine, Vol. 40, No. 6, pp. 661–667, 2011.
– Levitan, R., Mechem, C., Ochroch, E., Shofer, F., Hollander, J. (2003). Head-Elevated Laryngoscopy Position: Improving Laryngeal Exposure During Laryngoscopy by Increasing Head Elevation, Ann Emerg Med. 2003;41:322-330.
– Shah, K., Kwong, B., Hazan, A., Newman, D., Weiner, D. (2011). Success of the gum elastic bougie as a rescue airway in the emergency department. J Emerg Med. 2011 Jan;40(1):1-6.
– Levitan RM, Pisaturo JT, Kinkle WC, Butler K, Everett WW. (2006). Stylet bend angles and tracheal tube passage using a straight-to-cuff shape. Acad Emerg Med, 2006; 13: 1255-8
– Stewart, C., (2006). Managing The Pediatric Airway In The ED. Pediatric Emergency Medicine Practice, EBMedicine.net. January 2006, Volume 3, Number 1.
– Litman, R. (2013). Basics of Pediatric Anesthesia. http://basicsofpediatricanesthesia.com
– Strayer, R. (2010). Lecture Slides for Advanced Airway Management For The Emergency Physician, available here: http://emupdates.com/wp-content/uploads/2010/06/Advanced-Airway-Management-Lecture.pdf
– Dr. Richard Levitan’s website: http://www.airwaycam.com/