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CHAPTER 29A: Tracheal Intubation 179 • Convert the SGA (King LT or i-gel) with a gum elastic bougie. Insert the gum elastic bougie though the King LT into the trachea and then remove the King LT, leaving the gum elastic bougie in place. Then pass a standard endotracheal tube over the bougie. This is a “blind” exchange, meaning that the operator does not visualize the glottis during the conversion. While this maneuver can be attempted with the standard LMA, it often fails. 59 Limited data describe this technique with the i-gel. • Convert the SGA (i-gel, King LT, or LMA) with a fiberoptic bronchoscope. Use an intubating catheter (Aintree; Cook Medical, Inc., Bloomington, IN), which is similar to a bougie but is hollow, allowing placement over a fiberoptic bronchoscope. First, place the catheter over the fiberoptic scope, and then direct the scope into the trachea. Next, remove the fiberoptic scope and SGA, leaving the catheter in the trachea. Finally, direct a standard endotracheal tube over the catheter into the trachea. This technique allows for visualization of the glottis but requires expertise in the use of a fiberoptic bronchoscope. This technique is not possible with the Shiley ® . • Leave the SGA in place and perform a surgical airway (cricothy roidotomy or tracheostomy). This is often chosen after an SGA insertion followed difficulties with standard intubation and if the patient requires prolonged mechanical ventilation. This can be done either in the operating room or in the ED if needed, depending on the patient’s condition, available resources, and skills of the provider. REFERENCES The complete reference list is available online at www.TintinalliEM.com. Tracheal Intubation Henry E. Wang Jestin N. Carlson INTRODUCTION Tracheal intubation is a cornerstone of emergency airway management, creating a direct conduit to the trachea, allowing airway patency, aiding oxygenation and ventilation, and preventing aspiration. Intubation may also be needed to safely allow sedation or paralysis needed in critically ill patients requiring diagnostic or therapeutic interventions. Intubation is one component of the spectrum of emer gency airway interventions. Supraglottic airways and the conversion of a supraglottic airway to an endotracheal tube (ETT) are discussed in Chapter 28, “Noninvasive Airway Management and Supraglottic Airways. ” PREPARATION Proper preparation is key to successful intubation. Table 29A-1 lists emergency airway equipment needed at the bedside before beginning intubation. Have basic airway, intubation, rescue, and surgical airway equipment immediately accessible, ideally in the same cart with other airway management equipment. If treating a child, have enough and appropriately sized pediatric airway devices accessible (see Chapter 113, “Intubation and Ventilation in Infants and Children”). Key starting tasks are imperative: Ensure ongoing cardiac rhythm monitoring with continuous displays of the heart rate, blood pressure, oxygen saturation, and end-tidal capnography. Establish IV access and appropriate fluids. Raise the patient to the level of the operator’s xiphoid (Figure 29A-1). Although ventilation and intubation are typically performed with the CHAPTER 29A patient fully supine, positioning the patient so that the external ear is aligned with the sternal notch may improve glottis visualization (Figure 29A-2).

ate fluids. Raise the patient to the level of the operator’s xiphoid (Figure 29A-1). Although ventilation and intubation are typically performed with the CHAPTER 29A patient fully supine, positioning the patient so that the external ear is aligned with the sternal notch may improve glottis visualization (Figure 29A-2). Refrain from applying padding under the shoulders or neck as this position is suboptimal for facilitating emergency intubation. A more upright position for intubation may be necessary if the patient cannot lay supine—for example, the patient with severe pulmonary edema or morbid obesity (Figure 29A-3). Ensure that the oxygen source and regulator are functional. Have a bag-valve-mask ventilator and oral and nasal airways at the bedside, and make sure that a large-diameter suction catheter and functional suction unit are ready. For potential uncontrolled emesis, use an assistant to place a Y ankauer catheter or the suction tubing itself in the side of the mouth, so suctioning can be done throughout the intubation process. Another option for large-volume suction or in instances where suc tion is required to remove large particles of material (e.g., food debris) is to use another ETT attached to suction tubing, placing it to the left oropharynx to allow continuous large-volume suction (suction-assisted laryngoscopy airway decontamination) 1,2 (Figure 29A-4). Verify the function of primary and backup intubation equipment, including laryngoscope blade, bulbs, and video laryngoscope screens. Test the cuffs of selected ETTs, usually the size you think is best and one smaller. Verify the availability of rescue supraglottic airways and surgical airway kits. Confirm that a mechanical ventilator is available for application immediately after intubation. Estimate the patient’s body mass and calculate appropriate doses of any adjunctive intubation medications. Before proceeding with intubation, assess all available clinical infor mation, including the patient’s suspected condition, history, anatomy, physiology, and goals of care. Develop an emergency airway manage ment plan—one that anticipates failure and has alternative options—and review this plan with the entire care team. Discuss the plan for prepa ration, medications, intubation, postintubation sedation, and rescue airway management. A checklist may facilitate decision making and reduce errors. Try to normalize patient heart rate and blood pressure, and try to optimize oxygen saturation prior to drug administration and laryngos copy; peri-intubation cardiac arrest is likely if any of these parameters is abnormal. Anticipate airway difficulty; if anatomic abnormalities will impede basic airway techniques or will not improve with rapid-sequence intubation, consider awake intubation.

ze oxygen saturation prior to drug administration and laryngos copy; peri-intubation cardiac arrest is likely if any of these parameters is abnormal. Anticipate airway difficulty; if anatomic abnormalities will impede basic airway techniques or will not improve with rapid-sequence intubation, consider awake intubation. TABLE 29A-1 Equipment Needed for Airway Management •  Oxygen  source and tubing •  Ambu  bag •  Mask  with valve, various sizes and shapes •  Oropharyngeal  airways—small, medium, large •  Nasopharyngeal  airways—small, medium, large •   Suction catheters: Yankauer, tracheal suction catheters, nasogastric suction connection tubing for particulate and large amounts of vomitus •  Suction  source •  Pulse  oximetry •  Carbon  dioxide detector •  Endotracheal  tubes—various sizes •  Laryngoscope  blades and handles •  Syringes •  Magill  forceps •  Stylets,  assorted •  Tongue  blade •  Intubating  stylet (gum elastic bougie) •  Water-soluble  lubricant or anesthetic jelly •   Rescue devices: video laryngoscopes, laryngeal mask airway, intubating laryngeal mask airway, i-gel® (Intersurgical Inc., Liverpool, NY), King LT® (King Systems, Noblesville, IN) •  Surgical  cricothyroidotomy kit •  Medications  for topical airway anesthesia, sedation, and rapid-sequence intubation Tintinalli_Sec04_p0143-0228.indd 179 7/31/19 1:43 PM

es, laryngeal mask airway, intubating laryngeal mask airway, i-gel® (Intersurgical Inc., Liverpool, NY), King LT® (King Systems, Noblesville, IN) •  Surgical  cricothyroidotomy kit •  Medications  for topical airway anesthesia, sedation, and rapid-sequence intubation Tintinalli_Sec04_p0143-0228.indd 179 7/31/19 1:43 PM 180 SECTION 4: Resuscitative Procedures FIGURE 29A-2. Patient positioning for optimal laryngoscopy. Align the external auditory canal and the sternal notch. [Reproduced with permission from Knoop K, Stack L, Storrow A, Thurman RJ: Atlas of Emergency Medicine , 4th ed. © 2016, McGraw-Hill,  Inc., New York. Figure 22.10 Part C. Photo contributor: Lawrence B. Stack, MD.] FIGURE 29A-3. An upright position may be necessary for intubation of select patients. [Reproduced with permission from Knoop K, Stack L, Storrow A, Thurman RJ: Atlas of Emergency Medicine, 4th ed. © 2016, McGraw-Hill, Inc., New York. Figure 22.6. Photo contributor: Lawrence B. Stack, MD.] FIGURE 29A-1. Correct patient-stretcher height, so that the patient’s head is just below the intubator’s xiphoid. [Reproduced with permission from Knoop K, Stack L, Storrow A, Thurman RJ: Atlas of Emergency Medicine, 4th ed. © 2016, McGraw-Hill, Inc., New York. Figure 22.14. Photo contributor: Lawrence B. Stack, MD.] AIRWAY ASSESSMENT Approximately up to 15% of initial emergency airway attempts and 1% to 3% of overall attempts at tracheal intubation fail with standard techniques.4 It is best to expect difficulty with all emergency airway cases, applying a uniform approach to all patients. While the terms difficult intubation and difficult laryngoscopy are often used interchangeably, there are important distinctions. Difficult intubation refers to a situa tion where multiple attempts are made at intubation, whereas difficult laryngoscopy refers to challenges with or inability to visualize the glottis. Tintinalli_Sec04_p0143-0228.indd 180 7/31/19 1:43 PM

laryngoscopy are often used interchangeably, there are important distinctions. Difficult intubation refers to a situa tion where multiple attempts are made at intubation, whereas difficult laryngoscopy refers to challenges with or inability to visualize the glottis. Tintinalli_Sec04_p0143-0228.indd 180 7/31/19 1:43 PM CHAPTER 29A: Tracheal Intubation 181 FIGURE 29A-4. Suction-assisted laryngoscopy airway decontamination (SALAD) approach for suctioning. A. SALAD set up. B. View of suction in the esophagus. TABLE 29A-2 Factors Associated With Airway Management Difficulty •  Obesity •  Facial  hair •  Edentulous  anatomy •  History  of snoring/sleep apnea •  Short  neck •  Limited  neck mobility •  Small  or large chin •  Prominent  incisors •  High  arched palate •  Facial  or airway trauma •  Head  and neck tumors •  Angioedema •  Ludwig’s  angina •  Inflammation  of the airway (e.g., airway burns) Class I Class II Class III Class IV FIGURE 29A-5. The Mallampati score. [Reproduced with permission from Samsoon Y: Difficult tracheal intubation: a retrospective study. Anaesthesia 42: 487-490, 1987.] OROTRACHEAL INTUBATION  PREOXYGENATION Oxygen desaturation to <70% is associated with increased risk of dysrhythmias, decompensation, and cardiac arrest. 6 Preoxygenation displaces nitrogen from the alveoli, creating a potential oxygen reservoir that may prevent hypoxia and hypoxemia during apnea. In the healthy operating room patient, preoxygenation increases safe apnea time (time to desaturation to <90%) from 1 to 8 minutes. However, in critically ill patients such as those with chest injuries or shock states, safe apnea time is shorter. Begin preoxygenation as soon as possible before intubation, even for patients with no apparent hypoxia or hypoxemia. Administer 100% oxygen for at least 3 minutes using a non-rebreather mask supplied with at least 15 L/min of oxygen. Non-rebreather masks typically deliver 60% to 70% oxygen. Higher oxygen delivery is possible by increasing the oxygen regulator to its maximum “flush” rate, which will provide 90% to 97% oxygen, between 40 and 60 L/min. 7 Preoxygenation must occur with tidal volume breathing and/or a good mask seal. If unable to achieve oxygen saturation >95% with spontaneous breathing, consider the use of bag-valve-mask ventilation, application of a positive endexpiratory pressure valve, or the use of continuous positive airway pressure or bilevel positive airway pressure. Elevating the head of the patient 20 to 30 degrees may improve preoxygenation. With agitated patients, some clinicians selectively use sedation with induction agents to facilitate preoxygenation. Nasal cannulas with low flow alone do not provide optimal preoxy genation. However, some clinicians use apneic oxygenation—oxygen at ≥15 L/min via nasal cannula—concurrently with bag-valve-mask (or bilevel positive airway pressure) ventilation and subsequent laryngoscopy. During laryngoscopy, the continued high oxygen flow creates a pressure gradient, facilitating airflow from the pharynx to the lungs. Factors associated with airway management and intubation difficulty are listed in Table 29A-2. Obesity or the lack of neck flexibility may make it difficult to align the oral, pharyngeal, and tracheal axes needed for intubation. Physical airway obstruction (foreign body, tumor, angioedema, epiglottitis) may limit the physician to nasal techniques or a surgical airway (see Chapter 30, “Surgical Airways”). Some anesthesia scales associate anatomical features with intubation difficulty; for example, Mallampati criteria relate the degree of posterior pharyngeal obstruction by the tongue with intubation difficulty 5 (Figure 29A-5).

the physician to nasal techniques or a surgical airway (see Chapter 30, “Surgical Airways”). Some anesthesia scales associate anatomical features with intubation difficulty; for example, Mallampati criteria relate the degree of posterior pharyngeal obstruction by the tongue with intubation difficulty 5 (Figure 29A-5). Although potentially applicable to some ED patients, in select situations, formal airway assessment may be impractical or impossible.Tintinalli_Sec04_p0143-0228.indd 181 7/31/19 1:43 PM

the physician to nasal techniques or a surgical airway (see Chapter 30, “Surgical Airways”). Some anesthesia scales associate anatomical features with intubation difficulty; for example, Mallampati criteria relate the degree of posterior pharyngeal obstruction by the tongue with intubation difficulty 5 (Figure 29A-5). Although potentially applicable to some ED patients, in select situations, formal airway assessment may be impractical or impossible.Tintinalli_Sec04_p0143-0228.indd 181 7/31/19 1:43 PM 182 SECTION 4: Resuscitative Procedures TABLE 29A-3 Steps of Tracheal Intubation Step Comments 1. Clear the oropharynx. Remove dentures and any obscuring blood, secre tions, or vomitus. Suction airway clear. 2. Hold laryngoscope in left hand. Hold the laryngoscope at the base, where the blade inserts to the handle. 3. Use right hand to: Open the mouth. Operate suction catheter. Manipulate larynx to enhance visualization. Insert the ETT. Use a scissor motion to open the mouth and facili tate laryngoscope passage by pressing caudally on the patient’s lower incisors with the operator’s thumb and cranially on the patient’s upper incisors with the operator’s index finger. Use a properly sized stylet to assist with tube placement. The tip of the stylet must not extend beyond the end of the ETT or exit the Murphy eye. 4. Insert blade into the right corner of the patient’s mouth. Carefully advance blade into oropharynx. Lift and hyperextend the head. Use the vertical flange of the curved Macintosh blade to push the tongue toward the left side of the oropharynx. 5. Visualize and lift the epiglottis. Lift the epiglottis directly with the straight blade (Miller) or indirectly with the curved blade (Macintosh). 6. Visualize vocal cords (arytenoids). Look for the arytenoid cartilages to avoid overly deep insertion of the blade, which is a common error. BURP maneuver may improve visualization. 7. Advance ETT. Visualize tube and cuff passing through vocal cords. Correct tube placement is a minimum of 2 cm above the carina (approximately 23 cm at the inci sors in men and 21 cm in women). 8. Inflate balloon. Use 5–7 mL of air. Check cuff pressure to avoid tracheal injury from pressure (target 25–40 cm 2O). 9. Confirm ETT placement. Listen for bilateral breath sounds and the absence of epigastric sounds. Confirm placement with capnography or colorimetric carbon dioxide detector. 10. Secure ETT. Use commercial tube holder, adhesive tape, or umbilical tape. Abbreviations: BURP = backward-upward-rightward pressure; ETT = endotracheal tube. Oral axis Pharyngeal axis Laryngeal axis Elevate occiput 10 cm FIGURE 29A-6. Alignment of oral, pharyngeal, and laryngeal axes during intubation.  PROCEDURE Table 29A-3 summarizes the steps of tracheal intubation. The objective of laryngoscopy is to align the oral, pharyngeal, and laryngeal axes to provide an unobstructed direct view of the glottis and allow passage of the ETT between the vocal cords ( Figure 29A-6). (See Video: Orotra cheal Intubation.) Select the appropriate-size ETT: 8.0- to 8.5-mm inner diameter for an average adult male and 7.5- to 8.0-mm inner diameter for an adult female. Check the cuffs for air leaks with a 10-mL syringe. Choose an ETT with a high-volume, low-pressure cuff. The second hole at the end of the ETT (Murphy eye) permits some uninterrupted airflow if the tip is occluded. Insert a lightly lubricated stylet to aid ETT direction and placement. The Macintosh and Miller blades are most commonly used in direct laryngoscopy. The curved Macintosh blade tip is placed in the vallecula to indirectly lift the epiglottis off the larynx. The straight Miller blade physically lifts the epiglottis to visualize the larynx. Blade selection is a matter of personal preference. Be sure to test the light on the laryngo scope after attaching the appropriate-size blade (Figure 29A-7). With the curved Macintosh blade, choose a #3 for most adults or a #4 for larger patients.

ht Miller blade physically lifts the epiglottis to visualize the larynx. Blade selection is a matter of personal preference. Be sure to test the light on the laryngo scope after attaching the appropriate-size blade (Figure 29A-7). With the curved Macintosh blade, choose a #3 for most adults or a #4 for larger patients. Holding the laryngoscope with the left hand, insert the curved blade deeply into the far right side of the patient’s mouth. Use the broad vertical flange to sweep the tongue to the left while simultaneously placing the blade tip in the vallecula. Apply pressure upon the vallecula via the hyoepiglottic ligament to facilitate elevation of the epiglottis and exposure of the vocal cords. Lift upward to flex the lower neck and extend at the atlanto-occipital joint. The goal is to align the oral, pharyngeal, and laryngeal axes, facilitating a direct view of the glottis. Laryngoscopy should be performed in a single fluid motion. With the straight Miller blade, choose a #3 for most adults. Insert the straight blade at the far right side of the mouth at an angle, aiming to expose and lift the glottis in a single motion. Bring the handle to midline, using the broad part of the blade to lift the tongue. Optimal intubation occurs with a full, unobstructed view of the glottis. Often, no matter what blade chosen, the glottis is not seen; a common error is inserting the tip of a blade too deep. Withdraw the blade slowly and slightly; the glottis often “drops” into view. If the glottis and vocal cords are not seen clearly, esophageal tube placement is more likely. Anesthesiologists characterize glottic exposure using the Cormack-Lehane system; grade 1 reflects a fully exposed glottic view, and grade 4 reflects the inability to visualize any of the vocal cord (Figure 29A-8). The percentage of glottic opening provides an alternate glottic visualization rating from 0% to 100%. 11 Abort the attempt if you cannot visualize the larynx. Glottic exposure may be aided by backward-upward-rightward pres sure (BURP maneuver) applied to the thyroid cartilage. 12 Another effective technique is bimanual laryngoscopy, where the intubator manipulates the larynx with the right hand until ideal visualization and then an assistant maintains this position. 13 The Sellick or cricoid maneuver (application of direct pressure on the cricoid ring) can hamper bagvalve-mask ventilation, laryngoscopic view, and ETT insertion.14 Where there is concern for cervical spine fracture or injury, use inline stabilization of the cervical spine without extension of the head or neck during laryngoscopy. This stabilization may make laryngoscopy and glottic exposure more difficult; because of this, some experts ques tion the utility of manual inline stabilization and wonder if it really affords adequate spinal cord protection. Gently insert the ETT through the glottis, inflate the cuff, and remove the stylet. The typical correct tube insertion depth is 22 cm, measured at the patient’s incisors. Difficulties in passing the ETT may result from the failure to maintain optimal laryngoscopic view, selecting too large a tube, applying cricoid pressure, or suboptimal shaping of the ETT stylet. Switching to a smaller tube, altering the curve of the stylet, and rotating the tube 90 degrees to align the bevel with the glottic opening are other techniques for facilitating ETT insertion. Multiple intubation attempts are associated with adverse events including cardiac arrest. 4,16 To minimize oxygen desaturation, limit each intubation attempt (insertion of blade) to no more than 30 seconds. Between intubation attempts, use a bag-valve mask to reoxygenate the patient to 100% oxygen saturation.

nsertion. Multiple intubation attempts are associated with adverse events including cardiac arrest. 4,16 To minimize oxygen desaturation, limit each intubation attempt (insertion of blade) to no more than 30 seconds. Between intubation attempts, use a bag-valve mask to reoxygenate the patient to 100% oxygen saturation. For anyone in extremis or with anticipated difficulty, first-pass success is more vital; have the most experienced person perform intubation in these situations. The gum elastic bougie (“bougie ”) introducer aids orotracheal intubation, especially when the glottis cannot be fully visualized Tintinalli_Sec04_p0143-0228.indd 182 7/31/19 1:43 PM

r with anticipated difficulty, first-pass success is more vital; have the most experienced person perform intubation in these situations. The gum elastic bougie (“bougie ”) introducer aids orotracheal intubation, especially when the glottis cannot be fully visualized Tintinalli_Sec04_p0143-0228.indd 182 7/31/19 1:43 PM CHAPTER 29A: Tracheal Intubation 183 (Figure 29A-9). After laryngoscopy and best exposure of the vocal cords, insert the angled tip of the bougie through the glottis. When correctly inserted, you may feel the bougie tip moving over the tracheal rings. Thread the ETT over the introducer into the trachea, inflate the ETT cuff, and then remove the introducer. First-pass success is higher with bougie-assisted intubation. 17 Never force the tube through the vocal cords, which can avulse the arytenoid cartilages or lacerate the vocal cords.  CONFIRM ENDOTRACHEAL TUBE LOCATION Mainstem bronchial or esophageal intubation may cause hypoxia, hypoxemia, hypercarbia, bradycardia, and cardiac arrest. Confirm intratracheal tube positioning with multiple methods; no single technique is infallible. Although directly visualizing the tube between the vocal cords is the best method for confirming successful placement, trauma or a small oropharynx may limit visual assessment. Other clini cal assessments include chest and epigastric auscultation and observa tion for tube condensation or symmetric chest wall expansion. Capnometers and capnographs measure carbon dioxide in expired air of the ETT ( Figure 29A-10). The presence of carbon dioxide sug gests intratracheal tube placement. The absence of carbon dioxide FIGURE 29A-7. A. Curved or Macintosh blade. B. Straight or Miller blade. FIGURE 29A-8. Cormack-Lehane scale for rating glottic exposure. [Reproduced with permission from Stone CK, Humphries RL, Drigalla D, Stephan M (eds): Current Diagnosis & Treatment: Pediatric Emergency Medicine. McGraw-Hill Education, Inc. © 2015. Figure 9-6.] Grade 1G rade 2 Grade 3 Grade 4 FIGURE 29A-9. Gum elastic bougie. Tintinalli_Sec04_p0143-0228.indd 183 7/31/19 1:44 PM

sure. [Reproduced with permission from Stone CK, Humphries RL, Drigalla D, Stephan M (eds): Current Diagnosis & Treatment: Pediatric Emergency Medicine. McGraw-Hill Education, Inc. © 2015. Figure 9-6.] Grade 1G rade 2 Grade 3 Grade 4 FIGURE 29A-9. Gum elastic bougie. Tintinalli_Sec04_p0143-0228.indd 183 7/31/19 1:44 PM 184 SECTION 4: Resuscitative Procedures FIGURE 29A-10. End-tidal carbon dioxide detectors. A. Colorimetric. B. Combined digital and waveform. TABLE 29A-4 Conditions Associated With False Colorimetric or False Capnographic Carbon Dioxide Readings False-Negative Reading •   Low pulmonary perfusion—cardiac arrest, inadequate chest compressions, massive pulmonary embolism, shock •  Massive  obesity •  Tube  obstruction (secretions, blood, foreign body) False-Positive Reading •  Recent  ingestion of carbonated beverage (should not persist beyond 6 breaths) •  Heated  humidifier, nebulizer, or endotracheal epinephrine (transient false readings) FIGURE 29A-11. Use of ultrasonography for confirmation of tracheal tube placement. [Reproduced with permission from Reichman EF (ed): Reichman’s Emergency Medicine Procedures, 3rd ed. © 2019, McGraw-Hill, Inc., New York. Figure 19-7.] suggests ETT misplacement. Colorimetric end-tidal carbon dioxide detectors have a pH-sensitive filter paper that changes color from yel low to purple with carbon dioxide exposure. Capnography measures expired carbon dioxide in real time, displaying either the peak value with each breath or continuous graphical waveforms. Clear, regular waveforms or carbon dioxide measurements >30 mm Hg correlating with exhalations suggest proper ETT placement. Rarely, a misplaced hypopharyngeal glottic tube tip may result in normal oximetry and capnography in a spontaneously breathing patient. In cardiac arrest states, expired carbon dioxide will be low due to poor perfusion; con tinuous capnography waveforms may still be detectable in these cases. Table 29A-4 notes conditions associated with false colorimetric or capnographic carbon dioxide readings. The esophageal detection device may also indicate ETT placement. When the ETT is in the esophagus, the soft, noncartilaginous walls will collapse, and air cannot be easily aspirated with an esophageal detector. Esophageal detection devices use either syringe aspiration or a compressible bulb technique. If the ETT tube is in the esophagus, the vacuum causes the esophagus to collapse around the tube, creating resistance to aspiration or preventing the bulb from refilling. Conversely, syringe aspiration or bulb refilling is rapid when the ETT is in the trachea. Recent studies suggest ultrasonography as an alternate technique for confirmation of intratracheal ETT placement. 18,19 Position the US probe cephalad to the cricoid membrane, just above the sternal notch (Figures 29A-11 and 29A-12). The ETT should be visualized within the lumen of the trachea. The visualization of two separate structures (“double track sign”) likely indicates esophageal intubation. Some operators inflate the ETT cuff with water to improve its visualization on ultrasonography. A chest radiograph is customarily obtained after intubation to verify correct vertical positioning of the ETT. However, a chest radiograph does not reliably distinguish ETT placement in the trachea from the esophagus. Other important postintubation radiograph findings include the presence of a pneumothorax and consolidations suggestive of pneumonitis (due to aspiration or infection). Never assume correct ETT positioning and patency if the patient is deteriorating after intubation. Suctioning may help to clear secretions from obstructing the tube. If the ETT cuff leaks after the intubation, check the inflation valve.

orax and consolidations suggestive of pneumonitis (due to aspiration or infection). Never assume correct ETT positioning and patency if the patient is deteriorating after intubation. Suctioning may help to clear secretions from obstructing the tube. If the ETT cuff leaks after the intubation, check the inflation valve. If the tube needs to be replaced, use a tube changer or bougie; insert the changer into the ETT, withdraw the ETT, and then insert a new ETT over the catheter and reconfirm placement. If in doubt about its position, withdraw and replace the ETT or restart bag-valve-mask assistance. After successful intubation, secure the ETT to prevent device dislodgement during subsequent patient care. Tube displacement can occur during patient movement or any care if not properly secured. During EMS transfer of the patient into the stretcher, have an assistant hold the ETT in place during the transfer. Once the patient is stabi lized, the most common approach to securing the ETT is wrapping adhesive tape around the neck and the ETT (Lillehei method). 20 Flat umbilical “twill” cloth tape may also be used to tie the tube in place. Commercial tube holders consist of a plastic bite block strapped to the patient’s face using Velcro tape and a plastic strap or screw clamp to hold Tintinalli_Sec04_p0143-0228.indd 184 7/31/19 1:44 PM

the neck and the ETT (Lillehei method). 20 Flat umbilical “twill” cloth tape may also be used to tie the tube in place. Commercial tube holders consist of a plastic bite block strapped to the patient’s face using Velcro tape and a plastic strap or screw clamp to hold Tintinalli_Sec04_p0143-0228.indd 184 7/31/19 1:44 PM CHAPTER 29A: Tracheal Intubation 185 FIGURE 29A-12. A and B. Ultrasonographic view of intratracheal (left) and esophageal (right) endotracheal tube placement. [Images used with permission of Jordan Chenkin, MD.] the ETT in place. One cadaver study found that conventional adhesive taping surpassed most commercial ETT holders.20 Finally, if not already done, place an orogastric tube and connect it to suction.  COMPLICATIONS OF ENDOTRACHEAL INTUBATION Many complications can be avoided with preparation ( Table 29A-5). Although some events are directly associated with the procedure (e.g., ETT misplacement), other indirect events are also important (e.g., hyperventilation and CPR interruption). Be especially vigilant for peri-intubation hypotension and cardiac arrest, which occur after 23% and 4% of ED intubations, respectively. 21-23 Some advocate for bolusdose or ‘push-dose’ vasopressors to mitigate hypotension. However the ideal pressor and dose is not yet evidence-based. See Chapter 20, Pharmacology of Vasopressors and Inotropes, ‘Bolus-Dose Administration of Vasopressors’ and Table 20-1 for further discussion. RAPID-SEQUENCE INTUBATION Rapid-sequence intubation (RSI) is the sequential administration of an induction agent and neuromuscular blocking agent to facilitate endo tracheal intubation (Table 29A-6). The goal of RSI is to facilitate rapid insertion of the ETT while minimizing physiologic perturbations. RSI is superior to sedation alone, allows the highest intubation success rate in properly selected emergency airway cases, and is the method of choice for emergency airway management. Not all patients are best managed with RSI. Patients who are deeply comatose or in cardiac or respiratory arrest may be intubated without TABLE 29A-5 Complications of Endotracheal Intubation, Preventive Strategies, and Potential Corrective Actions Complication Preventive Strategies Corrective Action ETT misplacement View ETT entry through glottis Quick recognition. Remove and replace ETT. ETT dislodgement Secure ETT, minimize patient movement, use continuous capnography Quick recognition. Remove and replace ETT. Mainstem intubation View ETT entry through glottis, know appropriate ETT depth Quick recognition. Adjust ETT position. Oxygen desaturation Preoxygenate patient prior to intubation Verify ETT position. Clear ETT. Hyperventilate. Hypotension Ensure adequate blood pressure before intubation efforts, minimize use of medications known to induce hypotension Place patient in Trendelenburg position. Give IV fluids. Give pressors. Avoid hyperventilation. Bradycardia Ensure adequate heart rate before intubation efforts Hyperventilate. Give atropine or epinephrine. Cardiac arrest Ensure adequate heart rate, blood pressure, oxygen saturation before intubation efforts Initiate CPR. Aspiration Avoid aggressive BVM ventilation, keep patient upright before intubation Large-bore suction or oropharynx and ETT. Injury to oropharynx or hypopharynx Careful laryngoscopy Pneumothorax Careful laryngoscopy, avoid aggressive BVM ventilation Insert chest tube or pigtail. Gastric/visceral perforation Careful laryngoscopy, avoid aggressive BVM ventilation Vocal cord injury Careful laryngoscopy, careful ETT placement ETT cuff leak Check cuff before intubation, avoid rubbing cuff against teeth Remove and replace ETT. ETT obstruction (secretions, vomitus, foreign body) Suction oropharynx before intubation efforts Suction ETT. Clear obstruction.

d aggressive BVM ventilation Vocal cord injury Careful laryngoscopy, careful ETT placement ETT cuff leak Check cuff before intubation, avoid rubbing cuff against teeth Remove and replace ETT. ETT obstruction (secretions, vomitus, foreign body) Suction oropharynx before intubation efforts Suction ETT. Clear obstruction. Hyperventilation Judicious control of manual ventilations Interruptions in CPR chest compressions Minimize CPR interruptions during intubation, use a supraglottic airway instead of ETT Failed intubation/Inability to intubate Anticipate and plan for intubation difficulty Immediate rescue with supraglottic or other airway. Abbreviations: BVM = bag-valve mask; ETT = endotracheal tube. Tintinalli_Sec04_p0143-0228.indd 185 7/31/19 1:44 PM

Hyperventilation Judicious control of manual ventilations Interruptions in CPR chest compressions Minimize CPR interruptions during intubation, use a supraglottic airway instead of ETT Failed intubation/Inability to intubate Anticipate and plan for intubation difficulty Immediate rescue with supraglottic or other airway. Abbreviations: BVM = bag-valve mask; ETT = endotracheal tube. Tintinalli_Sec04_p0143-0228.indd 185 7/31/19 1:44 PM 186 SECTION 4: Resuscitative Procedures TABLE 29A-8 Rapid-Sequence Intubation Induction Agents Agent Dose Onset Duration Benefits Caveats Etomidate 0.3–0.5 milligram/kg IV <1 min 10–20 min ↓ ICP Myoclonic jerking or seizures and vomiting in awake patients ↓ Intraocular pressure No analgesia Neutral BP ↓ Cortisol Propofol 0.5–1.5 milligrams/kg IV  20–40 s 8–15 min Antiemetic Apnea Anticonvulsant ↓ BP ↓ ICP No analgesia Ketamine 1–2 milligrams/kg IV  1 min 10–20 min Bronchodilator ↑ Secretions “Dissociative” amnesia ↑ BP Analgesia Emergence phenomenon Abbreviations: BP = blood pressure; ICP = intracranial pressure. TABLE 29A-6 Rapid-Sequence Intubation Steps •  Discuss  airway management strategy with the team. •  Set  up IV access, cardiac monitor, oximetry, and capnography/capnometry. •  Plan  procedure. Assess physiologic status and airway difficulty. •  Prepare  equipment, suction, and potential rescue devices. •  Preoxygenate. •  Consider  pretreatment agents. •  Give  sedative agent immediately followed by neuromuscular blocking agent. •  Intubate  trachea. •  Confirm  tube placement. •  Secure  tube. •  Adjust  mechanical ventilation and provide postintubation sedation. TABLE 29A-7 Rapid-Sequence Intubation Pretreatment Agents Agent Dose Indications Precautions Lidocaine 1.5 milligrams/ kg IV/topically Elevated ICP Bronchospasm, asthma Lack of evidence-based studies on effectiveness in ICP No evidence of improved outcome and may not be better than inhaled albuterol Fentanyl 3 micrograms/ kg IV Elevated ICP Cardiac ischemia Aortic dissection Respiratory depression Hypotension Chest wall rigidity Abbreviations: ICP = intracranial pressure. pharmacologic assistance. Relative contraindications to RSI include anticipated airway management difficulty and clinical scenarios where muscle relaxation will not improve laryngeal exposure (e.g., massive edema, immobile jaw from injury or infection, oral tumors or obstruc tion). Always be prepared for failure and have rescue airway plan and equipment ready.  PRETREATMENT AGENTS Sympathetic responses to laryngoscopy and intubation include increases in heart rate, blood pressure, and intracranial pressure. These effects may be particularly important in select clinical settings such as trau matic brain injury, hemorrhagic stroke, myocardial ischemia, or aortic dissection. Laryngeal stimulation may cause laryngospasm, cough, and bronchospasm. Pretreatment medications may help to mitigate these responses prior to RSI ( Table 29A-7). However, since the effectiveness of these measures is unclear, many clinicians omit this step. If used, administer pretreatment agents 3 to 5 minutes before initiation of RSI.  INDUCTION AGENTS The ideal RSI induction agent achieves rapid, deep sedation of limited duration, avoids hypotension, and mitigates the physiologic response to laryngoscopy and intubation. There is no single induction agent of choice. Commonly used agents offer advantages and risks in specific clinical conditions (Table 29A-8). Etomidate, a nonbarbiturate hypnotic, has a short duration of action, protects from myocardial and cerebral ischemia, causes minimal his tamine release, and causes little hemodynamic depression in most patients. Myoclonus, nausea, and vomiting can occur in awake patients, but these effects are less important in the setting of RSI. Etomidate is not an analgesic, and it does not blunt the sympathetic response to intuba tion.

l ischemia, causes minimal his tamine release, and causes little hemodynamic depression in most patients. Myoclonus, nausea, and vomiting can occur in awake patients, but these effects are less important in the setting of RSI. Etomidate is not an analgesic, and it does not blunt the sympathetic response to intuba tion. Single-dose etomidate given for ED RSI can cause cortisol inhibi tion, but the clinical significance of this association is unclear. Propofol is a highly lipophilic, rapid-acting sedative. Propofol has a more rapid onset of action and shorter duration of action than etomidate. It has anticonvulsant and antiemetic properties, and it may lower intracranial pressure without triggering histamine release. Important side effects of propofol include hypotension through myocardial depression and vasodilation, making it less appealing for trauma patients or shock states. Ketamine, a phencyclidine derivative, is a dissociative agent that provides analgesia and amnesia. Ketamine preserves the respiratory drive, an ideal feature for sedation during awake intubation. Ketamine increases blood pressure and heart rate through catecholamine release, which may be useful in hypovolemic or hypotensive states. Ketamine causes direct smooth muscle relaxation and bronchodilation and is often used in those with refractory status asthmaticus. Despite theoretic concerns about γ-aminobutyric acid–altering effects that could worsen CNS function, ketamine is a good option in patients with head injury and hypotension. Ketamine does not cause consistent increased intracranial pressure in sedated and ventilated patients, and some studies suggest that the drug has possible cerebroprotective effects. Avoid ketamine in the elderly or for patients with suspected acute cardiac ischemia because of the potential for associated tachycardia and hypertension. Other Agents Barbiturates commonly cause hypotension from myo cardial depression and venous dilatation; they have been largely replaced with etomidate or propofol. Benzodiazepines such as midazolam may be used when other agents are contraindicated or unavailable, but their depth and speed of onset are less reliable.  PARALYTIC (NEUROMUSCULAR BLOCKING) AGENTS Neuromuscular blockade eliminates protective airway reflexes (Table 29A-9). Neuromuscular blockade can facilitate tracheal intuba tion, improve mechanical ventilation, and help control intracranial hypertension. Neuromuscular blockade limits assessments of neurologic status, and long-term use increases the risks of polyneuropathy and posttraumatic stress disorder. Neuromuscular blockers are neither anxiolytics nor analgesics, so delivering concurrent sedation is mandatory. Neuromuscular blockers include depolarizing and nondepolarizing agents. Depolarizing neuromuscular blocking agents have high affin ity for cholinergic receptors of the motor end plate and are resistant to Tintinalli_Sec04_p0143-0228.indd 186 7/31/19 1:44 PM

or analgesics, so delivering concurrent sedation is mandatory. Neuromuscular blockers include depolarizing and nondepolarizing agents. Depolarizing neuromuscular blocking agents have high affin ity for cholinergic receptors of the motor end plate and are resistant to Tintinalli_Sec04_p0143-0228.indd 186 7/31/19 1:44 PM CHAPTER 29A: Tracheal Intubation 187 TABLE 29A-9 Rapid-Sequence Intubation Paralytic (Neuromuscular Blocking) Agents Agent Adult Intubating IV Dose Onset Duration Comments Rocuronium (intermediate/long) 1 milligram/kg 1–3 min 30–45 min Tachycardia. Longer duration of action and onset com pared to succinylcholine. Most common alternative to succinylcholine. Vecuronium (intermediate/long) 0.08–0.15 milligram/kg 0.15–0.28 milligram/kg (high-dose protocol) 2–4 min 25–40 min 60–120 min Prolonged recovery time in obese or elderly, or if there is hepatorenal dysfunction.

onger duration of action and onset com pared to succinylcholine. Most common alternative to succinylcholine. Vecuronium (intermediate/long) 0.08–0.15 milligram/kg 0.15–0.28 milligram/kg (high-dose protocol) 2–4 min 25–40 min 60–120 min Prolonged recovery time in obese or elderly, or if there is hepatorenal dysfunction. Succinylcholine 1.5 milligrams/kg 45–60 s 5–9 min Provides optimal intubating conditions most rapidly. There are several rare but important contraindications (see Table 29A-10). acetylcholinesterase. Depolarizing blockade is not antagonized and may be enhanced by anticholinesterase agents. Nondepolarizing neuromuscular blocking agents compete with acetylcholine for the cholinergic receptors and usually can be antagonized by anticholinesterase agents. Succinylcholine is the most commonly used agent for neuromus cular blockade in ED RSI. A depolarizing agent, succinylcholine is two joined acetylcholine molecules and is rapidly hydrolyzed by plasma cholinesterase. It has a rapid onset after IV dosing and a shorter dura tion of action than nondepolarizing agents. After brief fasciculation, complete relaxation occurs at 60 seconds, with maximal paralysis at 2 to 3 minutes. Effective respirations resume in 8 to 12 minutes. IM succinylcholine (4 milligrams/kg) acts more slowly and lasts longer; this is best reserved for the rare setting where paralysis is required absent IV access. If choosing succinylcholine, know its side effects ( Table 29A-10). Serum potassium will transiently rise in all patients by an average of 0.5 mEq/L with succinylcholine, usually without any clinical impact. Due to acetylcholine receptor upregulation at the neuromuscular junction, an exaggerated hyperkalemic response may occur 5 or more days after a burn, denervation, or crush injury, or in patients with preexist ing myopathies. Do not use succinylcholine in patients with sus pected preexisting significant hyperkalemia (especially renal failure), myopathies, or myasthenia gravis. Repeated doses can cause cardiac dysrhythmias including bradycardia and asystole. Genetically susceptible individuals may develop malignant hyperthermia after succinylcholine. Suspect malignant hyperthermia if unexplained rapid fever with muscle rigidity, acidosis, or hyperkalemia occurs after succinylcholine. Treat with IV dantrolene sodium (2.5 milligrams/kg) and temperature control. Patients with acquired or genetic atypical or low plasma cholinesterase may have prolonged paralysis. Cocaine is metabolized by plasma cholinesterase, which reduces the amount of enzyme available for succinylcholine metabolism. If known plasma cholinesterase deficiency is suspected, use a nondepolarizing agent (usually rocuronium) instead of succinylcholine. Rocuronium is an intermediate-duration nondepolarizing agent that is an excellent alternative to succinylcholine for RSI due to its shorter duration of action. By increasing the dose of rocuronium to 0.9 to 1.2 milligrams/kg, the onset of action approximates that of succinylcholine, but the duration of action is prolonged. Vecuronium bromide is an intermediate- to long-acting nondepolarizing agent. Vecuronium has no cardiac effects. Hypersensitivity reactions are rare, doses are only minimally cumulative, and excretion is biliary. Despite the lack of histamine release, hypotension may occur through other mechanisms that include sympathetic ganglia block and less venous return from altered or absent muscle tone and positivepressure ventilation. Sugammadex is a reversal agent that reverses blockade from rocuronium or vecuronium by encapsulating the molecules of the nondepolarizing agents circulating in plasma. 25 The dose is 2 to 4 milligrams/kg, depending on the intensity of neuromuscular paralysis, and the drug takes effect within minutes.

ssure ventilation. Sugammadex is a reversal agent that reverses blockade from rocuronium or vecuronium by encapsulating the molecules of the nondepolarizing agents circulating in plasma. 25 The dose is 2 to 4 milligrams/kg, depending on the intensity of neuromuscular paralysis, and the drug takes effect within minutes. Neostigmine, a cholinesterase inhibitor, may be used to reverse neuromuscular blockade, but it has undesirable cardiac and cholinergic side effects. VIDEO LARYNGOSCOPY Video laryngoscopes (VLs) use an integrated high-resolution camera and video monitor to facilitate indirect glottic visualization and ETT placement. VL creates a magnified view that cannot be obtained through direct laryngoscopy. VL also allows shared visualization and video recording useful for quality review, education, and training. VL may be used as the primary or rescue intubation technique. While first-pass and overall intubation success rates are similar between direct laryngoscopy and VL, VL improves glottic visualization and reduces intubation complications, including rates of esophageal intubation. 26-28 However, compared with conventional direct laryngoscopy, the glottic view with VL may be inferior in a small subset of patients. 29 VL may be most useful in patients with difficult airway anatomy, including obese patients and those with limited mouth opening or neck mobility. Avoid VL and use direct laryngoscopy if the camera may be obscured by emesis. Laryngoscopic technique is slightly different with VL than conventional laryngoscopy. First, the operator performs the intubation watch ing a video screen rather than looking directly into the oropharynx. Second, VL often uses a hyperangulated blade. The combination of these two features allows visualization of the glottis with only limited exten sion of the head and neck. A specially designed stylet is required when VL is used in this manner. In contrast to traditional laryngoscopy, a midline insertion approach is preferred and a tongue sweep is not needed with VL. Once past the teeth, the operator identifies the midline by finding the uvula. The blade is then slowly advanced down the tongue until the epiglottis is seen. The ideal view is usually obtained by insertion into the vallecula, much like a Macintosh blade. The handle is then gently tilted forward until visualization of the glottic opening is obtained. The two most studied VLs are the GlideScope Video Laryngoscope (Verathon, Bothell, W A) and the C-MAC Video Laryngoscope ø (Karl Storz, Tuttlingen, Germany) ( Figure 29A-13). Both brands also have conventionally curved blades available, allowing the device to function much like a conventional laryngoscope; this feature allows for supervi sion of novice intubators during the traditional intubation technique. (See Video: Intubation: C-MAC Video Laryngoscope.) TABLE 29A-10 Succinylcholine Complications and Contraindications Complications •  Fasciculations •  Transient  increased intragastric, intraocular, and intracranial pressure •  Bradycardia •  Masseter  spasm •  Malignant  hyperthermia •  Prolonged  apnea with pseudocholinesterase deficiency or myasthenia gravis Contraindications •  Preexisting  hyperkalemia •  Burns  >5 d old •  Denervation  injury >5 d old •  Significant  crush injuries >5 d old •  Severe  infection >5 d old Preexisting myopathies Tintinalli_Sec04_p0143-0228.indd 187 7/31/19 1:44 PM

Prolonged  apnea with pseudocholinesterase deficiency or myasthenia gravis Contraindications •  Preexisting  hyperkalemia •  Burns  >5 d old •  Denervation  injury >5 d old •  Significant  crush injuries >5 d old •  Severe  infection >5 d old Preexisting myopathies Tintinalli_Sec04_p0143-0228.indd 187 7/31/19 1:44 PM 188 SECTION 4: Resuscitative Procedures FIGURE 29A-13. Video laryngoscopes. A. GlideScope® . B. C-MAC® . FIGURE 29A-14. Flexible fiberoptic intubation (Ambu Airscope; Ambu, Ballerup Denmark). A. Flexible fiberoptic scope B. Flexible fiberoptic scope with screen. FLEXIBLE FIBEROPTIC LARYNGOSCOPY The flexible fiberoptic laryngoscope (FFL) uses fiberoptic technology embedded in a flexible tube to facilitate visualization of and access to the airway (Figure 29A-14). Newer flexible scopes use video technology, not fiberoptics, and interface directly with VL monitors. FFL aids when anatomic limitations, such as angioedema, epiglottitis, Ludwig’s angina, congenital anatomic abnormalities, and cervical spine immobility, pre vent traditional laryngoscopy. Growing numbers of ED practitioners are becoming skilled with FFL. 30 FFL requires proper equipment as well as appropriate training. If equipment or expertise is not available in the ED, consult an expert with fiberoptic skills and tools. FFL requires setup time as well as a compliant, spontaneously breathing patient. Patients needing an immediate airway, with near-complete obstruction, with large bleeding or vomitus, and who cannot be venti lated to maintain saturation are poor FFL candidates. Topical anesthesia is essential for FFL intubation success. Use atomized or nebulized topical anesthetics, such as 4% lidocaine. An Tintinalli_Sec04_p0143-0228.indd 188 7/31/19 1:44 PM

ear-complete obstruction, with large bleeding or vomitus, and who cannot be venti lated to maintain saturation are poor FFL candidates. Topical anesthesia is essential for FFL intubation success. Use atomized or nebulized topical anesthetics, such as 4% lidocaine. An Tintinalli_Sec04_p0143-0228.indd 188 7/31/19 1:44 PM CHAPTER 29A: Tracheal Intubation 189 antisialagogue, such as glycopyrrolate 0.01 milligram/kg, or homatro pine reduces secretions and enhances topical anesthesia, but should be given 20 minutes prior to intubation for best effect. If sedation is necessary to facilitate FFL, ketamine is a good choice as it will preserve spontaneous breathing. If using the nasal route, instill a topical vasoconstrictor such as phenylephrine or oxymetazoline. Nasal viscous lidocaine followed by a nasal airway allows topical anesthesia and enhanced pas sage of the scope through the airway; remember to remove the nasal tube prior to the passage of an ETT. Focus the eyepiece if needed and lubricate the flexible shaft. Immerse the lens at the tip of the laryngoscope in warm water or apply antifog ging solution. Intermittent insufflation of oxygen at 10 to 15 L/min through the suction port will keep the optic tip clear. If possible, use a #7.5 ETT. Remove the adapter from the ETT and slip the lubricated tube over the FFL up to the handle. If the distal end of the FFL does not extend beyond the end of the ETT, the scope is too small and should not be used for intubation. FFL is often easiest through the nasal route, allowing easier midline airway positioning and entry of the glottis at a less acute angle. If using the oral route, tongue extrusion, anterior mandibular displacement, or the use of a specially designed oral airway or bite block may help (Figure 29A-15). Advance the scope through the hypopharynx. Hold the laryngoscope in the opposite hand to control tip deflection while advancing it through the vocal cords. Spraying 4% lidocaine through the working channel when the scope is over the glottic opening may help to suppress the gag or cough reflex. Once the scope is through the cords, pass the ETT over the scope in Seldinger fashion and remove the scope. Resistance at the cords is best overcome with tube rotation rather than forceful insertion. A valuable adjunct to FFL is the Aintree catheter (Cook Medical, Bloomington, IN), a hollow stylet that can be inserted over an FFL. After intratracheal placement of the Aintree catheter, the FFL may be removed and a standard ETT inserted over the Aintree much like a bougie. The Aintree may be inserted via FFL through a properly placed supraglottic airway (e.g., laryngeal mask airway), allowing for conversion to an ETT. BLIND NASOTRACHEAL INTUBATION Blind nasotracheal intubation may be helpful where laryngoscopy may be difficult, RSI is contraindicated, and FFL is not available. Nasotra cheal intubation is less common given other available options. Severe traumatic nasal or pharyngeal hemorrhages are relative contraindica tions to nasotracheal intubation. Position the patient upright with the head in a neutral or slightly extended position (“sniffing position”). Stand to the side of the patient with one hand on the tube and with the thumb and index finger of the other hand straddling the larynx. Insert and advance the lubricated tube along the nasal floor; the right naris is often larger. Pass the ETT straight back toward the occiput (not upward), and then advance it while rotating it medially 15 to 30 degrees until maximal airflow is heard through the tube. Steady, gentle pressure or slow rotation of the tube usually bypasses small obstructions. Gently but swiftly advance the tube at the initiation (upswing) of inspiration.

back toward the occiput (not upward), and then advance it while rotating it medially 15 to 30 degrees until maximal airflow is heard through the tube. Steady, gentle pressure or slow rotation of the tube usually bypasses small obstructions. Gently but swiftly advance the tube at the initiation (upswing) of inspiration. The typical optimal depth of nasotracheal tube placement is 28 cm at the nares in men and 26 cm at the nares in women. Confirm tracheal placement using multiple methods. MANAGING INTUBATION DIFFICULTY  ANTICIPATED INTUBATION DIFFICULTY Several factors can help identify a potentially difficult intubation (Table 29A-2).31 Assess the patient’s clinical condition and identify factors that will impede successful intubation. Weigh these observations against the urgency of the patient’s condition. If patient consciousness or agitation is the sole anticipated obstruction, proceed with seda tion and paralysis. In the presence of major anatomic barriers (tumor, trauma, obesity, difficult anatomy), consider deferring RSI, preserving the patient’s natural respiratory drive and protective airway reflexes. In these situations, strategies of awake intubation using FFL or (for those skilled with the technique) blind nasotracheal intubation are options. In the case of severe facial trauma, immediate or urgent surgical airway placement (cricothyroidotomy or tracheostomy) is always an option. Awake orotracheal intubation with topical anesthetic is theoretically possible but rarely achievable in the emergency setting. Where immediately available, emergent assistance from anesthesiologists, surgeons, or otolaryngologists may aid. The use of bilevel positive airway pressure, continuous positive airway pressure, or high-flow nasal cannula oxygen may mitigate the patient’s deterioration, affording additional time to assemble resources.  UNANTICIPATED INTUBATION DIFFICULTY The more challenging clinical scenario is the case of unanticipated intubation difficulty occurring after the administration of sedative and paralytic medications. A single failed laryngoscopy attempt should signal potential airway difficulty and prompt corrective action. Although there is no single pathway or approach to unanticipated intubation difficulty, operators should consider several guiding principles. Stay calm. Think clearly. Communicate directly and clearly. Use available team members (nurses, respiratory therapists, technicians, and other physicians) to assist with care and mobilize needed equipment, medications, and personnel. Use of cognitive aids (e.g., checklists and difficult airway algorithms) can help to minimize the stress while providing cognitive offloading. Call for help. Where readily available, assistance from anesthesiologists, surgeons, otolaryngologists, intensiv ists, or fellow emergency physicians may be helpful but often requires time to mobilize. If you anticipate the need for assistance, call for help early. Plan and communicate the next two steps. Plan not only the next therapeutic intervention but also the subsequent intervention in the event of failure. For example, “I will switch to a Miller blade with bougie insertion. If unsuccessful, I will insert a laryngeal mask airway. ” Engage team members so that they are aware of your planned actions. Alter airway techniques with each attempt. Modify intubation blade type, blade size, approach, or operator with each attempt. Do not repeat the same unsuccessful methods with successive attempts. Let RSI medica tions wear off. Recovery of even a minimal degree of protective airway reflexes and spontaneous respirations may facilitate critically needed FIGURE 29A-15. Bite block for oral passage of flexible fiberoptic laryngoscope (ConMed, Utica, NY). Tintinalli_Sec04_p0143-0228.indd 189 7/31/19 1:44 PM